Radionuclide composition and method of using same for controlled release of metallodrugs

Abstract

The present invention provides a compound having the structure (A) or (B).

Description

Our Docket 92299-PCT / GJG / YXRADIONUCLIDE COMPOSITION AND METHOD OF USING SAME FOR CONTROLLED RELEASE OF METALLODRUGS

[0001] This application claims priority of U. S. Provisional Application No. 63 / 587,976, filed October 4, 2023, the content of which is hereby incorporated by reference.

[0002] Throughout this application, various publications are referenced, including referenced in parenthesis. Tire disclosures of all publications mentioned in this application in their entireties are hereby incorporated by reference into this application in order to provide additional description of the art to which this invention pertains and of the features in the art which can be employed with this invention.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] This invention was made with government support under EB032349 awarded by National Institutes of Health. Hie government has certain rights in the invention.BACKGROUND OF THE INVENTION

[0004] Activation of metallo-prodrugs or prodrug activation using transition-metal catalysts represent attractive, emerging strategies for drug development; however, to date these are frequently hampered by poor spatiotemporal control and limited catalytic turn-over (Figure 10).

[0005] This invention demonstrates that metal-complex mediated, autolytic release of active metallodrugs can be successfully employed to prepare clinical grade (radio-)pharmaceuticals. Lewis-acidic metal-ion, chelate, amino-acid linker and biological targeting vector provides means to release peptide-based (radio-)metallophannaceuticals in solution and from solid phase using metal-mediated, autolytic amide bond cleavage (MMAAC).

[0006] Coordinative polarization of an amide bond by strong, trivalent Lewis acids such as Ga3+and Sc3+adjacent to serine results in N,0 acyl shift and hydrolysis of the corresponding ester without dissociation of the corresponding metal complex. This hypothesis was further affirmed by mass-selective infrared spectroscopy (MS-IR) and supported by quantum chemical calculations. Hydrolysis proceeds at 37 °C and 80 °C with average rates of 0.0023±0.0001 h1and 0.1071±0.008 h1respectively for Ga3+, whereas room temperature cleavage rates remain too slow on relevant timescales. A proof-of-concept system, [b8Ga]Ga-10, incorporating a cleavable and non-cleavable attachment point on the chelate macrocycle, was synthesized and used to demonstrate that the amide-bond adjacent serine effectively triggered hydrolysis in solution and from solid phase, whereas functionalization byway of carbon backbone remained unaffected. The corresponding radiolabeled, solid-phase released compound, [68Ga]Ga-8 demonstrated superior in vivo perfonnance in a mouse tumor model compared to [58Ga]Ga-8 producedusing conventional, solution-phase radiolabeling. A second proof-of-concept system, [b7Ga]Ga-17A (serine linked) and |',7Ga|Ga-17B (glycine linked) binding to human and murine serum albumin via the incorporated ibuprofen moiety was also synthesized (Figure 16). These constructs were employed to demonstrate the effective and complete release of the corresponding [68Ga]Ga-NOTA complex from [67Ga]Ga-17A in naive mice within 12 hours, as traceable in urine and blood metabolites, while the glycine linked control [68Ga]Ga-17B remained intact. Conclusively, MMAAC provides an attractive tool for selective, thermal and metal-ion mediated control of metallodrug activation compatible with biological conditions.BRIEF SUMMARY OF THE INVENTION

[0007] The present invention provides a compound having the structure:Y,wherein Yi and Y2 are each independently, -H, alkyl -N^CChRj)?, alkyl-N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CChH, alkylar l-CCYH. alkylhctcroaryl-CCFH. alkyl-CO2R4. alkylaryl-NH-CC>2R4, alkylaryl-CChR alkylheteroaryl-CChRi, alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CC>2H)2, alkyl -N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl-N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH. -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, Rus -OH, -NH2. -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Rus -OH or -NH2;wherein L is a chemical linker;wherein A is H, NH2,, or a targeting moiety;Owherein Ri is H, NH2, -, an antigen, an antibody, a therapeutic agent or a targeting moiety;wherein R2is H, NH2,NH2, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0008] The present invention provides a metal complex having the structure:Yi' — Peptide linker ]— 1<2wherein Yi and Y2 are each independently, -H, alkyl-N-iCChRj):. alkyl-N-ialkvl-CCFRA alkylheteroaryl, alkyl-CCFH, alkylaryl-CChH. alkylhctcroaryl-COjH. alkyl-CCFRj. alkylaryl -NH-CO2R4. alkylaryl-CO2R, alkylheteroaryl -CO2R4, alkyl-OH, alkylaryl-OH, alkylhctcroaryl-OH. alkyl-N(alkylaryl);. alkyl-N(alkylaryl-CO2H)2, alkyl-Nialkylhetcroaryl-CCFH);. alkyl-N^lkylaryl-CCTRA, alkyl-N^lkylheteroaryl-CCTRA, alkyl-N(alkylaryl-OH)2, alkyl-N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(0)(0H)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(0)(0H)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyL -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CF3, or -Si(alkyl)3; preferably, R3IS -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably RAs -OH or -NH2;wherein M is a metal ion;wherein L is a chemical linker;Owherein A is H. NH2, JC. or a targeting moiety;Owherein Ri is H, NH2, ■H Han anpgen,anantibody, a therapeutic agent, or a targeting moiety;Owherein R2 is H, NH2, A H -, an antigen, an antibody, a therapeutic agent, or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0009] The present invention provides a process of producing a composition having following structures: Yicomprising chelating the compound of the following structure with a metal ionwherein Yi and Y2 are each independently, -H, alkyl-N-(CO2R4)2, alkyl-N-Calkyl-CCTRA alkylheteroaryl, alkyl-COzH, alkylaryl-CXYH. alkylheteroaryl-CCTH, alkyl-CCfRj. alkylaryl-NH-CChRi, alkylaryl-COjRi. alkylheteroaryl-CChRi, alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl -N(alkylheteroaryl-CO H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl -N(alkyl-CCbHh, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaiy TOH)(alkyl-COH). alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2. -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl) preferably, R4IS -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably RAs -OH or -NH2;Owherein A is H, NH2, ■NH2. or a targeting moiety;wherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0010] Hie present invention provides a process of producing a composition having following structures:comprising chelating the compound of the following structure with a metal ionwherein Yi and Y2 are each independently, -H, alkyl-N^CChRi, alkyl-N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CO2H, alkylaryl-CChH, alkylheteroaryl-CCH I. alkyl-CO2R4, alkylaryl-NH-CC>2R4, alkylaryl-CChR alkylheteroaryl-CO2R4, alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2, alkyl -Nialkylhctcroaryl-CCYHh. alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroai l-0H)(alkyl-C02H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH);or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH. -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -SiialkylR preferably, Rus -OH, -NH2. -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Rus -OH or -NH2;Owherein Ri is H, NH2, N 112>anantigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2is H, NH2, I 112 anantigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1. Summary' of previously employed metal-ion mediated bond cleavage and prodrugactivation approaches reported in literature; all rely on labile metal ion binding and bimolecular reaction mechanisms which are inherently limiting in vivo. This is not the case for MMAAC which does not depend on exogenous catalyst concentration and proceeds with an autolytic mechanism. Structural components denoted in blue are cleaved / hydrolized in response of catalyst / metal ion binding stimulus.

[0012] Figure 2. Model peptide-chelate conjugates and corresponding metal complexes screened for autolytic amide bond cleavage activity producing cleaved, chelate-adjacent amide bond to release the metal chelate and tripeptide. Complex-adjacent amino acid X = glycine (G), serine (S) was varied to probe sequence-dependence of activity.

[0013] Figure 3,. (A) Step-wise radiochemical labeling and reaction scheme to monitor autolytic amide bond cleavage. (B) Stacked chromatograms monitoring bond cleavage reaction at 80 °C. (C) Quantitation of reactant and product based on radio-HPLC chromatograms (D) Comparison of time course of macroscopic cleavage reaction and corresponding reaction at tracer shows that both reactions show nearidentical kinetics.

[0014] Figure 4. (A) Proposed reaction mechanisms proceeding via the NsOs-coordination mode (low pH, top) and N4O2 mode (high pH, bottom), with both resulting in N. O acyl shift followed by ester hydrolysis to form the products. (B) Representative HPLC chromatograms of reactant (grey box), N,0 acyl shifted intermediate (gold box) and cleaved peptide product (red box). (C) Species time course analysis and quantification. (D) Determination of individual reaction rates for rearrangement and hydrolysis reaction (n=2,3). R =GW-C0NH2.

[0015] Figure 5. Vibrational spectra of mass-selected (NO2A)-S-G-W-CONH2>the corresponding Ga complex, and the isotopically labeled analogue demonstrating clearly identifiable carbonyl stretches across the entire molecule. The coordinated carbonyl (orange) red shifts and gains intensity compared to the metal-free complex. * denotes the carbonyl associated with13C.

[0016] Figure 6. (A) Structures observed by MS-IR analysis. (B) IR spectra of NO2A-S-G-W-CONH3+(blue) and its sodiated reaction intermediate (gold) as prepared. (C) Spectra for as-prepared (dark) and incubated (2 hr, shaded) NO2A-S-G-W-CONH;, and its sodiated intermediate (gold: monoisotopic; green: isotop ically-labelled). denotes specific peaks that decrease in intensity upon incubation, while “+” denotes peaks that increase in intensity.

[0017] Figure 7. (A) Reaction scheme for the proof-of-concept systems based on compound 10 with amide bond cleavage in solution and on solid phase. The cleavable sequence is shown in purple. (B) HPLCmonitoring of amide bond cleavage in solution for the conversion of67Ga(10) to Ga(8) (C) Quantitation of the68Ga(8) product released from TG-10 per time (gold) and cumulative (pink) (D) Monitoring of stability of67Ga(8) at 80 °C demonstrating no degradation.

[0018] Figure 8. (A) Schematic description of MMAAC mediated radiosynthesis of [68Ga]Ga-8 following generator elution. (B) photograph of experimental setup for MMAAC with heated syringe sleeve to induce metal-mediated hydrolysis following chelation step. (C) Coronal PET-CT images 90 minutes post injection of mice injected with 50 pCi [bSGa]Ga-8 synthesized with MMAAC (left) or conventional solution-phase synthesis (right). (D) Biodistribution analysis 2 hours post injection (n=4).

[0019] Figure 9. (A) Probe design, mechanism of action of sequence-dependent cleavage in vivo. (B) In vitro binding experiment probing binding affinity' to human serum albumin (n=3). (C) Urine metabolite analysis of [b7Ga][Ga(17A)]+(blue box) with appearing target metabolite [67Ga]Ga(NOTA) (grey box) (D) Urine metabolite analysis of [67Ga][Ga(17B)]+(purple box).

[0020] Figure 10. Prodrug illustration.

[0021] Figure 11. Schematic description of68Ga radiolabeling procedure and corresponding in vivo studies along wgith timeline; far right image shows coronal PET-CT image slice acquired 90 min post injection with68Ga-31 produced using SPRP in a PSMA+ / - mouse xenograft model; activity localizes predominantly in the PSMA+ PC-3 xenograft on the right shoulder.

[0022] Figure 12. Thermal reactor for on bead radiopharmaceuticals

[0023] Figure 13. A. Automated workflow for modular radiosynthesis. B. 3D printed systems

[0024] Figure 14. Scheme SI. Synthesis pathway of 3, 4, 4* and 5.

[0025] Figure 15. Scheme S2. Synthesis pathway of PSMA derivatives.

[0026] Figure 16. Scheme S3. Synthesis pathway of ibuprofen derivatives 17A and 17B.

[0027] Figure 17. Scheme S4. Complexation pathway for [natGa][Ga(3)]+, [natCu]Cu(3), [natSc][Sc(3)]+, [natGa][Ga(4)J+, [natCu]Cu(4). [natSc][Sc(4)]+, [natGa][Ga(5)]+, [natCu]Cu(5). [natSc][Sc(5)]+, [natGa][Ga(17A)]+, and [natGa][Ga(17B)]+.

[0028] Figure 18. Scheme S5. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0029] Figure 19. Scheme S6. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0030] Figure 20. Scheme S7. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0031] Figure 21. Scheme S8. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0032] Figure 22. Scheme S9. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0033] Figure 23. (A) Schematic description of incubation of ligand 3. (B) Analytical HPLC chromatograms showing no autolytic release of NOTA molecule. (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0034] Figure 24. (A) Schematic description of incubation of ligand 4. (B) Analytical HPLC chromatograms showing no autolytic release of NOTA molecule. (C) Quantification of the pH-dcpcndcnt cleavage at 80 °C.

[0035] Figure 25. (A) Schematic description of preparation and direct complexation procedure of [natGa(4)]+. (B) Analytical HPLC chromatograms showing autolytic release of the desired productnatGa-NOTA. (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0036] Figure 26. (A) Schematic description of preparation and direct complexation procedure of [natGa(4)]+(B) Analytical HPLC chromatograms showing autolytic release of the desired productnatGa-NOTA. (C) Quantification of the pH-dependent cleavage at 80 °C and pH 5.5.

[0037] Figure 27. (A) Schematic description of preparation and direct complexation procedure of [natGa(4)]+. (B) Analytical HPLC chromatograms showing autolytic release of the desired productnatGa-NOTA. (C) Quantification of the pH-dependent cleavage at 80 °C and pH 6.5.

[0038] Figure 28. (A) Schematic description of preparation and direct complexation procedure of [natGa(4)]+. (B) Analytical HPLC chromatograms showing autolytic release of the desired productnatGa-NOTA. (C) Quantification of the pH-dependent cleavage at 80 °C and pH 7.5.

[0039] Figure 29. (A) Schematic description of preparation and direct complexation procedure of [natGa(4)]+. (B) Analytical HPLC chromatograms showing autolytic release of the desired productnatGa-NOTA. (C) Quantification of the pH-dependent cleavage at 37 °C and pH 4.5.

[0040] Figure 30. (A) Schematic description of preparation and direct complexation procedure of [natGa(DO3A)]+-S-G-W-CONH2. (B) Analytical HPLC chromatograms showing no autolytic release of thenatGa(DOTA). (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0041] Figure 31. (A) Schematic description of preparation and direct complexation procedure ofnatCu(3). (B) Analytical HPLC chromatograms showing no autolytic release of thenatCu(NOTA). (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0042] Figure 32. (A) Schematic description of preparation and direct complexation procedure ofnatCu(4). (B) Analytical HPLC chromatograms showing no autolytic release of thenatCu(NOTA). (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0043] Figure 33. (A) Schematic description of preparation and direct complexation procedure ofnatCu(5). (B) Analytical HPLC chromatograms showing no autolytic release of thenatCu(DOTA). (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0044] Figure 34. (A) Schematic description of preparation and direct complexation procedure ofnatSc(5). (B) Analytical HPLC chromatograms showing no autolytic release of thenatSc(DOTA). (C) Quantification of the pH-dependent cleavage at 80 °C and pH 4.5.

[0045] Figure 35. (A) Schematic description of preparation and direct complexation procedure of [natGa(17A)]+. (B) Analytical HPLC chromatograms showing autolytic release of thenatGa(NOTA). (C) Quantification of the cleavage at 25 °C.

[0046] Figure 36. (A) Schematic description of preparation and direct complexation procedure of [natGa(17A)]+. (B) Analytical HPLC chromatograms showing autolytic release of thenatGa(NOTA). (C) Quantification of the cleavage at 37 °C.

[0047] Figure 37. (A) Schematic description of preparation and direct complexation procedure of [natGa(17B)]+. (B) Analytical HPLC chromatograms showing autolytic release of thenatGa(NOTA). (C) Quantification of the cleavage at 25 °C.

[0048] Figure 38. (A) Schematic description of preparation and direct complexation procedure of [natGa(17B)]+. (B) Analytical HPLC chromatograms showing autolytic release of thenatGa(NOTA). (C) Quantification of the cleavage at 37 °C.

[0049] Figure 39. Reaction scheme and corresponding radio-HPLC trace. Yields reported as an average of n=3 reactions.

[0050] Figure 40. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [b7Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from | ’7Ga||Ga(NO2A)| -S-G-W-CONH2 at 80 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0051] Figure 41. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [67Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-S-G-W-CONH2 at 37 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0052] Figure 42. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [67Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-S-G-W-CONH2at RT. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0053] Figure 43. (A) Schematic description of preparation and direct radiolabeling procedure of Gly-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [67Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-G-G-W-CONH2 at 80 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0054] Figure 44. (A) Schematic description of preparation and direct radiolabeling procedure of Gly-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing lack of fast autolytic release. (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-G-G-W-CONH2at 37 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions

[0055] Figure 45. (A) Schematic description of preparation and direct radiolabeling procedure of Gly-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature -dependent release of radiopharmaceutical from [67Ga] [Ga(NO2A)]+-G-G-W-CONH2 at 25 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0056] Figure 46. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(DO3A)]+-S-G-W-CONH2 at 80 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0057] Figure 47. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature -dependent release of radiopharmaceutical from [67Ga] [Ga(DO3 A)]+-S-G-W-CONH2 at 37 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0058] Figure 48.. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature -dependent release of radiopharmaceutical from [67Ga] [Ga(DO3 A)]+-S-G-W-CONH2 at 25 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0059] Figure 49. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [67Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-S-EDA-IBP at 80 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0060] Figure 50. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing autolytic release of the desired product [67Ga]Ga(NOTA). (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-S-EDA-IBP at 37 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0061] Figure 51. (A) Schematic description of preparation and direct radiolabeling procedure of Scr-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga] [Ga(NO2A)]+-S-EDA-IBP at 25 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0062] Figure 52. (A) Schematic description of preparation and direct radiolabeling procedure of Ser-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing lack of fast autolytic release. (C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-G-EDA-IBP at 80 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0063] Figure 53. (A) Schematic description of preparation and direct radiolabeling procedure of Gly-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-G-EDA-IBP at 37 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0064] Figure 54. (A) Schematic description of preparation and direct radiolabeling procedure of Gly-containing radiopharmaceutical. (B) Analytical radioHPLC chromatograms showing no autolytic release.(C) Quantification of the temperature -dependent release of radiopharmaceutical from [67Ga][Ga(NO2A)]+-G-EDA-IBP at 25 °C. RCY: Radiochemical Yield. Yields reported as an average of n=3 reactions.

[0065] Figure 55. Variable Temperature mass spectra ofnatGa-4 complex plotted in terms of differences in mass between the unhydrated complex and each hydrated complex.

[0066] Figure 56. Derived speciation curves of thenatGa-4 complex showing the absence of inner sphere water. Complexes containing the same number of water adducts are depicted by colored boxes that match the speciation plot assignments.

[0067] Figure 57. Variable Temperature mass spectra of Tripeptide + NOTA plotted in terms of differences in mass between the unhydrated complex and each hydrated complex.

[0068] Figure 58. Derived speciation curves of the tripeptide + NOTA depicting the incorporation of water adducts. Complexes containing the same number of water adducts are depicted by colored boxes that match the speciation plot assignments.

[0069] Figure 59. CIVP spectrum of the N₂-tagged Tripeptide-NOTA (pink) and the N₂-tagged isotopically labeled Tripeptide-NOTA (green).

[0070] Figure 60. CIVP spectrum of the N2-tagged Ga-NOTA (natGa-4) complex (red) and the N2-tagged Ga-NOTA (natGa-4*) complex with isotopically labeled serine (teal).

[0071] Figure 61. Computed vibrational spectra for truncated analogues to (top) [Ga(NO2A)]+-S-G-W-CONH2. (middle) the acyl-shifted N3O3 intermediate, and (bottom) the acyl-shifted N4O2 intermediate. Spectra of isotopically-labeled complexes are shown in gray. Corresponding minimum-energy structures are included inset to the right.

[0072] Figure 62. (A) Reaction scheme for the proof-of-concept systems based on compound 10 with amide bond cleavage in solution. (B) Quantification of the temperature-dependent release of radiopharmaceutical from [67Ga][G(10)]+at 37 °C. (C) Quantification ofthe temperature-dependent release of radiopharmaceutical from [67Ga][G(10)]+at 80 °C. Yields reported as an average of n=3 reactions.DETAILED DESCRIPTION OF THE INVENTION

[0073] The present invention provides a compound having the structure:L" R|° > oN N. JI ■ Peptide linker 1— AorY — Peptide linker j —2 \ - 1 wherein Yi and Y2 are each independently, -H, alkyl -N^CChRi)?, alkyl-N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CChH, alkylar l-CCYH. alkylhctcroaryl-CCLH. alkyl-CO2R4. alkylaryl-NH-CC>2R4, alkylaryl-CChR alkylheteroaryl-CChRi, alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl -N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-Nlalkylhctcroaryl-CChRjk. alkyl-N(alkylaryl-OH)2, alkyl-N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-0H)(alkyl-C02H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH. -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)s; preferably, Rus -OH, -NH2. -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Riis -OH or -NH2;wherein L is a chemical linker;wherein A is H, NH2,, or a targeting moiety;wherein Ri is H, NH2,, an antigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2is H, NH2, - H -, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0074] In some embodiments, the first amino acid linked to the carbonyl group is serine.

[0075] In some embodiments, when the compound is chelated with a metal ion. the bond between the peptide linker and the carbonyl group automatically cleaves off.

[0076] In some embodiments, when the compound is chelated with a metal ion, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:Y,° andwherein M is the metal ion.

[0077] In some embodiments, when the compound is chelated with a metal ion, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:wherein M is the metal ion.

[0078] In some embodiments, Yi and Y2 are each independently alkyl-CChH, alkylaryl-CCYH. alkyl-N-(CChRth, alkyl-N-lalkyl-CChl )?. alkylheteroaryl-COzH, alkyl-CChRi, alkylaryl-NH-CChRj alkylaryl-CO2R, alkylheteroaryl-CChR^ alkyl-N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-Nlalkylaryl-CChR z, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OHXalkyl-CChH). alkyl-N(alkylheteroaryl-OH)(alkyl-CC>2H). or alkylheteroaryl- P(O)(OH)2.

[0079] In some embodiments, Yi and Y2are each independently alkyl-CCXH, alkyl-N-(CO2R4)2, alkyl-N-(alkyl-CO2R4)2, alkylaryl-CChH. alkylheteroaryl-CChH, alkyl-N(alkylaryl-CO: H)2. alkyl-N(alkylheteroaryl-CC>2H)2, alkyl-N(alkyl-CO2H)2. alkyl-N(alkylaryl-OH)(alkyl-CC>2H). alkyl-N(alkylheteroaryl-OH)(alkyl-CC>2H), or alkylheteroaryl- P(O)(OH)2.

[0080] In some embodiments, Yi and Y2 are each independently alkyl-CCPH. alkyl-N-(CO2R4)2. alkyl-N-(alkyl-CO2R4)2, or alkyl-N(alkyl-CO2H)2.

[0081] In some embodiments, Y 1 and Y2 are each independently alkyl-CChH, CH2-N-(CO2H)2. or CH2-N-(alkyl-CO2R4)2.

[0082] In some embodiments, Y 1 and Y2 are the same.

[0083] In some embodiments, Y 1 and Y2 are different.

[0084] In some embodiments, Y 1 and Y2 are each independentlyPO3H2

[0085] In some embodiments, Yi and Y2are each independentlyOH

[0086] In some embodiments, Y i and Y2are each independentlyOH

[0087] In some embodiments, Y i and Y2 are each independentlyOH

[0088] In some embodiments, Y 1 and Y2are each independentlyOH

[0089] In some embodiments, Y 1 and Y2are each independentlyVXXCO2H or O

[0090] In some embodiments, Yi and Y2areL-1

[0091] In some embodiments, the peptide linker is a sequence of 10 amino acids

[0092] In some embodiments, the peptide linker is a sequence of 9 amino acids.

[0093] hr some embodiments, the peptide linker is a sequence of 8 amino acids.

[0094] In some embodiments, the peptide linker is a sequence of 7 amino acids.

[0095] In some embodiments, the peptide linker is a sequence of 6 amino acids.

[0096] In some embodiments, the peptide linker is a sequence of 5 amino acids.

[0097] In some embodiments, the peptide linker is a sequence of 4 amino acids.

[0098] In some embodiments, the peptide linker is a sequence of 3 amino acids.

[0099] In some embodiments, the peptide linker is glycerin-glycerin-tryptophan (G-G-W).

[0100] In some embodiments, the peptide linker is glycerin-tryptophan-glycerin (G-W-G).

[0101] hi some embodiments, the peptide linker is glycerin-serine-tryptophan (G-S-W.

[0102] In some embodiments, the peptide linker is glycerin-tryptophan-serine (G-W-S).

[0103] In some embodiments, the peptide linker is glycerin-serine-tryptophan (G-S-G).

[0104] In some embodiments, the peptide linker is glycerin- glycerin-serine (G-G-S).

[0105] In some embodiments, the peptide linker is serine -glycerin-tryptophan (S-G-W).

[0106] In some embodiments, the peptide linker is serine -tryptophan-glycerin (S-W-G).

[0107] In some embodiments, the peptide linker is serine- glycerin-serine (S-G-S).

[0108] In some embodiments, the peptide linker is serine-serine-glycerin (S-S-G).

[0109] In some embodiments, the peptide linker is serine -tryptophan-serine (S-W-S).

[0110] In some embodiments, the peptide linker is serine-serine-tryptophan (S-S-W).

[0111] In some embodiments, A and Ri are each independently a targeting moiety.

[0112] In some embodiments, the targeting moiety is a moiety with specificity for a target protein on the surface of a cell.

[0113] In some embodiments, the targeting moiety is a moiety with specificity for a target antigen on the surface of a cell.

[0114] In some embodiments, the targeting moiety is a small molecule, a peptide or an antibody or a derivative or fragment thereof.

[0115] In some embodiments, the targeting moiety is trastuzumab, bombesin, somatostatin or 2-[3-( 1,3-dicarboxypropyl)ureido]pentanedioic acid (DUPA) or a derivative or fragment thereof.

[0116] In some embodiments, A and Ri are each independently a drag.

[0117] In some embodiments, the drug is an anti-inflammatory drag.

[0118] In some embodiments, the drag is a nonsteroidal anti-inflammatory drag.

[0119] In some embodiments, the drag is diclofenac, diflunisal, etodolac, fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen.

[0120] In some embodiments, the drug is fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen.

[0121] In some embodiments, the drug is ibuprofen, indomethacin, or ketoprofen.

[0122] In some embodiments, the drug is ibuprofen.

[0123] In some embodiments, A has the following structure:wherein R3, R5 and Rs are each, independently. -H, alkyl, alkenyl, alkynyl, alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CFs or -Si(alkyl)3.

[0124] In some embodiments, the bond between Ri and the chemical linker L is formed by reacting a first terminal reactive group on Ri with a second tenninal reactive group on the chemical linker L.

[0125] In some embodiments, the bond between the Ri and the chemical linker L is formed by reacting a carboxylic acid moiety on Ri with an amine moiety on the chemical linker L.

[0126] In some embodiments, the chemical linker L is a releasable linker.

[0127] In some embodiments, the chemical linker L is a non-releasable linker.

[0128] In some embodiments, the chemical linker L is an alkyl, alkenyl, alkynyl, alkylether, alkylthioether, alkylamino, alkylamido, alkylester, alkylaryl, alklyheteroaryl, aryl, heteroaryl, a natural amino acid, an unnatural amino acid, a disulfide or thioether containing linker or combinations thereof.

[0129] In some embodiments, the bond between A and the peptide linker is formed by reacting a first terminal reactive group on A with a second terminal reactive group on the peptide linker.

[0130] In some embodiments, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on A with an amine moiety on the peptide linker.

[0131] In some embodiments, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on A.

[0132] In some embodiments, the bond between R2 and the peptide linker is formed by reacting a first terminal reactive group on R2 with a second terminal reactive group on the peptide linker.

[0133] In some embodiments, the bond between R2 and the peptide linker is formed by reacting a carboxylic acid moiety on R2with an amine moiety on the peptide linker.

[0134] In some embodiments, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on R2.

[0135] In some embodiments, the solid support surface is a resin.

[0136] In some embodiments, the resin is a rink amide resin, a wang resin, an agarose resin, a tentagel resin or an ion-exchange resin.

[0137] In some embodiments, the resin is a tentagel resin.

[0138] In some embodiments, the metal ion is Gallium-67 (67Ga). Gallium-68 (68Ga). Copper-62 (62Cu), Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 (44Sc), Scandium-47 (47Sc), Scandium-43 (43Sc), Lanthanum-132 (132La), Lanthanum-135 (135La), Yttrium-86 (86Y), Yttrium-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (152Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb).

[0139] In some embodiments, the metal ion is Gallium-67 (67Ga).

[0140] In some embodiments, the metal ion is Gallium-68 C’sGa).

[0141] The present invention provides a compound having the following structure:

[0142] The present invention provides a compound having the following structure:o o■ Peptide linker j—wherein Y, and Y- are each independently, -H, alkyl-N-(CO2R4)2, alkyl -N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CO2H, alkyl aryl -CO2H, alkylheteroaryl-CO2H, alkyl-CO2R, alkylaryl-NH-CO2R4, alkylaryl-CO2R4, alkylheteroaryl-CO2R4, alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2. alkyl-N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH- alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CF3, or -Si(alkyl)3; preferably, R4 is -OH, -NH2, -O-(Ci-Ce alkyl), or NH-(Ci-Ce alkyl), more preferably R4 is -OH or -NH2;wherein M is a metal ion;wherein L is a chemical linker;Owherein A is H, NH2,N-, or a targeting moiety;Owherein Ri is H, NH2, ■HANNH-, an antigen, an antibody, a therapeutic agent, or a targeting moiety;Owherein R2 is H, NH2,-, an antigen, an antibody, a therapeutic agent, or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0144] In some embodiments, the first amino acid linked to the carbonyl group is serine.

[0145] In some embodiments, the first amino acid linked to the carbonyl group is serine.

[0146] In some embodiments, the bond between the peptide linker and the carbonyl group automatically cleaves off after a period of time.

[0147] In some embodiments, the period of time is 1-60 minutes.

[0148] In some embodiments, the period of time is 1-30 minutes.

[0149] In some embodiments, the period of time is 1-15 minutes.

[0150] hi some embodiments, the period of time is 1-10 minutes.

[0151] In some embodiments, the period of time is 1-5 minutes.

[0152] In some embodiments, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:< (M) / o II

[0153] In some embodiments, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures: / 1Ji Peptide linker R2

[0154] In some embodiments, Yi and Y2 are each independently alkyl-CChH, alkylaryl-CO; H. alkyl-N-(CChRrh, alkyl -NXalkyl-COiR+h, alkylheteroaryl-CC H, alkyl-CChRi, alkylaryl -NH-CO2R4, alkylaryl -CO2R4, alkylheteroaryl-CO2R4, alkyl-N(alkylaryl-CC>2H)2, alkyl-N(alkylheteroaryl-CC>2H)2. alkyl-N(alkylaryl-CC>2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2- alkyl-N(alkyl-CC>2H)2, alkyl-N(alkylaryl-OHXalkyl-CChH), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), or alkylhcteroaryl- P(O)(OH)2.

[0155] In some embodiments, Yi and Y2are each independently alkyl-CO H. alkyl-N- CChR^ alkyl-N-(alkyl-CO2R4)2, alkylaryl-COzH, alkylheteroaryl-CChH, alkyl-N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CC>2H)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CC>2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), or alkylheteroaryl- P(O)(OH)2.

[0156] In some embodiments, Yi and Y2are each independently alkyl-CChH, alkyl -NXCCXR+X, alkyl -N-(alkyl-CO2R4)2, or alkyl-N(alkyl-CO2H)2.

[0157] In some embodiments, Yi and Y2are each independently alkyl-CChH, CH2-N-(CO2H)2, or CH2-N-(alkyl-CO2R4)2.

[0158] In some embodiments, Yi and Y2are the same.

[0159] In some embodiments, Y 1 and Y2 are different.

[0160] In some embodiments, Y 1 and Y2 are each independently

[0162] In some embodiments, Y i and Y 2 are each independently

[0163] In some embodiments, Y i and Y 2 are each independentlyOH

[0164] In some embodiments, Y 1 and Y2are each independentlyOH

[0165] In some embodiments, Yi and Y2are each independently'Y (’041or 0

[0166] In some embodiments, Y 1 and Y2arcCO2H

[0167] In some embodiments, the peptide linker is a sequence of 10 amino acids

[0168] In some embodiments, the peptide linker is a sequence of 9 amino acids.

[0169] In some embodiments, the peptide linker is a sequence of 8 amino acids.

[0170] In some embodiments, the peptide linker is a sequence of 7 amino acids.

[0171] In some embodiments, the peptide linker is a sequence of 6 amino acids.

[0172] In some embodiments, the peptide linker is a sequence of 5 amino acids.

[0173] In some embodiments, the peptide linker is a sequence of 4 amino acids.

[0174] In some embodiments, the peptide linker is a sequence of 3 amino acids.

[0175] In some embodiments, the peptide linker is glycerin-glycerin-tryptophan (G-G-W).

[0176] In some embodiments, the peptide linker is glycerin-tryptophan -glycerin (G-W-G).

[0177] In some embodiments, the peptide linker is glycerin-serine-tryptophan (G-S-W.

[0178] hi some embodiments, the peptide linker is glycerin-tryptophan-serine (G-W-S).

[0179] In some embodiments, the peptide linker is glycerin-serine-tryptophan (G-S-G).

[0180] In some embodiments, the peptide linker is glycerin- glycerin-serine (G-G-S).

[0181] In some embodiments, the peptide linker is serine -glycerin-tryptophan (S-G-W).

[0182] In some embodiments, the peptide linker is serine-tryptophan-glycerin (S-W-G).

[0183] In some embodiments, the peptide linker is serine- glycerin-serine (S-G-S).

[0184] In some embodiments, the peptide linker is serine-serine-glycerin (S-S-G).

[0185] In some embodiments, the peptide linker is serine -tryptophan-serine (S-W-S).

[0186] In some embodiments, the peptide linker is serine-serine-tryptophan (S-S-W).

[0187] In some embodiments, A and Ri are each independently a targeting moiety.

[0188] In some embodiments, the targeting moiety is a moiety with specificity for a target protein on the surface of a cell.

[0189] In some embodiments, the targeting molecule is a moiety with specificity for a target antigen on the surface of a cell.

[0190] In some embodiments, the targeting moiety is a small molecule, a peptide or an antibody or a derivative or fragment thereof,

[0191] In some embodiments, the targeting moiety is trastuzumab, bombesin, somatostatin or 2-[3-( 1,3-dicarboxypropyl)urcido Ipcntanedioic acid (DUPA) or a derivative or fragment thereof.

[0192] In some embodiments, A and Ri are each independently a drug.

[0193] In some embodiments, the drug is an anti-inflammatory drug.

[0194] In some embodiments, the drug is a nonsteroidal anti-inflammatory drug.

[0195] In some embodiments, the drug is diclofenac, diflunisal, etodolac. fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen.

[0196] In some embodiments, the drug is fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen.

[0197] In some embodiments, the drug is ibuprofen, indomethacin, or ketoprofen.

[0198] In some embodiments, the drug is ibuprofen.

[0199] In some embodiments, A has the following structure:wherein R3, R5 and Rs are each, independently. -H, alkyl, alkenyl, alkynyl, alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CFs or -Si(alkyl)3.

[0200] In some embodiments, the bond between Ri and the chemical linker L is formed by reacting a first terminal reactive group on Ri with a second tenninal reactive group on the chemical linker L.

[0201] In some embodiments, the bond between Ri and the chemical linker L is formed by reacting a carboxylic acid moiety on Ri with an amine moiety on the chemical linker L.

[0202] In some embodiments, the chemical linker L is a releasable linker.

[0203] In some embodiments, the chemical linker L is a non-releasable linker.

[0204] In some embodiments, the chemical linker L is an alkyl, alkenyl, alkynyl, alkylether, alkylthioether, alkylamino, alkylamido, alkylester, alkylaryl, alklyheteroaryl, aryl, heteroaryl, a natural amino acid, an unnatural amino acid, a disulfide or thioether containing linker or combinations thereof.

[0205] In some embodiments, the bond between A and the peptide linker is formed by reacting a first terminal reactive group on A with a second terminal reactive group on the peptide linker.

[0206] In some embodiments, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on A with an amine moiety on the peptide linker.

[0207] In some embodiments, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on A.

[0208] In some embodiments, the bond between R2 and the peptide linker is formed by reacting a first terminal reactive group on R2 with a second terminal reactive group on the peptide linker.

[0209] In some embodiments, the bond between R2 and the peptide linker is formed by reacting a carboxylic acid moiety on R2with an amine moiety on the peptide linker.

[0210] In some embodiments, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on R2.

[0211] In some embodiments, the solid support surface is a resin.

[0212] In some embodiments, the resin is a rink amide resin, a wang resin, an agarose resin, a tentagel resin or an ion-exchange resin.

[0213] In some embodiments, the resin is a tentagel resin.

[0214] The present invention provides a metal complex having the following structure:

[0215] The present invention provides a metal complex having the following structure:oo

[0216] In some embodiments, the metal ion is Gallium-67 (b7Ga), Gallium-68 (6SGa), Copper-62 (b2Cu), Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 (44Sc), Scandium-47 (47Sc), Scandium-43 (43Sc), Lanthanum-132 (132La), Lanthanum-135 (135La), Yttrium-86 (86Y), Yttrium-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (lb2Tb), Terbium-155 (lb5Tb) or Terbium-161 (151Tb).

[0217] In some embodiments, the metal ion is Gallium-67 (67Ga), Copper-62 (62Cu), Copper-64 (64Cu), or Copper-67 (67Cu).

[0218] In some embodiments, the metal ion is Gallium-67 (67Ga).

[0219] In some embodiments, the metal ion is Gallium-68 (68Ga).

[0220] The present invention provides a pharmaceutical composition comprising the metal complex described in the present invention and a pharmaceutically acceptable carrier.

[0221] The present invention provides a pharmaceutical composition comprising the compound described in the present invention and a pharmaceutically acceptable carrier.

[0222] The present invention provides a pharmaceutical composition comprising:Peptide linker Awherein Yi and Y2 are each independently, -H, alkyl-N-(CO2R4)2, alkyl-N-falkyl-CChlG):. alkylheteroaryl. alkyl-CCfH. alkylaryl-CCLH. alkylheteroaryl-CCLH, alkyl-CChRj. alkylaryl-NH-CCTRe alkylaryl-CChRj. alkylhctcroaryl-CCTRj. alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2. alkyl-N(alkylaryl-CC>2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CC>2R4)2, alkyl-Nialkylhctcroaryl-CCFICh. alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl -N(alkyl-CO2H)2. alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroand-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, Rais -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Rais -OH or -NH2;Owherein A is H, NH2, ■ANH -, or a targeting moiety:wherein M is a metal ion;wherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0223] Hie present invention provides a pharmaceutical composition comprisingwherein Yi and Y2 are each independently, -H, alkyl -N-iCtYRi);. alkyl-hHalkyl-CC RiK alkylheteroaryl, alkyl-CCYH. alkylaryl-COjH. alkylheteroaryl-CChH, alkyl-COiRi. alkylaryl-NH-COiRi alkylaryl-COiRi. alkylhctcroaryl-CChRi. alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl -N(alkylheteroaryl-CO2H)2, alkyl-Nlalkylaryl-CChlAh, alkyl-Nlalkylheteroaryl-CChlH, alkyl-N(alkylaryl-OH)2, alkyl-N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2 or alkylhctcroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH- alkyl, -CHF2, -CF3. -OCHF2. -OCF3. amide, alkenyl, alkynyl. alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, R4IS -OH, -NH2, -O-(Ci-Ce alkyl), or NH-(Ci-Ce alkyl), more preferably R i is -OH or -NH2;wherein M is a metal ion;wherein Ri is H, NH2,, an antigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2is H, NH2, ■H H -, an antigen, an antibody, a therapeutic agent or a solid support surface;wherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0224] The present invention provides a method of detecting cancer cells in a subject comprising administering an effective amount of the metal complex described in the present invention or the composition described in the present invention to the subject, and imaging the subject with a molecular imaging device to detect the metal complex or composition in the subject, wherein the cancer cells areprostate cancer cells, wherein the cancer cells have elevated levels of prostate-specific membrane antigen (PSMA).

[0225] The present invention provides a method of detecting cancer cells in a subject comprising administering an effective amount of the metal complex or composition described in the present invention and imaging tire subject with a molecular imaging device to detect the metal complex or composition in the subject.

[0226] In some embodiements, the cell is a cancer cell or tumor cell.

[0227] In some embodiements, the cancer is lung cancer, breast cancer, prostate cancer, cervical cancer, pancreatic cancer, colon cancer, ovarian cancer, stomach cancer, esophagus cancer, skin cancer, heart cancer, liver cancer, bronchial cancer, testicular cancer, kidney cancer, bladder cancer, spleen, cancer, thymus cancer, thyroid cancer, brain cancer, or gall bladder cancer.

[0228] In some embodiements, the tumor is bone tumor, brain tumor, malignant soft tissue tumor, organ tumor, ovarian germ cell tumor, gland tumor, lymphatic tumor, or skin tumor.

[0229] In some embodiments, the cancer cells are prostate cancer cells.

[0230] In some embodiments, tire cancer cells have elevated levels of prostate-specific membrane antigen (PSMA).

[0231] Hie present invention provides a method of an autolytic release of a metallodrug in a subject comprising (a) administering to the subject an effective amount of the compound or the composition described in the current invention at 35-45°C, preferably at 37°C: (b) administering a metal ion to the subject.

[0232] The present invention provides a method of an autolytic release of a metallodrug in a subject by administering the metal complexes described in the current invention at 37°C.

[0233] In some embodiments, the autolytic release of the metallodrug occurred at a pH of 4.5-8.

[0234] In some embodiments, the autolytic release of the metallodrug occurred at a pH of 5-6.5.

[0235] In some embodiments, the autolytic release of the metallodrug occurred at a pH of 5.5-6.

[0236] Hie present invention provides a method of treating an inflammation in a subject comprising administering an effective amount of the compounds, or the metal complexes described in the current invention to the subject.

[0237] The present invention provides a method of treating an inflammation, comprising (a) administering to a subject an effective amount of the compound described in the current invention or thecomposition described in the current invention at 35-45°C, preferably at 37°C; (b) administering a metal ion to the subject.

[0238] The present invention provides a method of imaging prostate cancer cells in a subject comprising:a) administering to the subject an effective amount of the metal complex described in the present invention or a pharmaceutically acceptable salt thereof, or the composition described in the present invention,wherein the compound specifically accumulates at prostate cancer cells in the subject; b) detecting in the subject the location of the metal complex or the composition; andc) obtaining an image of tire cancer cells in the subject based on the location of the metal complex or the composition in the subject.

[0239] The present invention provides a method of imaging prostate cancer cells in a subject comprising:a) administering to the subject an effective amount of the metal complex described in the present invention or a pharmaceutically acceptable salt thereof, or the composition described in the present invention,wherein the metal complex specifically accumulates at prostate cancer cells in the subject; b) detecting in the subject the location of the metal complex or the composition; and c) obtaining an image of the cancer cells in the subject based on the location of the metal complex or the composition in the subject.

[0240] The present invention provides a method of detecting the presence of prostate cancer cells in a subject which comprises determining if an amount of the metal complex described in the present invention or a pharmaceutically acceptable salt thereof, or the composition described in the present invention is present in the subject at a period of time after administration of the metal complex or composition to the subject, thereby detecting the presence of the prostate cancer cells based on the amount of tire metal complex or composition detennined to be present in the subject.

[0241] Hie present invention provides a method of reducing the size of a prostate tumor or inhibiting proliferation of prostate cancer cells comprising contacting the tumor or cancer cells with the metal complex described in the present invention or a pharmaceutically acceptable salt thereof, or the composition described in the present invention, so as to thereby reducing the size of the tumor or inhibiting proliferation of the cancer cells.

[0242] The present invention provides a method of imaging cells in a subject comprising:a) administering to the subject an effective amount of the composition described in the invention, wherein the composition specifically accumulates at the cells in the subject;b) detecting in the subject the location of the composition; andc) obtaining an image of the cancer cells in the subject based on tire location of the metal complex or the composition in the subject.

[0243] The present invention provides a method of detecting the presence of cells in a subject which comprises determining if an amount of the composition described in tire invention is present in the subject at a period of time after administration of the composition to the subject, thereby detecting the presence of the cells based on the amount of the composition determined to be present in the subject.

[0244] In some embodiments of the method, the period of time is 24 hours, 48 hours, 72, hours, 96 hours, 120 hours, or 144 hours.

[0245] In some embodiments of the method, the period of time is 72 hours.

[0246] In some embodiments of the method, the cells are cancer cells or tumor cells.

[0247] In some embodiments of the method, the cancer cells or tumor cells have elevated levels of proteins or antigens, or both.

[0248] In some embodiments of the method, the cancer is lung cancer, breast cancer, prostate cancer, cervical cancer, pancreatic cancer, colon cancer, ovarian cancer, stomach cancer, esophagus cancer, skin cancer, heart cancer, liver cancer, bronchial cancer, testicular cancer, kidney cancer, bladder cancer, spleen cancer, thymus cancer, thyroid cancer, brain cancer, or gall bladder cancer.

[0249] In some embodiments of the method, the cancer is pancreatic cancer.

[0250] In some embodiments of the method, the tumor is bone tumor, brain tumor, malignant soft tissue tumor, organ tumor, ovarian germ cell tumor, gland tumor, lymphatic tumor, or skin tumor.

[0251] In some embodiments of the method, the subject is a mammal.

[0252] In some embodiments of the method, the subject is a human.

[0253] In some embodiments of the method, the molecular imaging device is a PET imaging device.

[0254] The present invention provides a use of an effective amount of the composition described in the invention to image a subject with a molecular imaging device to detect cells in a subject.

[0255] The present invention provides a pharmaceutical composition comprising the compound of the present invention, an anti-inflammatory drug and a pharmaceutically acceptable carrier.

[0256] The present invention provides a pharmaceutical composition comprising the compound of the present invention, ibuprofen and a pharmaceutically acceptable carrier.

[0257] In some embodiments, the method further comprising administering an amount of an antiinflammatory drug to the subject.

[0258] In some embodiments of the method, the amount of anti-inflammatory drug administered to the subject is at least 25% less than the clinically recommended dose for the subject.

[0259] In some embodiments of the method, the amount of anti -tuberculosis drug administered to the subject is at least 50% less than the clinically recommended dose for the subject.

[0260] In some embodiments of the method, the amount of anti -tuberculosis drug administered to the subject is at least 75% less than the clinically recommended dose for the subject.

[0261] In some embodiments of the method, the amount of the compound and the amount of the antiinflammatory drug when taken together is more effective to treat the inflammatory infection than the antiinflammatory’ drug alone.

[0262] In some embodiments of the method, the amount of the compound causes the inflammation in the subject to be more susceptible to treatment with the anti-inflammatory drug.

[0263] In some embodiments of the method, the amount of the compound enhances the antiinflammatory effect of the anti-inflammatory drug.

[0264] Tire present invention also provides a method of treating a subject infected with inflammation comprising administering to the subject an amount of the compound of the present invention in combination with one or more anti-inflammatory drugs so as to thereby treat the subject.

[0265] The present invention also provides a method of treating a subject infected with inflammation comprising administering to the subject an amount of the compound of the present invention in combination with two or more anti-inflammatory drugs so as to thereby treat the subject.

[0266] The present invention also provides a method of treating a subject infected with inflammation comprising administering to the subject an amount of the compound of the present invention in combination with three or more anti-inflammatory drugs so as to thereby treat the subject.

[0267] The present invention also provides a method of treating a subject infected with inflammation comprising administering to the subject an amount of tire compound ofthe present invention in combination with four or more anti-inflammatory’ drugs so as to thereby treat tire subject.

[0268] The compounds of the present invention enhance the effectiveness of anti-inflammatory agents such as ibuprofen, thereby providing shorter, more effective, less toxic and / or less expensive antiinflammatory regimes.

[0269] In some embodiments of the method, the amount of the compound reduces the duration of treatment with tire anti-inflammatory agent by 10% or more.

[0270] In some embodiments of the method, the amount of the compound reduces the duration of treatment with tire anti -tuberculosis agent by 20% or more.

[0271] In some embodiments of the method, the amount of the compound reduces the duration of treatment with tire anti -tuberculosis agent by 50% or more.

[0272] In some embodiments of the method, the amount of the compound reduces the duration of treatment with tire anti-tubcrculosis agent by 75% or more.

[0273] In some embodiments of the method, the amount of the compound reduces the duration of treatment with tire anti-tuberculosis agent by 90%.

[0274] In some embodiments of the method, the amount of the compound enhances the effectiveness of the amount of the anti-inflammatory agent administered to the subject.

[0275] In some embodiments of the method, the amount of the compound reduces the amount of antiinflammatory agent needed to effectively treat the inflammation.

[0276] In some embodiments of the method, the amount of the compound and the amount of the antiinflammatory agent when taken together is effective to reduce a clinical symptom of the inflammatory infection in the subject.

[0277] The present invention provides a pharmacal composition comprising an amount of the compound of the present invention for use in treating a subject afflicted with inflammatory as an add-on therapy or in combination with, or simultaneously, contemporaneously or concomitantly with an antiinflammatory agent.

[0278] In some embodiments of any of the above methods or uses, the compound and anti-inflammatory agent are orally administered to the subject.

[0279] In some embodiments, tire inflammatory infection has developed resistance to one or more drugs.

[0280] In some embodiments, the chemical linker may be cleavable, non-cleavable or a releasable linker.

[0281] In some embodiments, the chemical linker is a cleavable linker.

[0282] The present invention provides a process of producing a composition comprising:Peptide linker Awherein the process comprises chelate the compound of the following structure with a metal ionPeptide linker Awherein Yi, Y2 are each independently, -H, alkyl-NXCCXRih, alkyl-NXalkyl-CC i alkylheteroaryl, alkyl-CCTH, alkylaryl-CCXH, alkylheteroaryl-COiH. alkyl-CCXRr, alkylaryl-NH-CCFRj alkylaryl-CChRr, alkylheteroaryl-CC>2R4, alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl -N alkylheteroaryl-CChHh, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl);,; preferably, RHs -OH, -NH2, -O-(Ci- Cg alkyl), or NH-(Ci-Cs alkyl), more preferably Riis -OH or -NH2;Owherein A is H. NH2.N1, *2. or a targeting moiety:wherein M is the metal ion;wherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0283] The present invention provides a process of producing a composition comprising: / K| / °N. Jk. Peptide linkerwherein the process comprises chelate the compound of the following structure with a metal ionL"RI4-N-A> O'N N' Peptide linker ji — p2wherein Yi, Y2 are each independently, -H, alkyl -N-(CO2RI)2, alkyl -N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CCEH, alkylaryl-CCEH, alkylheteroaryl-CCH I. alkyl-CO2R4, alkylaryl-NI [-CO2R4 alkylaryl-CChR alkylheteroaryl-CCERi, alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2, alkyl -Nialkylhctcroaryl-CChHh. alkyl-N(alkylaryl-CO2R4)2, alkyl-Nialkylhctcroaryl-CCERiE. alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H). alkyl-P(O)(OH)2, alkylary l-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH. -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl ),; preferably, Rus -OH, -NH2. -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Rus -OH or -NH2;wherein M is the metal ion;wherein Ri is H, NH2,, an antigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2is H, NH2,N-, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

[0284] The term "cleaveable linker" is intended to mean a moiety that is unstable in vivo. The linker may be cleaved in vivo by the biological environment. The cleavage may come from any process without limitation, e.g., enzymatic, reductive, pH, etc. The cleaveable group may be selected so that activation occurs at the desired site of action, which can be a site in or near the target cells (e.g., bacteria cells).

[0285] Hie cleavable linker can be cleaved from the azasteroid core by, for example, enzymatic cleavage in vivo, to release the anti -tuberculosis drug. The compound may bind to a cell and become internalized prior to the anti -tuberculosis drug being enzymatically released to become activated inside the cell. Examples of the linker include, but are not limited to, heteroaryl linkers, peptide linkers, self-immolativelinkers, disulfide linkers, thioether linkers, hydrazine linkers, maleimide linkers, hydrophilic linkers or other linkers that are generally known in the art.

[0286] The compounds of the present invention include all hydrates, solvates, and complexes of the compounds used by this invention. If a chiral center or another form of an isomeric center is present in a compound of the present invention, all forms of such isomer or isomers, including enantiomers and diastereomers, are intended to be covered herein. Compounds containing a chiral center may be used as a racemic mixture, an enantiomerically enriched mixture, or the racemic mixture may be separated using well-known techniques and an individual enantiomer may be used alone. The compounds described in the present invention are in racemic form or as individual enantiomers. The enantiomers can be separated using known techniques, such as those described in Pure and Applied Che istry 69, 1469-1474, (1997) IUPAC. In cases in which compounds have unsaturated carbon-carbon double bonds, both the cis (Z) and trans (E) isomers are within the scope of this invention.

[0287] Exemplary' functional groups of Yi, Y2, Y3, Y4are described in U. S. Patent Application Publication No. 2021 / 0276971 Al, International Application No. US / 2022 / 078389, and International Application No. PCT / US2023 / 064637, the contents of which are hereby incorporated by reference.

[0288] Compounds and metal complexes disclosed and tested in U. S. Patent Application Publication No. 2021 / 0276971 Al, International Application No. US / 2022 / 078389, and International Application No. PCT / US2023 / 064637 can be used to attach to a guest molecule as disclosed in the subject application. The contents of U. S. Patent Application Publication No. 2021 / 0276971 Al, International Application No. US / 2022 / 078389, and International Application No. PCT / US2023 / 064637 are hereby incorporated by reference.

[0289] Compounds and metal complexes disclosed and tested in U. S. Patent Application Publication No. 2021 / 0276971 Al, International Application No. US / 2022 / 078389, and International Application No. PCT / US2023 / 064637 can be used to attach to a guest molecule as disclosed in the subject application for PET imaging in a subject. The contents of U. S. Patent Application Publication No. 2021 / 0276971 Al, International Application No. US / 2022 / 078389, and International Application No. PCT / US2023 / 064637 are hereby incorporated by reference.

[0290] The compounds of the subject invention may have spontaneous tautomeric forms. In cases wherein compounds may exist in tautomeric forms, such as keto-enol tautomers, each tautomeric form is contemplated as being included within this invention whether existing in equilibrium or predominantly in one form.

[0291] In the compound structures depicted herein, hydrogen atoms are not shown for carbon atoms having less than four bonds to non-hydrogen atoms. However, it is understood that enough hydrogen atoms exist on said carbon atoms to satisfy the octet rule.

[0292] This invention also provides isotopic variants of the compounds disclosed herein, including wherein the isotopic atom is2H and / or wherein the isotopic atom13C. Accordingly, in the compounds provided herein hydrogen can be enriched in the deuterium isotope. It is to be understood that the invention encompasses all such isotopic forms.

[0293] It is understood that the structures described in the embodiments of the methods hereinabove can be the same as the structures of the compounds described hereinabove.

[0294] It is understood that where a numerical range is recited herein, the present invention contemplates each integer between, and including, the upper and lower limits, unless otherwise stated.

[0295] Except where otherwise specified, if the structure of a compound of this invention includes an asymmetric carbon atom, it is understood that the compound occurs as a racemate, racemic mixture, and isolated single enantiomer. All such isomeric forms of these compounds are expressly included in this invention. Except where otherwise specified, each stereogenic carbon may be of the R or S configuration. It is to be understood accordingly that the isomers arising from such asymmetry' (e.g., all enantiomers and diastereomers) are included within the scope of this invention, unless indicated otherwise. Such isomers can be obtained in substantially pure fonn by classical separation techniques and by stereochemically controlled synthesis, such as those described in " Enantiomers, Racemates and Resolutions" by J. Jacques, A. Collet and S. Wilen, Pub. John Wiley & Sons, NY, 1981. For example, the resolution may be carried out by preparative chromatography on a chiral column.

[0296] The subject invention is also intended to include all isotopes of atoms occurring on the compounds disclosed herein. Isotopes include those atoms having the same atomic number but different mass numbers. By way of general example and without limitation, isotopes of hydrogen include tritium and deuterium. Isotopes of carbon include C-13 and C-14.

[0297] It will be noted that any notation of a carbon in structures throughout this application, when used without further notation, are intended to represent all isotopes of carbon, such as12C,13C, or,4C. Furthermore, any compounds containing13C or14C may specifically have the structure of any of the compounds disclosed herein.

[0298] It will also be noted that any notation of a hydrogen in structures throughout this application, when used without further notation, are intended to represent all isotopes of hydrogen, such as 'H.2H. or3H. Furthermore, any compounds containing2H or3H may specifically have the structure of any of the compounds disclosed herein.

[0299] Isotopically-labeled compounds can generally be prepared by conventional techniques known to those skilled in the art using appropriate isotopically-labeled reagents in place of the non-labeled reagents employed.

[0300] In the compounds used in the method of the present invention, the substituents may be substituted or unsubstituted, unless specifically defined otherwise.

[0301] In the compounds used in the method of the present invention, alkyl, heteroalkyl, monocycle, bicycle, aryl, heteroaryl and heterocycle groups can be further substituted by replacing one or more hydrogen atoms with alternative non-hydrogen groups. These include, but are not limited to, halo, hydroxy, mercapto, amino, carboxy, cyano, carbamoyl and aminocarbonyl and aminothiocarbonyl.

[0302] It is understood that substituents and substitution patterns on the compounds used in the method of the present invention can be selected by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art from readily available starting materials. If a substituent is itself substituted with more than one group, it is understood that these multiple groups may be on the same carbon or on different carbons, so long as a stable structure results.

[0303] In choosing the compounds used in the method of the present invention, one of ordinary skill in the art will recognize that the various substituents, i.e. Ri, R2, etc. are to be chosen in conformity with well-known principles of chemical structure connectivity.

[0304] As used herein, the term ‘‘biological marker” refers to a broad subcategory of medical signs -that is, objective indications of medical state observed from outside the patient - which can be measured accurately and reproducibly. Medical signs stand in contrast to medical symptoms, which are limited to those indications of health or illness perceived by patients themselves. In 1998, the National Institutes of Health Biomarkers Definitions Working Group defined a biomarker as ‘'a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.” A joint venture on chemical safety, the International Programme on Chemical Safety, led by the World Health Organization (WHO) and in coordination with the United Nations and the International Labor Organization, has defined a biomarker as “any substance, structure, or process that can be measured in the body or its products and influence or predict the incidence of outcome or disease”. An even broader definition takes into account not just incidence and outcome of disease, but also the effects of treatments, interventions, and even unintended environmental exposure, such as to chemicals or nutrients. In their report on the validity of biomarkers inenvironment risk assessment, the WHO has stated that a true definition of biomarkers includes “almost any measurement reflecting an interaction between a biological system and a potential hazard, which may be chemical, physical, or biological. The measured response may be functional and physiological, biochemical at the cellular level, or a molecular interaction.” Examples of biomarkers include everything from pulse and blood pressure through basic chemistries to more complex laboratory tests of blood and other tissues.

[0305] As used herein, the term “Guest-Host” refers to host guest interactions involving two molecules or materials that can form complexes through unique structural relationships and noncovalent binding. Also referred to as molecular recognition, this type of interaction is widely found in biorecognition processes, such as enzyme-inhibitor and antigen-antibody interactions.

[0306] As used herein the term “Prostate-specific antigen (PSA)” is always present in low concentrations in the blood of adult males. An elevated PSA level in the blood may indicate prostate cancer, but other conditions such as benign prostatic hyperplasia (BPH) and prostatitis can also raise PSA levels. PSA levels are used to evaluate how a patient has responded to treatment and to check for tumor recurrence.

[0307] As used herein the term “Prostatic acid phosphatase (PAP)” originates in the prostate and is normally present in small amounts in the blood. In addition to prostate cancer, elevated levels of PAP may indicate testicular cancer, leukemia, and non-Hodgkin's lymphoma, as well as some noncancerous conditions.

[0308] As used herein, ovarian cancer is the most common cause of elevated CA 125, but cancers of the uterus, cervix, pancreas, liver, colon, breast, lung, and digestive tract can also raise CA 125 levels. Several noncancerous conditions can also elevate CA 125. CA 125 is mainly used to monitor the treatment of ovarian cancer.

[0309] As used herein “Carcinoembryonic antigen (CEA)” is normally found in small amounts in the blood. Colorectal cancer is the most common cancer that raises this tumor marker. Several other cancers can also raise levels of carcinoembryonic antigen.

[0310] As used herein “Alpha-fetoprotein (AFP)” is normally elevated in pregnant women since it is produced by the fetus. However, AFP is not usually found in the blood of adults. In men, and in women who are not pregnant, an elevated level of AFP may indicate liver cancer or cancer of the ovary or testicle. Noncancerous conditions may also cause elevated AFP levels.

[0311] As used herein “Human chorionic gondadotropin (HCG)” is another substance that appears normally in pregnancy and is produced by the placenta. If pregnancy is ruled out, HCG may indicate cancer in the testis, ovary, liver, stomach, pancreas, and lung. Marijuana use can also raise HCG levels.

[0312] As used herein “CA 19-9” marker is associated with cancers in the colon, stomach, and bile duct. Elevated levels of CA 19-9 may indicate advanced cancer in the pancreas, but it is also associated with noncancerous conditions, including gallstones, pancreatitis, cirrhosis of the liver, and cholecystitis.

[0313] As used herein ‘'CA 15-3” marker is most useful in evaluating the effect of treatment for women with advanced breast cancer. Elevated levels of CA 15-3 are also associated with cancers of the ovary, lung, and prostate, as well as noncancerous conditions such as benign breast or ovarian disease, endometriosis, pelvic inflammatory disease, and hepatitis. Pregnancy and lactation also can raise CA 15-3 levels.

[0314] As used herein “CA 27-29” marker, like CA 15-3, is used to follow the course of treatment in women with advanced breast cancer. Cancers of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver may also raise CA 27-29 levels. Noncancerous conditions associated with this substance are first trimester pregnancy, endometriosis, ovarian cysts, benign breast disease, kidney disease, and liver disease.

[0315] As used herein " Lactate dyhydrogenase (LDH)” is a protein that normally appears throughout the body in small amounts. Many cancers can raise LDH levels, so it is not useful in identifying a specific kind of cancer. Measuring LDH levels can be helpful in monitoring treatment for cancer. Noncancerous conditions that can raise LDH levels include heart failure, hypothyroidism, anemia, and lung or liver disease.

[0316] As used herein “Neuroson-specific enolase (NSE)” is associated with several cancers, but it is used most often to monitor treatment in patients with neuroblastoma or small cell lung cancer.

[0317] As used herein, "alkyl" is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms. Thus, Ci-Cnas in “Ci-Cnalkyl" is defined to include groups having 1,2 n-1 or n carbons in a linear or branched arrangement, and specifically includes methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, isopropyl, isobutyl, sec-butyl and so on. An embodiment can be C1-C12 alkyl, C2-C12 alkyl, C3-C12 alkyl, C4-C12 alkyl and so on. ’’Alkoxy" represents an alkyl group as described above attached through an oxygen bridge.

[0318] The term "alkenyl" refers to a non-aromatic hydrocarbon radical, straight or branched, containing at least 1 carbon to carbon double bond, and up to the maximum possible number of non-aromatic carboncarbon double bonds may be present. Thus, C2-Cnalkenyl is defined to include groups having 1, 2...., n-1 or n carbons. For example, " C2-C6 alkenyl" means an alkenyl radical having 2, 3, 4, 5, or 6 carbon atoms, and at least 1 carbon-carbon double bond, and up to, for example, 3 carbon-carbon double bonds in the case of a Ce alkenyl, respectively. Alkenyl groups include ethenyl, propenyl, butenyl and cyclohexenyl. As described above with respect to alkyl, the straight, branched or cyclic portion of the alkenyl group maycontain double bonds and may be substituted if a substituted alkenyl group is indicated. An embodiment can be C2-C12 alkenyl, C3-C12 alkenyl, C4-C12 alkenyl and so on.

[0319] The term "alkynyl" refers to a hydrocarbon radical straight or branched, containing at least 1 carbon to carbon triple bond, and up to the maximum possible number of non-aromatic carbon-carbon triple bonds may be present. Thus, C2-Cnalkynyl is defined to include groups having 1, 2...., n-1 or n carbons. For example, " C2-C6 alkynyl" means an alkynyl radical having 2 or 3 carbon atoms, and 1 carbon-carbon triple bond, or having 4 or 5 carbon atoms, and up to 2 carbon-carbon triple bonds, or having 6 carbon atoms, and up to 3 carbon-carbon triple bonds. Alkynyl groups include ethynyl. propynyl and butynyl. As described above with respect to alkyl, the straight or branched portion of the alkynyl group may contain triple bonds and may be substituted if a substituted alkynyl group is indicated. An embodiment can be a C2-Cnalkynyl. An embodiment can be C2-C12 alkynyl, C3-C12 alkynyl, C4-C12 alkynyl and so on.

[0320] ‘‘Alkylene”, “alkenylene” and “alkynylene” shall mean, respectively, a divalent alkane, alkene and alkyne radical, respectively. It is understood that an alkylene, alkenylene, and alkynylene may be straight or branched. An alkylene, alkenylene, and alkynylene may be unsubstituted or substituted.

[0321] As used herein, "hctcroalkyl" includes both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms and at least 1 heteroatom within the chain or branch.

[0322] As used herein, "heterocycle" or "heterocyclyl" as used herein is intended to mean a 5- to 10-membered nonaromatic ring containing from 1 to 4 heteroatoms selected from the group consisting of O, N and S, and includes bicyclic groups. " Heterocyclyl" therefore includes, but is not limited to the following: imidazolyl, piperazinyl, piperidinyl, pyrrolidinyl, morpholinyl, thiomorpholinyl, tetrahydropyranyl, dihydropiperidinyl, tetrahydrothiophenyl and the like. If the heterocycle contains a nitrogen, it is understood that the corresponding N-oxides thereof are also encompassed by this definition.

[0323] As herein, "cycloalkyl" shall mean cyclic rings of alkanes of three to eight total carbon atoms, or any number within this range (i.e., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl).

[0324] As used herein, "monocycle" includes any stable polyatomic carbon ring of up to 10 atoms and may be unsubstituted or substituted. Examples of such non-aromatic monocycle elements include but are not limited to: cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl. Examples of such aromatic monocycle elements include but are not limited to: phenyl.

[0325] As used herein, "bicycle" includes any stable polyatomic carbon ring of up to 10 atoms that is fused to a polyatomic carbon ring of up to 10 atoms with each ring being independently unsubstituted orsubstituted. Examples of such non-aromatic bicycle elements include but are not limited to: decahydronaphthalene. Examples of such aromatic bicycle elements include but are not limited to: naphthalene.

[0326] As used herein, "aryl" is intended to mean any stable monocyclic, bicyclic or polycyclic carbon ring of up to 10 atoms in each ring, wherein at least one ring is aromatic, and may be unsubstituted or substituted. Examples of such aryl elements include phenyl, p-toluenyl (4-methylphenyl), naphthyl, tetrahydro-naphthyl, indanyl, biphenyl, phenanthryl, anthryl or acenaphthyl. In cases where the aryl substituent is bicyclic and one ring is non-aromatic, it is understood that attachment is via the aromatic ring.

[0327] As used herein, the tenn “polycyclic” refers to unsaturated or partially unsaturated multiple fused ring structures, which may be unsubstituted or substituted.

[0328] The term “arylalkyl” refers to alkyl groups as described above wherein one or more bonds to hydrogen contained therein are replaced by a bond to an aryl group as described above. It is understood that an “arylalkyl” group is connected to a core molecule through a bond from the alkyl group and that the aryl group acts as a substituent on the alkyl group. Examples of arylalkyl moieties include, but are not limited to, benzyl (phcnylmcthyl), p-trifluoromcthylbcnzyl (4-trifluoromcthylphcnylmcthyl), 1-phcnylcthyl, 2-phenylethyl, 3-phenylpropyl, 2-phenylpropyl and the like.

[0329] Hie term "heteroaryl", as used herein, represents a stable monocyclic, bicyclic or polycyclic ring of up to 10 atoms in each ring, wherein at least one ring is aromatic and contains from 1 to 4 heteroatoms selected from the group consisting of O, N and S. Bicyclic aromatic heteroaryl groups include phenyl, pyridine, pyrimidine or pyridizine rings that are (a) fused to a 6-membered aromatic (unsaturated) heterocyclic ring having one nitrogen atom; (b) fused to a 5- or 6-membered aromatic (unsaturated) heterocyclic ring having two nitrogen atoms; (c) fused to a 5-membered aromatic (unsaturated) heterocyclic ring having one nitrogen atom together with either one oxygen or one sulfur atom; or (d) fused to a 5-membered aromatic (unsaturated) heterocyclic ring having one heteroatom selected from O, N or S. Heteroaryl groups within the scope of this definition include but are not limited to: benzoimidazolyl, benzofuranyl, benzofurazanyl, benzopyrazolyl, benzotriazolyl, benzothiophenyl, benzoxazolyl, carbazolyl, carbolinyl, cinnolinyl, furanyl, indolinyl, indolyl, indolazinyl, indazolyl, isobenzofuranyl, isoindolyl, isoquinolyl, isothiazolyl, isoxazolyl, naphthpyridinyl, oxadiazolyl, oxazolyl, oxazoline, isoxazoline, oxetanyl, pyranyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridopyridinyl, pyridazinyl, pyridyl, pyrimidyl, pyrrolyl, quinazolinyl, quinolyl, quinoxalinyl, tetrazolyl, tetrazolopyridyl, thiadiazolyl, thiazolyl, thienyl, triazolyl, azetidinyl, aziridinyl, 1,4-dioxanyl. hexahydroazepinyl, dihydrobenzoimidazolyl, dihydrobenzofuranyl, dihydrobenzothiophenyl, dihydrobenzoxazolyl, dihydrofuranyl, dihydroimidazolyl, dihydroindolyl, dihydroisooxazolyl, dihydroisothiazolyl, dihydrooxadiazolyl, dihydrooxazolyl,dihydropyrazinyl, dihydropyrazolyl, dihydropyridinyl, dihydropyrimidinyl, dihydropyrrolyl, dihydroquinolinyl, dihydrotetrazolyl, dihydrothiadiazolyl, dihydrothiazolyl, dihydrothienyl, dihydrotriazolyl, dihydroazetidinyl, methylenedioxybenzoyl, tetrahydrofuranyl, tetrahydrothienyl, acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrrazolyl, indolyl, benzotriazolyl, benzothiazolyl, benzoxazolyl, isoxazolyl, isothiazolyl, furanyl, thienyl, benzothienyl, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, indolyl, pyrazinyl, pyridazinyl, pyridinyl. pyrimidinyl, pyrrolyl, tetra-hydroquinoline. In cases where the heteroaryl substituent is bicyclic and one ring is non-aromatic or contains no heteroatoms, it is understood that attachment is via the aromatic ring or via the heteroatom containing ring, respectively. If the heteroaryl contains nitrogen atoms, it is understood that the corresponding N-oxides thereof are also encompassed by this definition.

[0330] Hie term “alkylheteroaryl” refers to alkyl groups as described above wherein one or more bonds to hydrogen contained therein are replaced by a bond to an heteroaryl group as described above. It is understood that an alkylheteroaryl" group is connected to a core molecule through a bond from the alkyl group and that the heteroaryl group acts as a substituent on the alkyl group. Examples of alkylheteroaryl moieties include, but are not limited to, -CH2-(CsH4N), -CIL-CEb^CsEEN) and the like.

[0331] The term "heterocycle" or “heterocyclyl” refers to a mono- or poly-cyclic ring system which can be saturated or contains one or more degrees of unsaturation and contains one or more heteroatoms. Preferred heteroatoms include N, 0, and / or S, including N-oxides, sulfur oxides, and dioxides. Preferably the ring is three to ten-membered and is either saturated or has one or more degrees of unsaturation. The heterocycle may be unsubstituted or substituted, with multiple degrees of substitution being allowed. Such rings may be optionally fused to one or more of another "heterocyclic" ring(s), heteroaryl ring(s), aryl ring(s), or cycloalkyl ring(s). Examples of heterocycles include, but are not limited to, tetrahydrofuran, pyran, 1,4-dioxane, 1,3-dioxane, piperidine, piperazine, pyrrolidine, morpholine, thiomorpholine, tetrahydrothiopyran, tetrahydrothiophene, 1,3 -oxathiolane, and the like.

[0332] The alkyl, alkenyl, alkynyl, aryl, heteroaryl and heterocyclyl substituents may be substituted or unsubstituted, unless specifically defined otherwise. In the compounds of the present invention, alkyl, alkenyl, alkynyl, aryl, heterocyclyl and heteroaryl groups can be further substituted by replacing one or more hydrogen atoms with alternative non-hydrogen groups. These include, but are not limited to, halo, hydroxy, mercapto, amino, carboxy, cyano and carbamoyl.

[0333] As used herein, the term ‘"halogen” refers to F, Cl, Br. and I.

[0334] Hie tenns “substitution”, "‘substituted” and “substituent” refer to a functional group as described above in which one or more bonds to a hydrogen atom contained therein are replaced by a bond to non-hydrogen or non-carbon atoms, provided that normal valencies are maintained and that the substitution results in a stable compound. Substituted groups also include groups in which one or more bonds to a carbon(s) or hydrogen(s) atom are replaced by one or more bonds, including double or triple bonds, to a heteroatom. Examples of substituent groups include the functional groups described above, and halogens (i.e.. F, Cl, Br, and I); alkyl groups, such as methyl, ethyl, n-propyl, isopropryl, n-butyl, tert-butyl, and trifluoromethyl; hydroxyl; alkoxy groups, such as methoxy, ethoxy, n-propoxy, and isopropoxy; aryloxy groups, such as phenoxy; arylalkyloxy, such as benzyloxy (phenylmethoxy) and p-trifluoromethylbenzyloxy (4-trifluoromethylphenylmethoxy); hetcroaryloxy groups; sulfonyl groups, such as trifluoromethanesulfonyl, methanesulfonyl, and p-toluenesulfonyl; nitro, nitrosyl; mercapto; sulfanyl groups, such as methylsulfanyl, ethylsulfanyl and propylsulfanyl; cyano; amino groups, such as amino, methylamino, dimethylamino, ethylamino, and diethylamino; and carboxyl. Where multiple substituent moieties are disclosed or claimed, the substituted compound can be independently substituted by one or more of the disclosed or claimed substituent moieties, singly or pluraly. By independently substituted, it is meant that the (tw o or more) substituents can be the same or different.

[0335] It is understood that substituents and substitution patterns on the compounds of the instant invention can be selected by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art, as well as those methods set forth below, from readily available starting materials. If a substituent is itself substituted with more than one group, it is understood that these multiple groups may be on the same carbon or on different carbons, so long as a stable structure results.

[0336] In choosing the compounds of the present invention, one of ordinary skill in the art will recognize that the various substituents, i.e. Ri. R2. etc. are to be chosen in conformity with well-known principles of chemical structure connectivity.

[0337] The various R groups attached to the aromatic rings of the compounds disclosed herein may be added to the rings by standard procedures, for example those set forth in Advanced Organic Chemistry: Part B: Reaction and Synthesis, Francis Carey and Richard Sundberg, (Springer) 5th ed. Edition. (2007), the content of which is hereby incorporated by reference.

[0338] Hie compounds used in the method of the present invention may be prepared by techniques well known in organic synthesis and familiar to a practitioner ordinarily skilled in the art. How ever, these may not be the only means by which to synthesize or obtain the desired compounds.

[0339] Hie compounds used in the method of the present invention may be prepared by techniques described in Vogel’s Textbook of Practical Organic Chemistry, A. I. Vogel, A. R. Tatchell, B. S. Fumis. A. J.Hannaford, P. W. G. Smith, (Prentice Hall) 5thEdition (1996), March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, Michael B. Smith, Jerry March, (Wiley-Interscience) 5thEdition (2007), and references therein, which are incorporated by reference herein. However, these may not be the only means by which to synthesize or obtain the desired compounds.

[0340] Another aspect of the invention comprises a compound used in the method of the present invention as a pharmacal composition.

[0341] In some embodiments, a pharmaceutical composition comprising the compound of the present invention and a pharmaceutically acceptable carrier.

[0342] As used herein, the term “pharmaceutically active agent” means any substance or compound suitable for administration to a subject and furnishes biological activity or other direct effect in the treatment, cure, mitigation, diagnosis, or prevention of disease, or affects the structure or any function of the subject. Pharmaceutically active agents include, but are not limited to. substances and compounds described in the Physicians’ Desk Reference (PDR Network, LLC; 64th edition; November 15, 2009) and “Approved Drug Products with Therapeutic Equivalence Evaluations” (U. S. Department Of Health And Human Services, 30thedition, 2010), which arc hereby incorporated by reference. Phannaccutically active agents which have pendant carboxylic acid groups may be modified in accordance with the present invention using standard esterification reactions and methods readily available and known to those having ordinary skill in the art of chemical synthesis. Where a pharmaceutically active agent does not possess a carboxylic acid group, the ordinarily skilled artisan will be able to design and incorporate a carboxylic acid group into the pharmaceutically active agent where esterification may subsequently be carried out so long as the modification docs not interfere with tire pharmaceutically active agent’s biological activity or effect.

[0343] Hie compounds used in the method of the present invention may be in a salt form. As used herein, a “salt” is a salt of the instant compounds which has been modified by making acid or base salts of the compounds. In the case of compounds used to treat an infection or disease caused by a pathogen, the salt is pharmaceutically acceptable. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as phenols. The salts can be made using an organic or inorganic acid. Such acid salts are chlorides, bromides, sulfates, nitrates, phosphates, sulfonates, formates, tartrates, maleates, malates, citrates, benzoates, salicylates, ascorbates, and the like. Phenolate salts are the alkaline earth metal salts, sodium, potassium or lithium. Tire term "pharmacally acceptable salt" in this respect, refers to the relatively non-toxic. inorganic and organic acid or base addition salts of compounds of the present invention. These salts can be prepared in situ during the final isolation and purification of the compounds of the invention, or by separately reacting a purified compound of the invention in its free base or free acid form with asuitable organic or inorganic acid or base, and isolating the salt thus formed. Representative salts include the hydrobromide, hydrochloride, sulfate, bisulfate, phosphate, nitrate, acetate, valerate, oleate, palmitate, stearate, laurate, benzoate, lactate, phosphate, tosylate, citrate, maleate, fumarate, succinate, tartrate, napthylate, mesylate, glucoheptonate, lactobionate, and lauryl sulphonate salts and the like. (See, e.g., Berge et al. (1977) " Pharmacal Salts", Pharm. Set. 66:1-19).

[0344] The compounds of the present invention may also fonn salts with basic amino acids such a lysine, arginine, etc. and with basic sugars such as N-methylglucamine, 2-amino-2-deoxyglucose, etc. and any other physiologically non-toxic basic substance.

[0345] As used herein, “administering” an agent may be perfonned using any of the various methods or delivery systems well known to those skilled in the art. The administering can be performed, for example, orally, parenterally, intraperitoneally, intravenously, intraarterially, transdermally, sublingually, intramuscularly, rectally, transbuccally, intranasally, liposomally, via inhalation, vaginally, intraoccularly, via local delivery, subcutaneously, intraadiposally, intraarticularly, intrathecally, into a cerebral ventricle, intraventicularly, intratumorally, into cerebral parenchyma or intraparenchchymally.

[0346] The compounds used in the method of the present invention may be administered in various fonns, including those detailed herein. The treatment with the compound may be a component of a combination therapy or an adjunct therapy, i.e. the subject or patient in need of the drug is treated or given another drug for the disease in conjunction with one or more of the instant compounds. This combination therapy can be sequential therapy where the patient is treated first with one drug and then the other or the two drugs are given simultaneously. These can be administered independently by the same route or by two or more different routes of administration depending on the dosage fomis employed.

[0347] As used herein, a "pharmaceutically acceptable carrier" is a pharmaceutically acceptable solvent, suspending agent or vehicle, for delivering the instant compounds to the animal or human. The carrier may be liquid or solid and is selected w ith the planned manner of administration in mind. Liposomes are also a pharmaceutically acceptable carrier as are slow-release vehicles.

[0348] The dosage of the compounds administered in treatment will vary depending upon factors such as the pharmacodynamic characteristics of a specific chemotherapeutic agent and its mode and route of administration; the age, sex, metabolic rate, absorptive efficiency, health and weight of the recipient; the nature and extent of the symptoms; the kind of concurrent treatment being administered; the frequency of treatment with; and the desired therapeutic effect.

[0349] A dosage unit of the compounds used in the method of the present invention may comprise a single compound or mixtures thereof with additional antitumor agents. The compounds can be administeredin oral dosage forms as tablets, capsules, pills, powders, granules, elixirs, tinctures, suspensions, syrups, and emulsions. The compounds may also be administered in intravenous (bolus or infusion), intraperitoneal, subcutaneous, or intramuscular form, or introduced directly, e.g. by injection, topical application, or other methods, into or topically onto a site of disease or lesion, all using dosage fonns well known to those of ordinary skill in the pharmaceutical arts.

[0350] The compounds used in the method of the present invention can be administered in admixture with suitable pharmaceutical diluents, extenders, excipients, or in earners such as the novel programmable sustained-release multi-compartmental nanospheres (collectively referred to herein as a pharmacally acceptable carrier) suitably selected with respect to the intended form of administration and as consistent with conventional pharmaceutical practices. Tire unit will be in a form suitable for oral, nasal, rectal, topical, intravenous or direct injection or parenteral administration. The compounds can be administered alone or mixed with a pharmaceutically acceptable carrier. This carrier can be a solid or liquid, and the type of carrier is generally chosen based on the type of administration being used. Tire active agent can be co-administered in the form of a tablet or capsule, liposome, as an agglomerated powder or in a liquid form. Examples of suitable solid carriers include lactose, sucrose, gelatin and agar. Capsule or tablets can be easily formulated and can be made easy to swallow or chew; other solid forms include granules, and bulk powders. Tablets may contain suitable binders, lubricants, diluents, disintegrating agents, coloring agents, flavoring agents, flow-inducing agents, and melting agents. Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmacally acceptable fats and oils, alcohols or other organic solvents, including esters, emulsions, symps or elixirs, suspensions, solutions and / or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents. Oral dosage fomrs optionally contain flavorants and coloring agents. Parenteral and intravenous forms may also include minerals and other materials to make them compatible with the type of injection or delivery system chosen.

[0351] Techniques and compositions for making dosage fonns useful in the present invention are described in the following references: 7 Modem Pharmaceutics. Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Pharmaceutical Dosage Forms: Tablets (Lieberman et al., 1981); Ansel, Introduction to Pharmaceutical Dosage Forms 2nd Edition (1976); Remington's Pharmaceutical Sciences, 17th ed. (Mack Publishing Company, Easton, Pa., 1985); Advances in Pharmacal Sciences (David Ganderton, Trevor Jones, Eds., 1992); Advances in Pharmacal Sciences Vol. 7. (David Ganderton, Trevor Jones, James McGinity, Eds., 1995); Aqueous Polymeric Coatings for Pharmaceutical Dosage Forms (Drugs and tire Pharmaceutical Sciences, Series 36 (James McGinity, Ed., 1989); Pharmaceutical Particulate Carriers:Therapeutic Applications: Drugs and the Pharmaceutical Sciences, Vol 61 (Alain Rolland, Ed., 1993); Drug Delivery to the Gastrointestinal Tract (Ellis Horwood Books in the Biological Sciences. Series in Pharmaceutical Technology; J. G. Hardy, S. S. Davis, Clive G. Wilson, Eds.); Modem Pharmaceutics Drugs and tire Pharmaceutical Sciences, Vol 40 (Gilbert S. Banker, Christopher T. Rhodes, Eds.). All of the aforementioned publications are incorporated by reference herein.

[0352] Tablets may contain suitable binders, lubricants, disintegrating agents, coloring agents, flavoring agents, flow-inducing agents, and melting agents. For instance, for oral administration in the dosage unit form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic, pharmaceutically acceptable, inert carrier such as lactose, gelatin, agar, starch, sucrose, glucose, methyl cellulose, magnesium stearate, dicalcium phosphate, calcium sulfate, mannitol, sorbitol and the like. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, com sweeteners, natural and synthetic gums such as acacia, tragacanth, or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes, and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride, and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum, and the like.

[0353] The compounds used in the method of the present invention may also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids such as lecithin, sphingomyelin, proteolipids, protein-encapsulated vesicles or from cholesterol, stearylamine, or phosphatidylcholines. Hie compounds may be administered as components of tissue-targeted emulsions.

[0354] The compounds used in the method of the present invention may also be coupled to soluble polymers as targetable drug carriers or as a prodrug. Such polymers include polyvinylpyrrolidone, pyran copohmer, polyhydroxylpropylmethacrylamide-phenol, polyhydroxyethylasparta-midephenol, or polyethyleneoxide-polylysine substituted with palmitoyl residues. Furthermore, the compounds may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyglycolic acid, copolymers of polylactic and polyglycolic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacylates, and crosslinked or amphipathic block copolymers of hydrogels.

[0355] Gelatin capsules may contain the active ingredient compounds and powdered carriers, such as lactose, starch, cellulose derivatives, magnesium stearate, stearic acid, and the like. Similar diluents can be used to make compressed tablets. Both tablets and capsules can be manufactured as immediate release products or as sustained release products to provide for continuous release of medication over a period ofhours. Compressed tablets can be sugar-coated or film-coated to mask any unpleasant taste and protect the tablet from the atmosphere, or enteric coated for selective disintegration in the gastrointestinal tract.

[0356] For oral administration in liquid dosage fonn, the oral drug components are combined with any oral, non-toxic, pharmaceutically acceptable inert carrier such as ethanol, glycerol, water, and the like. Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmaceutically acceptable fats and oils, alcohols or other organic solvents, including esters, emulsions, syrups or elixirs, suspensions, solutions and / or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents.

[0357] Liquid dosage forms for oral administration can contain coloring and flavoring to increase patient acceptance. In general, water, asuitable oil, saline, aqueous dextrose (glucose), and related sugar solutions and glycols such as propylene glycol or polyethylene glycols are suitable carriers for parenteral solutions. Solutions for parenteral administration preferably contain a water soluble salt of the active ingredient, suitable stabilizing agents, and if necessary, buffer substances. Antioxidizing agents such as sodium bisulfite, sodium sulfite, or ascorbic acid, either alone or combined, are suitable stabilizing agents. Also used are citric acid and its salts and sodium EDTA. In addition, parenteral solutions can contain preservatives, such as benzalkonium chloride, methyl- or propyl-paraben, and chlorobutanol. Suitable pharmaceutical carriers are described in Remington's Pharmacal Sciences, Mack Publishing Company, a standard reference text in this field.

[0358] The compounds used in tire method of the present invention may also be administered in intranasal form via use of suitable intranasal vehicles, or via transdennal routes, using those forms of transdennal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdennal delivery system, the dosage administration will generally be continuous rather than intermittent throughout the dosage regimen.

[0359] Parenteral and intravenous forms may also include minerals and other materials such as solutol and / or ethanol to make them compatible with the type of injection or delivery system chosen.

[0360] The compounds and compositions of the present invention can be administered in oral dosage forms as tablets, capsules, pills, powders, granules, elixirs, tinctures, suspensions, syrups, and emulsions. The compounds may also be administered in intravenous (bolus or infusion), intraperitoneal, subcutaneous, or intramuscular form, or introduced directly, e.g. by topical administration, injection or other methods, tothe afflicted area, such as a wound, including ulcers of the skin, all using dosage forms well known to those of ordinary skill in the pharmaceutical arts.

[0361] Specific examples of pharmaceutically acceptable carriers and excipients that may be used to formulate oral dosage forms of the present invention are described in U. S. Pat. No. 3,903,297 to Robert, issued Sept. 2, 1975. Techniques and compositions for making dosage forms useful in the present invention are described-in the following references: 7 Modem Pharmaceutics, Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Pharmaceutical Dosage Forms: Tablets (Lieberman et al., 1981); Ansel, Introduction to Pharmaceutical Dosage Forms 2nd Edition (1976); Remington's Pharmaceutical Sciences, 17th ed. (Mack Publishing Company, Easton, Pa., 1985); Advances in Pharmaceutical Sciences (David Ganderton, Trevor Jones, Eds., 1992); Advances in Pharmaceutical Sciences Vol 7. (David Ganderton, Trevor Jones, James McGinity, Eds., 1995); Aqueous Polymeric Coatings for Pharmaceutical Dosage Forms (Drugs and the Pharmaceutical Sciences, Series 36 (James McGinity, Ed., 1989); Pharmaceutical Particulate Carriers: Therapeutic Applications: Drugs and the Pharmaceutical Sciences. Vol 61 (Alain Rolland, Ed., 1993); Drug Deliver.’ to the Gastrointestinal Tract (Ellis Horwood Books in the Biological Sciences. Series in Pharmaceutical Technology; J. G. Hardy, S. S. Davis, Clive G. Wilson, Eds.): Modem Pharmaceutics Drugs and the Pharmaceutical Sciences, Vol 40 (Gilbert S. Banker, Christopher T. Rhodes, Eds.). All of the aforementioned publications are incorporated by reference herein.

[0362] Hie active ingredient can be administered orally in solid dosage forms, such as capsules, tablets, powders, and chewing gum; or in liquid dosage forms, such as elixirs, syrups, and suspensions, including, but not limited to, mouthwash and toothpaste. It can also be administered parentally, in sterile liquid dosage forms.

[0363] Solid dosage forms, such as capsules and tablets, may be enteric-coated to prevent release of the active ingredient compounds before they reach the small intestine. Materials that may be used as enteric coatings include, but are not limited to, sugars, fatty acids, proteinaceous substances such as gelatin, waxes, shellac, cellulose acetate phthalate (CAP), methyl acrylate-methacrylic acid copolymers, cellulose acetate succinate, hydroxy propyl methyl cellulose phthalate, hydroxy propyl methyl cellulose acetate succinate (hypromellose acetate succinate), polyvinyl acetate phthalate (PVAP), and methyl methacrylatemethacrylic acid copolymers.

[0364] Hie compounds and compositions of the invention can be coated onto stents for temporary or permanent implantation into the cardiovascular system of a subject.

[0365] Variations on those general synthetic methods will be readily apparent to those of ordinary skill in the art and are deemed to be within the scope of the present invention.

[0366] Each embodiment disclosed herein is contemplated as being applicable to each of the other disclosed embodiments. Thus, all combinations of the various elements described herein are within the scope of the invention.

[0367] This invention will be better understood by reference to the Experimental Details which follow, but those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative of the invention as described more fully in the claims which follow thereafter.

[0368] Hie present involves host-guest chemistry, CB7-Adma driven pre-targeting platform. Three copper-64-labeled Adma guest molecules (1-3) were synthesized and characterized. The in vivo profile of the ligands in pre-targeting strategy were evaluated with using a CB7-modified carcinoembryonic antigen (CEA) targeting humanized full-length antibody (CB7-M5A) as the secondary pre-targeting agent. The pretargeting studies were performed in CEA+ and CEA- human pancreatic cancer mouse xenografts. The biodistribution of the pre-targeted Adma-radioligand was compared to that of a zirconium-89-labeled directly radiolabeled antibody. The dosimetry of the two antibody-based imaging approaches were compared. It was hypothesized that the highly stability, mutual high affinity and human compatibility of the proposed CB7-Adma pre-targeting agents provide a great basis for a pre-targeting platform.MATERIALS AND METHODS1. EXPERIMENTAL PROCEDURES

[0369] 1.1 Materials

[0370] All starting materials were purchased from Acres Organics, Alfa Acsar, Milliporc Sigma or TCI America and used without further purification. Fmoc-protected amino acids were purchased from Bachem. NOTA-bis(t-Bu ester), DOTA-tris(t-Bu ester) and p-NH2-Bn-NOTA compounds were obtained from Macrocyclics. Rink Amide resin, Wang resin and TentaGel™ S-NH2 resins were purchased from Millipore Sigma.67Ga-citrate was received from Jubilant Radiopharma.68GaC13 was obtained from a68Ge / 68Ga generator (Eckhard & Ziegler, 10 mCi).

[0371] 1.2 General Methods of Characterization

[0372] Mass spectrometry: High-resolution ESI mass spectrometry was carried out at the Stony Brook University Center for Advanced Study of Drug Action (CASDA) mass spectrometry facility with an Agilent LC-UV-TOF spectrometer. MALDI-TOF MS and high-resolution (ESI) mass spectrometry was carried out at the Stony Brook University Institute for Chemical Biology and Drug Discovery (ICB& DD) Mass Spectrometry Facility with an Agilent LC / MSD and Agilent LC-UV-TOF spectrometers, respectively.

[0373] NMR spectra (1H,13C) were collected on a 700 MHz Advance III Broker, 500 MHz, or 400 MHz Broker instrument at 25 °C and processed nsing TopSpin 4.0.7. Chemical shifts are reported as parts per million (ppm).

[0374] Inductively coupled plasma spectroscopy (ICP) was performed on an Agilent Technologies ICP-OES (Model 5110). A 10-point standard with respect to gallium or copper was used and lines of best fit were found with R2of 0.999. UV-vis spectra were collected with a NanoDrop 1 C instrument (AZY 1706045).

[0375] High-Performance Liquid Chromatography (HPLC): Semi-Preparative HPLC was carried out using a Shimadzu HPLC -2 OAR equipped with a binary gradient, pump, UV-vis detector, and manual injector on a Phenomenex Luna C18 column (250 mm x 21.2 mm, 100 A, AX1A packed). Method A (Preparative Purification Method). A = 0.1% TFA in water, B = 0.1% TFA in MeCN. Gradient: 0-5 min: 95% A; 5-24 min: 5-95% B gradient. Analytical HPLC analysis was carried out using a Shimadzu HPLC-20AR equipped with a binary gradient, pump, UV-vis detector, autoinjector, and Laura radio-detector on a Phenomenex Luna C18 column (150 mm x 3 mm, 100 A). MethodB (Analytical HPLC analysis). A = 0.1% TFA in water, B = 0.1% TFA in MeCN with a flow rate of 0.8 mL / min, UV detection at 220 and 270 mn. Gradient 0-2 mm: 5% B; 2-14 mm 5-95% B; 14-16 min 95% B: 16-16.5 mm 95-5% B; 16.5-20 min 5% B. Method C (Analytical HPLC analysis). A = 0.1% FA in water, B = 0.1% FA in MeCN with a flow rate of 0.8 mL / min, UV detection at 220 and 270 nm. Gradient 0-3 min: 5% B; 3-10 min 5-95% B; 10-13 min 95% B; 13-13.5 min 95-5% B; 13.5-16 min 5% B. Radio-HPLC analysis was carried out using a Shimadzu HPLC-20AR equipped with a binary gradient, pump, UV-vis detector, autoinjector, and Laura radiodetector on a Phenomenex Luna C18 column (150 mm x 3 mm, 100 A). Method D (Radioanalysis). A = 0.1% TFA in water. B = 0.1% TFA in MeCN with a flow rate of 0.8 mL / min. Gradient 0-2 min: 5% B: 2- 14min 5-95% B; 14-16 min 95%B; 16-16.5 min 95-5%B; 16.5-20min 5%B. Method E ( C-MS analysis). A = 0.1% FA in water, B = 0.1% FA in MeCN with a flow rate of 0.8 mL / min, UV detection at 220 and 270 nm. Gradient 0-3 min: 5% B; 3-10 min 5-95% B; 10-13 min 95% B; 13-13.5 min 95-5% B; 13.5-16 min 5% B. Method ]<’ analysis). A = 0. 1% NH4CH3CO2 in water, B = 0.1 % NHjCH. CCFm MeCN with a flow rate of 0.8 mL / min. UV detection at 220 and 270 nm. Gradient 0-3 min: 5% B; 3-10 min 5-95% B; 10-13 min 95% B; 13-13.5 min 95-5% B; 13.5-16 min 5% B.

[0376] VTMS and CIVP: All experiments were carried out in a home-built quadrupole time-of-flight mass spectrometer described elsewhere.1Briefly, the complexes were introduced into the gas phase via an electrospray ionization (ESI) source purged with dry air using PEEK tubing of 50 pm inner diameter. All samples were diluted to 50-100 pM in 50 / 50 acetonitrile / water from 500 pM stock solutions and an optimized flow rate of 0.6 pL / min was employed. The ESI voltages were typically 2050-2080 V, lowenough to prevent sample degradation while still ensuring steady signal. Once generated, the ions were introduced into a vacuum system and stored in a room temperature octopole trap. Ions were extracted from this trap and mass selected by a quadrupole mass filter (Extrel), then guided into a cryogenically cooled ion trap capable of operating in a temperature range of 310 K- 3 K. For Variable temperature mass spectrometry (VTMS) measurements (Lee, M, et al., 2020), a mixture of water and helium was introduced via a pulsed valve allowing the formation of hydrated complexes, if thermodynamically feasible. A fraction of ions was then extracted, at 10 Hz, into a reflectron time-of-flight (TOF) mass spectrometer to analyze the relative intensities of the resulting hydrates. Tire trap was cooled down from 310 K at a rate of ~1 K / min and mass spectra were collected by summing 1000 scans at 10 K intervals in the cooling down period. The partial pressure of water was maintained between 4x10-8to 2x10-7Torr as detected by a residual gas analyzer (Extorr). Vibrational spectra were recorded using a method known as Cryogenic Ion Vibrational Predissociation (CIVP) spectroscopy as described previously (Yang. 2019). Briefly, a mixture of N₂ and helium was seeded into the cryogenic ion trap, encouraging the formation of nitrogen adducts (so-called “tags”) typically between 45 K - 48 K. Tagged complexes were extracted into the TOF and intersected by a tunable infrared laser pulse from a Nd: YAG pumped OPO / OPA system (LaserVision). The tagged ions absorb a single photon when the wavelength is resonant with a vibrational transition, resulting in tire desorption of the tag from the ions. Fragment ion yields were subsequently quantified by a reflectron mass spectrometer. The ratio of fragment to tagged ions, corrected for the laser power, at each wavelength thus yields a linear absorption spectrum of the ions of interest that can be analyzed in tire same way as a typical FTIR spectrum.

[0377] 1.3 In vitro and in vivo assays

[0378] Cell binding assay. Cells were maintained in DMEM with 5 % FBS at 37 °C and 5 % CO2 PC-3 PiP or PC-3 Flu cells were seeded in 24-well plates (~5 x 105cells in 2 mL standard growth medium / well) allowing adhesion and growth overnight. Tire cells were washed twice with PBS, prior to the addition of DMEM cell culture medium (950 pL / well) and the corresponding radioligand [68Ga]Ga(8) (50 pCi, 50 uL per well, diluted in saline containing 0.05% bovine serum albumin). Hie well plates were incubated for 90 min at 37 °C and 5% CO2. To determine the uptake of radioligand, the cells were washed three times with ice-cooled PBS. All cell samples were lysed by addition of NaOH (1 M, 1 mL) to each well and the radioactivity was quantified by gamma counting and expressed as %IA per 10” cells.

[0379] In vivo biodistribution and pharmacokinetics in naive BALB / C mice models. All animal experiments were conducted according to the guidelines of the Institutional Animal Care and Use Committee (IACUC) at Stony Brook Medicine. Female BALB / C mice (8 weeks) were purchased from Charles River Laboratory. 0.2-0.4 MBq of [67Ga][Ga(17A)]+and [67Ga][Ga(17B)]+(control) wereintravenously injected via tail vein catheter in naive mice. Mice were sacrificed 2, 6, 12, 24 h p.i. and select organs were harvested. Radioactivity was counted by using a gamma counter, and the radioactivity associated with each organ was expressed as % ID / g.

[0380] HSA binding assay. To measure HSA binding of [67Ga][Ga(17A)]+and [67Ga][Ga(17B)]+, 50 uCi of each complex in 4.5% w / v HSA was prepared and pipetted into a Amicon Ultra-0.5 Centifugal Filter Unit (50 KDa cutoff. Millipore, UFC500396). The mixture was incubated at 37 °C for 15 min and subsequently centrifuged at 12000 rpm for 10 min. Binding is determined by measurement of radioconjugates content in the filtrate by using a gamma counter and compared to non-specific binding to the filter in absence of HSA.

[0381] In vivo biodistribution and pharmacokinetics in C57BL / 6J mice models. RM1-PGLS cells were maintained in RPM1 1640 with 5 % FBS at 37 °C and 5 % CO2Parental mouse prostate cancer cells RM1 were stably transduced with human PSMA and display heterogeneous hPSMA expression with a hPSMA-low and hPSMA-high subpopulation, verified by flow cytometry prior to implantation using anti-hPSMA-APC (REA408, Miltenyi) and REA control (S)-APC (REA293, Miltenyi)4Mycoplasma contamination was excluded using the Venor®GeM Mycoplasma detection kit (Sigma- Aldrich). Male C57BL / 6J mice (8 weeks, The Jackson Laboratory) were implanted subcutaneously on the right shoulder with 0.1 x 106RM1-PGLS cells suspended in Matrigel (1:1). When the tumors reached 500 mm3the mice were randomized based on tumor volumes into 3 groups (4 mice per group) for single dose compound administration. Group 1 received [68Ga]Ga(8) obtained from MMAC protocol; group 2 received [68Ga]Ga(8) from radiolabeling in solution; group 3 received [68Ga]Ga(8) with 100 nmol excess of free ligand. Group 1 received 0.2 mCi with a specific activity of 0.2 mCi / nmol. Group 2 received 0.2 mCi with a specific activity of > 2 mCi / nmol. Group 3 received 0.2 mCi with a specific activity with 100 nmol excess of free ligand. At 2 h, mice were sacrificed, and select organs were harvested. Radioactivity was quantified by gamma counting, and the radioactivity associated with each organ was expressed as % ID / g.2. SYNTHESIS AND CHARACTERIZATION OF PEPTIDES

[0382] 2.1 Synthesis of Model Tripeptides

[0383] Hie synthesis of model tripeptides Gly-Gly-Trp (1) and Ser-Gly-Trp (2) was carried out on a 0.093 mmol scale using a Rink Amide (RA) resin (150 mg, 0.62 mmol / g). The RA resin was swollen in DCM (3 mL) and DMF (3 mL) for 1 min three times each. Fmoc-Trp(Boc)-OH (153 mg, 0.29 mmol) was loaded onto the resin using Benzotriazole- 1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBOP) (100 mg, 0.19 mmol) as coupling reagent in the presence of N, N-Diisopropylethylamine (DIEA) (65 pL, 0.38 mmol) within 12 h. The standard capping step has been carried out using acetic anhydride / pyridine mixture (3:2) for 30 min. The Fmoc group was subsequently removed by treatment ofthe resin with 20% piperidine in DMF (3 mL) for 20 min. Subsequent amino acids were coupled in the same manner until the full sequences were assembled giving RA-1 (Gly-Gly-Trp) and RA-2 (Ser-Gly-Trp) (see Scheme SI). Finally, the Fmoc group on N-tenninus was deprotected and NOTA-bis(t-Bu ester) (120 mg, 0.29 mmol) was coupled using PyBOP (100 mg, 0.19 mmol) as coupling reagent in the presence of DIEA (65 pL. 0.38 mmol) within 12 h resulting in RA-3 and RA-4. Additionally, DOTA-tris(t-Bu ester) (162 mg, 0.29 mmol) was coupled to RA-2 using PyBOP (100 mg, 0.19 mmol) as coupling reagent in the presence of DIEA (65 pL, 0.38 mmol) within 12 h resulting in RA-5. Eventually, the products RA-3, RA-4, and RA-5 were washed, dried, and stored until use. In order to release the final model tripeptides from the solid support, the appropriate resin-appended ligands were treated with a mixture of TFA / TIS / FfO (95% / 2.5% / 2.5%). (Figure 14).

[0384] 2.2Synthesis of PSMA Peptides

[0385] The synthesis of the PSMA-targeting peptide (8, Glu-urea-Lys-nap-trans-ADPA-Bn-NOTA) was carried out on a 0.16 mmol scale using a Wang resin (200 mg, 0.8 mmol / g) (see Scheme S2A). The starting material, Glu-urea-Lys-Nap-trans, was synthesized according our previously established protocol.4The Fmoc group from N-terminus was removed by shaking the resin with solution of 20% piperidine in DMF for 20 min. The peptide was elongated (WA-6) by coupling the adipic acid using PyBOP (166 mg, 0.32 mmol) as the coupling reagent in the presence of DIEA (115 pL, 0.64 mmol) within 12 h. Subsequently, the NHS active ester of PSMA-targeting peptide (WA-7) was synthesized by addition of excess of NHS (1104 mg, 8.0 mmol) and EDC (1.522 g, 8.0 mmol) as the coupling reagent in tire presence of DIEA (1.39 mL, 8.00 mmol) within 16 h. After coupling, all resin was washed, dried and treated with a mixture of TFA / TIS / H2O (95% / 2.5% / 2.5%) to cleave compound 7 from the resin. Compound 7 (61.3 mg, 0.07 mmol) was purified by reverse-phase semi-preparative HPLC and the coupling to the p-NFL-Bn-NOTA (18 mg, 0.04 mmol) was carried out in the presence of DIEA (24 pL, 0.14 mmol) at 50 °C within 16 h resulting in compound 8. In order to obtain the auto-cleavable Ser-containing construct (10), the coupling between the pre-activated Gly-Ser-NOTA-Bn-ADPA-NHS molecule and the Glu-urea-Lys-Nap-trans targeting sequence was carried out in the presence of DIEA (202 pL, 1.16 mmol) at 50 °C within 16 h (see Scheme S2B). Finally, the same auto-cleavable Ser-containing construct was prepared on tentagel resin (TG-10).The Glu-urea-Lys-Nap-trans targeting sequence (19 mg, 0.03 mmol) was re-appended to TG-11 resin (50 mg, 0.26 mmol / g) in the presence of DIEA (226 pL, 1.30 mmol) at 50 °C within 16 h (see Scheme S2C).After coupling, the tentagel resin was washed, dried and treated with a mixture of TFA / TIS / FLO (95% / 2.5% / 2.5%) for 1 h to remove the side-chain protecting group, resulting in resin-appended conjugate TG-10. (Figure 15)

[0386] 2.4 HRMS, HR-ESI-MS and HPLC Characterization Data

[0387] (S)-2-(2-(2-aminoacetamido)acetamido)-3-(lH-indol-3-yl)propanamide, H-G-G-W-CONH2, (1). Compound 1 (50 mg, 0.031 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound RA. The product was isolated as a colorless solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (3.5 mg, 0.011 mmol, 36 %). Rt(Method B): 5.91 min. ’HNMR (400 MHz, D2O): 57.7 (d. 1H), 7.5 (d, 1H), 7.3 (t. 2H), 7.2 (t. 1H), 4.7 (t. 1H), 3.9 (d, 2H), 3.78 (s. 2H), 3.37-3.32 (m, 2H).13C NMR (100 MHz, D2O): 5 176.13 (C10), 170.83 (C14), 167.60 (C12), 136.02 (C1), 126.87 (C6), 124.53 (C7), 121.92 (C3), 119.33 (C4), 118.32 (C5), 111.87 (C2), 108.90 (C8), 54.16 (C11), 42.14 (C13), 40.27 (C15), 27.00 (C9). HR-ESI-MS [M+H]‘ calc, for C15H19N5O3317.148790, found 318.1557.

[0388] (R)-2-amino-N-(2-(((S)-l -amino-3-(l H-indol-3-yl)-l -oxopropan-2-yl)amino)-2-oxoethyl)-3-hydroxypropanamide, H-S-G-W-CONH2, (2). Compound 2 (50 mg, 0.031 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound RA. The product was isolated as a colorless solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (3.9 mg. 0.011 mmol. 36 %). Rt(Method B): 5.91 min. 'HNMR (400 MHz, D2O): 5 7.7 (d, 1H), 7.5 (d, 1H), 7.2 (d, 2H), 7.1 (d, 1H), 4.67 (s, 1H), 4.12 (s, 1H), 3.99-3.87 (m, 4H), 3.34-3.21 (m, 2H).13C NMR (100 MHz, D2O): 5176.12 (C10), 170.66 (C14), 168.31 (C12), 136.10 (C1), 126.85 (C6), 124.52 (C7), 121.93 (C3), 119.33 (C4), 118.32 (C5), 111.87 (C2), 108.90 (C8), 59.99 (C16), 54.50 (C11), 54.16 (C15), 42.25 (C13). 27.04 (C9). HR-ESI-MS |M+H| calc, for Ci6H2iN5O4347.159355. found 348.1660.

[0389] (R)-2-(ammo-l5N)-N-(2-(((S)-l-ammo-3-(lH-mdol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)-3-hydroxypropanamide-l.2.3-!3( H-S*-G-W-CONH2, (2). Compound 2* (50 mg, 0.031 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound RA. The product was isolated as a white solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (5.7 mg, 0.016 mmol, 52 %). R (Method B): 5.90 min. HR-ESI-MS [M+H]4calc, for [13C]3[15N]ICI3H22N4O4352.17428, found 352.1742.

[0390] (S)-2,2'-(7-(2-((2-((2-((l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)ammo)-2-oxoethyl)-l.4, 7-triazonane-l, 4-diyl)diacetic acid, NOTA-G-G-W-CONH2, (3). Compound 3 (150 mg, 0.093 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound 1. The product was isolated as a colorless solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (11.9 mg, 0.020 mmol, 21 %). R (Method B): 6.39 min. 'H NMR (400 MHz, D2O): 57.68 (d, 1H), 7.51 (d, 1H), 7.2 (m, 2H), 7.18 (t, 1H), 4.69 (t, 1H), 3.96-3.63 (m, 11H), 3.37-3.13 (m, 1 OH), 2.97 (s, 4H).13C NMR (100 MHz, D2O): 5176.24 (C21 19), 172.43 (C10), 171.58 (C12), 171.22(C14 16), 136.09 (C1), 126.87 (C6), 124.22 (C7), 121.99 (C3), 119.36 (C4), 118.35 (C5), 111.87 (C2), 109.08 (C8), 58.46 (C17), 56.13 (C18-20), 53.89 (C11), 50.51 (C^1), 49.41 (Ccycl), 48.87 (Ccycl), 42.28 (C13), 42.20 (C15), 26.90 (C9). HR-ESI-MS [M+H]+calc, for C27H38N8O8602.281262, found 603.2888.

[0391] 2,2 '-(7-(2-( ( (R)-l-( (2-(( (S)-l-amino-3-( 1 H-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy-l-oxopropan-2-yl)amino)-2-oxoethyl)-l,4, 7 -tri azonane -1,4-diyl) diacetic acid, NOTA-S-G-W-CONH2, (4). Compound 4 (150 mg, 0.093 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound 2. The product was isolated as a colorless solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (11.5 mg, 0.018 mmol, 20 %). Rt (Method B): 6.30 min. ’H NMR (400 MHz, D2O): 57.69 (d, 1H), 7.51 (d, 1H), 7.2 (m, 2H), 7.18 (t, 1H), 4.68 (t, 1H), 4.44 (t, 1H), 3.97-3.80 (m, 8H), 3.69 (s, 2H), 3.34-3.14 (m, 10H), 3.07-2.96 (m, 4H).13C NMR (100 MHz, D2O): 8 176.15 (C2n), 172.51 (C22), 172.25 (C10), 172.12 (C14), 171.13 (C12 17), 136.07 (C1), 126.88 (C6), 124.14 (C7), 121.99 (C3), 119.36 (C4). 118.38 (C5), 111.86 (C2). 109.16 (C8), 60.69 (C16), 57.96 (C18). 56.47 (C15), 55.79 (C19’21), 53.95 (C11). 50.57 (CcycL), 49.60 (CcycL), 49.10 (Ccycl), 42.49 (C13), 27.01 (C9). HR-ESI-MS [M+H]+calc, for C28H4oN809632.291827, found 633.2990.

[0392] 2, 2 '-(7-(2-( ( (R)-l -((2-(((S)-l -amino-3-( lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy-l -oxopropan-2-yl-l,2,3-I3C3)amino-I5N)-2-oxoethyl)-l,4, 7 -tri azonane -1,4-diyl)diacetic acid, NOTA-S*-G-W-CONH2, (4*). Compound 4* (100 mg, 0.062 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound 2*. The product was isolated as a white solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (5.1 mg, 0.008 mmol, 13 %). R (Method B): 6.33 min. HR-ESI-MS [M+H]+calc, for [13C]3[15N]iC25H4iN7O9637.30675. found 637.3066.

[0393] 2,2'.2"-(10-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy-l-oxopropan-2-yl)amino)-2-oxoethyl)-l,4.7, 10-tetraazacyclododecane-l,4, 7-triyl)triacetic acid, DOTA-S-G-W-CONH2, (5). Compound 5 (150 mg, 0.093 mmol) was synthesized using the general coupling strategy outlined in Section 2.1 and Scheme SI from compound 2. The product was isolated as a colorless solid follow ing deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (20.2 mg, 0.028 mmol, 30 %). Rt(Method B): 5.95 min. 'H NMR (400 MHz, D2O): 87.70 (d, 1H), 7.52 (d, 1H). 7.26 (m, 2H), 7.20 (t, 1H), 4.68 (t, 1H), 4.36 (s, 1H), 3.92 (s, 3H), 3.81 (s, 4H), 3.38-3.17 (m).13C NMR (100 MHz, D2O): 8 176.28 (C12 17-20-22-24), 171.21 (C10 14), 136.13 (C1), 126.84 (C6), 124.34 (C7), 122.01 (C3), 119.34 (C4), 118.41 (C5), 111.91 (C2), 109.16 (C8), 60.74 (C11 16), 55.63 (C19-21-23), 53.95 (C15 18), 42.36 (C13), 27.02 (C9). HR-ESI-MS [M+H]" calc. for C32H47N90n 733.339506, found 734.3471.

[0394] (((1 S)-l-carboxy-5-(2-( (Ir, 4S)-4-((5-carboxypentanamido)methyl)cyclohexane-l-carboxamido)-3-(naphthalen-2-yl)propanamido)pertyl)carbamoyl)-L-ghitamic acid, (6). Compound 6 (100 mg, 0.08 mmol) was synthesized using the general coupling strategy outlined in Section 2.2 and Scheme S2 from compound WA-Glu-urea-Lys-Nap-trans. The product was isolated as a white solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (20.1 mg, 0.026 mmol, 32 %). Rt (Method B): 8.28 min. HR-ESI-MS [M+H]+calc, for CszUnNgOn 784.37690, found 784.3762.

[0395] (((lS)-l-carboxy-5-(2-((lr,4S)-4-((6-((2,5-dioxopyrrolidin-l-yl)oxy)-6-oxohexanamido)methyl)cyclohexane-l-carboxamido)-3-(naphthalen-2-yl)propanamido)pentyl)carbamoyl)-L-glutamic acid, (7). Compound 7 (100 mg, 0.08 mmol) was synthesized using the general coupling strategy outlined in Section 2.2 and Scheme S2 from compound 6.The product was isolated as a white solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (25.1 mg, 0.029 mmol, 36 %). Rt (Method B): 8.85 min. HR-ESI-MS [M+H]+calc, for C32H47N9O11 881.39328, found 881.3919.

[0396] (((lS)-l-carboxy-5-(3-(naphthalen-2-yl)-2-((lr,4S)-4-((6-oxo-6-((4-((l,4, 7-tris(carboxymethyl)- 1,4, 7-triazonan-2-yl)methyl)phenyl)amino)hexanamido)methyl)cyclohexane-l-carboxamido)propanamido)pentyl)carbamoyl)-L-glutamic acid, (8). Compound 8 (50 mg, 0.04 mmol) was synthesized using the general coupling strategy outlined in Section 2.2 and Scheme S2 from compound 7.Tire product was isolated as a white solid following deprotection and purification using Method A and characterized using mass spectrometry and HPLC chromatography. Yield: (5.0 mg, 0.004 mmol, 11 %). Rt (Method B): 8.25 min. HR-ESI-MS [M+H]1calc, for C32H47N9O11 1174.56722, found 1174.5657.

[0397] tert-butyl (2-(2-(4-isobutylphenyl)propanamido)ethyl)carbamate, (12). Compound 12 (493 mg, 1.4 mmol). Ibuprofen (1000 mg, 4.85 mmol) was pre-activated with 1 equivalent of DCC (1000 mg, 4.85 mmol) in 5 mL DCM for 5 minutes. 1 equivalent of N-Boc-ethylenediamine (736 pL, 4.85 mmol) and a catalytic amount of DMAP (approximately 0.05 eq, 29.6 mg, 0.242 mmol) were dissolved in 15 mL DCM in an ice bath and stirred as the DCC-ibuprofen mixture was added. The solution was stirred for 5 minutes before removal of the ice bath, stirred continuously overnight as it wamied to room temperature. The solution was subsequently filtered and washed three times with NaHCCL for solvent extraction, and the organic layer was dried with Na2SC>4. The resulting solution was filtered once more and dried in vacuo. The crude product was then purified using a silica column with hexanes and ethyl acetate (80:20 hexanes: EtOAc). The product was isolated as a colorless solid and characterized using mass spectrometry. NMR, and HPLC. Yield: (493.1 mg, 1.4 mmol, 29.2 %). Rt(Method E): 10.2 min.]H NMR (400 MHz, CDCL): 57.18 (d, 2H, H6 8), 7.09 (d, 2H, H5 7), 3.53-3.49 (q, 1H, H9), 3.33-3.25 (m, 2H, H11), 3.23-3.18(m, 2H, H12), 2.44 (d, 2H, H4), 1.88-1.81 (m, 1H, H3), 1.49 (d, 3H, H10), 1.42 (s, 9H, H13 14■15), 0.89 (d, 6H, H1 2).13C NMR (100 MHz, CDCh): 5 175.32 (C13), 156.80 (C17), 140.81 (C5), 138.63 (C10), 129.74 (C6-8), 127.41 (C7"). 79.70 (C18), 46.89 (C4), 45.16 (C11), 40.71 (C15), 40.45 (C15), 34.07 (C14), 30.29 (C3), 28.49 (C19’20 21), 22.55 (C1 2), 18.63 (C12). HR-ESI-MS [M+H]+calc, for C20H32N2O3 348.241293, found 349.2483.

[0398] N-(2-aminoethyl)-2-(4-isobutylphenyl)propcmamide, Compound 13. Compound 13 was dissolved in 3 mL DCM. TFA was added such that TFA: DCM was 1: 1 and the solution was stirred at room temperature for 30 min, reaction progress was monitored via TFC and verified by FCMS. The product was dried in vacuo and stored as a light yellow oil. Rt(Method E): 7.2 min. ’H and13C NMR analysis matched reported literature. HR-ESI-MS [M+H]+calc, for C15H2 N2O 248.188863, found 249.1961.

[0399] (9H-f!uoren-9-yl)methyl ( ( 2R)-3-(tert-hutoxy)- 1-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-l-oxopropan-2-yl)carbamate, Compound 14-A (47.3 mg, 0.0771 mmol). Fmoc-Ser(tBu)-OH (271.5 mg, 0.709 mmol) was pre-activated with 1 equivalent of DCC (146.2 mg, 0.709 mmol) in 5 mL DCM for 5 minutes. Compound 13 (76 mg, 0.306 mmol), 4 eq DIPEA (271.8 pL.2.83 mmol), and a catalytic amount of DMAP (approx. 0.05 equivalents, 4.33 mg.0.0354 mmol) were dissolved in 15 mL DCM in an ice bath and stirred as the activated carboxylic acid mixture was added. The solution was stirred for 5 minutes before removal of the ice bath, stirred continuously overnight as it warmed to room temperature. The solution was subsequently filtered and washed three times with NaHCCE for solvent extraction, and the organic layer was dried with NazSC The resulting solution was filtered once more and dried in vacuo. The crude product was then purified using a silica column using 5% methanol in DCM. The product was isolated as a colorless solid and characterized using mass spectrometry, NMR, and HPLC. Yield: (47.3 mg. 0.0771 mmol. 25.3 %). Rt(Method E): 11.4 mm. H NMR (400 MHz. CDCE): 57.76 (d, 2H, H20 27), 7.60 (s, 2H, H23-24), 7.39 (t, 2H, H22 25), 7.30 (t, 2H, H21 26), 7.15 (d, 2H, H”8), 7.08 (t, 2H, H657), 4.43 (d, 2H, H13 18), 4.23 (t, 1H, H19), 3.50 (d, 1H, H14), 3039-3.24 (m, 6H, H9”■12), 2.42 (d, 2H, H4), 1.86-1.79 (m, 1H, H4), 1.49-1.46 (m, 2H, H10), 1.16 (s, 9H, H15 16’17), 0.88 (d, 6H, Hb 2).13C NMR (100 MHz, CDCE): 8 141.42, 140.96, 138.34, 138.25, 129.78, 127.90, 127.51, 127.24, 125.25. 120.15, 74.27. 67.42, 61.77. 54.96, 54.66, 47.28. 46.76, 45.13. 40.13, 39.95, 39.83. 39.70, 30.28. 27.55, 22.77, 22.53, 19.00, 18.49, 17.74. HR-ESI-MS [M+H]+calc, for C37H47N3O 613.351572, found 614.3578.

[0400] (9H-fluoren-9-yl)methyl (2-((2-(2-(4-isobutylphenyl)propanamido)ethyl)ammo)-2-oxoelhyl)carbamaie. Compound 14-B (263.4 mg, 0.4995 mmol). Fmoc-Gly-OH (210.67 mg, 1.01 mmol) was pre-activated with 1 equivalent of DCC (146.2 mg, 0.709 mmol) in 5 mL DCM for 5 minutes. Compound 13 (252 mg, 0.709 mmol) and a catalytic amount of DMAP (approx. 0.05 equivalents, 4.33 mg, 0.0354 mmol) were dissolved in 15 mL DCM in an ice bath and stirred as the activated carboxylic acidmixture was added. The solution was stirred for 5 minutes before removal of the ice bath, stirred continuously overnight as it warmed to room temperature. The solution was subsequently filtered and washed three times with NaHCO3for solvent extraction, and the organic layer was dried with Na2SO4. The resulting solution was filtered once more and dried in vacuo. Tire crude product was then purified using a silica column using 5% methanol in DCM. The product was isolated as a colorless solid and characterized using mass spectrometry, NMR and HPLC. Yield: (263.4 mg. 0.4995 mmol, 49.3 %). Rt(Method E): 10.4 min. ‘HNMR: (400 MHz, DMSO): 57.94-7.71 (m, 4H, H16-23), 7.53 (d, 2H, H19 20), 7.44-7.40 (m, 2H, H1821), 7.37-7.31 (m, 2H, H17 22), 7.19 (d, 2H, H'8), 7.06 (d, 2H, H5 7), 4.31-4.22 (m, 2H, H14 15), 3.64-3.02 (m, 9H, H9”■12 13), 2.40 (d, 2H, H4), 1.82-1.60 (m, 2H, H3), 1.30-1.09 (m, 5H, H10), 0.84 (d, 6H, H1 2).13C NMR: (100 MHz, DMSO): 8 174.14, 169.69, 156.94, 144.32, 143.10, 141.20, 139.93, 139.65, 137.90, 129.39, 129.22, 128.10. 127.75, 127.54, 127.41, 125.72. 121.85, 120.58, 120.49, 110.19. 66.20, 47.12, 45.34. 44.71, 44.01, 38.84, 33.82. 30.07, 25.80, 24.93, 22.64. 19.06. HR-ESI-MS [M+H]+calc, for C32H37N3O4527.278407, found 528.2855.

[0401] (2R)-2-amino-3-(tert-butoxy)-N-(2-(2-(4-isobutylphenyl)propanamido)ethyl)propanamide, Compound 15- A was synthesized by suspending compound 14-A and 60 eq of polymer-bound piperazine in 3-5 mL DMF for 48 h. The resulting solution was filtered and used without further purification. (Method E): 7.7 min. HR-ESI-MS [M+H]+calc, for C22H37N3O3391.283492, found 392.290.

[0402] N-(2-(2-aminoacetamido)ethyl)-2-(4-isobiitylphenyl)propanamide, Compound 15-B was synthesized by suspending compound 14-B and 60 eq of polymer-bound piperazine in 3-5 mL DMF for 48 h. Tire resulting solution was filtered and used without further purification. R (Method E): 7.1 min. -ESIMS [M+H]1calc, for CI7H27N3O2305.210327, found 306.2176.

[0403] di-lerl-bulyl 2,2’-(7-(2-(((2R)-3-(tert-butoxy)-l-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-l-oxopropan-2-yl)amino)-2-oxoethyl)-l,4, 7-triazonane-l,4-diyl)diacetate, Compound 16-A (46 mg, 0.0583 mmol). NOTA-bis(tBu)-ester (31.5 mg, 0.0759 mmol) was dissolved in 2 mL DMF and preactivated with 1 eq PyBOP (39.5 mg, 0.0759 mmol) and 4 eq DIPEA (29.1 pL, 0.304 mmol). Compound 15-A (29.7 mg, 0.0759 mmol) was dissolved in 1 mL DMF and added to the solution. The reaction was left to stir at room temperature for 2 h. Yield: (46 mg, 0.0583 mmol, 76.8 %). R (Method E): 9.4 min. ’H NMR: (400 MHz, DMSO): 87.19 (d, 2H, H6 8), 7.05 (d, 2H, H5 7). 4.33-4.30 (m, 1H, H13), 4.06 (s, 7H, H9”’12’14), 3.53-3.38 (m, 8H. H18, 19’20). 3.13-2.99 (m, 14H. Hcycl), 2.39 (d, 2H. H4), 1.42-1.24 (m, 20H, H3 1CI-21-22-23-24-25-26), 1.10 (s, 9H, H15 16-17), 0.85 (d, 6H, H1-2).13C NMR: (100 MHz, DMSO): 8 139.87, 139.66, 129.20, 127.36, 80.65, 73.24, 62.16, 57.94, 54.15, 53.78, 48.64, 48.43, 48.22, 48.01, 47.80, 47.58, 47.37, 46.31, 46.27, 45.33, 44.71, 38.91, 38.61, 30.08, 28.22, 27.59, 26.39, 26.31, 22.57, 19.02. HR-ESI-MS [M+H]+calc, for C42H72N6O8788.541164, found 789.5483.

[0404] di-tert-butyl 2,2'-(7-(2-((2-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-2-oxoethyl)amino)-2-oxoethyl)-l,4, 7 -triazonane- l,4-diyl)diacetate, Compound 16-B (142 mg. 0.202 mmol). NOTA-bis(tBu)-ester (95.0 mg, 0.229 mmol) was dissolved in 2 mL DMF and preactivated with 1 eq PyBOP (119.0 mg, 0.229 mmol) and 4 eq DIEA (87.7 pL, 0.915 mmol). Compound 15-B (69.8 mg, 0.229 mmol) was dissolved in 1 mL DMF and added to the solution. The reaction was left to stir at room temperature for 2 h. Yield: (142 mg, 0.202 mmol, 88.8 %). Rt(Method E): 8.7 min.’H NMR: (700 MHz, DMSO): 57.24 (d, 2H, H6-8), 7.11 (d, 2H, H5 7), 3.82-3.30 (m, 8H, H14 15-16), 3.17-3.05 (m, 11H, H9-n-12-13), 2.46 (d, 2H, H4), 1.87-1.83 (m, 1H, H3), 1.50-1.44 (m, 19H, H10> 17 19 20-21-22), 0.90 (s, 6H, H1 2).13C NMR: (175 MHz, DMSO): 5 176.56, 170.44, 170.03, 169.53, 159.84, 159.59, 159.37, 159.18, 140.13, 138.90, 128.93, 126.78, 116.53, 114.89, 82.39, 57.69, 55.22, 49.43. 49.15, 45.82, 44.63, 41.73, 39.24, 38.55, 30.06, 26.99, 21.32, 17.58. HR-ESI-MS [M+H]+calc, for C37H62N6O7702.467999, found 703.4750.

[0405] 2,2'-(7-(2-(((2R)-3-hydroxy-l-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-l-oxopropan-2-yl)amino)-2-oxoethyl)-l,4, 7 -triazonane- 1,4-diyl)diacetic acid, NOTA-S-EDA-IBP (17-A) (14.2 mg. 0.0229 mmol). Compound 16-A was dissolved in 3 mL DCM. TFA was added such that TFA: DCM was 1:1 and the solution was stirred at room temperature for 6 h, reaction progress was verified by LCMS. The product was dried in vacuo and stored as a light yellow oil. Yield: (14.2 mg, 0.0229 mmol, 30.9 %). Rt (Method E): 7.5 min. 'H NMR: (700 MHz, MeOD): 5 7.25 (d, 2H, H6 8), 7.10 (d, 2H, H5 7), 4.42-4.40 (m, 1H, H13), 3.88-3.74 (m, 6H, H11 12-14), 3.65-3.62 (m, 1H, H9), 3.34-3.52 (m, 4H, H15 16-17), 3.29-2.80 (m, 13H, H"'cl), 2.45 (d. 2H, H4), 1.88-1.82 (m, 1H, H3), 1.43 (t. 3H, H10). 0.90 (s. 6H, H1 2).13C NMR: (175 MHz, MeOD): 5 176.38, 172.17, 171.21, 171.20. 143.54, 140.01, 139.06. 138.98. 128.87, 126.81, 126.79, 61.33, 61.31, 60.81, 60.76, 56.96, 45.71, 45.69, 44.64, 38.96, 38.93, 38.62, 38.61, 30.07, 21.32, 17.58, 17.51. HR-ESI-MS [M+H]+calc, for CsofLsNgOs 620.353364, found 621.3609.

[0406] 2,2 '-(7-(2-((2-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-2-oxoethyl)amino)-2-oxoethyl)-l,4,7-triazonane-l,4-diyl)diacetic acid, NOTA-G-EDA-IBP (17-B) (95 mg, 0.161 mmol). Compound 16-B was dissolved in 3 mL DCM. TFA was added such that TFA: DCM was 1:1 and the solution was stirred at room temperature for 6 h, reaction progress was verified by LCMS. The product was dried in vacuo and stored as a light yellow oil. Yield: (95 mg, 0.161 mmol, 66.9 %). R (Method E): 7.5 min. H NMR: (400 MHz, MeOD): 57.23 (d, 2H, H6 8), 7.11 (d, 2H, H5 7), 3.87-3.50 (m, 9H, H9"■12-13), 3.14 (m, 8H, Hcycl), 2.99 (s, 4H, H14> 15-16), 2.45 (d, 2H, H4), 1.90-1.80 (m, 1H, H3), 1.44 (d, 3H, H10), 0.90 (d, 6H, H1’2).13C NMR: (100 MHz, MeOD): 5 176.65, 171.66, 171.17, 170.24, 140.14, 138.89, 128.93, 126.78, 58.55, 54.61, 49.94, 49.22, 49.10, 45.80, 44.62, 41.79, 39.17, 38.54, 30.06, 21.30, 17.23. HR-ESI-MS [M+H]+calc, for C29H46N6O7590.342799, found 591.3502.

[0407] Cleavage assay for ligands is shown in Figures 23-24.

[0408] Synthesis and Characterization of Coordination Complexes

[0409] 3.1 General Complexation Protocol

[0410] A 5 mg aliquot of the peptide 3, 4, 5, 17-A, or 17-B was dissolved in 500 pL of room-temperature distilled water. Two equivalents of thenaGa3+.natCu3+. orna‘Sc3+salt were added to the solution, which was left to react. Complexation of the NOTA derivatives occurred at room temperature for 1 h, while complexation of the DOTA derivative (5) took place at 80 °C for 3 h. Full complexation was confirmed by LCMS. Tire complex was then purified using a Sep-Pak Plus C18 short cartridge. Tire concentration was determined using ICP-OES, and the complexes were further characterized via analytical HPLC and NMR.(Figure 17)

[0411] 3.2HRMS, HR-ESI-MS and HPLC Data for Coordination Complexes

[0412] “‘Gallium (S)-2,2'-(7-(2-((2-((2-((l-amino-3-( lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)amino)-2 -oxoethyl)-!, 4, 7-triazonane-l,4-diyl)diacetate, ([natGa(3)]+).Complex [natGa(3)]+(3.0 mg, 0.004 mmol, 56 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 3 (5.0 mg, 0.008 mmol) and Ga(NC>3)3-3H2O (4.25 mg, 0.017 mmol). The product was isolated as a pale solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (3.0 mg, 0.004 mmol, 56 %). Rt (Method B): 5.93 min. ’HNMR (400 MHz, D2O): 8 7.74 (d, 1H), 7.53 (d, 1H), 7.28 (m, 2H), 7.20 (t, 1H), 4.67 (t, 1H). 4.3 (s, 2H), 4.21 (s, 2H), 3.88-3.74 (m, 4H), 3.55-3.02 (m, 17H).13C NMR (100 MHz, D2O): 8 176.35 (C21), 174.53 (C19). 174.42 (C10), 174.28 (C12), 170.65 (C14), 168.76 (C16), 136.06 (C1), 126.91 (C6), 124.57 (C7), 121.98 (C3), 119.41 (C4), 118.41 (C5), 111.88 (C2), 109.14 (C8), 61.83 (C18), 61.63 (C20), 59.69 (C17), 54.12 (C^cl), 53.37 (Cc^cl), 53.29 (C^cl), 53.19 (Cc^cl), 53.01 (Cc^cl), 52.94 (Cc^cl), 52.79 (Cc^cl), 43.69 (C11), 42.23 (C13-15), 26.94 (C9). HR-ESI-MS [M+H]+calc, for C27H36GaN8O8669.191193, found 669.1899.

[0413] “‘Copper (S)-2,2'-(7-(2-((2-((2-((l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)amino)-2 -oxoethyl)- 1,4,7-triazonane- 1,4-diyl)diacetate, (natCu(3)).Compoundna‘Cu(3) (1.5 mg, 0.0023 mmol, 54 %) was synthesized using the general coupling strategy- outlined in Section 3.1 and Scheme S2 from compound 3 (2.5 mg, 0.0042 mmol) and CuSO4-5H2O (2.07 mg, 0.0083 mmol). The product was isolated as a pale blue solid following complexation and purification using Sep-Pak Plus C18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (1.5 mg, 0.0023 mmol, 54 %). R (Method B): 6.90 min. HR-ESI-MS [M+H]+calc, for C27H36CuN8O8663.195211, found 664.2020.

[0414] “Scandium (S)-2,2'-(7-(2-((2-((2-((l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)amino)-2-oxoethyl)-l,4,7-triazonane-l,4-diyl)diacetate, ([natSc(3)]+).Compound [natSc(3)]+(1.7 mg, 0.0026 mmol, 43 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 4 (3.7 mg, 0.0061 mmol) and SCCI3 6H2O (3.19 mg, 0.012 mmol). Tire product was isolated as a pale white solid following complexation and purification using a Sep-Pak Plus Cl 8 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (1.7 mg, 0.0026 mmol, 43 %). Rt (Method B): 6.32 min. HR-ESI-MS [M+H]+calc, for CzrHssNsOsSc 645.221526, found 645.2205.

[0415] “‘Gallium 2,2'-(7-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7-triazonane- 1,4-diyl)diacetate, ([natGa(4)]+). Complex [natGa(4)]+(6.2 mg, 0.009 mmol, 55 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 4 (10.0 mg, 0.016 mmol) and Ga(NO3)3-3H2O (8.09 mg, 0.032 mmol). The product was isolated as a colorless solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized by mass spectrometry and HPLC chromatography. Yield: (6.2 mg, 0.009 mmol, 55 %). Rt(Method B): 5.97 min. ’HNMR(400 MHz, D2O): 87.71 (d, 1H), 7.53 (d, 1H), 7.28-7.29 (m, 2H), 7.19 (t, 1H), 4.71 (m, 2H), 4.38-4.26 (m, 2H), 3.97-3.81 (m, 9H), 3.76-3.16 (m, 13H), 2.98 (m, 1H).13C NMR (100 MHz, D2O): 8 176.32 (C10), 174.49 (C22), 174.34 (C20), 170.46 (C14), 169.51 (C12), 168.32 (C17), 136.11 (C1). 126.92 (C6), 124.46 (C7), 121.95 (C3), 119.35 (C4). 118.38 (C5), 111.88 (C2). 108.99 (C8), 61.86 (C16), 61.83 (C11). 60.51 (C15), 59.80 (C19), 57.58 (C21).54.50 (Ccycl).54.05 (Ccycl), 53.42 (Ccycl), 53.33 (Ccycl), 53.24 (Ccycl), 53.09 (Ccycl), 52.97 (Ccycl), 42.34 (C1S), 38.70 (C13), 27.04 (C9). HR-ESI-MS [M+H]+calc, for C28H38GaN8O9699.201757, found 699.2015.

[0416] “‘Gallium 2,2'-(7-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy- 1 -oxopropan-2-yl- 1, 2, 3-13C3)amino-15N)-2 -oxoethyl)-!,4,7 -triazonane- 1,4-diyl)diacetate, ([natGa(4*)]+). Compound [natGa(4*)]+(2.1 mg, 0.003 mmol, 47 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 4* (4.0 mg, 0.0063 mmol) and Ga(NO3)3-3H2O (3.21 mg, 0.013 mmol). The product was isolated as a pale brown solid following complexation and purification using a Sep-Pak Plus C 18 short cartridge and characterized by mass spectrometry and HPLC chromatography. Yield: (2.1 mg, 0.003 mmol, 47 %). Rt(Method B): 5.97 min. HR-ESI-MS [M]+calc, for C25[13C]3H3SGaN7[15N]O9703.20885, found 703.2076.

[0417] “‘Copper 2,2'-(7-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7-triazonane- 1,4-diyl)diacetate, (Cu(4)). Compound Cu(4) (1.1 mg, 0.0016 mmol, 36 %) was synthesized using the general couplingstrategy outlined in Section 3.1 and Scheme S2 from compound 4 (2.8 mg, 0.0044 mmol) and CuSO4’5H2O (2.21 mg, 0.0089 mmol). The product was isolated as a pale blue solid following complexation and purification using a Sep-Pak Plus C 18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (1.1 mg, 0.0016mmol, 36 %). Rt (MethodB): 6.25 min. HR-ESI-MS [M+H]+calc, for C28H38CuN8O9693.205776, found 694.2133.

[0418] natScandium 2,2'-(7-(2-(((R)-l-((2-(((S)-l-amino-3-( lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy-l-oxopropan-2-yl)amino)-2-oxoethyl)-l,4,7-triazonane-l,4-diyl)diacetate, ([natSc(4)]+). Compound [natSc(4)]+(1.5 mg. 0.0022 mmol. 39 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 4 (3.6 mg, 0.0057 mmol) and ScCl3·6H2O (2.95 mg, 0.011 mmol). The product was isolated as a pale solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (1.5 mg, 0.0022 mmol, 39 %). Rt (Method B): 6.27 min. HR-ESI-MS [M+H]+calc, for C28H38N8O9SC 675.232091, found 675.2307.

[0419] natGallium 2,2',2"-(10-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3 -hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7, 10-tetraazacyclododecane- 1.4.7-triyl)triacetate. ([natGa(5)]+). Complex [natGa(5)]+(4.8 mg. 0.006 mmol. 63 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 5 (7.0 mg, 0.0095 mmol) and Ga(NO3)3’3H2O (4.88 mg, 0.019 mmol). Tire product was isolated as a colorless solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (4.8 mg, 0.006 mmol. 63 %). Rt(Method B): 5.90 min. 'HNMR (400 MHz. D2O): 57.68 (d, 1H), 7.53 (d, 1H). 7.30-7.24 (m, 2H), 7.20 (t, 1H), 4.70 (t, 1H), 4.40 (t. 1H), 4.00-3.71 (m, 15H). 3.61-3.06 (m. 16H).13C NMR (100 MHz, D2O): 5 176.10 (C10), 173.38 (C20), 173.31 (C24), 172.29 (C22), 171.38 (C14), 171.09 (C12), 168.80 (C17), 136.02 (C1), 126.85 (C6), 124.08 (C7), 122.01 (C3), 119.41 (C4), 118.39 (C5), 111.91 (C2), 109.24 (C8), 61.48 (C16), 61.25 (C11), 60.72 (C15), 59.29 (C13), 57.29 (Ccycl), 57.11 (Ccycl), 55.74 (Ccycl), 54.79 (Ccycl), 54.42 (Ccycl), 54.35 (C19), 53.90 (C21), 42.48 (C18), 27.03 (C9). HR-ESI-MS [M+H]+calc, for C32H47GaN9O11802.265087, found 800.2486.

[0420] “‘Copper 2,2',2"-( 10-(2-(((R)- 1 -((2-(((S)- 1 -amino-3 -( lH-indol-3 -yl)- 1 -oxopropan-2-yl)amino)-2-oxoethyl)amino)-3 -hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7, 10-tetraazacyclododecane- 1.4.7-triyl)triacetate, (natCu(5)). CompoundnatCu(5) (1.3 mg. 0.0016 mmol, 40 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 5 (3.0 mg, 0.0041 mmol) and CuSO4·5H2O (2.04 mg, 0.0082 mmol). The product was isolated as a pale blue solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized using massspectrometry and HPLC chromatography. Yield: (1.3 mg, 0.0016 mmol, 40 %). Rt (Method B): 6.12 min. HR-ESI-MS [M+H]+calc, for C32H47CuN9O11796.269105, found 795.2597.

[0421] “‘Scandium 2,2',2"-( 10-(2-(((R)- 1 -((2-(((S)- 1 -amino-3 -( 1 H-indol-3 -yl)- 1 -oxopropan-2-yl)amino)-2-oxoethyl)amino)-3-hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7, 10-tetraazacyclododecane-l,4,7-triyl)triacetate, ([natSc(5)]+). Compound [natSc(5)]+(1.8 mg, 0.002 mmol, 42 %) was synthesized using tire general coupling strategy outlined in Section 3.1 and Scheme S2 from compound 5 (4.0 mg, 0.0055 mmol) and ScCl3·6H2O (2.83 mg, 0.011 mmol). Tire product was isolated as a pale solid following complexation and purification using a Sep-Pak Plus Cl 8 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (1.8 mg, 0.002 mmol, 42 %). Rt (Method B): 5.75 min. HR-ESI-MS [M+H]+calc, for C32H47N9O11SC 778.295419, found 776.2796.

[0422] “‘Gallium (((lS)-l-carboxy-5-(3-(naphthalen-2-yl)-2-((lr,4S)-4-((6-oxo-6-((4-((l,4,7-tris(carboxymethyl)-l,4,7-triazonan-2-yl)methyl)phenyl)amino)hexanamido)methyl)cyclohexane-l-carboxamido)propanamido)pentyl)carbamoyl)-L -glutamic acid triacetate, (natGa(8)). CompoundnatGa(8) (1.5 mg, 0.0012 mmol, 46 %) was synthesized using the general coupling strategy outlined in Section 3.1 and Scheme S3 from compound 8 (3.0 mg, 0.0026 mmol) and Ga(NO3)3’3H2O (1.33 mg, 0.0052 mmol, ). Hie product was isolated as a white solid following complexation and purification using a Sep-Pak Plus C 18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: ( 1.5 mg, 0.0012 mmol, 46 %). Rt (Method B): 7.93 min. HR-ESI-MS [M+H]+calc, for C58H77GaN9O171240.46932, found 1240.4690.

[0423] “‘Gallium 2,2'-(7-(2-(((2R)-3-hydroxy-l-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-1 -oxopropan-2-yl)amino)-2-oxocthyl)- 1,4,7-triazonanc- 1,4-diyl)diacctatc, [natGa(17A)]+. Complex [natGa(17A)]+was synthesized using the general complexation protocol outlined in Section 3.1 and Scheme S2 from compound 17A (7.0 mg, 0.0113 mmol) and Ga(NO3)3’3H2O (7.8 mg. 0.0285 mmol). The product was isolated as a pale solid following complexation and purification using a Sep-Pak Plus C18 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (5 mg, 0.007 mmol, 64 %). Rt(Method B): 8.23 min. ‘HNMR: (700 MHz, D2O): 57.89 (d, 1H, H8), 7.29-7.23 (m, 3H, H5 6 7), 4.47 (d, 1H, H13), 4.38-4.29 (q, 2H, H4), 3.91-3.67 (m, 6H, H15-16-17), 3.57-3.51 (m, 4H, Hcycl), 3.41-3.08 (m. 8H, H9 11 n), 2.48 (d, 2H, H4), 1.85-1.81 (m, 1H, H3), 1.44-1.42 (t, 3H, H10), 0.87 (d, 5H. H1 2).13C NMR: (175 MHz. D2O): 5 174.40, 174.35. 174.32. 174.28, 168.83, 168.80, 141.37. 138.39. 138.17, 129.69, 61.92, 60.47, 59.75, 57.96, 57.90, 53.42, 53.36, 53.09, 45.72, 44.11, 39.05, 38.32, 38.20, 38.14, 29.67, 21.54, 17.21, 16.94. HR-ESI-MS [M+H]+calc, for C30H47GaN6O8687.263295, found 687.2628.

[0424] “‘Gallium 2,2'-(7-(2-((2-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-2-oxoethyl)amino)-2 -oxoethyl)-!, 4, 7-triazonane-l,4-diyl)diacetate, [natGa(17B)]+. Complex[natGa(17B)]+was synthesized using the general complexation protocol outlined in Section 3.1 and Scheme S2 from compound 17B (1.0 mg, 0.00169 mmol) and Ga(NO3)3’3H2O (1.7 mg, 0.00621 mmol). The product was isolated as a pale solid following complexation and purification using a Sep-Pak Plus Cl 8 short cartridge and characterized using mass spectrometry and HPLC chromatography. Yield: (0.07 mg, 0.00107 mmol. 70 %). Rt(Method B): 8.39 min. 'HNMR: (400 MHz, D2O): 87.29-7.24 (m, 3H, H5-6-7-8), 4.31 (s, 1H, H9). 4.01-3.52 (m, 8H, H11, 12’13 cycl), 3.42-3.23 (m, 7H. H14, 15-16 cycl), 2.49 (d, 2H, H4). 1.89-1.79 (m, 1H, H3), 1.44 (d, 3H, H10), 0.88 (d, 5H, H‘2).13C NMR: (100 MHz, D2O): 8 178.27, 174.51, 174.42, 168.30, 141.42, 138.36, 129.71, 127.03, 61.91, 53.39, 53.18, 53.08, 45.75, 44.10, 38.90, 37.98, 26.68, 21.53, 16.98. HR-ESI-MS [M+H]+calc, for C29H45GaN6O7657.252729, found 657.2522.

[0425] 3.4 Cleavage Assay for cold complexes

[0426] Cleavage of the cold model complexes was observed over a range of physiological pH conditions, including pH values of 4.5, 5.5, 6.5, and 7.5. Aqueous buffer solutions were prepared using 10 mM sodium acetate (pH 4.5 and 5.5) or 10 mM HEPES (pH 6.5 and 7.5), which were subsequently adjusted to the desired pH using NaOH and / or HC1. An aliquot of the complex was placed in an aqueous solution of the desired pH and incubated for 48 hours at 80 °C, monitored regularly via LCMS. (Figures 25-38).

[0427] 4. Synthesis and Characterization of Radiochemical Complexes

[0428] 4.1 General Radiolabeling Protocol

[0429] 4.1.1 Radiolabeling with67Ga.

[0430] 67Ga-citrate was purchased from Jubilant Radiopharma at an average specific activity of 205.0 MBq / mL. The67Ga-citrate solution was first converted to67GaC13 using an established solid-phase extraction protocol (Sun, Y et al.2020). The resulting average specific activity of the obtained67Ga-chloride solution used for solution radio-labelling was 80.5 MBq / mL. For radio-labeling of NOTA-based model peptides or compound 10. a 20 pL aliquot containing 4.5 MBq of67GaC13 was added to tire conjugate (10 nmol, 300 pL) in 10 mM of sodium acetate (NaOAc) buffer. The pH of the solution was adjusted to 5.0. Radiolabeling was completed after 20 minutes at room temperature. The radiolabeled conjugates were characterized with radio-HPLC.

[0431] 4.1.2 Radiolabeling with68Ga.

[0432] 68Ga-chloride was obtained from Dr. Jacob Houghton, Department of Radiology, Stony Brook University, Stony Brook, New York, at an average specific activity of 370.0 MBq / mL. For radio-labeling ofNOTA-Bn-Ada-PSMA, a 1.0 mL aliquot containing 38.8 MBq of68GaC13 was added to the resin-bound conjugate (10 nmol, 300 pL) in 1.0 M of sodium acetate (NaOAc) buffer. The pH of tire solution wasadjusted to 5.0. Radiolabeling was completed after 20 minutes at room temperature. The radiolabeled conjugate was photocleaved for 10 min and characterized with radio-HPLC. Examples of68Ga radiolabeling procedure are in Figures 11-13.

[0433] 4.1.3 Synthesis of 67Ga-radiolabeled complexes.

[0434] 67Gallium (S)-2,2'-(7-(2-((2-((2-((1-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)amino)-2-oxoethyl)-l,4,7-triazonane-l,4-diyl)diacetate,[67Ga][Ga(NO2A)]+-G-G-W-CONHi, ([67Ga][Ga(3)]+). Compound [67Ga] [Ga(3)]+was synthesized using the general radiolabeling protocol from compound 3. The product was characterized using radio-HPLC chromatography. Rt(Method D): 6.02 min. SA: 10.0 pCi / nmol, RCY: 99 %, RCP: 99 %. (Figure 18).

[0435] 67Gallium 2,2'-(7-(2-(((R)-l-((2-(((S)-l-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3 -hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7-triazonane-1,4-diyl)diacetate, [67Ga][Ga(NO2A)]+-S-G-W-CONH2, ([67Ga][Ga(4)]+). Compound [67Ga][Ga(4)]+was synthesized using the general radiolabeling protocol from compound 6. The product was characterized using radio-HPLC chromatography. Rt (Method D): 6.05 min. SA: 10.0 pCi / nmol, RCY: 99 %, RCP: 99%. (Figure 19).

[0436] 67Gallium 2,2',2"-(10-(2-(((R)-1-((2-(((S)-1-amino-3-(lH-indol-3-yl)-l-oxopropan-2-yl)amino)-2-oxoethyl)amino)-3 -hydroxy- 1 -oxopropan-2-yl)amino)-2 -oxoethyl)- 1,4,7, 10-tetraazacyclododecane-l,4,7-triyl)triacetate, [67Ga][Ga(DO3A)]+-S-G-W-CONH2, ([67Ga][Ga(5)]+). Compound [67Ga][Ga(5)]+was synthesized using the general radiolabeling protocol from intermediate 5. The product was characterized using radio-HPLC chromatography. Rt (Method D): 5.95 min. SA: 10.0 pCi / nmol, RCY: 99 %, RCP: 99 %. (Figure 20).

[0437] 67Gallium-2,2'-(7-(2-(((2R)-3-hydroxy-l-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-l-oxopropan-2 -yl)amino)-2 -oxoethyl)-!, 4, 7-triazonane-l,4-diyl)diacetate, [67Ga][Ga(NO2A)]+-S-EDA-IBP ([67Ga][Ga(17A)]+). Compound [67Ga][Ga(17A)]+was synthesized using the general radiolabeling protocol from ligand 17A. The product was characterized using radio-HPLC chromatography. Rt (Method D): 8.23 min. SA: 10.0 pCi / nmol, RCY: 95 %, RCP: 95 %. (Figure 21).

[0438] 67Gallium 2,2'-(7-(2-((2-((2-(2-(4-isobutylphenyl)propanamido)ethyl)amino)-2-oxoethyl)amino)-2 -oxoethyl)-!, 4, 7-triazonane-l,4-diyl)diacetate, [67Ga][Ga(NO2A)]+-G-EDA-IBP ([67Ga][Ga(17B)]+). Compound [67Ga][Ga(17B)]+was synthesized using the general radiolabeling protocol from ligand 17B. The product was characterized using radio-HPLC chromatography. Rt (Method D): 8.39 min. SA: 10.0 pCi / nmol, RCY: 95 %, RCP: 95 %. (Figure 39).

[0439] 4.1.4 Synthesis of68Ga-radiolabeled complexes.

[0440] 68Gallium (((1S)-1-carboxy-5-(3-(naphthalen-2-yl)-2-(( lr,4S)-4-((6-oxo-6-((4-((l,4,7-tris(carboxymethyl)-l,4,7-triazonan-2-yl)methyl)phenyl)amino)hexanamido)methyl)cyclohexane-l-carboxamido)propanamido)pentyl)carbamoyl)-L -glutamic acid triacetate, ([68Ga]Ga(8)). Compound [68Ga]Ga(8) was synthesized using the general radiolabeling protocol from ligand 8. The product was characterized using radio-HPLC chromatography. Rt (Method D): 7.93 min. SA: 10.0 pCi / nmol, RCY: 95 %. RCP: 95 %. (Figure 22).

[0441] 4.2 Cleavage assay for radiolabeled complexes is shown in Figures 40-54.

[0442] 5. VTMS and CIVP data.

[0443] Data Analysis and Detailed Discussion. The variable temperature mass spectra (Figure 55 and Figure 57) and corresponding speciation curves of the protonated tripeptide+NOTA (4) and the Ga-tripeptide-NOTA complex (natGa-4) are shown in Figure 56 and Figure 58. At the highest temperature shown in both figures, no water adduct is observed. The first hydrate of the ligand and the Ga-complex were observed at 220 K. The speciation curves (Figure 56 and Figure 58) show the sequential addition of multiple water molecules at lower temperature. The gas-phase enthalpies, entropies, and free energies of hydration for the 1sthydrate arc reported in Table S 1. AG298for the hydrated Ga complex was found to be well within the range of possible AG298values for a second sphere water (-34 kJ / mol) reported (Yu, B, et al. 2018). Similar values were found for the metal-free complex, further confirming that only second sphere hydration events were observed.

[0444] Table SI. AH, AS and AG298(kJ / mol) values for the binding of the first second sphere water for the tripeptide +NOTA and Ga-tripeptide-NOTA complexes as determined by VTMS.Compound AH (kJ / mol) AS(J / mol K) AG (kJ / mol) Tripeptide+NOTA -55.4 + / - 0.5 -91.3 + / - 2.2 -28.2 + / - 0.8Ga-Tripeptide-NOTA -48.9 + / - 2.6 -62.9 + / - 17.5 -30.1 + / - 2.7

[0445] CIVP spectra of the tripeptide+NOTA ligand and its isotopologue are shown in Figure 59. and the Ga complex, and the Ga complex and its isotopologue are shown in Figure 60. In all cases, notable shifts are seen in the Amide A, I, and II regions as expected for isotopic substitution on serine. Focusing on the Ga-complex, a single peak isotopically shifted by 8 cm'1is observed for a strong transition near 3271 cm1, identifying this feature as the serine NH stretch undergoing a weak internal hydrogen bond commonly seen for gas phase peptides (Yu, B, et al. 2018 and Wang, X, et al. 2018). The carbonyl stretching region between 1600-1800 cm1serves as an efficient diagnostic tool in elucidating the structure of the complex. To that end, understanding the carbonyl signature in the ligand was the first logical step in the spectroscopic structural elucidation of the complex. Focusing first on the metal-free complex,13C and15N isotopicsubstitution of the serine in the tripeptide backbone established that the two higher energy peaks belong to the carbonyl groups in the NOTA moiety. Specifically, these transitions are derived from the OCO antisymmetric stretching modes of the C=O in NOTA similar to those found for EDTA-bound metal ions (Folk, D. S. et al. 2010), and are unaffected by isotopic labeling.

[0446] The much broader, lower energy feature is a composite peak corresponding to the carbonyls in the tripeptide backbone. For the native isotopomer, this feature is only partially resolved, but for the isotopeexchanged species, it clearly splits into five distinguishable peaks. It was expected six total carbonyl stretches in this complex, suggesting the coexistence of at least two isomers in the absence of Ga. Upon complexation with Ga, five sharp, distinct peaks were found in the same spectral region of the that can be separated in three types of carbonyls in the complex. The two highest energy peaks remain the carbonyls in the NOTA, having undergone slight shifts and changes in intensity due to complexation with Ga. The next two lower energy peaks can be identified as the carbonyls in the tripeptide back bone, falling in the usual range for such modes (Wang et al. 2018). Indeed, upon isotopic substitution, one of these two peaks reduces in intensity, with a new peak lower in energy by 42 cm'1appearing consistent with expectations for13C substitution (Yu, B et al. 2018). This suggests that the lower energy of the two peaks is composed of two amide carbonyl stretches, fully accounting for all carbonyls in the complex. The identity of lowest-energy, the brightest peak in the spectrum, centered at 1603 cm'1is also confirmed by isotopic substitution of serine in the Ga-complex (third spectrum in Fig 5) The 13 cm-1red shift is too small to be caused by isotopic substitution of the carbonyl carbon. However, it is consistent with substitution of the adjacent nitrogen and carbon, as motions of these atoms are coupled to motions of the carbonyl carbon and oxygen and thus isotopic substitution will indirectly increase the reduced mass of this normal mode. Thus, this peak is best assigned to the carbonyl on NOTA. The fact that it is significantly red shifted from the expected position in the amide I region confirms that it is coordinated with the metal center through the oxygen. This assignment agrees with stretching frequencies of carbonyls involved in coordination via the oxygen in complexes of divalent cations and acetylacetonate ligands (Graf, et al. 2012). A conceivable explanation for the large red shift of the coordinated carbonyl is that coordination to the Ga3+metal center weakens the double bond character of the C = O bond, moving the vibrational energy of this mode towards that of an alcohol C-0 stretch typically observed near 1000-1200 cm1.

[0447] Quantum chemical calculations were performed at the B3LYP / cc-pVDZ level of theory’ using Gaussian 16 (Guo et al. 2022). Structures were optimized from reported crystal structures (Jacobsen et al.2006) and vibrational spectra were computed in tire harmonic approximation (Figure 61). Computed frequencies were multiplied by 0.96 to approximately correct for anharmonic effects and deficiencies in the quantum chemical method.

[0448] 7. Tabulated data

[0449] Table S2. Percent of each species as a function of time at pH 4.5 during 80 °C incubation ofnatGa-4. Values reported as an average of n=2 assays.Time (h) % Complex % Intermediate % Peptide0 100.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 1 38.54 ± 1.31 38.30 ± 2.07 23.17 ± 0.76 2 27. 10 ± 0.42 35.98 ± 1.74 36.93 ± 2.16 3 20.57 ± 0.35 30.66 ± 1.19 48.77 ± 1.54 6 6.38 ± 1.96 23.71 ± 0.78 69.91 ± 3.74 24 0.00 ± 0.00 8.28 ± 1.68 91.72 ± 1.68

[0450] Table S3. Percent of each species as a function of time at pH 5.5 during 80 °C incubation ofnatGa-4. Values reported as an average of n=3 assays.Time (h) % Complex % Intermediate % Peptide0 100.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 1 21.80 ± 1.00 68.74 ± 1.75 9.45 ± 1.15 2 18.58 ± 0.36 63.41 ± 2.35 18.02 ± 2.01 3 15.01 ± 0.38 59.79 ± 1.78 25.20 ± 1.92 6 9.18 ± 0.64 47.71 ± 1.63 43.11 ± 1.00 11 6.35 ± 0.51 39.79 ± 0.88 53.86 ± 1.38 22 1.26 ± 1.11 24.03 ± 2.19 74.71 ± 1.14

[0451] Table S4. Percent of each species as a function of time at pH 6.5 during 80 °C incubation of "a‘Ga-4. Values reported as an average of n=3 assays.Time (h) % Complex % Intermediate % Peptide0 78.96 ± 4.25 21.04 ± 4.25 0.00 ± 0.00 1 18.05 ± 0.37 73.69 ± 1.18 8.27 ± 1.35 2 16.27 ± 0.48 68.07 ± 1.33 15.66 ± 1.02 3 14.03 ± 0.56 63.85 ± 1.99 22. 12 ± 1.46 6 7.99 ± 1.96 54.19 ± 1.44 37.82 ± 1.23 22 0.00 ± 0.00 26.76 ±1.03 73.24 ± 1.03

[0452] Table S5. Percent of each species as a function of time at pH 7.5 during 80 °C incubation ofnatGa-4. Values reported as an average of n=3 assays.Time (h) % Complex % Intermediate % Peptide0 60.78 ± 10.2 39.22 ± 10.2 0.00 ± 0.00 1 15.83 ± 0.55 79.32 ± 0.06 4.85 ± 0.48 2 14.36 ± 2.17 76.77 ± 1.70 8.87 ± 0.71 3 13.21 ± 2.29 73.46 ± 2.23 13.33 ± 1.11 6 10.85 ± 0.16 63.13 ± 0.39 26.02 ± 0.24 10 8.57 ± 0.46 55.97 ± 1.27 35.46 ± 1.63 23 4.88 ± 0.37 31.59 ± 0.65 63.53 ± 0.99

[0453] Table S6. Kinetic rates of reaction calculated for each measured pH using a first-order kinetic fit. Values reported as an average of n=3 assays.pH N, O rearrangement rate (h1) Ester hydrolysis rate (h-1)4.5 0.365 ± 0.071 0.107 ± 0.0085.5 0.172 ± 0.006 0.062 ± 0.0086.3 0.172 ± 0.058 0.069 ± 0.0097.5 0.0663 ± 0.006 0.401 ± 0.003

[0454] Table S7. Quantitation of the [68Ga]Ga(8) product released from TG-10 per time vs. cumulative release.Time (min) Activity released Cumulative released activity [%]per time [%]1014.2 ± 1.57 14.2 ± 1.572017.9 ± 0.97 32.1 ± 0.6030 18.9 ± 0.61 50.9 ± 1.216015.4 ± 0.85 66.3 ± 0.369011.5 ± 0.84 77.8 ± 1.201209.2 ± 1.56 87.0 ± 2.76

[0455] Table S8. Cell binding dataCell type [68Ga]Ga(8) [%] [68Ga]Ga(8) [%] (n=3) (n=3)PC3 PiP 19.57 ± 1.38 16.45 ± 0.63 PC3 Flu 0.60 ± 0.09 0.38 ± 0.10

[0456] Table S9. HSA binding data.HSA [67Ga][Ga(17A)]+[67Ga][Ga(17B)]+80 °C for 2 h15 min (n=3) 15 min (n=3) (50 % released)15 min (n=3) 4.5%w / vHSA 95.96 ± 1.62 92.18 ± 2.19 41.90 ± 3.78

[0457] Table S10. Decay-corrected biodistribution of [67Ga][Ga(17A)]+and [67Ga] [Ga(17B)]+post- injection (n=3) in naive Balb / c mice models.Organ [67Ga][Ga(17A)]+[67Ga][Ga(17B)]+2 h (n=3) 2 h (n=3)Blood 0.12 ± 0.0012 0.08 ± 0.0017 Heart 0.07 ± 0.0007 0.04 ± 0.0007 Lung 0.36 ± 0.0036 0.39 ± 0.0087 Liver 1.03 ± 0.0110 0.63 ± 0.0145 Spleen 0.07 ± 0.0007 0.06 ± 0.0009 Kidney 1.15 ± 0.0116 0.43 ± 0.0064 Sm lnt 0.20 ± 0.0023 0.19 ± 0.0043 Muscle 0.03 ± 0.0002 0.04 ± 0.0007 Bone 0.05 ± 0.0005 0.03 ± 0.0004

[0458] Table Sil. Decay-corrected biodistribution of [67Ga][Ga(17A)]+and [67Ga] [Ga(17B)]+6 h post- injection (n=3) in naive Balb / c mice models.Organ [67Ga][Ga(17A)]+[67Ga][Ga(17B)]+6 h (n=3) 6 h (n=3)Blood 0.11 ± 0.0002 0.15 ± 0.0002 Heart 0.09 ± 0.0003 0.06 ± 0.00002 Lung 0.20 ± 0.0002 0.17 ± 0.0001 1 Liver 0.45 ± 0.0017 0.38 ± 0.00040 Spleen 0.11 ± 0.0006 0.08 ± 0.00027 Kidney 0.53 ± 0.0031 0.24 ± 0.00038 Sm lnt 0.11 ± 0.00051 0.12 ± 0.00085Muscle 0.02 ± 0.00002 0.02 ± 0.0001 1Bone 0.06 ± 0.00007 0.09 ± 0.00027

[0459] Table S12. Decay-corrected biodistribution of [67Ga][Ga(17A)]+and [67Ga][Ga(17B)]+1 post- injection (n=3) in naive Balb / c mice models.Organ [67Ga][Ga(17A)]+[67Ga][Ga(17B)]+12 h (n=3) 12 h (n=3)Blood 0.09 ± 0.00033 0.07 ± 0.0002 Heart 0.04 ± 0.00015 0.04 ± 0.0002 Lung 0.15 ± 0.00066 0.24 ± 0.0029 Liver 0.35 ± 0.00163 0.26 ± 0.0005 Spleen 0.10 ± 0.00038 0.12 ± 0.0011 Kidney 0.33 ± 0.00174 0.15 ± 0.0002 Sm lnt 0.07 ± 0.00029 0.05 ± 0.0003 Muscle 0.03 ± 0.00008 0.02 ± 0.0000 Bone 0.10 ± 0.00037 0.08 ± 0.0002

[0460] Table S13. Decay-corrected biodistribution of [67Ga][Ga(17A)]+and [67Ga][Ga(17B)]+24 h post- injection (n=3) in naive Balb / c mice models.Organ [67Ga][Ga(17A)]+[67Ga][Ga(17B)]+24 h (n=3) 24 h (n=3)Blood 0.02 ± 0.00012 0.02 ± 0.00012 Heart 0.02 ± 0.00007 0.02 ± 0.00003 Lung 0.05 ± 0.00034 0.04 ± 0.00019 Liver 0.08 ± 0.00089 0.08 ± 0.00079 Spleen 0.03 ± 0.00020 0.03 ± 0.00012 Kidney 0.22 ± 0.00074 0.19 ± 0.00087 Sm lnt 0.02 ± 0.00011 0.02 ± 0.00008 Muscle 0.02 ± 0.00010 0.01 ± 0.00006 Bone 0.03 ± 0.00038 0.02 ± 0.00023

[0461] Table S14. Decay-corrected biodistribution of [68Ga]Ga(8) and [68Ga]Ga(8) 24 h post- injection (n=3) in C57BL / 6J mice models.Organ [68Ga]Ga(8) [68Ga]Ga(8) [68Ga]Ga(8)(MM AC) (solution) (blocking)2 h ( n 3) 2 h (n=3) 2 h (n=3)Blood 0.47 ± 0.00474 0.57 ± 0.00120 0.16 ± 0.00039 Heart 0.13 ± 0.00039 0.18 ± 0.00054 0.06 ± 0.00007 Lung 0.37 ± 0.00098 0.50 ± 0.00086 0.15 ± 0.00048 Liver 1.02 ± 0.00070 1.57 ± 0.01026 0.21 ± 0.00024 Spleen 0.56 ± 0.00010 0.77 ± 0.00318 0.07 ± 0.00005 Kidney 3.74 ± 0.01569 3.62 ± 0.00919 0.82 ± 0.00215 Sm lnt 0.23 ± 0.00170 0.21 ± 0.00027 0.09 ± 0.00019 Muscle 0.07 ± 0.00044 0.07 ± 0.00018 0.02 ± 0.00002 Bone 0.19 ± 0.00041 0.21 ± 0.00012 0.07 ± 0.00070 Tumor 2.45 ± 0.00514 0.97 ± 0.00398 0.21 ± 0.00022DISCUSSION

[0462] Clinically viable prodrugs require close spatiotemporal control and release of activated, potent drug molecules at the site of interest (Twilton et al. 2017, Lee, M et al. 2020, Bolitho, E. M et al. 2021 and Alonso-de Castro, et al. 2017),. Common bond-cleavage strategies incorporate triggers such as pH, UV irradiation or enzyme proteolysis to modulate drug selectivity, function and pharmacokinetics (Sun Y, 2020, Yu, B. et al. 2018, Wang, X, 2018 and Folk, D. 2010). However, dependence of exogenous triggers and their relative abundance in the extracellular milieu can drastically limit applicability and drug efficacy. ( Graf, N.; et al. 2012, Guo, Z, et al. 2022, Jacobsen et al. 2006 and Yuan et al. 2015).

[0463] Stimuli-responsive pro-drugs that involve metal ions can exhibit similar limitations, where efficient pro-drag activation with external stimuli and close control of pharmacokinetics remains challenging and therefore represents a current area of research interest (Zhao, et al. 2022, Velema et al.2014, and Gawnc et al. 2022). Strategics such as transition metal mediated, cell-compatible catalysis or photodynamic triggering for drug activation or release have shown efficacy. (Oliveira et al. 2020, Zhang et al. 2020, Sabatino et al. 2019 and 2022, Wang et al. 2019. Hsu, et al. 2016, van Rixel, et al. 2019. Cole, et al. 2021 and Roque III, et al. 2022). However, the dependence on external stimulus or catalyst concentration can pose significant limitations on the accessibility or threshold abundance of the biological target. (Chang et al. 2021, Neumann et al. 2018, Vanjari et al. 2022, and Bray et al. 2018).

[0464] Selective, metal-ion mediated amide bond cleavage is a well-characterized process in nature: a range of metallo-proteases exist and exhibit great specificity and efficacy in aqueous media and ambient temperature. (McCall et al. 2000, Femandez-Patron et al. 2000, and Gao et al. 2020). Inspired by these metalloezymes, Groves, Burstyn et al. demonstrated that Co3+, Cu2+small molecular chelate systems were capable of amide bond scission via formation of a metal bound, ternary hydroxo ligand acting as a nucleophile (Groves, et al. 2020, Kita et al. 2012 and Hegg et al. 1995). More recently, Bal and coworkers employed Ni2chelating peptides that were selectively cleaved adjacent to serine by N,0 acyl shift and subsequent ester hydrolysis, a process also viable using Lewis acidic V-oxo species and Sc3+. (Krezel et al.2010, Wezynfeld et al, 2020 and Ho, P. H. et al. 2012). However, these systems relied on excess metal aqua-ion in solution orhemi-labile coordination complexes to conduct bimolecular bond cleavage reactions, which compromises their utility for controlled pro-drug activation and release under trace or in vivo conditions (Figure 1). (Wezynfeld et al. 2016, Yang et al.. 2016. Jbara, et al. 2020 and Latocheski et al.2020).

[0465] The present invention develops, enhances, and validates in vivo Metal-Mediated. Autolytic Amide bond Cleavage (MMAAC), a modular approach for the selective metal-complexation induced release and activation of metallodrugs. Using a model system, the present invention elucidates optimal combination of peptide sequence, chelate and metal ion, and probe reaction rates at temperatures and pH conditions of interest. Subsequently, the present invention demonstrates the feasibility to release active (radio)pharmaceuticals via MMAAC in solution and from solid support and in live mice.

[0466] Initial screening and scope

[0467] To probe the impact of metal ion, chelator, and mctal-complcx adjacent amino acid, a modular tripeptide sequence capped by an aza-macrocyclic metal chelator on the N-terminus was prepared. Specifically. 1,4,7-triazacyclononane-triacetic acid (NOTA) or 1,4,7, 10-tetraazacyclododecane-l, 4, 7,10-tetraacetic acid (DOTA), to H-X-G-W-NH2 (where X = S or G) was linked. Tryptophan (W) was incorporated to provide a spectroscopic handle for HPLC monitoring and G provided an additional short spacer to reduce steric encumbrance around the metal complex. Subsequently, chelation of the Lewis-acidic Ga3+, Sc3+and Cu2+ions produced model systems for further testing. These ions were selected as they are efficiently chelated by both macrocyclic chelator systems and possess biomedically relevant radioactive isotopes.

[0468] Amide bond hydrolysis was induced by complexation by the metal ion at pH 4.5 followed by immediate adjustment of reaction temperature. Reaction progress was monitored using high-performance liquid chromatography and mass spectrometry (HPLC-MS). In absence of metal ions, model peptides did not hydrolyze at any temperature tested (25, 37 and 80 °C). Only slow hydrolysis was observed for[M(NO2A)]n+-G-G-W-CONH2 under forcing conditions, while [M(DO3A)]n+-G-G-W-CONH2 peptides were not hydrolyzed, regardless of the identity of the metal ion. However, [M(NO2A)]n+-S-G-W-NH2exhibited observable amide bond hydrolysis for M = Ga3+, Sc3+with accelerating kinetic rates as temperature was increased. All Cu2+complexes tested remained hydrolytically stable withing the investigated time frame (Figures S39-S48 in the U. S. Provisional Application No. 63 / 587,976).

[0469] The investigated DOTA complexes do not involve sufficient amide bond coordination and polarization, and Cu2+favors formation of a 5-coordinate complex with NO2A without coordinative involvement of the amide, resulting also in decreased bond polarization. [Ga(NO2A-amide)]+and [Sc(NO2A-amide)]+complexes however both efficiently catalyzed amide bond hydrolysis adjacent to a serine. Figure 2 summarizes observed reactivity.

[0470] Encouraged bynatGa-triggered cleavage, the present invention next probed the selective release of radiolabeled complexes at tracer concentrations, to affirm that the proteolytic activity was governed by the complexed metal ion and not by any free metal ion present in macroscopic excess. The model peptides (10 nmol) were radiolabeled with 100 pCi of67Ga (corresponding to 2.5 pmol), at room temperature and pH 4.5 (10 mM sodium acetate). Radiochemical labeling yields (RCY) of >99% were observed for all model peptides at room temperature within 10 min. (see Figures 17-19). Following radiochemical complexation, the autolytic cleavage was monitored at different temperatures in accordance with macroscopic, non-radioactive experiments (25, 37 and 80 °C). The [67Ga]Ga(NOTA) complex was released from conjugate [67Ga][Ga(NO2A)]+-S-G-W-CONH2. The autolytic amide bond cleavage resulted in clean product formation at 80 °C as well as 37 °C (Figure 3B-D). Tire corresponding [67Ga][M(DOTA)]-S-G-W-CONH2 control was hydrolytically stable within the investigated time frame (Figure S55 in the U. S. Provisional Application No. 63 / 587,976). While corresponding Sc complexes exhibited analogous behavior, radiochemical studies were not conducted with the corresponding radioactive isotope as [Sc(NO2A-amide)]+complexes do not exhibit sufficient kinetic inertness for in vivo applications and drug development. (Majkowska-Pilip et al. 2011)

[0471] Kinetic studies

[0472] As the amide bond cleavage occurs only at appreciable reaction rates with model peptides containing [Ga(NO2A)]+-amide and [Sc(NO2A)]+-amide linked to a serine, multiple mechanistic pathways involving the metal complex were considered as plausible: (i) activation of a ternary aqua ligand by direct coordination to the metal center, (ii) activation / destabilization the complex-adjacent peptide bond by coordination of the carbonyl oxygen and (iii) N, O acyl shift rearrangement involving transient coordination of the alpha-amine of the serine (Figure 4A). (Wezynfeld, et al. 2016).

[0473] The cleavage assay at varying pH ranging from 4.5, 5.5, 6.5, 7.5, and 8.5 at 80 °C using the [Ga(NO2A)]+-S-G-W-CONH2model sequence was performed which was identified during the structural screen. To monitor and quantify substrate consumption and formation ofrelevantintermediates or products, analysis was conducted using HPLC-MS.

[0474] After adjustment of pH and temperature, HPLC-MS analysis revealed a second peak with the same mass signal as the substrate but shifted retention time (Figure 4B). This indicated the formation of the acyl N,0 shifted ester intermediate, followed by appearance of the desired products H-S-G-W-CONH2 and [Ga(NOTA)]. Observation of the putative structural isomer ester intermediate corroborates that amide bond hydrolysis occurs by N,0 acyl shift. (Kopera, et al. 2010). NO2A-amide ligands exhibit coordination of the carbonyl oxygen (N3O3 donor set) or amide nitrogen (N4O2) with gallium, with the coordinative switch occurring between pH 3-5. (Shetty et al. 2010) Both coordinative modes can induce N. O acyl shift rearrangement, followed by subsequent ester hydrolysis. (Ho, P. H, et al. 2011)

[0475] The presence of two reaction mechanisms resulting in N,0 acyl shift is further supported by the uncharacteristic pH dependence of the observed reaction rates detennined in accordance with previous reports. Accelerated rearrangement and ester hydrolysis at pH 4.5 was observed, when compared with data acquired at 5.5 and 6.5. This is opposite of the typically observed pH dependence of N,0 acyl shift-mediated autoproteolysis reactions that show fastest reaction rates at pH 5.5-6. Data obtained at pH 5.5-7.5, where the N4O2 complex species dominates, corroborates the general trend well (Figure 4D). (Shao et al. 1997 and Johansson et al. 2009) While some amount of substrate is hydrolyzed by attack of an exogenous nucleophilic water / OH‘ cannot be excluded, as indicated by observed, slow tum-over of G-linked test sequences vide supra, the observed pH dependence renders this process less probable and likely only a minor contributor.

[0476] Characterization of the N3O3 species with VT-MS, MS-IR

[0477] In accordance with previous studies on quantification of the inner-sphere hydration of coordination complexes using variable temperature mass-spectrometry (VT-MS), a corresponding analysis on the positively charged N3O3 species of [Ga(NO2A)]+-S-G-W-CONH2to probe ternary aqua complex formation in the gas phase was carried out. (Racow et al. 2019 and Vaughn et al. 2021). Inner-sphere water was excluded; the binding energy was found to be -30.1+2.7 kJ / mol, within the threshold of -34 kJ / mol established for inner-sphere water and consistent with the result for the metal-free NO2A-S-G-W-CONH3 (Figure S58 and S60 in the U. S. Provisional Application No. 63 / 587,976). This indicates that even at elevated pH, the complex-adjacent amide bond is not nucleophilically attacked by the inner-sphere water. Therefore, such a reaction mechanism (mechanism (i) vide supra) can likely be excluded. Furthermore,formation of a ternary aqua complex was not supported by previous studies using solid-state X-ray structural data of [Ga(N02A-amide)]+complexes. (She tty. et al. 2010)

[0478] The present invention structurally characterizes the species observed in the HPLC-MS experiments using mass-selective infrared spectroscopy (MS-IR). Briefly, this technique isolates the analyte in a mass spectrometer, allowing an infrared absorption spectrum of a well-defined hydration state to be recorded. Carbonyl stretches in [Ga(NO2A)]+-S-G-W-CONH2 and its isotopically labeled analogue could be identified to provide confinnative structural assignment of the N3O3 motif. Figure 5 compares the spectra of NO2A-S-G-W-CONH3+. [Ga(NO2A)]+-S-G-W-CONH2, and [Ga(NO2A)]+-*S-G-W-CONH2a corresponding analogue containing N-15 / C-13 labeled serine (Figure S63 in the U. S. Provisional Application No. 63 / 587,976). The incorporation of the metal ion enables clear identification of the carboxy stretches at 1719 and 1767 cm'1(Figure 5, purple), following the pattern for EDTA-chelated metal ions reported recently. (Foreman et al. 2022). These features appear broader in the metal-free species, likely due to isomers involving different arrangements of the carboxylic acid groups in the absence of Ga. Introduction of isotopically labeled serine residue induces a distinct red shift of the13C-carbonyl amide to lower wavenumbers (denoted by *) and provides means to assign other peptide-backbone amide carbonyl stretches (Figure 5, blue).’1Finally, the coordination of the amido carbonyl (Figure 5, orange) to the Ga3metal center yields a red shift and intensity increase as expected, and the adjacent ”N of the seryl residue further lowers the vibrational frequency in the labeled complex. (Meyer et al. 2022 and Seco et al. 1989). These assignments are supported by quantum chemical calculations, which confirm that complexation of the carbonyl leads to an 85 cm'1red shift (Figure 61).

[0479] With this spectroscopic signature understood, the structure of the intermediate was identified. It was expected the N3O3 coordination mode to retain the coordinated amido carbonyl feature and the N4O2mode to lose it. Given that the N4O2complex is neutral, it was observed in the mass spectrum as a sodium adduct. Figure 6B compares the spectra of the native to the sodiated species. Sodiation yields a clear free OH stretching signal, highlighting the intact serine OH, and removes the Ga-coordinated carbonyl stretching feature, identifying this as the N4O2 complex. Shifts in the free NH stretches upon sodiation are attributed to the breaking of backbone NH- OC hydrogen bonds in favor of chelation of the sodium ion by the amid carbonyls.

[0480] Having positively identified both the N3O3 and N4O2complexes, the changes to their spectra upon 2 hours of incubation was tracked (shaded spectra in Figure 6C). No changes are observed in the spectrum of [Ga(NO2A)]+-S-G-W-CONH3+, but the intensity of its signal in the mass spectrum reduces with incubation time in a similar manner to the HPLC-MS results in Figure 4. Combined with a concomitant increase in the sodium adduct signal, this suggests the depletion of N3O3 and production of N4O2as thereaction progresses. Moving to the spectrum of the sodium adduct, much of the spectrum is similar after incubation, but the OH stretching feature (identified by in Figure 6C) is substantially reduced. Further inspection of the spectrum of the isotopically-enriched species reveals a simultaneous reduction of the intensity of the serine amide stretch near 3400 cm1(also marked withwhich suffers a 6 cm’1red shift upon exchange with15N. Quantum chemical predictions (Figure 62) suggest more than a hundred-fold reduction of the intensity of this NH stretch after the acyl shift. Thus, the spectra indicate depletion of the unreacted complex and the generation of a structurally similar species lacking OH and serine NH moieties that we identify as the acyl-shifted N4O2 intermediate.

[0481] Proof-of-concept (1): selective release of high molar activity radiopharmaceuticals

[0482] Subsequently the present invention conducted a first validation of the MMAAC strategy for prodrug activation. To this end, the present invention designed a [Ga(NO2A-bb-Bn)]-linked, targeted construct with a cleavable, serine-glycine prodmg cap. The present invention prepared the NOTA-linked short peptide conjugate 10, targeting the prostate specific membrane antigen (PSMA). The construct includes a doubly functionalized NOTA chelator, that incorporates a cleavable G-S (glycine -serine) cap by amidation; a PSMA-targeting peptide was introduced via backbone functionalization of the macrocycle in accordance with methods established by us previously (Figure 7A). (Smilowicz et al. 2022)

[0483] Radiochemical labeling and autocleavage efficiency were probed with the radioactive isotope67Ga. The direct, in solution radiolabeling to produce [67Ga]Ga(10) resulted in high radiochemical yield (>90%) at pH 5.0 and at 37 °C. Incubation of [67Ga]Ga(10) at 37 °C. and 80 °C revealed the selective release of67Ga-NOTA-Bn-PSMA ([67Ga]Ga(8)) with ti / 2= 22.2 h and 0.81 h, respectively (Figure 7B, Figure S64 in the U. S. Provisional Application No. 63 / 587,976). The resulting product [67Ga]Ga(8) was not sensitive to further degradation or radiolysis within 80 h at 80 °C (Figure 7D, Figure S64 in the U. S.Provisional Application No. 63 / 587,976). Tire significantly accelerated amide bond cleavage even at 37°C indicates that the autolytic amide bond cleavage mechanism can be modulated by greater steric encumbrance and may be compatible with prodrug activation by release in vivo systems.

[0484] With these optimized drug -release conditions validated in solution, selective release of radiopharmaceutical from solid support upon binding of the metal ion would be feasible (Figure 62). If successfully implemented, MMAAC would result in the release of only the desired radiometal complex into solution, while the unreacted precursor would remain on the solid support, maximizing achievable molar activities. This contrasts with conventional, in-solution radiochelation which produces the radiolabeled complex in presence of 4-5-orders of magnitude excess ligand (e.g. typically 1:1000 M: U ratio), limiting achievable molar activities which, consequently can inhibit or reduce effective binding of in vivo targets. (Eder et ala. 2014).

[0485] The synthesis of tentagel appended PSMA-NOTA (TG-10) prodrug was conducted using a postsynthetic, terminal resin loading strategy (see Figure 15). To validate MMAAC as an efficient strategy for preparation of radiopharmaceuticals, the68Ga-PSMA derivative was prepared([68Ga]Ga-8) by selective release from resin-appended prodrug using68Ga sourced from a commercial68Ge / 68Ga-generator. The [68Ga]Ga-8 radiotracer was tested for radiochemical labeling efficiency, radiochemical purity and autocleavage efficiency using the tentagel appended PSMA-NOTA (TG-10) prodrug. To this end, a commercial68Ge / 68Ga-generator was eluted, buffered to pH 5 and loaded directly onto the functionalized resin TG-10 in at total reaction volume of 1 mL. Radiolabeling was conducted at 37 °C using 10 nmol peptide on resin (Figure 7A, 8A). The direct solid-phase radiolabeling step retained >90% of the loaded activity. Subsequent incubation of TG-10 at 80 °C produced [68Ga]Ga(NOTA)-Bn- PSMA ([68Ga]Ga-8)) with ti / 2= 0.5 h (Figure 7C) and efficient release of >95% of bound activity from the resin. Tire resulting product was hydrolytically stable at 80 °C (Figure 7D). Co-registration of UV signal with the resin-eluate indicates that the quantity of released peptide is too low to be detectable, which is in accordance with anticipated, high molar activity of the product.

[0486] To validate the performance of the high molar activity construct, [68Ga] [Ga(8)] in a corresponding mouse model was tested. Specifically, the RM-1 murine prostate cancer cell line compatible with immunocompetent mice was employed. In contrast with the human-derived PSMA-expressing cell lines PC-3 PiP (500,000 receptor copies per cell), RM-1 only expresses approximately 80,000 copies of the PSMA receptor per cell. (Fendler, et al. 2017, Smilowicz, D et al. 2022) This induces a greater sensitivity to the molar activity of radiopharmaceuticals, with low molar activity reducing probe uptake in target tissues. Radiosynthesis of [68Ga]Ga-8 using MMAAC was conducted, followed by administration to tumorbearing mice, positron emission tomography (PET) imaging at 90 min post injection and biodistribution analysis at 2 hours post injection. Uptake in the tumor reached 2.45 % ID / g at 2 hours post injection, demonstrating good tumor conspicuity and significant target accumulation (Figure 8C-D, '‘MMAAC, pink bars). Comparatively, when a conventional, in-solution radiosynthesis, imaging and biodistribution analysis with 0.2 mCi / mnol molar activity was conducted, probe accumulation reached only 0.97 % ID / g in the tumor (Figures 8C-D, “conventional” - grey bars). A corresponding blocking experiment at 0.01 mCi / nmol molar activity further demonstrated the reduction of target-specific uptake and sensitivity of this cell line and tumor model to the radiopharmaceuticals’ molar activity (Figure 8D, striped bars).

[0487] Proof-of-concept (2): pro-drug release in vivo

[0488] Due to the feasibility of MMAAC at 37 °C, it is posited that the hydrolysis of the metal complex could also be observed in vivo. To this end. a proof-of-concept constructs 17 and 18 was designed, which incorporate the [M(N02A)]n+-X (X = G, S) motif appended to en-ibuprofen. This moiety has previouslyshown to bind effectively to murine and human serum albumin and thus would exhibit prolonged in vivo circulation to track reaction progress using radiochemical tracing with the longer-lived isotope67Ga (Figure 9A). (Boros, et al. 2013 and Deberle et al. 2020). In solution chemical synthesis of 17A (X = S, cleavable) and 17B (X = G, non-cleavable control) was achieved by sequential solution phase amide bond couplings (Figure 16). Sensitivity to hydrolysis of [Ga(17A)]+was verified and the human serum-albumin (HSA) binding of [G7Ga][Ga(17A)]+and [67Ga][Ga(17B)]+was 96 and 92% respectively (Figure 9B). Hydrolysis of 50% of [67Ga][Ga(17A)]+resulted in 42% bound activity to HSA, demonstrating that the hydrolyzed complex [67Ga]Ga(NOTA) did not exhibit significant binding (Figure 8B).

[0489] With |',7Ga||Ga(17A)| and [67Ga][Ga(17B)]+validated, in vivo metabolite tracking experiments were conducted next. 200 pCi of the constructs was administered to separate cohorts naive balb / C mice and cohorts (n=3) were sacrificed at 2, 6, 12 and 24 hours post-injection. In addition to biodistribution, blood and urine metabolite analysis was conducted with radioHPLC. as intact probe and hydrolyzed complex metabolite are easily distinguishable by retention time. Effective MMAAC release of the [67Ga]Ga(NOTA) complex for [b7Ga][Ga(17A)]+in blood and urine was observed (Figure 9C), while [b7Ga][Ga(17B)]+was stable and appeared as the only detectable metabolite at sampled time points (Figure 9D). In contrast with previously determined kinetic rates ex vivo, [67Ga][Ga(17A)]+was fully hydrolyzed at the 12 hour mark, which indicates that the in vivo hydrolysis proceeds with a significantly faster rate than in the test tube. It is hypothesized that the more lipophilic protein environment of serum albumin accelerates the MMAAC rate when [67Ga][Ga(17A)]+is bound; future experiments beyond the scope of this work are planned to address and further study how MMAAC rates can be modulated selectively in vitro and in vivo.

[0490] In summary, the present invention demonstrates autolytic, metal-complex mediated amide bond cleavage, which represents a viable method for prodrug-activation and synthesis of metalldrougs. The activation of corresponding prodrug structures by N, O acyl shift mechanism occurs only following formation of the corresponding coordination complex. Conveniently, reaction rates remain (too) slow at room temperature and significantly accelerate at elevated temperature (37 / 80 °C) The strict dependence of the observed reactivity on direct adjacency to serine provides a convenient tool to build clearly defined prodrug structures that employ metal complexes as release triggers.

[0491] The MMAAC approach is compatible with trace concentrations of pro-drug and metal ions without the need for exogenous catalyst or reactant to produce the desired product, as demonstrated by studies conducted at macroscopic (pmol) and radiotracer (pmol) scale. The corresponding proof-of-concept studies indicate that autolytic, metal-complex mediated amide bond cleavage is suitable for the synthesis of “slow-re lease” and high specific activity radiopharmaceuticals: two in vivo experiments were carried out to demonstrate that (1) high molar activity radiophannaceuticals synthesized with MMAAC can exhibitimproved in vivo performance and (2) MMAAC can be employed to induce selective compound degradation in vivo. Future work will entail expansion of scope beyond Ga3+and Sc3metal ions and tuning of reaction rates by modification of peptide sequence, ionic strength, and polarity of the chemical environment.REFERENCES1. Twilton, J.; Le, C. C.; Zhang, P.; Shaw, M. H.; Evans, R. 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Claims

CLAIMS1. A compound having a structure:L" Rr~N— ' r'-N-"O5> oN N' Peptide linker j— N N — Peptide linker j— R2orwherein Yi and Y? are each independently, -H, alkyl-N-(CO-Rj. alkyl-N-(alkyl-COR4b alkylheteroaryl, alkyl-COzH. alkylar l-CCPH. alkylhetcroaryl-CCYH. alkyl -CO: Rj. alkylaryl -NH-CO2R4. alkylaryl-CCLRa, alkylheteroaryl-CCLRr, alkyl-OH, alkylaryl-OH. alkylhetcroaryl-OH. alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl -N(alkyl-CO2H)2. alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(0)(0H)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF;. -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, R4 is -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably RHs -OH or -NH2;wherein L is a chemical linker;Owherein A is H, NH2, -AN. or a targeting moiety:wherein Ri is H, NH2,N1, an antigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2 is H, NH2,Nl 2, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein tire first amino acid in the peptide linker is linked to the carbonyl group is cither a serine or a glycine.

2. The compound of claim 1, wherein(a) the first amino acid linked to the carbonyl group is serine; or(b) when the compound is chelated with a metal ion, the bond between the peptide linker and the carbonyl group automatically cleaves off.

3. The compound of any one of claims 1 -2, wherein when the compound is chelated with a metal ion, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:Y,wherein M is the metal ion; orwherein when the compound is chelated with a metal ion, the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:Peptide linkerandwherein M is the metal ion.

4. The compound of any one of claims 1-3, wherein Yi and Y2 are each independently alkyl-CChH, alkylaryl-CChH, alkyl-N- CChRrh, alkyl-N-(alkyl-CO2R4)2, alkylheteroaryl-CChH. alkyl-CCPR.;. alkylaryl-NH-CO-Rj alkylaryl-CO-Rj. alkylhctcroaryl-C(YR4. alkyl-N(alkylaryl-CC>2H)2, alkyl- N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl- N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO; H). alkyl-N(alkylheteroaryl-OH)(alkyl-CC>2H), or alkylheteroaryl- P(O)(OH)2; preferably, Y 1 and Y2 are each independently alkyl-CChH, alkyl-N- (CChRrh, alkyl-N-(alkyl-CO2R4)2, alkylaryl-CChH. alkylheteroaryl-CChH, alkyl -N (alkylaryl - CO2H)2. alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl- CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), or alkylheteroaryl-P(O)(OH)2; more preferably, Yi and Y2are each independently alkyl-CCTH, alkyl-N-(CO2R4)2, alkyl-N-(alkyl- CC R^ or alkyl-N(alkyl-CO2H)2; more preferably, Y 1 and Y2are each independently alkyl-CCTH, CH2-N-(CO2H)2, or CH2-N-(alkyl-CO2R4>2; more preferably, Yi and Y2 are same.

5. The compound of any one of claims 1-4, whereinYi and Y2are each independently -H,preferably Yi and Y2are each independentlyOHOHmore preferably, Yi and Y2are each independentlyCO2H Omore preferably, Y 1 and Y2 are each independentlyOHmore preferably, Y i and Y2 are each independentlyOHmore preferably, Y 1 and Y2 are each independentlymore preferably, Y 1 and Y2 are each ^ 'co2H6. The compound of any one of claims 1-5. wherein the peptide linker is a sequence of 10 amino acids;preferably, the peptide linker is a sequence of 9 amino acids; more preferably, the peptide linker is a sequence of 8 amino acids; more preferably, the peptide linker is a sequence of 7 amino acids: more preferably, the peptide linker is a sequence of 6 amino acids; more preferably, the peptide linker is a sequence of 5 amino acids; more preferably, the peptide linker is a sequence of 4 amino acids; more preferably, the peptide linker is a sequence of 3 amino acids; more prefearly, the peptide linker is(a) serine-glycerin-tryptophan (S-G-W);(b) serine-tryptophan-glycerin (S-W-G);(c) serine- glycerin-serine (S-G-S);(d) serine-serine-glycerin (S-S-G);(e) serine-tryptophan-serine (S-W-S);(f) serine-serine-tryptophan (S-S-W);(g) glycerin-glycerin-tryptophan (G-G-W);(h) glycerin-tryptophan-glycerin (G-W-G);(i) glycerin-serine-tryptophan (G-S-W);j) glycerin-tryptophan-serine (G-W-S);(k) gtycerin-serine-tryptophan (G-S-G); or(l) glycerin- glycerin-serine (G-G-S).

7. The compound of any one of claims 1-6, wherein A and Ri are each independently a targeting moiety, wherein the targeting moiety is a moiety with specificity for a target protein on the surface of a cell; preferably, the targeting moiety is a moiety with specificity for a target antigen on the surface of a cell; more preferably, the targeting moiety is a drug, small molecule, a peptide or an antibody or a derivative or fragment thereof; more preferably, tire targeting moiety is trastuzumab, bombesin, somatostatin or 2-[3-(l,3-dicarboxypropyl)ureido]pentanedioic acid (DUPA) or wherein A and Ri are each independently a drug, wherein the drug is an anti-inflammatory drug; preferably, the drug is a nonsteroidal anti-inflammatory drug; more preferably, the drug is diclofenac, diflunisal, etodolac, fenoprofen. flurbiprofen, ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is ibuprofen.

8. The compound of claim 7, wherein A has the structure:wherein R3, Rs and are each independently, -H, alkyl, alkenyl, alkynyl, alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CF3or -Si(alkyl)3.

9. The compound of any one of claims 1-8, wherein(a) the bond between Ri and the chemical linker L is formed by reacting a first terminal reactive group on Ri with a second terminal reactive group on the chemical linker L; preferably, the bond between Ri and the chemical linker L is formed by reacting a carboxylic acid moiety on Ri with an amine moiety on the chemical linker L;(b) the chemical linker L is a non-releasable linker;(c) the bond between R2and the peptide linker is formed by reacting a first terminal reactive group on R2with a second terminal reactive group on the peptide linker; preferably, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on R2with an amine moiety on the peptide linker; more preferably, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on R2; or(d) the bond between A and the peptide linker is formed by reacting a first terminal reactive group on A with a second terminal reactive group on the peptide linker; preferably, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on A with an amine moiety on the peptide linker; more preferable, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on A.

10. The compound of any one of claims 1-9, wherein the chemical linker L is an alkyl, alkenyl, alkynyl, alkylether, alkylthioether, alkylamino, alkylamido, alkylester, alkylaryl, alklyheteroaryl, aryl, heteroaryl, a natural amino acid, an unnatural amino acid, a disulfide or thioether containing linker or combinations thereof.

11. The compound of any one of claims 1-10, wherein the solid support surface is a resin, preferably, the resin is a rink amide resin, a wang resin, an agarose resin, a tentagel resin or an ion-exchange resin, more preferably the resin is a tentagel resin.

12. The compound of any one of claims 2-3, wherein the metal ion is Gallium-67 (67Ga), Gallium-68 (68Ga), Copper-62 (62Cu), Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 (44Sc), Scandium-47 (47Sc), Scandium-43 (43Sc), Tanthanum-132 (132La), Lanthanum-135 (135La), Yttrium-86 (86Y), Yttnum-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (152Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb); preferably, the metal is ion Gallium-67 (67Ga).

13. The compound of claim 3, wherein the peptide linker further cleaves off to produce A or R2.

14. The compound of claim 2, wherein the bond between the peptide linker and the carbonyl group automatically cleaves off by ester hydrolysis; preferably, the bond between the peptide linker and the carbonyl group automatically cleaves off at a pH of 4.5-8; preferably at a pH of 4.5-6.5; morepreferably, the bond between the peptide linker and the carbonyl group automatically cleaves off at a pH of 4.5-8; preferably at a pH of 4.5-6.5.

15. The compound of claim 1 having the following structure:

16. The compound of claim 1 having the following structure:o owherein is a solid support surface.

17. A metal complex having a structure:wherein Yi and Y2 are each independently, -H, alkyl-N-fCO R^, alkyl-N^alkyl-COiRi):. alkylheteroaryl. alkyl-CCfH. alkylaryl-CChH, alkylhetcroaryl-CCfH. alkyl-CCfRj. alkylaryl-NH-CChR-i, alkylaryl-COiRj. alkylhctcroaryl-CCfR^ alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl -N(alkyl-CO2H)2. alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, RAs -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably RAs -OH or -NH2;wherein M is a metal ion;wherein L is a chemical linker;owherein A is H, NH2,, or a targeting moiety;O- Iwherein Ri is H, NH2.

2. an antigen, an antibody, a therapeutic agent, or a targeting moiety;Owherein R2is H, NH2,N-, an antigen, an antibody, a therapeutic agent, or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

18. The metal complex of claim 17, wherein (a) the first amino acid linked to the carbonyl group is serine; or (b) the bond between the peptide linker and the carbonyl group automatically cleaves off after a period of time.

19. The metal complex of any one of claims 17-18, wherein the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:Y,Peptide linker j— Aandl;orwherein the bond between the peptide linker and the carbonyl group automatically cleaves off to produce the following structures:Peptide linker R2and20. The metal complex of any one of claims 17-19, wherein Yi and Y2are each independently alkyl- CO2H, alkylaryl-COeH, alkyl-N-(CO2R4)2, alkyl -N^alkyl-CC RA alkylheteroaryl-CO2H, alkyl- CO2R4, alkylaryl-NH-CO2R4, alkylaryl-CC Rj, alkylheteroaryl-CC Rt, alkyl-N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl- CO2H), or alkylheteroaryl- P(O)(OH)2; preferably, Yi and Y2are each independently alkyl-CO2H, alkyl-N-(CO2R4)2, alkyl-N-(alkyl-CO2R4)2, alkylaryl-CO2H, alkylheteroaryl-CO2H, alkyl- N(alkylaryl-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CCfH). alkyl-N(alkylheteroaryl-OH)(alkyl-CO2H), or alkylheteroaryl- P(O)(OH)2; more preferably, Y 1 and Y2are each independently alkyl-CO2H, alkyl-N-(CO2R )2, alkyl-N-(alkyl- CO2R4)2, or alkyl-N(alkyl-CO2H)2; more preferably, Y 1 and Y2are each independently alkyl-CO2H, CH2-N-(CO2H)2, or CH2-N-(alkyl-CO2R4)2; preferably, Yi and Y2are same.

21. The metal complex of any one of claims 17-20, whereinYi and Y2 are each independentlymore preferably, Y 1 and Y2arc each independentlyOHCO2Hmore preferably, Y i and Y2are each independentlyOHmore preferably, Y i and Y2are each independentlyOHmore preferably, Y i and Y2are each independentlyA^NH2^CO2HorO;more preferably, Y i and Y2are eachC02H22. The metal complex of any one of claims 17-21, wherein the peptide linker is a sequence of 10 amino acids: preferably, the peptide linker is a sequence of 9 amino acids: more preferably, the peptide linker is a sequence of 8 amino acids; more preferably, the peptide linker is a sequence of 7 amino acids; more preferably, the peptide linker is a sequence of 6 amino acids; more preferably, the peptide linker is a sequence of 5 amino acids; more preferably, the peptide linker is a sequenceof 4 amino acids; more preferably, the peptide linker is a sequence of 3 amino acids; more preferably, the peptide linker is(a) serine-glycerin-tryptophan (S-G-W);(b) scrinc-tryptophan-glyccrin (S-W-G);(c) serine- glycerin-serine (S-G-S);(d) serine-serine-glycerin (S-S-G);(e) serine-tryptophan-serine (S-W-S);(f) scnnc-scrinc-tryptophan (S-S-W);(g) glycerin-glycerin-tryptophan (G-G-W);(h) glycerin -tryptophan -glycerin (G-W-G);(i) glyccrin-scrine-tryptophan (G-S-W);(j) glycerin-tryptophan-serine (G-W-S);(k) glycerin-serine-tryptophan (G-S-G); or(l) glycerin- glycerin-serine (G-G-S).

23. The metal complex of any one of claims 17-22, wherein A and Ri are each independently a targeting moiety, wherein the targeting moiety is a moiety with specificity for a target protein on the surface of a cell; preferably, the targeting moiety is a moiety with specificity for a target antigen on the surface of a cell; more preferably, the targeting moiety is a drug, small molecule, a peptide or an antibody or a derivative or fragment thereof; more preferably, the targeting moiety is trastuzumab, bombesin, somatostatin or 2-[3-(l,3-dicarboxypropyl)ureido]pentanedioic acid (DUPA) or a derivative or fragment thereof; orwherein A and Ri are each independently a drug, wherein the drug is an anti-inflammatory drug; preferably, the drug is a nonsteroidal anti-inflammatory drug; more preferably, the drug is diclofenac, diflunisal, etodolac, fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is fenoprofen, flurbiprofen, ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is ibuprofen, indomethacin, or ketoprofen; more preferably, the drug is ibuprofen.

24. The metal complex of claim 23, wherein A has the structure:wherein R3, R? and R are each independently. -H, alkyl, alkenyl, alkynyl, alkyl-aryl, alkyl-heteroaryl, aryl, heteroaryl, alkyl-CF3or -Si(alkyl)3.

25. The metal complex of any one of claims 17-24, wherein(a) the bond between Ri and the chemical linker L is formed by reacting a first terminal reactive group on Ri with a second tenninal reactive group on the chemical linker L; preferably, the bond between Ri and the chemical linker L is formed by reacting a carboxylic acid moiety on Ri with an amine moiety on the chemical linker L;(b) the chemical linker L is a releasable linker:(c) the bond between A and the peptide linker is formed by reacting a first terminal reactive group on A with a second terminal reactive group on the peptide linker; preferably, the bond between A and the peptide linker is fonned by reacting a carboxylic acid moiety on A with an amine moiety on the peptide linker: more preferably, the bond between A and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on A; or(d) the bond between R2and the peptide linker is formed by reacting a first terminal reactive group on R2with a second terminal reactive group on the peptide linker; preferably, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on R2with an amine moiety on the peptide linker; more preferably, the bond between R2and the peptide linker is formed by reacting a carboxylic acid moiety on peptide linker with an amine moiety on R2.

26. The metal complex of any one of claims 17-25, wherein the chemical linker L is an alkyl, alkenyl, alkynyl, alkylether, alkylthioether, alkylamino, alkylamido, alkylester, alkylaryl, alklyheteroaryl, and, heteroaryl, a natural amino acid, an unnatural amino acid, a disulfide or thioether containing linker or combinations thereof.

27. The metal complex of any one of claims 17-26, wherein the solid support surface is a resin, preferably, the resin is a rink amide resin, a wang resin, an agarose resin, atentagel resin or an ionexchange resin, more preferably the resin is a tentagel resin.

28. The metal complex of claim 18, wherein the bond between the peptide linker and the carbonyl group automatically cleaves off by ester hydrolysis.

29. The metal complex of claims 19, wherein the bond between the peptide linker and the carbonyl group is further cleaved off to produce A or R2; preferably, the bond between the peptide linker and the carbonyl group automatically cleaves off at a pH of 4.5-8; preferably at a pH of 4.5-6.5; more preferably, the bond between the peptide linker and the carbonyl group automatically cleaves off at 20-80 °C; preferably, at 30-45°C; more preferably, at 37°C.

30. The metal complex of claim 17 having the following structure:ʼnllorwhereinis a solid support surface.

32. The metal complex of any one of claims 17-31, wherein the metal ion is Gallium-67 (67Ga), Gallium-68 (6SGa), Copper-62 (,2Cu). Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 (44Sc), Scandium-47 (47Sc), Scandium-43 (43Sc), Lanthanum-132 (132La), Lanthanum-135 (135La), Yttnum-86 (86Y), Yttrium-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (152Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb); preferably, the metal ion is Gallium-67 (67Ga).

33. A pharmaceutical composition comprising the compound of any one of claims 1-19 and a pharmaceutically acceptable carrier; or a pharmaceutical composition comprising the metal complex of any one of claims 20-38 and a pharmaceutically acceptable carrier.

34. A pharmaceutical composition comprising:' (M) / II- Peptide linker — \\ —! and > and / orwherein Yi, Y2 are each independently, -H, alkyl-N^CChRi):, alkyl-N-falkyl-CChRrh. alkylheteroaryl, alkyl-CCLH. alkylary I-CO2H, alkylheteroaryl-CCLH, alkyl-CO2R4, alkylaryl-NH-CC Rj. alkylaryl-CCLRj. alkylhctcroaryl-CCLFL. alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2. alkyl-N(alkylaryl-CO2H)2. alkyl-N(alkylheteroaryl-CO2H)2, alkyl-N(alkylaryl-CO2R4)2, alkyl-Njalkylhctcroaryl-CCFFLh. alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl -N(alkyl-CO2H)2. alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroar TOH)(alkyl-CO3H). alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R4 is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, ar l, heteroaryl, alkyl-CFs, or -Si(alkyl)3; preferably, R4 is -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably R4 is -OH or -NH2;wherein M is a metal ion;O,wherein A is H. NH2,NH2. or a targeting moiety:Owherein Ri is H, NH2, - NH, an antigen, an antibody, a therapeutic agent or a targeting moietv;wherein R2 is H, NH2,NH2, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

35. A method of an autolytic release of a metallodrug in a subject comprising:a) administering to the subject an effective amount of the compound of any one of claims 1- 16 or the composition of any one of claims 33-34 at 35-45°C, preferably at 37°C; and b) administering a metal ion to the subject; preferably, the metal ion is Gallium-67 (67Ga), Gallium-68 (68Ga), Copper-62 (62Cu), Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 (44Sc), Scandium -47 (47Sc). Scandium-43 (43Sc), Lanthanum- 132 (132La). Lanthanum-135 (13bLa), Yttrium-86 (8bY), Yttrium-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb),Terbium-152 (132Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb); more preferably, the metal is ion Gallium-67 (67Ga).

36. A method of an autolytic release of ametallodrug comprising administering to a subject an effective amount of tire metal complex of any one of claims 17-32 or the composition of any one of claims 33-34 at 35-45°C, preferably at 37°C.

37. The method of claim 36, wherein the autolytic release of the metallodrug occurred at a pH of 4.5- 8; preferably, at a pH of 5-6.5; more preferably, at a pH of 5.5-6.

38. A method of detecting cancer cells in a subject comprising administering an effective amount of the metal complex of any one of claims 17-32, or the composition of any one of claim 33-34 to the subject, and imaging the subject with a molecular imaging device to detect the metal complex or the composition in the subject; preferably, the cancer cells are prostate cancer cells; or the cancer cells have elevated levels of prostate-specific membrane antigen (PSMA).

39. A method of treating an inflammation in a subject comprising:(a) administering to the subject an effective amount of the compound of any one of claims 1-16 or the composition of any one of claim 33-34 at 35-45uC, preferably at 37°C; and (b) administering a metal ion to the subject; preferably, the metal ion is Gallium-67 (67Ga), Gallium-68 (6SGa), Copper-62 (62Cu). Copper-64 (64Cu), Copper-67 (67Cu), Scandium- 44 (^Sc), Scandium-47 (47Sc), Scandium-43 (43Sc), Lanthanum-132 (132La), Lanthanum-135 (135La), Yttrium-86 (86Y), Yttrium-90 (90Y), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (152Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb); more preferably, the metal is ion Gallium-67 (67Ga).

40. A method of imaging a cell in a subject comprising:a) administering to the subject an effective amount of the metal complex of any one of claims 17-32, or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34,wherein the metal complex specifically accumulates at the cell in the subject; b) detecting in the subject the location of the metal complex or the location of the composition; andc) obtaining an image of cell in the subject based on the location of the metal complex or the location of the composition in the subject;preferably, the cell is a cancer cell or tumor cell: more preferably, the cancer is lung cancer, breast cancer, prostate cancer, cervical cancer, pancreatic cancer, colon cancer, ovarian cancer, stomach cancer, esophagus cancer, skin cancer, heart cancer, liver cancer, bronchial cancer, testicular cancer, kidney cancer, bladder cancer, spleen, cancer, thymus cancer, thyroid cancer, brain cancer, or gall bladder cancer; orpreferably, the tumor is bone tumor, brain tumor, malignant soft tissue tumor, organ tumor, ovarian germ cell tumor, gland tumor, lymphatic tumor, or skin tumor.

41. A method of(a) detecting cancer cells in a subject comprising administering an effective amount of the metal complex of any one of claims 17-32, or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34 to the subject, and imaging the subject with amolecular imaging device to detect tire metal complex or composition in the subject, wherein the cancer cells are prostate cancer cells, and wherein the cancer cells have elevated levels of prostatespecific membrane antigen (PSMA);(b) detecting the presence of cancer cells in a subject, wherein the method comprises determining if an amount of the metal complex of any one of claims 17-32, or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34 is present in the subject at a period of time after administration of the metal complex or the composition to the subject, thereby detecting the presence of the cancer cells based on the amount of tire metal complex or the composition detennined to be present in the subject;(c) reducing the size of a tumor or of inhibiting proliferation of prostate cancer cells comprising contacting the tumor or cancer cells with the metal complex of any one of claims 17-32, or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34, so as to thereby reducing the size of the tumor or inhibit proliferation of the cancer cells;(d) detecting the presence of prostate cancer cells in a subject which comprises determining if an amount of the metal complex of any one of claims 17-32or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34 is present in the subject at a period of time after administration of the metal complex or composition to the subject, thereby detecting the presence of tire prostate cancer cells based on tire amount of the metal complex or composition detennined to be present in the subject; or(e) reducing the size of a prostate tumor or of inhibiting proliferation of prostate cancer cells comprising contacting the tumor or cancer cells with the metal complex of any one of claims 17-32, or a pharmaceutically acceptable salt thereof, or the composition of any one of claims 33-34, so as to thereby reducing the size of the tumor or inhibit proliferation of the cancer cells.

42. A process of producing a composition comprising:Y1wherein the process comprises chelate the compound of the following structure with a metal ionwherein Yi and Y2 are each independently, -H, alkyl -N-(CO2R4)2, alkyl-N-(alkyl-CO2R4)2, alkylheteroaryl, alkyl-CCkH, alkylaryl-CChH, alkylheteroaryl-CChH. alkyl-CO2R4. alkylaryl-NH-CChRj alkylaryl-CChR alkylhctcroaryl-COzR^ alkyl-OH, alkylaryl-OH. alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylai 1-CO2H)2, alkyl-N(alkylheteroaryl-CO2H)2, alkyl-Nlalkylaryl-CChl^h, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroaryl-OH)(alkyl-CC>2H), alkyl-P(0)(0H)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(0)(0H)2. andwherein each occurrence of R4 is independently, -H, -OH. -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl. alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFg, or -Si(alkyl)s; preferably, R4 is -OH, -NH2, -O-(Ci- Ce alkyl), or NH-(Ci-Ce alkyl), more preferably Rjis -OH or -NH2;wherein A is H, NH2,NHk or a targeting moiety; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

43. A process of producing a composition comprising:Peptide linker R.and *2wherein the process comprises chelate the compound of the following structure with a metal ionwherein Yi, Y2 are each independently, -H, alkyl-NXCCLR-ih, alkyl-NXalkyl-CC i alkylheteroaryl, alkyl-CCLH, alkylaryl-CCLH, alkylheteroaryl-COiH. alkyl-COiFtt. alkylaryl-NH-CCLRj alkylaryl-CCLRi, alkylheteroaryl-CC>2R4, alkyl-OH, alkylaryl-OH, alkylheteroaryl-OH, alkyl-N(alkylaryl)2, alkyl-N(alkylaryl-CO2H)2. alkyl -N alkylheteroaryl-CCLHh, alkyl-N(alkylaryl-CO2R4)2, alkyl-N(alkylheteroaryl-CO2R4)2, alkyl-N(alkylaryl-OH)2, alkyl -N(alkylheteroaryl-OH)2, alkyl-N(alkyl-CO2H)2, alkyl-N(alkylaryl-OH)(alkyl-CO2H), alkyl-N(alkylheteroar l-OH alkyl-CCLH), alkyl-P(O)(OH)2, alkylaryl-P(O)(OH)2or alkylheteroaryl- P(O)(OH)2, andwherein each occurrence of R+ is independently, -H, -OH, -NH2, halogen, alkyl, -O-alkyl, -NH-alkyl, -CHF2, -CF3, -OCHF2, -OCF3, amide, alkenyl, alkynyl, alkyl-aryl, alkylheteroaryl, aryl, heteroaryl, alkyl-CFs, or -Si(alkyl);,; preferably, Rus -OH, -NH2, -O-(Ci- Cg alkyl), or NH-(Ci-Cs alkyl), more preferably Riis -OH or -NH2;Owherein Ri is H. NH2. •NANI,2. an antigen, an antibody, a therapeutic agent or a targeting moiety;Owherein R2 is H, NH2, -ANNH -, an antigen, an antibody, a therapeutic agent or a solid support surface; andwherein the peptide linker comprises at least one amino acid directly linked to a carbonyl group, and wherein the first amino acid linked to the carbonyl group is either a serine or a glycine.

44. The process of any one of claims 42-43, wherein the metal ion is Gallium-67 (67Ga). Gallium-68 (68Ga), Copper-62 (62Cu), Copper-64 (64Cu), Copper-67 (67Cu), Scandium-44 ASc), Scandium-47 (47Sc), Scandium-43 (43Sc), Lanthanum-132 (132La), Lanthanum-135 (135La), Yttrium-86 (86Y), Yttnum-90 (9CY), Lutetium 177 (177Lu), Terbium -149 (149Tb), Terbium-152 (152Tb), Terbium-155 (155Tb) or Terbium-161 (161Tb); preferably, the metal is ion Gallium-67 (67Ga).

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