Tracer compounds and methods for preparing them

Abstract

Disclosed are tracer compounds, or pharma- ceutically acceptable salts or solvates thereof, the tracer compounds having a structure comprising a tetrazine moiety, a zwitterionic moiety, and a linker moiety, the linker moiety connecting the tetrazine moiety and the zwitterionic moiety to each other, the linker moiety being composed of a specific moiety S1-Y-S2 as disclosed herein.Further disclosed are adducts of the tracer compounds with trans-cyclooctene (TCO) derivatized targeting moieties, and methods for making the tracer compounds and the adducts.

Description

[Technical Field]

[0001] This disclosure generally relates to radiolabeled radiopharmaceuticals. This disclosure is not exclusive, but particularly relates to radiolabeled radiopharmaceuticals obtained by an inverse electron-demanded Diels-Alder cycloaddition (IEDDA) reaction between trans-cyclooctene and a tetrazine moiety. [Background technology]

[0002] This section provides useful background information without assuming that any of the technologies described herein represent the state of the art.

[0003] Bioorthogonal chemistry has demonstrated great potential in the synthesis of radiopharmaceuticals for diagnostic imaging. To date, the reverse electron-demanded Diels-Alder cycloaddition (IEDDA) between tetrazine and dienophile has shown the fastest reaction rate in bioorthogonal chemistry and is being used for the radiosynthesis of a variety of fluorine-18 labeled radiopharmaceuticals, from small molecules to large molecules such as peptides and antibody fragments. The IEDDA reaction is, 18 F, 68 Ga, 64 It is also used in pre-targeted PET imaging techniques that utilize radionuclides such as Cu. [Overview of the project]

[0004] The inventors have surprisingly found that highly modular tracer compounds can be obtained by synthesizing compounds containing a tetrazine moiety, a specific zwitterionic moiety, and a linker moiety between them, as described herein. Furthermore, an inverse electron-demanded Diels-Alder reaction (IEDDA) between trans-cyclooctene and the tetrazine moiety of the tracer compound can yield an adduct containing the tracer compound and a trans-cyclooctene (TCO) derivatization target moiety. The modularity of the linker moiety in the tracer compound enables the use of the adduct and tracer compound in the targeting of multiple diverse target entities in vivo and in vitro. Specific combinations of moieties contained in the tracer compound and adduct provide tracer compounds with good stability.

[0005] An object of this disclosure is to provide tracer compounds that exhibit high modularity with respect to targeting a number of different target entities in vivo and in vitro as part of an adduct. Another object of this disclosure is to provide tracer compounds that have the performance and / or stability to enable use in radiolabeling and radioimaging applications. Another object of this disclosure is to provide tracer compounds with improved properties when used to target target entities in vivo and in vitro. Yet another object of this disclosure is to provide adducts of tracer compounds and TCO-derivativeated target moieties that can be used to target entities in vivo and in vitro.

[0006] This application relates to the inventions defined in the attached independent claims and embodiments thereof disclosed below. The attached claims define the scope of protection. Methods, processes, products, or apparatus disclosed in the specification or drawings not described in the claims are not embodiments of the claimed invention but are provided as examples useful for understanding the claimed invention.

[0007] This specification describes tracer compounds and adducts of tracer compounds with trans-cyclooctene (TCO)-derivatized target moieties, which can be used, via radiolabeling, to target many diagnostic biomarkers both in vivo and in vitro, and can ultimately be detected by radioactive imaging methods. The inventors have surprisingly found that a tracer compound can be synthesized by a combination of a tetrazine moiety, a specific linker moiety, and an zwitterionic moiety, which has high modularity from the viewpoints of rapid synthesis and the ability of the target moiety to conjugate to the tracer compound via the TCO moiety, as shown in the following examples.

[0008] According to a first aspect, there is provided a tracer compound of formula (I), or a pharmaceutically acceptable salt or solvate thereof, [Chemical formula] (wherein, each R1 is independently hydrogen (H) or an alkyl substituent having the formula C <00,000, ,04>H <00,000, ,05>(wherein n is an integer selected from the range of 0 to 2); L is a linker moiety composed of S1-Y-S2, where: , Y is (-CH2-) <00,000, ,06>(wherein m is an integer selected from the range of 1 to 4), or Y is a polyethylene glycol linker -(PEG) <00,000, ,07>-(wherein (PEG) <00,000, ,08>comprises x repeating units of polyethylene oxide -CH2-CH2-O- groups, and x is an integer selected from the range of 1 to 20); and S1 is -(CH2) <00,000, ,09>-CO-NH-(CH2) <00,000, ,10>-, or S1 is -(CH2) <00,000, ,,, -NH-CO-(CH2) <00,000, ,12>(wherein each z is independently an integer selected from the range of 0 to 4); and S2 is -CH2- or S2 is -(CH2)f -CO-NH-(CH2) f - or S2 is -(CH2) f -NH-CO-(CH2) f -where each f is an integer independently selected from the range 0 to 4; and R2 is hydrogen (H) or a phenyl group substituent or formula C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0009] According to a second embodiment, an adduct of the tracer compound and the TCO derivatization target moiety according to the first embodiment, or a pharmaceutically acceptable salt or solvate thereof, is provided, obtained by an inverse electron-demanded Diels-Alder reaction (IEDDA) between the TCO moiety of the trans-cyclooctene (TCO) derivatization target moiety and the tetrazine moiety of the tracer compound.

[0010] According to a third aspect, an appendage of the second aspect is provided for use in radioimaging, preferably positron emission tomography, for the detection of target entities in a subject.

[0011] According to a fourth aspect, a method for producing the tracer compound of the first aspect is provided, the method being: a. A step of dissolving a starting material in a polar aprotic solvent, and reacting the starting material with 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane to provide an intermediate product; b. Dissolve the intermediate product in a polar aprotic solvent, and react the intermediate product with KHF2 in the presence of an acid such as HCl, water, and an organic solvent to provide a tracer compound. Includes, The starting material consists of a tetrazine moiety bonded to a tertiary amine (-N(CH3)2) via a linker moiety; here, The tetrazine portion consists of a 1,2,4,5-tetrazine ring, a phenyl ring bonded to C3 of the tetrazine ring, and R2 bonded to C6 of the tetrazine ring, where R2 is a hydrogen (H) or phenyl substituent or C2. S H 2S+1 One of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2); and The linker section consists of S1-Y-S2, where: Y is (-CH2-) m (wherein the formula, m is an integer selected from the range of 1 to 4) or Y is polyethylene glycol linker-(PEG) X -(in the formula, (PEG) X (where is a polyethylene oxide (CH2-CH2-O-) repeating unit, where x is an integer selected from 1 to 20); and S1 is -(CH2) Z -CO-NH-(CH2) Z - or S1 is -(CH2) Z -NH-CO-(CH2) Z -where each z is an integer independently selected from the range 0 to 4; and Is S2 -CH2- or is S2 -(CH2)? f -CO-NH-(CH2) f - or S2 is -(CH2) f -NH-CO-(CH2) f -where each f is an integer independently selected from the range 0 to 4.

[0012] According to the fifth aspect, a method is provided for producing an adduct of the second aspect or a pharmaceutically acceptable salt or solvate thereof, the method being: A step of providing a TCO-derivative target moiety; A step of providing a tracer compound according to a first embodiment; A step of reacting the tetrazine portion of the tracer compound with the TCO portion of the TCO derivatization target portion; and Additions to at least one 18Does it include a step of obtaining an adduct by radioactively labeling with F? Or the method is: A step of providing a TCO-derivative target moiety; A step of providing a tracer compound according to a first embodiment; The tracer compound of the first embodiment is at least one 18 The process of radioactively labeling with F; and The process includes a step of reacting the tetrazine portion of a radiolabeled tracer compound with the TCO portion of a TCO derivatization target to obtain an adduct.

[0013] According to a sixth aspect, the use of a tracer compound of the first aspect and / or an adduct of the second aspect is provided for the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct.

[0014] According to the seventh aspect, for the detection of a target entity in a subject by radioactive imaging 18 A kit for producing an F-labeled adduct is provided, the kit comprising at least one compartment containing a tracer compound of a first embodiment, at least one compartment containing at least one TCO derivatization target moiety, and for radiolabeling the tracer compound 18 At least one compartment including F, and optionally , inverse electron-demanded Diels-Alder reaction ( IEDDA ) for, as well as tracer compounds and / or adducts For radioactive labeling 、 It comprises an aqueous solvent and an organic solvent.

[0015] In a further embodiment, diagnostic and / or therapeutic use of a tracer compound of the first embodiment and / or an adduct of the second embodiment is provided in the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct.

[0016] In a further embodiment, a non-therapeutic use of the tracer compound of the first embodiment and / or the adduct of the second embodiment is provided in the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct. In a further embodiment, a non-diagnostic use of the tracer compound of the first embodiment and / or the adduct of the second embodiment is provided in the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct. In one embodiment, an example of non-diagnostic and / or non-therapeutic use is its use in the evaluation of a therapeutically targeted structure.

[0017] The tracer compounds of the present invention have the advantage of high modularity due to a modular linker portion, which in turn provides optimized conjugation with multiple different target entities. The tracer compounds of the first embodiment of the present invention have the advantage of low nonspecific tissue uptake, even when a TCO-derivative target portion is not conjugated to them. The tracer compounds of the first embodiment of the present invention have advantages in pre-targeted PET imaging.

[0018] The adducts of the second embodiment of the present invention have the advantage of enabling the rapid preparation of adducts that can be easily used at room temperature. The adducts of the second embodiment of the present invention have the advantage of being biocompatible for in vivo use. As shown in the examples provided below, the adducts of the second embodiment have the ability and specificity to enable visualization of target entities via specific binding of the target moiety of an IEDDA cyclization adduct product containing a radiolabeled tracer compound.

[0019] The adduct of the present invention in the second embodiment has the advantage of high target tissue-specific uptake and low non-specific tissue uptake. The radiolabeled adduct of the present invention in the second embodiment has the advantage of good metabolic stability and rapid clearance, mainly via the kidney. The adduct of the present invention in the second embodiment has the advantage of high modularity, and the pharmacokinetics of the adduct are ductile through modification of the structural components of the tracer compound.

[0020] The adduct of the present invention in a second embodiment has the advantage of having a high tumor-specific uptake rate, and the target portion of the adduct that is utilized targets biomolecules that suggest cancer growth. [Brief explanation of the drawing]

[0021] Several exemplary embodiments are described with reference to the accompanying drawings.

[0022] [Figure 1] The synthetic route and structural formula of the tracer compound AmBF3-Tz(4) according to an exemplary embodiment are shown. [Figure 2] The synthetic route and structural formula of the tracer compound AmBF3-PEG4-TZ(8) according to an exemplary embodiment are shown. [Figure 3] The synthetic route and structural formula of the tracer compound AmBF3-PEG9-Tz(12) according to an exemplary embodiment are shown. [Figure 4] The synthetic route and structural formula of trans-cyclooctenaldehyde (TCO-CHO) (15) and the structural formula of TCO-PEG3-aldehyde (16) according to exemplary embodiments are shown. [Figure 5] The synthetic route and structural formula of PSMA-trans-cyclooctene (PSMA-TCO) (18) according to exemplary embodiments are shown. [Figure 6] The synthetic route and structural formula of PSMA-tranexamic acid-TCO(24) according to an exemplary embodiment are shown. [Figure 7]This illustrates the reaction of AmBF3-Tz(4) to radiolabeling before IEDDA conjugation, resulting in 18F-labeled AmBF3-Tz([18F]4) according to an exemplary embodiment. [Figure 8a] An exemplary embodiment illustrates an alternative synthetic route for obtaining a radiolabeled adduct, which is an IEDDA cyclization product of the tracer compound AmBF3(4) and the TCO derivatization target moiety, where the target moiety is represented as a peptide. [Figure 8b] An exemplary embodiment illustrates an alternative synthetic route for obtaining a radiolabeled adduct, which is an IEDDA cyclization product of the tracer compound AmBF3(4) and the TCO derivatization target moiety, where the target moiety is represented as a peptide. [Figure 9] The graph shows the percentage of total radioactivity observed at different time points as free, cell membrane-bound, or internally distributed radioactivity after incubation of B16 / F10 melanoma cells with [18F]AmBF3-Tz([18F]4). Over 99% of the total radioactivity was present in the free fraction at each time point, suggesting low nonspecific binding of [18F]4 to the cell membrane. [Figure 10] The percentage of radioactivity in the intracellular compartment of AR42J cells from the total added radioactivity in the AR42J cell line is shown, and radioactivity was detected as a function of time, suggesting specific AR42J cell uptake of TOO-functionalized Tyr3-octreotide (TOC) coupled with [18F]AmBF3-Tz ([18F]4) to form [18F]AmBF3-Tyr3-octreotide ([18F]25) under baseline conditions (internal migration). Uptake under baseline conditions was inhibited by co-incubating cells with [18F]25 along with unmodified blocked octreotide (Blocked). [Figure 11] The images show additive PET / CT images of SCID mice 0-60 minutes after administration of [18F]AmBF3-Tz([18F]4). B.=bladder, GB=gallbladder, K.=kidney, L.=liver. [Figure 12a]The percentage of the injected dose per gram of tissue (%ID / g) quantifies the radioactivity in tissue 270±2 minutes after intravenous administration of [18F]AmBF3-Tz ([18F]4) in control SCID and C57BL / 6JRj mice (n=2-3 / strain), suggesting clearance and excretion of the radioactive tracer compound. [Figure 12b] The percentage of the injected dose per gram of tissue (%ID / g) quantifies radioactivity in urine and feces 270±2 minutes after intravenous administration of [18F]AmBF3-Tz ([18F]4) in control SCID and C57BL / 6JRj mice (n=2-3 / strain), suggesting clearance and excretion of the radioactive tracer compound. [Figure 13a] The standardized unloaded (SUV) values ​​measured in tissue 60 minutes after administration of [18F]AmBF3-Tz ([18F]4) in male SCID mice (n=1) are shown, suggesting the in vivo distribution and excretion of [18F]4. [Figure 13b] The standardized unloaded (SUV) values ​​measured in urine 60 minutes after administration of [18F]AmBF3-Tz ([18F]4) in male SCID mice (n=1) are shown, suggesting the in vivo distribution and excretion of [18F]4. [Figure 14] The percentage of injectable dose per gram of tissue (%ID / g) of [18F]25 measured in different tissues of Rj:NMRI-Foxn1 nu / nu mice (n=2-4) with AR42J tumors after intravenous administration of the radiolabeled adduct [18F]25, suggesting its in vivo distribution at various time points. [Figure 15] The images show additive PET / CT images of Rj:NMRI-Foxn1 nu / nu mice with AR42J tumors 20–80 minutes after administration of [18F]AmBF3-Tyr3-octreotide ([18F]25). Animals on the left were co-administered intravenously with unmodified blockade octreotide and [18F]25. Animals on the right were administered [18F]25 alone without blockade octreotide to allow visualization of subcutaneous AR42J tumors in the right shoulder. T = tumor. [Figure 16]The standardized uptake (SUV) measured in AR42J tumor tissue is shown as a function of time (minutes). Here, mice with AR42J tumors (n=2 / group) were administered either [18F]AmBF3-Tyr3-octreotide ([18F]25) alone (unblocked) or [18F]25 and blocked octreotide simultaneously (blocked). [Figure 17] The standardized uptake (SUV) values ​​measured in tissue, shown as a function of time (minutes), suggest radioactivity clearance after intravenous administration of [18F]AmBF3-Tyr3-octreotide ([18F]25) in tumor-bearing AR42J mice (n=1). [Figure 18] The images show the maximum intensity projections of PET / CT 15–90 minutes after infusion of [18F]AmBF3-tranexamic acid-PSMA ([18F]29). Animals on the right were administered 2-PMPA (blockade) and [18F]29 intravenously simultaneously. Animals on the left were administered [18F]29 alone without blockade 2-PMPA, allowing visualization of a subcutaneous C4-2 tumor in the left shoulder. T=tumor, G=gallbladder, K=kidney, U=bladder / urine. [Figure 19] The percentage of the injectable dose per gram of tissue (%ID / g) of [18F]29 measured in different tissues of SCID mice (n=3) with C4-2 tumors after intravenous administration of the radiolabeled adduct [18F]29, suggesting its distribution in the body 60 minutes after infusion. [Modes for carrying out the invention]

[0023] As used herein, the terms “tracer compound” or “tracer” mean a compound that can be tracked by a radiation detector. In embodiments, the tracer compound comprises one or more atoms replaced by radionuclides. In one embodiment, the tracer compound is a tracer compound according to a first embodiment.

[0024] As used herein, the term "IEDDA" refers to the inverse electron-demanded Diels-Alder reaction.

[0025] As used herein, the term “part” means a portion of a molecule that can be functionally or structurally identified in the structure of the molecule, such as a tracer compound or adduct as a whole. Therefore, parts can be named individually.

[0026] As used herein, the term “linker” or “linker portion” means a modular region connecting two adjacent portions within a tracer compound or adduct. In one embodiment, the linker portion means a linker portion according to a first embodiment that links the tetrazine portion and the zwitterionic portion of the tracer compound to each other. In one embodiment, S2 of the linker portion is bonded to N of the zwitterionic portion, and S1 of the linker portion is bonded to phenyl of the tetrazine portion of the tracer compound. In an alternative embodiment, “linker” or “linking portion” or “linker portion” means a linker portion in a TCO-derivative target portion that links the target portion and the TCO portion to each other.

[0027] As used herein, the term “tetrazine” means a six-membered aromatic tetrazine ring containing four nitrogen atoms. As used herein, the term tetrazine refers to the 1,2,4,5-tetrazine isomer.

[0028] As used herein, the term “tetrazine moiety” means a moiety containing a six-membered aromatic ring with four nitrogen atoms. The tetrazine structure in the tetrazine moiety is a 1,2,4,5-tetrazine isomer structure. The tetrazine moiety further contains a six-membered aromatic phenyl ring bonded to C3 of the tetrazine ring. The tetrazine moiety further contains R2 bonded to C6 of the tetrazine ring, where R2 is a hydrogen (H) or phenyl substituent or C S H 2S+1It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2). In one embodiment, the linker moiety L of the tracer compound according to formula (I) and the 1,2,4,5-tetrazine of the tetrazine moiety are bonded to the phenyl ring of the tetrazine moiety at the para position relative to each other according to formula (I).

[0029] As used herein, the term “zwitterion” refers to a molecule having at least two functional groups, and containing an equal number of positively and negatively charged functional groups. The total charge of a zwitterion molecule is zero. In one embodiment, the zwitterion is an organic trifluoroborate [ABF3] according to formula (I). - And here, A is [-CH2-N-(R1)2] + That is the case.

[0030] As used herein, the term “alkyl substituent” refers to a general (unspecified) alkane that, in relation to its chemical structure, is part of another molecule and lacks one hydrogen atom. The smallest “alkyl substituent” is a methyl group, with the formula CH3-.

[0031] As used herein, the term "polyethylene glycol linker (-(PEG) X -) means a module portion that connects two other adjacent portions within a tracer compound or adduct, where (PEG) X It contains x repeating units of polyethylene oxide-CH2-CH2-O- groups, where x is an integer. Linker (PEG) X The portion may be surrounded by separate linking portions, referred to herein as S1 and S2, which link the linker portion to the rest of the tracer compound or adduct.

[0032] As used herein, the term “integer” means a non-fractional integer that may be positive, negative, or zero.

[0033] As used herein, the term " 18"F" or "fluorine-18" refers to a fluorine radioactive isotope that decays primarily through positron emission.

[0034] As used herein, the term “adduct” refers to an addition product obtained by the addition of two or more distinct molecules, resulting in a single product. In one embodiment, the term “adduct” refers to an adduct of a tracer compound and a TCO derivatization target moiety.

[0035] As used herein, the term “trans-cyclooctene (TCO)” refers to the trans isomer of a cycloalkene having a chain of eight carbon atoms forming a cyclic hydrocarbon, where the two C=C single bonds on either side of the C=C double bond are located on opposite sides of the plane of the C=C double bond.

[0036] As used herein, the term “TCO moiety” refers to a TCO that is part of a molecule comprising at least one other moiety, such as a target moiety or a linking moiety, the at least one other moiety being linked to the TCO. As used herein, the term “TCO moiety” refers to the trans isomer of the cyclic TCO of the TCO derivatization target moiety prior to IEDDA conjugation.

[0037] As used herein, the term “TCO-derivativeized target moiety” means a target moiety derivatized with a trans-cyclooctene (TCO) moiety. In one embodiment, the TCO-derivativeized target moiety includes a bridging portion between the target moiety and the TCO moiety.

[0038] As used herein, the term “tertiary amine” refers to a compound comprising carbon, hydrogen, and nitrogen atoms, where three organic substituents are formed by the bonding of three carbons to the nitrogen of the amine. In one embodiment, the tertiary amine is N-(K)3, where each K is independently alkyl or aryl. In one embodiment, the tertiary amine is (-N(CH3)2), where the nitrogen is bonded to a third carbon that is part of another part of the compound, of which the tertiary amine is part. In one embodiment, the tertiary amine is (-N(CH3)2), where the nitrogen is bonded to a third carbon that is part of the linker moiety of a tracer compound.

[0039] As used herein, the term “target moiety” means a peptide, antibody, antibody fragment, or nanoparticle that targets a desired target entity through its arrangement and / or 3D (surface) structure. In one embodiment, the target moiety is part of a larger structure or compound that can guide the compound to or position it in the same location as the respective target entity, both in vitro and in vivo.

[0040] As used herein, the term “target entity” refers to an array and / or 3D (surface) structure that is targeted in vitro and / or in vivo by the adduct, i.e., the target moiety, and recognized via its array and / or 3D (surface) structure, thereby resulting in the target moiety and the target entity being located in the same place. An example of a target entity is a biomolecule.

[0041] As used herein, “peptide” is an amino acid sequence comprising multiple consecutive polymerized amino acid residues. For the purposes of this disclosure, a peptide is a molecule containing up to 50 amino acid residues. A peptide may include modified amino acid residues, naturally occurring amino acid residues not encoded by codons, and unnaturally occurring amino acid residues.

[0042] As used herein, the term “antibody” means an immunoglobulin protein that recognizes and binds to an antigen epitope via its fragment antigen-binding (Fab) variable region.

[0043] As used herein, the term “radioimaging” refers to a method of utilizing radioactive materials to visualize and measure the physiological structure and activity within macroscopic or microscopic organisms.

[0044] As used herein, the term “positron emission tomography (PET)” means an imaging technique that uses radioactive tracers to visualize and measure physiological structures and activities, utilizing medical scintigraphy techniques and gamma-ray detection by a gamma camera. As used herein, the term “positron emission tomography (PET)” also includes positron emission tomography-computed tomography (PET-CT), which further integrates an X-ray computed tomography (CT) scanner for acquiring sequential images, thereby forming a combined single superimposed (simultaneous positional) image.

[0045] As used herein, the term “pre-targeted PET imaging” refers to a two-step PET labeling process in which a target entity is first targeted and conjugated to a target moiety without a tracer compound being attached thereto. This is followed by a second step in which a radiolabeled tracer compound is delivered in contact with the target moiety and conjugated to the target moiety. In one embodiment, the target moiety is a TCO-derivativeized target moiety, and the conjugation of the TCO-derivativeized target moiety to the tracer compound occurs via IEDDA conjugation.

[0046] As used herein, the term “target tissue-specific uptake” means the uptake or binding of a tracer compound or adduct to a target tissue of interest via the binding of the target portion of the adduct to a specific target entity within the target tissue.

[0047] As used herein, the term “tumor-specific uptake” means the uptake or binding of a tracer compound or adduct to a target tissue of interest via the binding of the target portion of the adduct to a target entity within the target tissue, where the target tissue is cancerous tissue.

[0048] As used herein, the term “comprising” includes the broader meanings of “including,” “containing,” and “comprehending,” as well as the narrower expressions “consisting of” and “consisting only of.”

[0049] The term "fluorination" refers to a chemical reaction in which fluorine is introduced into a compound. In one embodiment, fluorine is the stable isotope fluorine-19( 19 F) In another embodiment, fluorine is a radioactive isotope 18 It is F.

[0050] As used herein, the term “organotrifluoroborate” refers to the general molecular formula [ABF3] - This refers to organoboron compounds that possess [a specific characteristic]. In the general formula for organotrifluoroborate, "A" can be a positively charged functional group A+, which makes the organotrifluoroborate moiety a zwitterion.

[0051] As used herein, the term "[ 18 "F[trifluoroborate]" means organic trifluoroborate, where at least one of three fluoride atoms [F] is 18 It can be replaced with an F-fluoride isotope.

[0052] As used herein, the term “biomolecule” means any molecule, analogue, or derivative thereof of medical, physiological, or scientific importance that may or may not be compatible with a biological system or possess biological activity.

[0053] As used herein, the term “antibody fragment” means a piece of the entire antibody molecule, such as the antigen-binding fragment (Fab) of the antibody molecule or the crystallizable fragment (Fc, tail region) of the antibody molecule.

[0054] As used herein, the term nanoparticle means any shape of material having dimensions between 1 and 300 nanometers (nm) in diameter. Examples of nanoparticles include organic nanocrystals, inorganic nanocrystals, or liposomes.

[0055] As used herein, -(CH2)0- means that CH2 is not present at the indicated position, -(CH2)1- means -CH2-, -(CH2)2- means -CH2-CH2-, -(CH2)3- means -CH2-CH2-CH2-, and -(CH2)4- means -CH2-CH2-CH2-CH2-.

[0056] As used herein, the term "Tyr 3 "Octreotide" means octapeptide, that is, an oligopeptide having 8 amino acids, where the phenylalanine at the 3rd position of octreotide is substituted with tyrosine. 3 - Both octreotides can pharmacologically mimic natural somatostatin and can bind to somatostatin receptors that are overexpressed in neuroendocrine tumors. Octreotides or Tyr 3 - Octreotide can be used as a target region or a model of the target region for the somatostatin receptor.

[0057] As used herein, the term “PSMA” means a type II membrane glycoprotein that is overexpressed in prostate cancer and is a prostate-specific membrane antigen. In relation to compounds 28 and 29 disclosed herein, the term “PSMA” means a PSMA target moiety that can function as a ligand for binding to the prostate-specific membrane antigen (PSMA). Thereafter, compounds 28 and 29 include a target moiety or a model of a target moiety for the prostate-specific membrane antigen.

[0058] As used herein, the term "tautomer" refers to any of at least two structural isomers of a compound that can coexist and are readily exchangeable by the migration of atoms or groups within the molecule.

[0059] As used herein, the term "non-therapeutic use" refers to a use that does not aim at any therapeutic aspect of disease management. In one embodiment, the term "non-therapeutic use" can refer to a use for diagnostic purposes. As used herein, the term "non-diagnostic use" refers to a use that does not aim at the diagnosis of a disease.

[0060] In one embodiment, the tracer compound includes a zwitterionic moiety, a linker moiety, and a tetrazine moiety. In certain other embodiments, the tracer compound also includes other moieties or side chain groups. In one embodiment, the linker moiety is positioned between the zwitterionic moiety and the tetrazine moiety.

[0061] In one embodiment, the zwitterionic moiety of the tracer compound includes an organic trifluoroborate. The organic trifluoroborate includes a (BF3) + moiety bonded to a positively ( - ) charged (cationic) group. More specifically, the (BF3) - group is bonded to a positively ( + ) charged (cationic) group (N(R1)2) + via -CH2.

[0062] In one embodiment, each R1 of the tracer compound is independently of the formula C n H 2n+1It is an alkyl substituent having the formula (wherein n is an integer selected from 0 to 2). In one embodiment, each R1 is independently an alkyl substituent having a carbon chain length of C2 or less. In one embodiment, each R1 of the tracer compound is independently an alkyl substituent having the formula C1H3. In one embodiment, each R1 of the tracer compound is independently an alkyl substituent having the formula C2H5. In one embodiment, each R1 is independently hydrogen (H). In one embodiment, each R1 is independently a methyl group. In one embodiment, each R1 is independently an ethyl group.

[0063] In one embodiment, each alkyl substituent R1 individually enables nucleophilic attack on the carbon between nitrogen (N) and boron (B) within the zwitterionic moiety. In one embodiment, each alkyl substituent R1 is a non-interfering group with respect to the fluorination of boron (B). Non-interference in this context means that R1 does not sufficiently or substantially prevent the fluorination of boron (B).

[0064] In one embodiment, the linker portion is composed of the unit S1-Y-S2, where Y represents the core unit structure of the linker, and S1 and S2 represent the chains on both sides of the core unit Y, with the linker portion on the S1 side being bonded to the tetrazine portion and the linker portion on the S2 side being bonded to the zwitterionic portion.

[0065] In one embodiment, tracer compound Y is (-CH2-) m (wherein m is 1, 2, 3, or 4). In one embodiment, m is an integer less than 5.

[0066] In one embodiment, Y in the linker portion is (-CH2-) m (In the formula, m is an integer selected from the range of 1 to 4), and S1 is -(CH2) Z -CO-NH-(CH2) Z -(wherein each z is an integer independently selected from 0 to 4), and S2 is -CH2, and each R1 of the tracer compound is independently C n H 2n+1(wherein n is an integer selected from the range of 0 to 2) is an alkyl substituent or hydrogen (H), and R2 of the tracer compound is hydrogen (H) or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0067] In one embodiment, Y in the linker portion is (-CH2-) m (In the formula, m is an integer selected from the range of 1 to 4), and S1 is -(CH2) Z -CO-NH-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -CO-NH-(CH2) f - (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0068] In one embodiment, Y in the linker portion is (-CH2-) m (In the formula, m is an integer selected from the range of 1 to 4), and S1 is -(CH2) Z -CO-NH-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -NH-CO-(CH2) f - (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1an alkyl substituent having (where n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or a formula C S H 2S+1 any one of alkyl substituents having (where s is an integer selected from the range of 0 to 2).

[0069] In one embodiment, Y of the linker moiety is (-CH2-) m (where m is an integer selected from the range of 1 to 4), S1 is -(CH2) Z -NH-CO-(CH2) Z -(where each z is independently an integer selected from the range of 0 to 4), and S2 is -CH2-, and each R1 of the tracer compound is independently H or a formula C n H 2n+1 an alkyl substituent having (where n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or a formula C S H 2S+1 any one of alkyl substituents having (where s is an integer selected from the range of 0 to 2).

[0070] In one embodiment, Y of the linker moiety is (-CH2-) m (where m is an integer selected from the range of 1 to 4), S1 is -(CH2) Z -NH-CO-(CH2) Z -(where each z is independently an integer selected from the range of 0 to 4), and S2 is -(CH2) f -CO-NH-(CH2) f -(where each f is independently an integer selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or a formula C n H 2n+1 an alkyl substituent having (where n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or a formula C S H 2S+1It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0071] In one embodiment, Y in the linker portion is (-CH2-) m (In the formula, m is an integer selected from the range of 1 to 4), and S1 is -(CH2) Z -NH-CO-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -NH-CO-(CH2) f - (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0072] In one embodiment, Y in the linker portion is (-CH2-) m(wherein m is an integer selected from 1 to 4) and S1 is -(CH2)1-CO-NH-(CH2)0- and S2 is -CH2. In one embodiment, Y is (-CH2-)1, S1 is -(CH2)1-CO-NH-(CH2)0- and S2 is -CH2. In one embodiment, Y is (-CH2-)2, S1 is -(CH2)1-CO-NH-(CH2)0- and S2 is -CH2-. In one embodiment, Y is (-CH2-)3, S1 is -(CH2)1-CO-NH-(CH2)0- and S2 is -CH2-. In one embodiment, Y is (-CH2-)4, S1 is -(CH2)1-CO-NH-(CH2)0- and S2 is -CH2-. In one embodiment, Y in the linker portion is (-CH2-)1, S1 is -(CH2)1-CO-NH-(CH2)0-, S2 is -CH2, both R1 are independently CH3, and R2 is H.

[0073] In one embodiment, Y in the linker portion is (-CH2-) m (wherein m is an integer selected from 1 to 4) and S1 is -(CH2)1-NH-CO-(CH2)0- and S2 is -CH2. In one embodiment, Y is (-CH2-)1, S1 is -(CH2)1-NH-CO-(CH2)0- and S2 is -CH2. In one embodiment, Y is (-CH2-)2, S1 is -(CH2)1-NH-CO-(CH2)0- and S2 is -CH2-. In one embodiment, Y is (-CH2-)3, S1 is -(CH2)1-NH-CO-(CH2)0- and S2 is -CH2-. In one embodiment, Y is (-CH2-)4, S1 is -(CH2)1-NH-CO-(CH2)0- and S2 is -CH2-.

[0074] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -CO-NH-(CH2) Z-(wherein each z is an integer independently selected from 0 to 4), and S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0075] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -CO-NH-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -CO-NH-(CH2) f (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0076] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -CO-NH-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -NH-CO-(CH2) f(wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0077] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -NH-CO-(CH2) Z -(wherein each z is an integer independently selected from 0 to 4), and S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0078] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -NH-CO-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -CO-NH-(CH2) f (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0079] In one embodiment, Y in the linker portion is -(PEG) X -(where x is an integer selected from the range 1 to 20) and S1 is -(CH2) Z -NH-CO-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4) and S2 is -(CH2) f -NH-CO-(CH2) f (wherein each f is an integer independently selected from the range of 0 to 4), and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0080] In one embodiment, a tracer compound according to formula (I), or a pharmaceutically acceptable salt or solvate thereof, is provided, where: each R1 is independently hydrogen (H) or C n H 2n+1 (wherein n is an integer selected from 0 to 2) is an alkyl substituent; L is a linker moiety composed of S1-Y-S2, where: Y is (-CH2-) m (wherein the formula, m is an integer selected from the range of 1 to 4) or Y is polyethylene glycol linker-(PEG) X -(in the formula, (PEG) Xcontains x repeating units of the polyethylene oxide -CH2-CH2-O- group, where x is an integer selected from the range of 1 to 20); and S1 is -CH2-NH-CO-(CH2) Z -, or -CH2-CO-NH-(CH2) Z -(where each z is an integer independently selected from the range of 0 to 4); and S2 is -(CH2) f , or -(CH2) f -CO-NH-CH2-CH2-, or -(CH2) f -NH-CO-CH2-CH2- (where each f is an integer independently selected from the range of 0 to 4); and R2 is hydrogen (H) or a phenyl substituent or an alkyl substituent having the formula C S H 2S+1 (where s is an integer selected from the range of 0 to 2).

[0081] In one embodiment, there is provided a tracer compound according to formula (I) or a pharmaceutically acceptable salt or solvate thereof, wherein: Each R1 is independently hydrogen (H) or an alkyl substituent having the formula C n H 2n+1 (where n is an integer selected from the range of 0 to 2); and L is a linker moiety composed of S1-Y-S2, where: Y is (-CH2-) m (where m is an integer selected from the range of 1 to 4), S1 is -CH2-CO-NH-, or -CH2-NH-CO-, and S2 is -CH2; or, Y is a polyethylene glycol linker -(PEG) X -(where (PEG) X contains x repeating units of the polyethylene oxide -CH2-CH2-O- group, where x is an integer selected from the range of 1 to 20); and S1 is -CH2-NH-CO-(CH2) Z-, or -CH2-CO-NH-(CH2) Z -(wherein each z is an integer independently selected from the range 0 to 4); and S2 is -(CH2) f -CO-NH-CH2-CH2- or -(CH2) f -NH-CO-CH2-CH2-(wherein each f is an integer independently selected from 0 to 4); and R2 is hydrogen (H) or a phenyl substituent or formula C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0082] In one embodiment, Y is polyethylene glycol linker-(PEG) X -(in the formula, (PEG) X (The tracer compound is a polyethylene oxide (-CH2-CH2-O- group) comprising x repeating units, where x is an integer selected from the range of 1 to 20). In one embodiment, the tracer compound is -(PEG) X In -, x is an integer selected from the range of 1 to 15 or the range of 1 to 10. In one embodiment, -(PEG) X In -, x is an integer selected from the range of 1 to 9, or from the range of 1 to 8, or from the range of 1 to 7, or from the range of 1 to 6, or from the range of 1 to 5, or from the range of 1 to 4, or from the range of 1 to 3, or from the range of 1 to 2, or x is 1. In one embodiment, the tracer compound -(PEG) X -x in - is 4 or 9. In one embodiment, the tracer compound -(PEG) X In -, x is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0083] In one embodiment, Y is (-CH2-) m(wherein m is an integer selected from 1 to 4), S1 is -CH2-CO-NH- and S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0084] In one embodiment, Y is (-CH2-) m (wherein m is an integer selected from 1 to 4), S1 is -CH2-NH-CO- and S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent having (wherein n is an integer selected from the range of 0 to 2), and R2 of the tracer compound is H or a phenyl substituent or C S H 2S+1 It is one of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2).

[0085] In one embodiment, Y is (-CH2-)1, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 is independently H or formula C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2), and R2 is a phenyl substituent.

[0086] In one embodiment, Y is (-CH2-)1, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 is independently H or formula C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2) and R2 is H.

[0087] In one embodiment, Y is (-CH2-)1, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 is independently H or formula C n H 2n+1 The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C1H3.

[0088] In one embodiment, Y is (-CH2-)1, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 is independently H or formula C n H 2n+1 The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C2H5.

[0089] In one embodiment, Y is (-CH2-)2, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2), and R2 is a phenyl substituent.

[0090] In one embodiment, Y is (-CH2-)2, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2) and R2 is H.

[0091] In one embodiment, Y is (-CH2-)2, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C1H3.

[0092] In one embodiment, Y is (-CH2-)2, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 R2 is an alkyl substituent having the formula C2H5, where n is an integer selected from 0 to 2.

[0093] In one embodiment, Y is (-CH2-)3, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2), and R2 is a phenyl substituent.

[0094] In one embodiment, Y is (-CH2-)3, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2) and R2 is H.

[0095] In one embodiment, Y is (-CH2-)3, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C1H3.

[0096] In one embodiment, Y is (-CH2-)3, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C2H5.

[0097] In one embodiment, Y is (-CH2-)4, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2), and R2 is a phenyl substituent.

[0098] In one embodiment, Y is (-CH2-)4, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has (wherein n is an integer selected from 0 to 2) and R2 is H.

[0099] In one embodiment, Y is (-CH2-)4, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1 The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C1H3.

[0100] In one embodiment, Y is (-CH2-)4, S1 is -CH2-CO-NH- or -CH2-NH-CO-, S2 is -CH2-, and each R1 of the tracer compound is independently H or C n H 2n+1The alkyl substituent has the formula (wherein n is an integer selected from 0 to 2), and R2 is an alkyl substituent having the formula C2H5.

[0101] In one embodiment, each R1 of the tracer compound is independently C1H3, Y is (-CH2-)1, S1 is -CH2-CO-NH-, S2 is -CH2-, and R2 is H.

[0102] In one embodiment, Y is -(PEG) X -, where S1 is -CH2-NH-CO-(CH2)0- and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)3-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)0-CO-NH-CH2-CH2-.

[0103] In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)0- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X- and S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)1-CO-NH-CH2-CH2-.

[0104] In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)0- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0105] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X- and S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)3-CO-NH-CH2-CH2-.

[0106] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, where S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)4-CO-NH-CH2-CH2-.

[0107] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X- and S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)3-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)0-NH-CO-CH2-CH2-.

[0108] In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)0- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)1-NH-CO-CH2-CH2-.

[0109] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X-, and S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0110] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, where S1 is -CH2-NH-CO-(CH2)2- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)3-, and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)3-NH-CO-CH2-CH2-.

[0111] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-NH-CO-(CH2)1- and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X-, and S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, where S1 is -CH2-NH-CO-(CH2)3- and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-NH-CO-(CH2)4- and S2 is -(CH2)4-NH-CO-CH2-CH2-.

[0112] In one embodiment, Y is -(PEG) X -, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-CO-NH-CH2-CH2. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)0-CO-NH-CH2-CH2. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)2- and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)0-CO-NH-CH2-CH2-.

[0113] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)1-CO-NH-CH2-CH2. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X- and S1 is -CH2-CO-NH-(CH2)2- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)1-CO-NH-CH2-CH2-.

[0114] In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)0- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0115] In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)0- and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X-, and S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)3-, and S2 is -(CH2)3-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)3-CO-NH-CH2-CH2-.

[0116] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)4-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)4-CO-NH-CH2-CH2-.

[0117] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X- and S1 is -CH2-CO-NH-(CH2)2- and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)3-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)0-NH-CO-CH2-CH2-.

[0118] In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)0- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)2- and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)3-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)1-NH-CO-CH2-CH2-.

[0119] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X-, and S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0120] In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)0- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)2- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)3- and S2 is -(CH2)3-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)3-NH-CO-CH2-CH2-.

[0121] In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X - and S1 is -CH2-CO-NH-(CH2)1- and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X-, and S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -, and S1 is -CH2-CO-NH-(CH2)3-, and S2 is -(CH2)4-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG) X -S1 is -CH2-CO-NH-(CH2)4- and S2 is -(CH2)4-NH-CO-CH2-CH2-.

[0122] In one embodiment, Y is polyethylene glycol linker-(PEG) X -and here, (PEG) X It contains four repeating units of polyethylene oxide -CH2-CH2-O- group, and S1 is -CH2-NH-CO-(CH2) Z - and S2 is -(CH2) f The molecule is -CO-NH-CH2-CH2-, where z and f are independently either 0 or 2.

[0123] In one embodiment, Y is polyethylene glycol linker-(PEG) X -and here, (PEG) X It contains four repeating units of polyethylene oxide -CH2-CH2-O- group, and S1 is -CH2-NH-CO-(CH2) Z - and S2 is -(CH2) f The molecule is -NH-CO-CH2-CH2-, where z and f are independently either 0 or 2.

[0124] In one embodiment, each R1 of the tracer compound is independently a methyl group, Y is a polyethylene glycol linker-(PEG)4- containing four repeating units of polyethylene oxide-CH2-CH2-O- groups, S1 is -CH2-NH-CO-(CH2)O-, S2 is -(CH2)2-CO-NH-CH2-CH2-, and R2 is H.

[0125] In one embodiment, each R1 of the tracer compound is independently a methyl group, Y is a polyethylene glycol linker-(PEG)4- containing four repeating units of polyethylene oxide-CH2-CH2-O- groups, S1 is -CH2-NH-CO-(CH2)O-, S2 is -(CH2)2-NH-CO-CH2-CH2-, and R2 is H.

[0126] In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0127] In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0128] In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0129] In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)4-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0130] In one embodiment, Y is polyethylene glycol linker-(PEG) X -and here, (PEG) X It contains nine repeating units of polyethylene oxide -CH2-CH2-O- group, and S1 is -CH2-NH-CO-(CH2) Z - and S2 is -(CH2) f The molecule is -CO-NH-CH2-CH2-, where z and f are independently either 0 or 2.

[0131] In one embodiment, Y is polyethylene glycol linker-(PEG) X -and here, (PEG) X It contains nine repeating units of polyethylene oxide -CH2-CH2-O- group, and S1 is -CH2-NH-CO-(CH2) Z - and S2 is -(CH2) f The molecule is -NH-CO-CH2-CH2-, where z and f are independently either 0 or 2.

[0132] In one embodiment, each R1 of the tracer compound is independently a methyl group, Y is a polyethylene glycol linker-(PEG)9- containing nine repeating units of polyethylene oxide-CH2-CH2-O- groups, S1 is -CH2-NH-CO-(CH2)O-, S2 is -(CH2)2-CO-NO-CH2-CH2-, and R2 is H.

[0133] In one embodiment, each R1 of the tracer compound is independently a methyl group, Y is a polyethylene glycol linker-(PEG)9- containing nine repeating units of polyethylene oxide-CH2-CH2-O- groups, S1 is -CH2-NH-CO-(CH2)O-, S2 is -(CH2)2-NH-CO-CH2-CH2-, and R2 is H.

[0134] In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0135] In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)1-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-NH-CO-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0136] In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)2-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)0-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)1-CO-NH-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-CO-NH-CH2-CH2-.

[0137] In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)0-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)1-, and S2 is -(CH2)2-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)0-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)1-NH-CO-CH2-CH2-. In one embodiment, Y is -(PEG)9-, S1 is -CH2-CO-NH-(CH2)2-, and S2 is -(CH2)2-NH-CO-CH2-CH2-.

[0138] In one embodiment, R2 of the tetrazine moiety of the tracer compound is a phenyl substituent. In one embodiment, R2 of the tetrazine moiety of the tracer compound is a phenyl substituent. n H 2n+1The alkyl substituent is having the formula C1H3, where n is an integer selected from 0 to 2. In one embodiment, R2 of the tetrazine moiety of the tracer compound is an alkyl substituent having the formula C1H3. In one embodiment, R2 of the tetrazine moiety of the tracer compound is an alkyl substituent having the formula C2H5. In one embodiment, R2 of the tetrazine moiety of the tracer compound is hydrogen (H).

[0139] In one embodiment, the tetrazine moiety of the tracer compound containing the R2 substituent is 3-phenyl-1,2,4,5-tetrazine. In one embodiment, the tetrazine moiety of the tracer compound containing the R2 substituent is 3-phenyl-6-methyl-1,2,4,5-tetrazine. In one embodiment, the tetrazine moiety of the tracer compound containing the R2 substituent is 3-phenyl-6-ethyl-1,2,4,5-tetrazine. In one embodiment, the tetrazine moiety of the tracer compound containing the R2 substituent is 3-phenyl-6-phenyl-1,2,4,5-tetrazine.

[0140] In one embodiment, substituent R2 is a non-interfering group with respect to the reactivity of IEDDA conjugation between the tracer compound and the TCO derivatization target moiety. Non-interference in this context means that R2 does not sufficiently or substantially prevent IEDDA conjugation.

[0141] In one embodiment, the tracer compound (BF3) - At least one F in the part is 18 F is used in one embodiment as a tracer compound (BF3). - One F in the part is 18 F is one of the remaining two. 19 It is F.

[0142] In one embodiment, the adduct is obtained by an inverse electron-demanded Diels-Alder reaction (IEDDA) between a trans-cyclooctene derivatization target moiety and a tetrazine moiety of a tracer compound.

[0143] In one embodiment, the tetrazine ring of the tetrazine moiety of the tracer compound is chemically bonded to the TCO moiety of the TCO derivatization target moiety in the adduct.

[0144] In one embodiment, the target moiety of the adduct is a protein, peptide, antibody, antibody fragment, or nanoparticle. The target moiety of the adduct targets specific biomolecules in vitro and in vivo and is conjugated to them through its sequence and / or 3D (surface) structure.

[0145] In one embodiment, the adduct (BF3) - At least one F in the part is 18 F is the adduct (BF3). In one embodiment, the adduct is (BF3). - One F in the part is 18 F is one of the remaining two. 19 It is F.

[0146] In one embodiment, the TCO portion of the TCO derivatized target moiety is directly bound to the target moiety. In certain other embodiments, the TCO portion of the TCO derivatized target moiety is indirectly bound to the target moiety via a linking portion such as a PEGX chain or a polylysine chain. In one embodiment, the polylysine chain is an α-polylysine chain. In one embodiment, the polylysine chain is an ε-polylysine chain. In one embodiment, the polylysine chain is a poly-I-lysine chain.

[0147] In one embodiment, the adduct or its pharmaceutically acceptable salt or solvate has a structure according to formula (II): [ka] In the formula, each R1 is independently hydrogen (H) or C n H 2n+1 An alkyl substituent having (wherein n is an integer selected from 0 to 2); and L is the linker section consisting of S1-Y-S2, where: Y is (-CH2-) m(wherein the formula, m is an integer selected from the range of 1 to 4) or Y is polyethylene glycol linker-(PEG) X -(in the formula, (PEG) X (where is a polyethylene oxide (CH2-CH2-O-) repeating unit, where x is an integer selected from 1 to 20); and S1 is -(CH2) Z -CO-NH-(CH2) Z Either S1 is -(CH2) Z -NH-CO-(CH2) Z -where each z is an integer independently selected from the range 0 to 4; and Is S2 -CH2- or is S2 -(CH2)? f -CO-NH-(CH2) f Either S2 is -(CH2) f -NH-CO-(CH2) f -where each f is an integer independently selected from 0 to 4; and R2 is hydrogen (H) or a phenyl substituent or formula C S H 2S+1 One of the alkyl substituents having (wherein s is an integer selected from the range of 0 to 2), and T includes the target portion of the adduct and optionally a connecting portion, where the connecting portion is (PEG) X - It is a chain or polylysine chain.

[0148] In one embodiment, the adduct is an IEDDA cyclization addition product of the TCO moiety of the TCO derivatization target moiety and the tetrazine ring of the tracer compound, and has a structure according to formula (II).

[0149] In one embodiment, in formula (II), the bases R1, R2, and L have the same meanings as defined herein for formula (I).

[0150] In one embodiment, the TCO derivatized target moiety includes a trans-cyclooctene moiety and a target moiety. In one embodiment, the TCO derivatized target moiety includes other moieties or side chain groups / side chains in addition to the trans-cyclooctene moiety and the target moiety. In one embodiment, one or more linking moieties are positioned between the TCO moiety and the target moiety, thereby linking the TCO moiety and the target moiety to each other.

[0151] In one embodiment, the linking portion between the TCO portion and the target portion is a polyethylene glycol linker containing repeating units of polyethylene oxide-CH2-CH2-O- groups. In one embodiment, the TCO derivatization target portion is TCO-(PEG) X -Contains an aldehyde, where x is an integer selected from 0 to 10. In one embodiment, the TCO derivatization target moiety contains TCO-(PEG)0-aldehyde. In one embodiment, the TCO derivatization target moiety contains TCO-(PEG)3-aldehyde. In one embodiment, the TCO derivatization target moiety contains TCO-(PEG)4-aldehyde. In one embodiment, the TCO derivatization target moiety contains TCO-(PEG)7-aldehyde.

[0152] In one embodiment, the TCO derivatization target moiety is TCO-(PEG) X The TCO-derivative target portion includes a target portion, where x is an integer selected from 0 to 10. In one embodiment, the TCO-derivative target portion includes a TCO-(PEG)0 target portion. In one embodiment, the TCO-derivative target portion includes a TCO-(PEG)4 target portion. In one embodiment, the TCO-derivative target portion includes a TCO-(PEG)7 target portion.

[0153] In one embodiment, the TCO derivatization target portion consists of a TCO portion and a Tyr portion as the target portion. 3 -Contains octreotide (TOC). In one embodiment, the TCO-derivative target moiety is TCO-(PEG) X-Includes TOC, where x is an integer selected from 0 to 10. In one embodiment, the TCO derivatization target moiety includes TCO-(PEG)4-TOC. In one embodiment, the TCO derivatization target moiety includes TCO-(PEG)7-TOC. In one embodiment, the TCO derivatization target moiety includes -(PEG) X The linking portion has the advantage of reducing the lipophilicity of the construct resulting from the TCO portion and the IEDDA cyclization product (Tz+TCO). In one embodiment, a polyethylene glycol linker-(PEG) is used between the TCO portion and the target portion. X - The linking portion is beneficial for regulating the pharmacokinetic and metabolic stability of the final adduct. In one embodiment, the linking portion between the TCO portion and the target portion is a polylysine linker, which is a biocompatible and biodegradable linker. In one embodiment, the polylysine binding portion between the TCO portion and the target portion is also beneficial for regulating the pharmacokinetic and metabolic stability of the final adduct.

[0154] In one embodiment, the structure and length of the linker portion (L) of the tracer compound are optimized to ensure optimal pharmacokinetics after coupling of the radiolabeled adduct with a specific target entity. The optimal structure and length of the linker portion of the tracer compound allows the adduct of the tracer compound and the TCO-derivativeized target moiety to obtain an optimal target-specific configuration once coupled, enabling specific binding of the target moiety to the target entity. Therefore, the modular structure and length of the linker portion of the tracer compound promote a high target-to-nontarget uptake ratio of the adduct in cells and tissues, both in vitro and in vivo. In one embodiment, the modular structure and length of the linker portion of the tracer compound enable PET imaging with a good signal-to-noise ratio.

[0155] In one embodiment, clearance of the tracer compound or adduct occurs primarily via the kidney. In one embodiment, the linker portion or adduct is directed almost entirely towards renal excretion in vivo.

[0156] In one embodiment, a method for producing a tracer compound is disclosed, where the linker portion of the starting material is composed of S1-Y-S2, where: Y is (-CH2-) m (wherein m is an integer selected from 1 to 4), S1 is -CH2-CO-NH- or -CH2-NH-CO-, and S2 is -CH2-; or, Y is polyethylene glycol linker (PEG). X -(in the formula, (PEG) X (It contains x repeating units of polyethylene oxide-CH2-CH2-O- groups, where x is an integer selected from the range of 1 to 20.) S1 is -CH2-NH-CO-(CH2) Z -, or -CH2-CO-NH-(CH2) Z -(In the formula, each z is an integer independently selected from the range 0 to 4), S2 is -(CH2) f -CO-NH-CH2-CH2- or -(CH2) f -NH-CO-CH2-CH2-(wherein each f is an integer independently selected from the range 0 to 4).

[0157] In one embodiment, the IEDDA reaction rate depends on the IEDDA reaction partner conjugated together and the reaction conditions, which are determined by at least the reagent concentration, reaction temperature, and reaction pH. In one embodiment, IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety takes 30 minutes or less, preferably 20 minutes or less, more preferably 15 minutes or less, even more preferably 10 minutes or less, and even more preferably 5 minutes or less. In the most preferred embodiment, IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety takes less than 1 minute, preferably less than 30 seconds, and more preferably less than 15 seconds, because IEDDA between the tetrazine ring and the TCO moiety is likely to occur within a few seconds. Nevertheless, in one embodiment, IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety is carried out at a temperature above +20°C for 20 to 30 minutes to improve the uniformity and stability of the tautomerism of the resulting adduct.

[0158] In one embodiment, IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety is performed at ambient temperature (room temperature). In another embodiment, IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety is efficiently performed at any temperature between +20°C and +80°C.

[0159] In one embodiment, a method for producing an adduct includes reacting the tetrazine portion of a radiolabeled tracer compound with the TCO portion of a TCO derivatization target portion at a temperature between 20 and 80°C, preferably between 40 and 70°C, more preferably between 55 and 65°C, and most preferably between 60°C. In one embodiment, the maximum reaction temperature for IEDDA conjugation between the tetrazine portion of the tracer compound and the TCO portion of the TCO derivatization target portion is 80°C. In embodiments where pre-target PET imaging is used to image the adduct, the reaction temperature for IEDDA conjugation is lower, and this temperature is determined by the subject's (body) temperature.

[0160] In one embodiment, heating the adduct to a temperature above +20°C improves the homogeneity of its tautomerism and reduces the amount of intermediate tautomers. In one embodiment, heating the adduct to 20-80°C, preferably 40-70°C, more preferably 55-65°C, and most preferably 60°C improves the homogeneity of its tautomerism. In one embodiment, heating the adduct at the above temperatures is performed for at least 5 minutes, preferably at least 10 minutes, or at least 15 minutes. In one embodiment, heating the adduct increases the homogeneity of its tautomerism and irreversibly reduces the amount of intermediate tautomers. In one embodiment, heating the adduct prevents the reverse conversion of the adduct to its intermediate tautomers after heating and during storage at ambient room temperature of +20°C. In one embodiment, the above heating treatment is used simultaneously with IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety. In one embodiment, the above treatment by heating is performed after IEDDA conjugation between the tetrazine moiety of the tracer compound and the TCO moiety of the TCO derivatization target moiety.

[0161] In one embodiment, the solvent in the IEDDA conjugation of the tracer compound and the TCO derivatization target moiety is water, an aqueous medium, an aqueous buffer, or a mixture of an organic solution and an aqueous solution, where the percentage of the organic solvent is less than 50%, preferably less than 10%, and the organic solvent includes, for example, DMSO, ethanol, acetonitrile (MeCN), or methanol.

[0162] In one embodiment, the tetrazine portion of the tracer compound reacts with the TCO portion of the TCO derivatization target portion under acidic conditions, undergoing IEDDA conjugation to obtain an adduct. In another embodiment, the tetrazine portion of the tracer compound is conjugated with the TCO portion of the TCO derivatization target portion under conditions where the pH is 2 to 7, preferably 2 to 4, most preferably 2 to 3.

[0163] In one embodiment, 18The reaction temperature for radiolabeling the tracer compound with the radioactive isotope F is between 80 and 100°C, preferably between 80 and 90°C, and more preferably between 85 and 90°C. In one embodiment, 18 The reaction temperature for radiolabeling tracer compounds with the radioactive isotope F is 85°C.

[0164] In one embodiment, 18 Radiolabeling of tracer compounds with the F radioactive isotope is performed at a pH between 2.0 and 3.0.

[0165] In one embodiment, 18 The radiolabeling reaction of the tracer compound with the radioactive isotope 1F is carried out in an acidic pH-controlled buffer containing a sufficient percentage of an organic solvent to dissolve the tracer, the organic solvent being, for example, MeCN or DMF. In one embodiment, at least one 18 The radiolabeling reaction of the tracer compound with the radioactive isotope 1F is carried out in a pyridazine HCl buffer containing an organic solvent such as MeCN or DMF.

[0166] In one embodiment, 18 The radioactive labeling of the adduct with the radioactive isotope F is carried out at a temperature between 80 and 100°C, preferably between 80 and 90°C, and more preferably between 85 and 90°C. In one embodiment, 18 Radioactive labeling of adducts with the F radioactive isotope is performed at a temperature of 85°C.

[0167] In one embodiment, 18 Radioactive labeling of adducts with the F radioactive isotope is performed at a pH between 2.0 and 3.0.

[0168] In one embodiment, 18 The radiolabeling reaction of the adduct with the radioactive isotope 1F is carried out in an acidic, pH-controlled buffer containing a sufficient percentage of an organic solvent to dissolve the tracer, the organic solvent being, for example, MeCN or DMF. In one embodiment, 18The radiolabeling reaction of the adduct with the radioactive isotope 1F is carried out in a pyridazine HCl buffer containing an organic solvent such as MeCN or DMF.

[0169] In one embodiment, the adduct is radiolabeled after IEDDA conjugation of the tracer compound and the TCO derivatization target moiety. Therefore, 18 Substitution of fluoride F with a radioactive isotope is performed first after IEDDA conjugation of the tracer compound to the TCO derivatization target moiety. By synthesizing the entire adduct before radiolabeling, it becomes possible to radiolabel the adduct immediately before use, thereby minimizing the decay of the radiolabel. In certain embodiments, byproducts are formed during IEDDA conjugation, which are difficult or impossible to remove from the reaction mixture. Therefore, radiolabeling the adduct after IEDDA conjugation is beneficial in ensuring the chemical purity of the resulting adduct.

[0170] In another embodiment, the zwitterionic moiety of the tracer compound is 18 It contains the radioactive isotope F. Therefore, at least one of the three fluoride (F) atoms bonded to the boron (B) zwitterion of the tracer compound is 18 It is a radioactive isotope of F. In one embodiment, 18 Substitution of fluoride F with the radioactive isotope F is performed before IEDDA conjugation of the tracer compound to the TCO derivatized target moiety. The specific target moiety is 18 It is sensitive to the conditions required for F radiolabeling. In such embodiments, the tracer compound 18 F radiolabeling is performed before IEDDA conjugation with the TCO derivatized target moiety. Therefore, in embodiments in which the adduct contains a sensitive and / or vulnerable target moiety, the tracer molecule 18F radiolabeling is performed before IEDDA conjugation. In one embodiment, the target moiety for such susceptibility and / or vulnerability is an antibody or an enzyme. This is beneficial in ensuring the integrity of the target moiety in the resulting adduct, as the above process sequence allows the target moiety to survive the radiolabeling process conditions.

[0171] In one embodiment, radiolabeling of the tracer compound before IEDDA conjugation is utilized when IEDDA conjugation between the tracer compound and the TCO derivatization target moiety occurs in vivo or in vitro within the subject. In this case, the tracer compound is first brought into contact with the TCO derivatization target moiety in the subject after the TCO derivatization target moiety has reached its target site. Radioimaging of the radiolabeled tracer compound using this methodology is a pre-target PET imaging technique.

[0172] In one embodiment, the use of a tracer compound and / or adduct of a first embodiment is provided in the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct. In one embodiment, a method is provided for detecting a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted with a radiolabeled tracer compound and / or adduct.

[0173] In one embodiment, the tracer compound and / or adduct is used in vivo in radioimaging via systemic administration of the adduct to a subject. In one embodiment, the tracer compound and / or adduct is used for radioimaging, more specifically for the detection of target entities in a subject by positron emission tomography, via imaging of radiolabeled target entities. In one embodiment, imaging of target entities refers to imaging of radiolabeled tracer compounds and / or adducts that can bind to selected target entities in vitro and in vivo.

[0174] In one embodiment, the tracer compound and / or adduct is administered to a subject undergoing radioimaging in an imaging-effective amount for the positron emission of the tracer compound and / or adduct.

[0175] In one embodiment, the tracer compound and / or adduct is used for in vitro radioimaging of tissues and / or cells. In another embodiment, the tracer compound and / or adduct is used for in vitro and in vivo labeling of target entities.

[0176] In one embodiment, the target portion of the adduct can bind to a target entity in vitro. In another embodiment, the target portion of the adduct can bind to a target entity in vivo. In one embodiment, the target entity is a biomolecule such as a receptor, enzyme, or nanoparticle. In another embodiment, the target entity to which the target portion of the adduct can bind is an indicator of a specific physiological disease such as cancer, neurodegeneration, inflammation, or infection.

[0177] In one embodiment, an adduct that does not contain a target moiety or in which the binding of the target moiety to the target entity is blocked exhibits low or insignificant binding to the target entity or biomolecule in vitro.

[0178] In one embodiment, the tracer compound and adduct exhibit good stability in plasma in vitro and in vivo. In one embodiment, the bone uptake rate of the tracer compound and adduct is low, which suggests good metabolic stability of the radiolabeling of the tracer compound and adduct. In one embodiment, the tracer compound and adduct show relatively low accumulation in non-target tissues.

[0179] In one embodiment, the radiolabeled tracer compound can be further processed and used for radioimaging up to 8 hours, preferably up to 5 hours, and most preferably up to 2 hours, after radiolabeling the tracer compound. In one embodiment, the radiolabeled adduct, which is an IEDDA cyclization addition product of the tracer compound and the TCO derivatized target moiety, can be further processed and used for radioimaging up to 8 hours, preferably up to 5 hours, and most preferably up to 2 hours, after radiolabeling the adduct.

[0180] In one embodiment, a kit for detecting a target entity in a subject by radioimaging comprises at least one compartment containing a tracer compound, at least one compartment containing at least one TCO-derivative target moiety, and a means for radiolabeling the tracer compound. 18 It comprises at least one compartment including F. In one embodiment, the kit also includes Inverse electron-demanded Diels-Alder reaction IEDDA ) for, as well as tracer compounds and / or adducts For radioactive labeling 、 The kit includes aqueous solvents and organic solvents. In one embodiment, the kit provides the materials necessary to radiolabel a tracer compound before IEDDA conjugation of the adduct. In one embodiment, the kit provides the materials necessary to radiolabel an adduct after IEDDA conjugation of the tracer compound with the TCO derivatized target moiety. In one embodiment, the kit is configured for use in pre-target PET imaging. In one embodiment, the kit provides all the components necessary to prepare a tracer compound and / or adduct for the detection of a target entity in a subject. In one embodiment, the kit provides most of the materials necessary to prepare a tracer compound and / or adduct for the detection of a target entity in a subject. [Examples]

[0181] Various embodiments have been presented. It should be understood that, in this specification, the words “comprise,” “include,” and “contain” are to be used as free expressions without any intended exclusivity.

[0182] Outline All reagents were purchased from commercial suppliers and used without further purification. Tetrazine was purchased from Conju-Probe, BroadPharm, or Jena Biosciences, and iodoborone pinacol ester was purchased from Enamine. Sep-Pak C18-Light cartridges were purchased from Waters, and PS-HCO3 cartridges (Macherey-Nagel™ Chromafix™) were purchased from Fisher Scientific. No carrier was added. 18 Fluoride was produced in-house using an IBA 10 / 5 medical cyclotron from Hyox-18 18O concentrated water purchased from Rotem Industries Limited (ALAVA, Israel). The synthesized precursor was analyzed by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance spectroscopy (NMR). Radiolabeled tracers were analyzed by radioactive high-performance liquid chromatography (radioactive HPLC). Resected organs were weighed and measured using a Wizard gamma counter. A Molecubes PET (β-CUBE) was coupled with a CT (γ-CUBE) to acquire a 60-minute dynamic positron emission tomography (PET) scan using computed tomography (CT).

[0183] Example 1. Synthesis of AmBF3-Tz (Compound 4 in Figure 1) 2-[4-(1,2,4,5-tetrazin-3-yl)phenyl]-N-[2-(dimethylamino)ethyl]acetamide(2). N,N-dimethylethylenediamine (13 μL, 0.12 mmol) was dissolved in 2 mL of DCM under argon, and then tetrazin NHS-ester(1) (25 mg, 0.08 mmol) was added to 3 mL of DCM, and this was added dropwise to a clear solution. The mixture was stirred at room temperature for 1.5 hours, and the crude reaction mixture was evaporated to dryness, resuspended in 1 mL of ultrapure water (Milli-Q), and purified with SEP-Pak silica (eluted with MeOH:DCM in a 1:9 ratio) to obtain a pink solid. The yield was 68 ± 26% (n=3) (11.5 mg, 0.04 mmol). 1 H NMR (300 MHz, acetonitrile-d3) δ 10.26 (s, 1H), 8.50 (d, J = 8.4 Hz, 2H), 7.56 (d, J = 8.2 Hz, 2H), 3.60 (s, 2H), 3.26 (s, 2H), 2.40 (s, 2H), 2.21 (s, 6H).

[0184] 2-(2-(4-(1,2,4,5-tetrazin-3-yl)phenyl)acetamide)-N,N-dimethyl-N-((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)methyl)ethane-1-aminium (3). Compound (2) (11.5 mg, 0.04 mmol) was dissolved in 1 mL of dry acetonitrile under argon, and then 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolan (10.8 mg, 0.04 mmol) was dissolved in 300 μL of dry acetonitrile. The reaction mixture was stirred overnight and evaporated to dryness. The yield was 58 ± 31% (n=3) (11.5 mg, 0.04 mmol). 1H NMR (300 MHz, acetonitrile-d3) δ 10.28 (s, 1H), 8.52 (d, J = 8.3 Hz, 2H), 7.58 (d, J = 8.2 Hz, 2H), 3.68 (s, 2H), 3.58 (s, 2H), 3.48 (s, 2H), 3.13 (s, 6H), 2.14 (s, 2H), 1.28 (s, 12H).

[0185] {[(2-{2-[4-(1,2,4,5-tetrazin-3-yl)phenyl]acetamidoethyl)dimethylammonio]methyl}trifluoroborate (4). Compound (3) (0.043 mmol, 18 mg) was dissolved in 15 mL of Falcon (LDPE) tube with 1153 μL of DMF, and then 387 μL of Milli-Q water, 577 μL of 4 M HCl, and 577 μL of 3 M KHF2 were added. The Falcon tube was closed, and the reaction mixture was heated at 70°C for 30 minutes, and the fluorination reaction was closely monitored by HPLC (PDA detector 534 nm, 0.1% TFA-ACN:0.1% TFA Milli-Q water (80:20) at a uniform concentration of 2.5 mL / min t R (AmBF3-Tz) = 10.3 mins), tetrazine degradation was avoided. This reaction yielded a quantitative conversion from compound (3) to compound (4). The reaction mixture was diluted with 6 mL of Milli-Q water and added to two parallel SPE C18 PLUS cartridges preconditioned with 5 mL of ACN and 10 mL of Milli-Q water, respectively. The C18 cartridges were washed with 20 mL of Milli-Q water, air-dried, and eluted with 1 mL of ACN to obtain 13.9 mg of compound 4. 1 H NMR (400 MHz, CD3CN) δ 10.30 (s, 1H), 8.54 (d, J = 8.5 Hz, 2H), 7.58 (d, J = 8.6 Hz, 2H), 3.68 - 3.56 (m, 4H), 3.34 (t, J = 6.7 Hz, 2H), 3.01 (s, 6H), 2.38 (s, 2H). 11 B NMR (128 MHz, CD3CN) δ 2.19, 1.80, 1.43, 1.03. 19F NMR (376 MHz, CD3CN) δ -138.77, -138.89, -139.04, -139.17. 13 C NMR (101 MHz, CD3CN) δ 171.47, 167.25, 158.98, 141.95, 131.82, 131.42, 129.05, 118.30, 65.43, 54.32, 43.42, 34.75, 1.32. HRMS Calculated value, C 15 H 21 BF3N6O + [M+H] + 369.18165 m / z, measured value, C 15 H 21 BF3N6O + [M+H] + 369.18134m / z (mass error -0.85ppm).

[0186] Example 2. Synthesis of AmBF3-PEG4-Tz (Compound 8 in Figure 2) N-(4-(1,2,4,5-tetrazin-3-yl)benzyl)-1-(3-(dimethylamino)propanamide)-3,6,9,12-tetraoxapentadecane-15-amide(6). 3-(dimethylamino)propanoic acid (4.8 mg, 31 μmol) in 0.3 mL of DMF under an argon atmosphere was mixed with HATU (8.5 mg, 23 μmol) in 0.1 mL of DMF and stirred at room temperature for 10 minutes. N-(4-(1,2,4,5-tetrazin-3-yl)benzyl)-1-amino-3,6,9,12-tetraoxapentadecane-15-amide (10 mg, 21 μmol)(5) and DIPEA (30 μL) were added, and the reaction mixture was stirred at room temperature for 2 hours. After evaporating the solvent, LC-MS analysis showed a purity of over 95%. LC-MS(+) calculated value for C25H40N7O5: 534 m / z [M+H] + Measured value, m / z (%) = 534 (100) [M + H] + , t R =8.5 minutes.

[0187] 1-(4-(1,2,4,5-tetrazin-3-yl)phenyl)-N,N-dimethyl-3,19-dioxo-N-((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)methyl)-6,9,12,15-tetraoxa-2,18-diazahenicosan-21-aminium (7). Compound (6) (2 mg, 3.56 μmol) was dissolved in 200 μL of dry acetonitrile under argon, and then 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolan (1.01 mg, 3.7 μmol) was dissolved in 100 μL of dry acetonitrile. The reaction mixture was stirred for 20 minutes and evaporated to dryness.

[0188] 24-(4-(1,2,4,5-tetrazin-3-yl)phenyl)-1,1,1-trifluoro-3,3-dimethyl-6,22-dioxo-10,13,16,19-tetraoxa-3,7,23-triaza-1-boratetracosan-3-ium-1-wido(8). Without further purification, compound (7) (3.56 μmol) was dissolved in 15 mL of Falcon (LDPE) tube with 14.94 μL of DMF, then 4.93 L of Milli-Q water, 7.47 μL of 4 M HCl, and 7.47 μL of 3 M KHF2 were added. The Falcon tube was closed and the reaction mixture was heated at 85°C for 10 minutes. The reaction mixture was diluted with 6 mL of Milli-Q and added to two parallel SPE C18 PLUS cartridges pre-conditioned with 5 mL of ACN and 10 mL of Milli-Q, respectively. The C18 cartridge was washed with 20 mL of Milli-Q, air-dried, and eluted with 1 mL of ACN to obtain 1.2 mg (1.95 μmol) of compound (8). After evaporating the solvent, analysis by LC-MS showed a purity of over 95%. LC-MS(+) Calculated value, C 26 H 41 596 m / z [MF] for BF2N7O6 + Actual measured value, m / z (%) = 596 (100) [MF] + , t R=11.5 minutes. 1H NMR (400 MHz, acetone-d6) δ 10.43 (s, 1H), 8.54 (s, 2H), 7.63 (s, 2H), 5.35 (s, 2H), 4.58 (s, 2H), 3.78 (s, 3H), 3.60 (s, 16H), 3.35 (s, 2H), 3.10 (s, 6H), 2.51 (s, 3H), 2.33 (s, 3H), 2.21 (s, 2H). 19F NMR (376 MHz, acetonitrile-d3) δ -138.98, -139.12, -139.25.

[0189] Example 3. Synthesis of AmBF3-PEG9-Tz (compound 12 in Figure 3). N 1 -(4-(1,2,4,5-tetrazin-3-yl)benzyl)-N 31 -(2-(dimethylamino)ethyl)-4,7,10,13,16,19,22,25,28-nonoxahentriacontanediamide(10). Dimethylethylenediamine (0.677 mg, 7.7 μmol) was dissolved in 400 μL of DCM under argon, and then tetrazine-PEG9-NHS-ester(9) (5 mg, 6.4 μmol) in 600 μL of DCM was added and this was added dropwise to a clear solution. The reaction product was converted to TLC (RP-TLC, ACN: MilliQ water (80:20), R f = Tetrazine 0.83, R f = Amine 0.00, R f The mixture was monitored with tetrazinamine (0.28%). After stirring the mixture at room temperature for 20 minutes, the crude reaction mixture was loaded onto a 3×C18 cartridge, air-dried, and eluted into four fractions with 3 mL of ACN. The pure fractions were combined and evaporated to dryness to obtain a pink solid. Yield ≥ 98% (1.3 mg, 0.0016 mmol). 1H NMR (400 MHz, acetonitrile-d3) δ 10.28 (s, 1H), 8.53 (d, J = 8.5 Hz, 2H), 7.57 (d, J = 8.7 Hz, 2H), 5.36 (s, 1H), 4.50 (d, J = 6.2 Hz, 2H), 3.74 (t, J = 6.0 Hz, 2H), 3.67 (t, J = 6.0 Hz, 2H), 3.59 (d, J = 0.9 Hz, 30H), 3.47 (q, J = 5.7 Hz, 2H), 3.29 (s, 1H), 3.04 (s, 2H), 2.73 (s, 6H), 2.48 (t, J = 6.0 Hz, 3H), 2.39 (t, J = 6.0 Hz, 3H).

[0190] 1-(4-(1,2,4,5-tetrazin-3-yl)phenyl)-N,N-dimethyl-3,33-dioxo-N-((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)methyl)-6,9,12,15,18,21,24,27,30-nonaoxa-2,34-diazahexatriacontane-36-aminium(11). 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolan (0.0017 mmol, 0.46 mg) was dissolved in dry acetonitrile and added dropwise to a stirred solution of compound (10) (0.0017 mmol, 1.3 mg) in ACN under an argon atmosphere overnight. The reaction was monitored by HPLC (PDA detector, 534 nm). The reaction mixture was evaporated to dryness and used immediately in the subsequent fluorination reaction.

[0191] 39-(4-(1,2,4,5-tetrazin-3-yl)phenyl)-1,1,1-trifluoro-3,3-dimethyl-7,37-dioxo-10,13,16,19,22,25,28,31,34-nonaoxa-3,6,38-triaza-1-boranonatricontan-3-ium-1-wido(12). Compound (11) (0.0017 mmol, 1.74 mg) was dissolved in 45.6 μL of DMF in a 15 mL Falcon (LDPE) tube, and then 15.5 μL of Milli-Q water, 22.8 μL of 4 M HCl, and 22.8 μL of 3 M KHF2 were added. The Falcon tube was closed, and the reaction mixture was heated at 70°C for 30 minutes. The fluorination reaction was closely monitored by HPLC (PDA detector, 534 nm) to avoid the degradation of tetrazine. This reaction resulted in the complete conversion of compound (11) to compound (12). The reaction mixture was diluted with 1 mL of Milli-Q water and added to an SPE C18 Light cartridge (preconditioning: 5 mL of ACN and 10 mL of Milli-Q water). The C18 cartridge was washed with 10 mL of Milli-Q water, air-dried, and eluted with 200 μL of ACN to obtain 1.9 mg of compound (12). 1 ¹H NMR (400 MHz, CD3CN) δ values: 10.29 (s, 1H), 8.56-8.54 (d, 2H), 7.60-7.58 (d, 2H), 7.22 (s, broad, 1H), 6.88 (s, broad, 1H), 4.53-4.51 (d, 2H), 3.75 (t, 2H), 3.67 (t, 2H), 3.62-3.56 (m, 32H), 3.33 (t, 2H), 3.03 (s, 6H), 2.49 (t, 2H), 2.38 (t, 2H). 19 F NMR (376 MHz, CD3CN) δ -138.80, -138.97, -139.08. 13 C-NMR (101 MHz, CD3CN). HRMS calculated value, C 36 H 62 BF3N7O 11 + [M+H] + 836.45470 m / z, measured value, C 36 H62 BF3N7O 11 + [M+H] + 836.45538m / z (mass error 0.82ppm).

[0192] Example 4. Synthesis of trans-cyclooctenaldehyde (TCO-CHO) (compound 15 in Figure 4). As shown in Figure 4, 15.6 mg (91 nmol, 1.5 equivalents) of compound (13) was dissolved in 500 μL of THF and 150 μL of DMSO under argon. Then, 9.7 mg of pyridine (122 nmol, 2.0 equivalents) in 100 μL of THF was added, and the solution was mixed for 10 minutes. 16.3 mg (61 nmol, 1.0 equivalent) of compound (14) was added dropwise, and the solution was stirred overnight at room temperature. The reaction product was monitored by normal-phase TLC using ethyl acetate:cyclohexane (1:1) as the mobile phase and stained with KMnO4 staining solution (t R (Pyridine) = 0.00, t R (1) = 0.00, t R (2) = 0.90, R T (3) = 0.80). To remove pyridine and unreacted compound (14), the crude mixture was purified using a Sep-Pak SPE-Sil cartridge (preconditioned with 50 mL of ultrapure water). The mixture was pressed into the SPE-Sil cartridge (Fraction 1) and eluted with 1 mL of DCM (Fraction 2). The recovered fraction was further purified by semi-preparative HPLC (Phenomenex Alltima C18 column, homogeneous concentration of 80% ACN + 0.1% TFA at 3 mL / min), where compound (15) was removed. R Elution occurred in 6 minutes. LC-MS(+)m / z(%)=288.36(27)[M+H] + , 310.30(19)[M+Na] + t R =9.3 minutes. 1 H NMR (400 MHz, CDCl3) δ ppm, 10.00, 7.86, 7.84, 7.45, 7.43, 5.53, 4.99, 4.41, 2.35, 1.97, 1.75, 1.57, 1.27, 1.26. 13C NMR (101 MHz, CDCl3) δ ppm, 191.81, 145.79, 135.64, 134.89, 133.01, 130.13, 127.77, 81.14, 44.70, 41.14, 38.67, 34.27, 32.50, 30.96.

[0193] Example 5. Aminooxy functionalized peptide (α-MSH-ONH2, exendin-4-ONH2, Tyr 3 A general procedure for functionalizing (octreotide-ONH2) with transcyclooctene. One equivalent of an aminooxy-functionalized custom synthetic peptide was dissolved in 600 μL of 0.3 M anilinium acetate buffer (pH 4.6). Commercial trans-cyclooctene-PEG3-aldehyde (Figure 4, compound 16) (1.5 equivalents) was dissolved in 17 μL of chloroform and added dropwise to the stirred peptide solution. The reaction was monitored by HPLC (PDA detector, 280 nm). The functionalized peptide was purified by HPLC (MeCN(B)-H2O(A) + 0.1% TFA; 20-30-20% B, 30 min). R =α-MSH-TCO; 23 minutes, t R TOC-TCO; 25 minutes, t R = Exendin-4-TCO; 15.5 min. MeCN in the fraction recovered from HPLC was evaporated with pressurized air, and the fraction mainly containing water was frozen (-80°C). The frozen fraction was freeze-dried and then used as is. If necessary, the fraction was used as is and mixed with selected tetrazine immediately after recovery from HPLC. In such cases, the solution was diluted so that it contained more than 95% water during the IEDDA cyclization addition.

[0194] Example 6. Synthesis of PSMA-trans-cyclooctene (Compound 18, Figure 5). TCO-NHS (4.5 mg, 17 μmol) and DIPEA (3.2 mg, 25 μmol) were added dropwise to dry DMF (250 μL) of PSMA-amine (17) (5 mg, 15.7 μmol) under an argon atmosphere, and the mixture was stirred overnight. PSMA-TCO(18) was purified by HPLC to obtain 5.3 mg (71%). LC-MS(+)m / z(%)=472.5(100)[M+H] + , 320.3(96)[M-TCO-formate] + t R =10.3 minutes. 1 H NMR (400 MHz, CD3OD) δ(ppm) = 5.59 (m, 1H), 5.50 (m, 1H), 4.31 (m, 1H), 4.25 (s, 1H), 3.31 (s, 2H), 3.06 (m, 2H), 2.41 (m, 2H), 2.33 (m, 2H), 2.33 (m, 2H), 2.15 (m, 2H), 1.94 (m, 6H), 1.68 (m, 4H), 1.40 (m, 4H), 1.29 (m, 2H), 13C NMR (101 MHz, CD3OD) δ (ppm) = 136.10, 133.76, 81.59, 54.07, 53.59, 42.23, 39.67, 35.18, 33.49, 33.25, 32.11, 31.15, 30.55, 29.03, 23.86.

[0195] Example 7. Synthesis of PSMA-tranexamic acid-trans-cyclooctene (compound 24, Figure 6) Di-tert-butyl((6-(4-(((((9H-fluoren-9-yl)methoxy)carbonyl)amino)methyl)cyclohexane-1-carboxamide)-1-(tert-butoxy)-1-oxohexane-2-yl)carbamoyl)glutamate (21). HBTU (76.6 mg, 201.5 μmol) and DIPEA (26.4 mg, 206 μmol) in dry DMF (400 μl) were mixed with Fmoc-tranexamic acid (19) (78 mg, 206 μmol) in dry DMF (600 μL) and stirred for 10 minutes under an argon atmosphere. Di-tert-butyl((6-amino-1-(tert-butoxy)-1-oxohexane-2-yl)carbamoyl) glutamate (20) (25 mg, 51.5 μmol) was added to dry DMF (400 μL) and stirred under argon for 2 hours. LC-MS(+) m / z(%) = 850.1(4) [M+H] + , 872.1(3)[M+Na] + t R =18.5 minutes.

[0196] Di-tert-butyl((6-(4-(aminomethyl)cyclohexane-1-carboxamide)-1-(tert-butoxy)-1-oxohexane-2-yl)carbamoyl)glutamate (22). Without further purification, 1.4 mL of piperidine was added to (21) and stirred at room temperature for more than 10 minutes. The solvent was evaporated and the product was extracted with 5 mL of ethyl acetate and 3 × 2 mL of brine solution. LC-MS(+)m / z(%)=628.0(100)[M+H] + t R =11.3 minutes.

[0197] ((5-(4-(aminomethyl)cyclohexane-1-carboxamide)-1-carboxypentyl)carbamoyl)glutamic acid (23). Without further purification, (22) was dissolved in 3 mL of CH2Cl2 / TFA (1:1) and stirred at room temperature for 90 minutes. The product was HPLC (t R Purification was performed by LC-MS (7.2 mins) to obtain 10.2 mg (43%). LC-MS (+) m / z (%) = 459 (100) [M + H] + t R=2.6 minutes.

[0198] (E)-((1-carboxy-5-(4-((((cycloocto-4-ene-1-yloxy)carbonyl)amino)methyl)cyclohexane-1-carboxamide)pentyl)carbamoyl)glutamic acid (24). TCO-NHS (13 mg, 49 μmol) and DIPEA (8.9 mg, 70 μmol) (23) in dry DMF (600 μL) were added dropwise in 250 μL of dry DMF and stirred overnight under an argon atmosphere. The product was HPLC (t R Purification by LC-MS (4.5 min) yielded 5.63 mg (41%). LC-MS (+) m / z (%) = 611 (100) [M + H] + t R =11.4 minutes. 1 H NMR (400 MHz, CD3OD) δ (ppm) = 5.61 (m, 1H), 5.52 (m, 1H), 4.32 (m, 2H), 4.26 (m, 1H), 3.17 (m, 2H), 3.01 (s, 1H), 2.92 (m, 2H), 2.88 (s, 1H), 2.43 (m, 2H), 2.34 (m, 2H), 2.15 (m, 2H), 1.98 (m, 4H), 1.80 (m, 5H), 1.70 (m, 4H), 1.51 (m, 2H), 1.44 (m, 5H), 0.98 (m, 2H), 13C NMR (101 MHz, CD3OD) δ (ppm) = 136.10, 133.77, 53.94, 53.50, 46.47, 42.24, 39.92, 39.65, 39.09, 35.18, 33.50, 33.19, 32.11, 30.95, 30.24, 29.97, 28.93, 26.45, 23.89.

[0199] Example 8. Procedure a) Before EDDA conjugation [ 18 F]4(AmBF3-Tz), [ 18 F]8 and [ 18 Radioactive labeling of F12 [ 18 [F] fluoride in 150 μL of 0.9% NaCl 18The reaction was eluted as F-NaF into a reaction vial and concentrated at 125°C for 10 minutes under argon gas flow to a reaction volume of 10-25 μL. Tetrazine (100 nmol) in 5 μL of acetonitrile was added to a polypropylene tube containing 10 μL of pyridazine HCl buffer (pH 2.0). The reaction mixture was heated further at 83°C for 10 minutes and quenched with 600 μL of Milli-Q:EtOH (50:50). Alternatively, [ 18 The [F] fluoride was captured in a PS-HCO3 cartridge and eluted into a tube containing tetrazine (100 μL, pyridazine HCl buffer, pH 2.0). The mixture was concentrated at 85°C under argon flow until it reached ~10-20 μL (t=15 min), quenched with ultrapure water (600 μL), and purified in a Sep-Pak C18 cartridge to obtain the tracer. Compound 4 (AmBF3-Tz) was then analyzed. 18 The radioactive isotope F was used for radiolabeling, and as a result, [ 18 The procedure that leads to F4 is shown in Figure 7. An example of procedure a) is shown in Figure 8a.

[0200] Example 9. Procedure b) Pre-IEDDA conjugation of AmBF3-Tz before radiolabeling To 20 μL of dry acetonitrile, tetrazine-AmBF4, 8, or 12 (1.85 μmol) was added, an equimolar amount of TCO-functionalized peptide 18 or 24 in Milli-Q water (800 μL) was added. The reaction mixture was heated to 60°C for 20 minutes. The product was purified by HPLC to obtain (28)(49%)(t R =7.9min)LC-MS(+)m / z(%)=811(100)[M+H] + t R =8.8 minutes obtained, or (29)(48%)(t R =9.5min)LC-MS(+)m / z(%)=950(100)[M+H] + t R = 9.5 minutes was obtained. An example of the synthesis route by procedure b) is shown in Figure 8b.

[0201] Example 10. TCO-functionalized peptide Tyr 3- Octreotide (25), α-MSH, exendin-4, PSMA (18) and PSMA-tranexamic acid (24), and [ 18 F]AmBF3-Tz([ 18 F]4) or its PEGylated derivatives[ 18 F]8 or [ 18 Conjugation of IEDDA with F12 produces the product [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18 F]25), [ 18 F]AmBF3-α-MSH([ 18 F]26), [ 18 F]AmBF3-Excendin-4([ 18 F]27) and [ 18 F]AmBF3-PEG9-Excendin-4([ 18 F]30), [ 18 F]AmBF3-PSMA([ 18 F]28) and [ 18 F]AmBF3-PSMA-Tranexamic Acid ([ 18 F]29) production. Peptides produced by trans-cyclooctene (α-MSH-ONH2, exendin-4-ONH2, Tyr 3 The functionalization of (-octreotide-ONH2) was carried out as described in Example 5. Transcyclooctene-functionalized peptide (20-50 μL, 50 nmol in Milli-Q water) was added to the reaction mixture of radiolabeled tetrazine (20 μL) and heated at 60°C for 15 minutes. The reaction mixture was diluted with Milli-Q water and purified in two C18 cartridges by washing with ultrapure Milli-Q water (45 mL), and eluted with 150 μL of ethanol and 200 μL of 0.01 M PBS. The purified peptide solution was diluted with 0.01 M PBS to contain less than 5% ethanol for intravenous administration. The crude mixture was analyzed for 30 minutes using HPLC: MeCN(B)-H2O(A) + 0.1% TFA 20-30-20% B. Retention time in HPLC: Compound [ 18 F]26([ 18 t for F]AmBF3-α-MSH) R ;14.7 min, compound [ 18F]25([ 18 F]AmBF3-Tyr 3 - Octreotide) R ;17.5 min, compound [ 18 F]27([ 18 F]AmBF3-excendin-4) against t R ;15.0~16.0 min, compound [ 18 F]30([ 18 F)AmBF3-PEG9-excendin-4) against t R , 15.8~16.5 minutes. HRMS(E / Z)-[ 18 The measured values ​​using F]25 are [M+H+Na] 2+ The reading was 1048.49255 (-0.0855 ppm). These results demonstrate that various different peptides can be rapidly radiolabeled under mild conditions by using tracer compounds.

[0202] [ka]

[0203] Example 11. Radiolabeling of pre-IEDDA products Fluorine-18 (1.8 GBq) was eluted from a PS-HCO3 cartridge with 100 μL of 0.9% NaCl solution or pyridazine HCl buffer (pH 2, 100 μL), and evaporated at 100°C (0.9% NaCl) or 80-85°C (when pyridazine HCl buffer was used) until the volume was 10-15 μL. 10 μL of fluorine-18 or fluorine-18 (100 nmol) in 10 μL of pyridazine buffer (pH=2) was added via an external line, and the resulting solution was heated at 85°C for 10 minutes. After dilution with 10 mL of Milli-Q water, the activity was loaded onto a pre-conditioned C18 cartridge, washed with an additional 40 mL of Milli-Q water, and then eluted with 400 μL of 50% EtOH / PBS to obtain a specific activity of (9.2 ± 3.8 GBq / μmol) [ 18 [F]28 (RCY: 5.2±1%) and has a specific activity of (16.3±4.3 GBq / μmol) 18F]29 (RCY: 11.8±3.1%) was obtained.

[0204] Example 12. Cells and Cell Culture The rat pancreatic tumor cell line AR42J, expressing SSTR, was obtained from the American Type Culture Collection (Manassas, VA). C4-2 cells (ATCC® CRL-3314®) were cultured in DMEM medium (Gibco) supplemented with 18% F12 medium (Sigma), 10% FBS (Gibco), and 1% T medium. Both cell lines were grown at 37°C in a humidified incubator containing 5% CO2. Cells grown to 80%–90% confluence were used for in vitro or in vivo experiments. Mouse cutaneous melanoma B16 / F10 cells were cultured at 37°C in a humidified incubator in CO2-bound media (Life Technologies Gibco, catalog no. 18045054) supplemented with GlutaMax (1× final concentration, 10% FBS and Pen-Strep). The viability of B16 / F10 cells was 97%. C4-2 cells (ATCC® CRL-3314®) were cultured in DMEM medium (Gibco) supplemented with 18% F12 medium (Sigma), 10% FBS (Gibco), and 1% T medium. Both cell lines were grown at 37°C in a humidified incubator containing 5% CO2. Cells grown to 80%–90% confluence were used in in vitro or in vivo experiments.

[0205] Example 13.[ 18 F]AmBF3-Tz([ 18 F]4) Uptake of nonspecific B16 / F10 melanoma cells. 500,000 cells / well were seeded overnight on a 6-well plate. The growth medium was removed and the radioactive tracer was placed [ 18Reaction medium containing [F]4 was added. To determine the amount of radioactive tracer in the free fraction, at the specified time points (15, 30, 60, and 120 minutes), the reaction medium was removed and collected in a microcentrifuge tube, then the cells were washed with 1 mL of cold 1×PBS and the supernatant was collected in the same microcentrifuge tube. The membrane-bound fraction was collected by adding cold glycine buffer (1 mL) to the cells, incubating on an ice bath for 5 minutes, removing the supernatant, repeating the procedure, washing the cells with cold 1×PBS, and collecting all supernatant in the same microcentrifuge tube. To determine the internal distribution fraction, 1 M NaOH was added to the cells and incubated at ambient temperature for 10 minutes. The supernatant was removed, the cells were washed twice with cold 1×PBS, and the supernatant was collected in the same microcentrifuge tube. The supernatants collected separately for each phase were measured with a gamma counter to determine the radioactivity ratio (%) of each fraction. Based on the radioactivity distribution determined among the free fraction, membrane-bound fraction, and internal distribution fraction, [ 18 Although F4 did not demonstrate nonspecific uptake in B16 / F10 cells, it was clearly shown to remain in the extracellular free fraction throughout the study (99.3±0.09% at 15 min to 99.3±0.08% at 240 min, n=3). Adducts[ 18 The nonspecific cellular uptake of [F]4 demonstrates that tracer compounds or adducts used to radiolabel the target region do not bind to entities on the cell membrane and do not migrate into the cell if the target region, such as a peptide, is absent. The radioactivity distribution of the aforementioned fractions is shown in Figure 9.

[0206] Example 14.[ 18 TCO-functionalized Tyr conjugated to F]AmBF3-Tz 3 - Octreotide ([ 18 F]AmBF3-Tyr 3 - Octreotide, [ 18 F]25) AR42J cell uptake. 1 million cells / well were seeded overnight on a 6-well plate. The growth medium was removed and the radioactive tracer was added. 18Reaction medium containing [F]25 was added. To study the specificity of cell uptake, a set of cells was co-incubated in the presence of a 1 μM solution of unmodified octreotide. The unmodified octreotide used as the blocking octreotide contained only the octreotide peptide and was not conjugated to the TCO moiety or tracer compound, and therefore not radiolabeled. To determine the amount of radiotrace in the free fraction, the reaction medium was removed and collected in microcentrifuge tubes at specified time points (15, 30, 60, and 120 minutes), and the cells were then washed with 1 mL of cold 1×PBS, and the supernatant was collected in the same microcentrifuge tube. The membrane-bound fraction was collected by adding cold glycine buffer (1 mL) to the cells, incubating on ice for 5 minutes, removing the supernatant, repeating the procedure, washing the cells with cold 1×PBS, and collecting all supernatant in the same microcentrifuge tube. To determine the internal migration fraction, 1 M NaOH was added to the cells and incubated at ambient temperature for 10 minutes. The supernatant was removed, the cells were washed twice with 1×PBS at low temperature, and the supernatant was collected in the same microtube. The supernatants collected separately for each phase were measured with a gamma counter to determine the radioactivity percentage of each fraction. Based on the determined radioactivity distribution of the free fraction, membrane-bound fraction, and internally transported fraction, [ 18 The cellular uptake of [F]25 was clearly specific. Uptake (internal transfer) (3.21±0.06% at 15 min to 6.12±0.63% at 240 min, n=3) was efficiently blocked by excessive unmodified octreotide (blockage: 0.58±0.11% at 15 min to 0.73±0.04% at 240 min, n=3). 18 Blocking of cellular uptake of [F]25 was efficient throughout the study, but uptake under unblocked conditions continued to increase over time. The radioactivity distribution of the aforementioned fractions under unblocked (internal migration) and blocked conditions is shown in Figure 10. AR42J cells and compound [ 18 These results using [F]25 demonstrate that the internal migration of radiolabeled adducts is target-specific (to the somatostatin receptor in this case) and can be prevented by blocking access of the target portion of the adduct to each target entity.

[0207] Example 15. In control SCID mice [ 18 F]AmBF3-Tz([ 18 F]4) PET / CT scan. [ 18 F]AmBF3-Tz([ 18 F)4) was formulated in 10% ethanol in 0.01M PBS and administered intravenously to SCID mice. PET / CT images were acquired using Inveon PET / CT and Molecubes PET and CT. In PEC / CT (Figure 11) and in vivo distribution studies (Figures 12a and 12b), the tracer ([ 18 F4) demonstrated superior stability, as evidenced by the lack of bone uptake. The primary elimination pathway for the tracer was via the kidney, although small amounts of accumulation were observed in the liver and gallbladder (Figure 11), indicating an optimal prosthetic group profile.

[0208] Example 16. SCID mice [ 18 F]AmBF3-Tz([ 18 F]4) Radioactivity elimination after intravenous administration and [ 18 F]AmBF3-Tz([ 18 F]4) Excretion of radioactivity in urine after intravenous administration. [ 18 F]AmBF3-Tz([ 18 F)4) was prepared in 10% ethanol in 0.01 M PBS and administered intravenously to SCID mice. A region of interest (ROI) around a selected organ (heart, liver, kidney, lung, muscle, bladder) was plotted, and the ratio of radioactivity per unit volume of that ROI was measured to determine the standard uptake value (SUV) (Figures 13a and 13b) that presents the elimination profile from the PET images, and this was standardized against the injection dose. Tracer ([ 18F)4) demonstrated superior stability, evidenced by the absence of bone uptake. The primary elimination pathway for the tracer was via the kidney, although trace amounts were observed in the liver and gallbladder, indicating an optimal prosthetic group profile. Time-dependent radioactivity elimination in mouse tissues (Figures 13a and 13b) suggests that the adduct is rapidly eliminated primarily via the kidney.

[0209] Example 17.[ 18 Distribution of F25 in the body [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18 F)25, 0.2 nmol, 150 μL, ~1 MBq) was prepared in 4% ethanol in 0.01 M PBS and administered intravenously to Rj:NMRI-Foxn1 nu / nu mice with AR42J tumors. At predetermined time points after administration (t=30, 60, 120, and 240 minutes), selected organs were extracted, washed with water, blot-dried, and gamma counted. Based on the gamma-counted data, the percentage of the injected dose per gram of tissue (ID) (ID% / g) was calculated using the formula [(observed gamma count / ID) × 100] / tissue weight (g). The resulting values ​​were plotted on the in vivo distribution graph shown in Figure 14. Tracer [ 18 F25 demonstrated tumor accumulation and prolonged blood circulation time, primarily through renal excretion, but also demonstrated some hepatic uptake. Bone uptake was remarkably low, suggesting that the tracer is extremely stable against in vivo defluoridation.

[0210] Example 18. In mice with AR42J tumors [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18 F]25) PET / CT. [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18[F]25, 0.2 nmol, 150 μL, ~1 MBq) was prepared in 4% ethanol in 0.01 M PBS and administered intravenously to Rj:NMRI-Foxn1 nu / nu mice with AR42J tumors. To investigate the specificity of uptake in AR42J tumors, the mice were co-administered a blocking octreotide (44 nmol) to block the accumulation of radioactivity. PET / CT images were acquired using Molecubes PET and CT. In PEC / CT (Figure 15), the tracer ([ 18 F

[25] demonstrated superior stability, as evidenced by the lack of bone uptake. The primary elimination route for the tracer was through the kidneys into the urine, but trace amounts of accumulation were detected in the liver, gallbladder, and intestines, which accounted for some background radioactivity levels in PET images. The first animal (the animal on the left in Figure 15) was treated with blocked octreotide and radiolabeled [ 18 F]25 was administered intravenously at the same time. The second animal (the animal on the right in Figure 15) was administered without blocking octreotide (45 μg, 44 nmol) [ 18 Receiving only F25 enabled visualization of a subcutaneous tumor in the right shoulder. Radiolabeled [ 18 Blocking of [F]25 was successful, demonstrating specific uptake of radioactivity in the tumor, as seen in the PET image comparison in Figure 15 (T = tumor).

[0211] Example 19. In mice with AR42J tumors [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18 F)25) Radioactivity elimination after intravenous administration [ 18 F]AmBF3-Tyr 3 - Octreotide ([ 18F)25, 0.2 nmol, 150 μL, ~1 MBq) was formulated in 4% ethanol in 0.01 M PBS and administered intravenously to Rj:NMRI-Foxn1 nu / nu mice with AR42J tumors. Standard uptake values ​​(SLIV) (Figures 16 and 17) presenting the efflux profile were determined from PET images (Figure 15) by ROI around selected organs (heart, liver, kidney, lung, muscle, bladder, tumor), and SUV was calculated as disclosed in Example 16. [ 18 After administering F]25 alone (non-blocking) or [ 18 By comparing intratumoral SUV at various time points after co-administration of F25 and blockade octreotide (blockade), we were able to compare the SUV in mice with AR42J tumors (n=2 / group). 18 The binding specificity of F25 was determined. The results showed that in AR42J tumors, [ 18 The binding of F]25 is specific and can be blocked by co-administration of blocking octreotide (Figure 16). Tracer ([ 18 [F]25) was mainly excreted via the kidneys, and accumulation in the liver decreased over time, remaining minimal (Figure 17). Radioactivity within the tumor peaked at approximately 40 minutes and remained relatively stable thereafter. Successful blocking of radioactivity within the tumor was demonstrated by SUV comparative data (Figure 17), proving that tumor uptake was specific to the target area.

[0212] Example 20.[ 18 F]AmBF3-PSMA([ 18 F]28) and [ 18 F]AmBF3-Tranexamic acid-PSMA([ 18 In vitro intracellular translocation of F]29) Place C4-2 cells or LNCaP cells in a 6-well plate (6 × 10⁶) 24 hours before the experiment. 5 The cells in each well were seeded, and the culture medium was changed to CO2-independent medium 30 minutes before the experiment. 18 F]28 or [ 18Cells were incubated in 1 mL of 250 nM solution of F29 (15-20 GBq / mmol) CO2-independent medium. Specific cell uptake was determined by blocking with 2-(phosphonomethyl)pentanedioic acid (2-PMPA) (final concentration, 400 μM, Sigma). All experiments were performed at 37°C. Incubation was terminated after 30, 60, and 120 minutes by washing twice with 1 mL of ice-cold phosphate-buffered saline. Subsequently, cells were incubated twice for 5 minutes each in 1 mL of glycine HCl buffer (50 mM; pH 2.8) to remove the surface-bound fraction, and the supernatant was collected. After a further washing step with 1 mL of ice-cold phosphate-buffered saline, cells were lysed and collected in 0.5 mL of NaOH (1N), and radioactivity was measured with a gamma counter. Specific cell uptake was determined by blocking with 10 5 Calculated as the percentage of the initial radioactivity added to each individual cell (%IA / 10 5 Cells). All experiments were repeated three times. Based on the results of this experiment, the tracer to the cells [ 18 F]28 and [ 18 F]29 uptake was significantly blocked at 60 minutes when challenged with 2-PMPA blockade. 18 F]28: 2.05±0.28% vs. 0.58±0.09% and [ 18 The results for F29 are 1.05±0.09% vs. 0.31±0.03%, indicating specificity.

[0213] Example 21.[ 18 F]AmBF3-PSMA([ 18 F]28) and [ 18 F]AmBF3-Tranexamic acid-PSMA([ 18 F]29) PET / CT. [ 18 F]28 or [ 18 PET / CT imaging of F29 was performed in mice with C4-2 tumors (n=3-4), and the specificity of uptake was challenged by blocking it with 2-PMPA. In order to block it, [ 18 F]28 or [ 18Thirty minutes before the injection of F]29, mice were injected with 0.4 mM 2-PMPA (100 μL; 40 nmol) by tail vein injection. Radiotrace, [ 18 F]28 or [ 18 F]29 was administered by tail vein injection as a 0.01 mM solution (100 μL; 1 nmol). PET / CT images were acquired using Inveon PET / CT and Molecubes PET and CT. In PET / CT, both tracers ([ 18 F]28 and [ 18 F]29) demonstrated good to excellent stability, as evidenced by the lack of bone uptake. The primary excretion route for the tracer was through the kidneys into the urine. 18 Regarding F]29, as shown in Figure 18, when tracer uptake was significantly reduced in tumors (T), specific tumor uptake was demonstrated by blocking uptake with 2-PMPA.

[0214] Example 22.[ 18 F]AmBF3-PSMA([ 18 F]28) and [ 18 F]AmBF3-Tranexamic acid-PSMA([ 18 Distribution of F]29) in the body. [ 18 F]28 or [ 18 The in vivo distribution of F29 was determined in mice with C4-2 tumors, and its uptake specificity was challenged by blocking it with 2-PMPA. Each experiment was repeated three times. To block it, [ 18 F]28 or [ 18 Thirty minutes before injecting F29, SCID mice were administered 0.4 mM 2-PMPA (100 μL; 40 nmol) by tail vein injection.

[0215] Radioactive tracer, 18 F]28 or [ 18F29 was administered by tail vein injection as a 0.01 mM solution (100 μL; 1 nmol). One hour after injection, the animals were slaughtered (CO2 asphyxiation), the target organs were dissected, blotted and dried, and weighed. Radioactivity was measured using a gamma counter (1480 Wizard, PerkinElmer) and calculated as a percentage of the injected dose per gram (%ID / g). Tracer [ 18 F]28 or [ 18 Tumor-associated uptake of F]29 (Figure 19) was blocked by pre-infusion of 2-PMPA. 18 F]28: 7.51±0.69% vs. 1.18±0.19% and [ 18 F

[29] was 12.87±4.83% vs. 1.90±0.66%. Other organs showing high uptake included the kidneys, spleen, and gallbladder, where uptake was also reduced by the application of blocking agents.

[0216] Example 23.[ 18 F]AmBF3-PSMA([ 18 F]28), [ 18 F]AmBF3-Tranexamic acid-PSMA([ 18 Storage life and plasma stability of F]29). [Formulated in 1x PBS] 18 F]28 or [ 18 To determine the shelf-life stability of F29, 5 μL samples were analyzed by radioactive TLC at 0.5, 1, 2, 3, 4, 5, and 6 hours after being stored at room temperature (n=3). 18 F]28 and [ 18 For F]29, stability in PBS (>95%) was demonstrated for up to 6 hours. To measure enzyme stability, 400 μL of human plasma was used in 400 μL of [ 18 F]28 or [ 18 The mixture was incubated with the F29 formulation at 37°C (n=3). After 0.5, 1, 2, 3, and 4 hours, 100 mL of the sample was removed from the mixture, and the protein was precipitated by adding 50 μL of acetonitrile and separated from the supernatant by centrifugation at 13,000 rpm. The supernatant was analyzed by radioactive TLC.18 F]28 and [ 18 For F29, stability in plasma (>95%) was demonstrated for up to 4 hours. Compound [ 18 F]28 and [ 18 F]29 did not show significant degradation in either the formulation solution or human plasma throughout the entire observation period of the experiment.

[0217] The foregoing description provides a complete and useful description of the best mode currently considered by the inventors for carrying out the invention, as non-limiting examples of specific embodiments and models. However, it will be apparent to those skilled in the art that the invention is not limited to the details of the embodiments presented above and can be carried out in other embodiments or different combinations of embodiments using equivalent means without departing from the features of the invention.

[0218] Furthermore, some of the features of the exemplary embodiments disclosed above may be used as advantages without corresponding use of other features. Therefore, the foregoing description should be considered merely illustrative of the principles of the invention and not limiting the invention. Accordingly, the scope of the invention is limited only by the appended claims.

[0219] Various non-binding exemplary embodiments and models have been described above. The embodiments described herein are used solely to illustrate selected embodiments or processes that may be used in various implementations. Some embodiments may be presented with reference only to specific exemplary models. It should be understood that corresponding embodiments may also apply to other exemplary models.

Claims

1. Tracer compound of formula (I), or a pharmaceutically acceptable salt or solvate thereof. 【Chemistry 1】 (In the formula, Each R1 can independently be hydrogen (H) or C n H 2n+1 The alkyl substituent is (wherein n is an integer selected from 1 to 2) in the formula; L is a linker section consisting of S1-Y-S2, where: Y is (-CH 2 -) m (wherein the formula, m is an integer selected from the range of 1 to 4) or Y is polyethylene glycol linker (PEG) X - (in the formula, (PEG) X is polyethylene oxide-CH 2 -CH 2 It consists of x repeating units of -O-base, where x is an integer selected from 1 to 20; and S1 is -(CH 2 ) Z -CO-NH-(CH 2 ) Z - or S1 is -(CH 2 ) Z -NH-CO-(CH 2 ) Z -, where each z is an integer independently selected from the range of 0 to 4; and S2 is -CH 2 - or S2 is - (CH 2 ) f -CO-NH-(CH 2 ) f - or S2 is - (CH 2 ) f -NH-CO-(CH 2 ) f - and in the formula, each f is an integer independently selected from the range 0 to 4; and R2 is hydrogen (H), or a phenyl substituent or formula C S H 2S+1 (wherein s is an integer selected from the range of 1 to 2) is one of the alkyl substituents.

2. Each R1 independently contains hydrogen (H) or C n H 2n+1 The alkyl substituent is (wherein n is an integer selected from 1 to 2) in the formula; L is the linker section composed of S1-Y-S2, where: Y is (-CH 2 -) m (In the formula, m is an integer selected from the range of 1 to 4), and S1 is -CH 2 -CO-NH-, or -CH 2 It is -NH-CO- and S2 is -CH 2 - or not; or Y is polyethylene glycol linker (PEG). X - (in the formula, (PEG) X is polyethylene oxide-CH 2 -CH 2 It consists of x repeating units of -O-base, where x is an integer selected from 1 to 20; and S1 is -CH 2 -NH-CO-(CH 2 ) Z -, or -CH 2 -CO-NH-(CH 2 ) Z - where each z is an integer independently selected from the range 0 to 4; and S2 is - (CH 2 ) f -CO-NH-CH 2 -CH 2 - or - (CH 2 ) f -NH-CO-CH 2 -CH 2 - where each f is an integer independently selected from the range 0 to 4; and R2 is hydrogen (H), or a phenyl substituent or formula C S H 2S+1 A tracer compound according to claim 1, or a pharmaceutically acceptable salt or solvate thereof, wherein the alkyl substituent is one of those having (wherein s is an integer selected from the range of 1 to 2).

3. - (PEG) X The tracer compound according to claim 1 or 2, or a pharmaceutically acceptable salt or solvate thereof, wherein x in - is an integer selected from the range of 1 to 15 or from the range of 1 to 10.

4. (BF 3 ) - At least one F in the part 18 F is the tracer compound according to any one of claims 1 to 3, or a pharmaceutically acceptable salt or solvate thereof.

5. An adduct of the tracer compound and the TCO derivatization target moiety according to any one of Claims 1 to 4, or a pharmaceutically acceptable salt or solvate thereof, obtained by an inverse electron-demanded Diels-Alder reaction (IEDDA) between the TCO moiety of the trans-cyclooctene (TCO) derivatization target moiety and the tetrazine moiety of the tracer compound according to any one of Claims 1 to 4.

6. The adduct according to claim 5, or a pharmaceutically acceptable salt or solvate thereof, wherein the tetrazine ring of the tetrazine portion of the tracer compound is chemically bonded to the TCO portion of the TCO derivatization target portion.

7. The adduct according to claim 5 or 6, or a pharmaceutically acceptable salt or solvate thereof, wherein the target portion is a protein, peptide, antibody, antibody fragment, or nanoparticle.

8. (BF 3 ) - At least one F in the part 18 F is the adduct according to any one of claims 5 to 7, or a pharmaceutically acceptable salt or solvate thereof.

9. An adduct according to any one of claims 5 to 8, or a pharmaceutically acceptable salt or solvate thereof, for use in the detection of a target entity in a subject by radioimaging.

10. The adduct according to claim 9, or a pharmaceutically acceptable salt or solvate thereof, wherein the radioactive imaging is positron emission tomography.

11. A method for producing a tracer compound according to any one of claims 1 to 3, a. A step of dissolving a starting material in a polar aprotic solvent, and reacting the starting material with 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane to provide an intermediate product; b. Dissolve the intermediate product in a polar aprotic solvent and burn the intermediate product in the presence of an acid, water, and an organic solvent in KHF 2 The step includes reacting with to provide the tracer compound; The aforementioned starting material, via the linker portion, is a tertiary amine (-N(CH) 3 ) 2 It consists of a tetrazine moiety bonded to it; where, The tetrazine portion is composed of a 1,2,4,5-tetrazine ring, a phenyl ring bonded to C3 of the tetrazine ring, and R2 bonded to C6 of the tetrazine ring, wherein R2 is hydrogen (H), or a phenyl substituent or C1 S H 2S+1 One of the alkyl substituents having (wherein s is an integer selected from the range of 1 to 2); and The aforementioned linker portion is composed of S1-Y-S2, where: Y is (-CH 2 -) m (wherein the formula m is an integer selected from the range of 1 to 4) or Y is polyethylene glycol linker (PEG) X - (in the formula, (PEG) X is polyethylene oxide-CH 2 -CH 2 It consists of x repeating units of -O-base, where x is an integer selected from 1 to 20; and S1 is - (CH 2 ) Z -CO-NH-(CH 2 ) Z - or S1 is - (CH 2 ) Z -NH-CO-(CH 2 ) Z - where each z is an integer independently selected from the range 0 to 4; and S2 is -CH 2 - or S2 is - (CH 2 ) f -CO-NH-(CH 2 ) f - or S2 is - (CH 2 ) f -NH-CO-(CH 2 ) f - and here each f is an integer independently selected from the range 0 to 4, in this way.

12. The linker portion of the starting material is composed of S1-Y-S2, where: Y is (—CH 2 —) m (where m is an integer selected from the range of 1 to 4), S1 is —CH 2 —CO—NH—, or —CH 2 —NH—CO—, and S2 is —CH 2 —; or Y is polyethylene glycol linker-(PEG) X -(wherein, (PEG) X is polyethylene oxide -CH 2 -CH 2 -O-group containing x repeating units, x is an integer selected from the range of 1 to 20); and S1 is -CH 2 -NH-CO-(CH 2 ) Z -, or -CH 2 -CO-NH-(CH 2 ) Z - (wherein each z is an integer independently selected from the range 0 to 4); and S2 is - (CH 2 ) f -CO-NH-CH 2 -CH 2 - or - (CH 2 ) f -NH-CO-CH 2 -CH 2 The method according to claim 11, wherein (wherein each f is an integer independently selected from the range of 0 to 4).

13. A method for producing an adduct according to any one of claims 5 to 10, or a pharmaceutically acceptable salt or solvate thereof, wherein the method is: A step of providing a TCO derivatization target moiety; A step of providing a tracer compound according to any one of claims 1 to 3; A step of reacting the tetrazine portion of the tracer compound with the TCO portion of the TCO derivatization target portion; and The aforementioned appendage is at least one 18 Does it include a step of obtaining an adduct by radioactively labeling with F? Or the method described above is A step of providing the TCO derivatization target portion; A step of providing the tracer compound according to any one of claims 1 to 3; The tracer compound according to any one of claims 1 to 3 is used to make at least one 18 The process of radioactively labeling with F; and A method comprising the step of reacting the tetrazine portion of the radiolabeled tracer compound with the TCO portion of the TCO derivatization target portion to obtain the adduct.

14. The method according to claim 13, comprising the step of reacting the tetrazine portion of the radiolabeled tracer compound with the TCO portion of the TCO derivatization target portion at a temperature between 20 and 80°C.

15. The use of a tracer compound according to any one of claims 1 to 4, or a pharmaceutically acceptable salt or solvate thereof, in the detection of a target entity in a subject by radioimaging of the subject, wherein the target entity is targeted by the radiolabeled tracer compound, or a pharmaceutically acceptable salt or solvate thereof.

16. For the detection of target entities in a subject using radioactive imaging. 18 A kit for producing an F-labeled adduct, comprising: at least one compartment containing a tracer compound according to any one of claims 1 to 3; at least one compartment containing at least one TCO derivatization target moiety; and a kit for radiolabeling the tracer compound. 18 A kit comprising at least one compartment containing F, and optionally an aqueous solvent and an organic solvent for an inverse electron-demanded Diels-Alder reaction (IEDDA) and for radiolabeling the tracer compound and / or the adduct.

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