Formulations and treatments using hydroxypyridonate actinide / lanthanide decorporation agents

Abstract

Providing methods of treating diseases SOLUTION: Provided herein is a method of treating a subject in need of treatment comprising administering to the subject in need of such treatment a therapeutically effective amount of one or more pharmaceutical compositions comprising a 1, 2-HOPO chelator and / or a 3, 2-HOPO chelator. The subject may be one who has been or will be exposed to one or more known or unknown actinides and / or lanthanides, or mixtures thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Government Assistance Statement This invention was made with government support from the National Institutes of Health (NIAID / NIH, Grant No. RAI087604Z) under Contract No. DE-AC02-05CH11231 from a laboratory affiliated with the U.S. Department of Energy. The United States Government has certain rights in this invention. [Background technology]

[0002] FIELD OF THE INVENTION The present invention relates generally to the treatment of metal poisoning.

[0003] 2. Description of Related Art Large numbers of people can be contaminated by exposure to radionuclides that are accidentally scattered, intentionally scattered by radiation dispersion devices, or dispersed by nuclear power plant accidents or nuclear device explosions. The public health impact of such contamination events can be enormous, as internalized radionuclides are highly toxic and can cause both acute and chronic radiation injury.

[0004] Chelation by chelating agents is one method for reducing exposure to certain incorporated isotopes, and diethylenetriaminepentaacetic acid (DTPA) has been the standard treatment for actinide / lanthanide elimination since its development and use by the U.S. Atomic Energy Commission in the 1950s. Summary of the Invention

[0005] Summary of the Invention Embodiments herein provide a method of treating a subject in need of treatment, comprising administering to the subject in need of such treatment a pharmaceutical composition comprising a therapeutically effective amount of one or more 1,2-HOPO and 3,2-HOPO chelators. This method is particularly useful when performed on subjects who have been or may be exposed to, contacted with, or contaminated with one or more known or unknown actinides and / or lanthanides, or mixtures thereof.

[0006] In some embodiments, a method for treating heavy metal exposure in a subject is provided. The method includes administering a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelator to a subject having an excess amount of one or more of gadolinium, lead, tin, yttrium, scandium, or cadmium, wherein the administering step results in excretion, elimination, or reduction of the amount of gadolinium, lead, tin, or cadmium from the subject. In some embodiments, the subject has been exposed to, contacted with, or contaminated with one or more actinides and / or lanthanides, or mixtures thereof.

[0007] In some embodiments, the administering step results in the excretion, elimination, or reduction of the amounts of actinide and / or lanthanide, or both, from one or more systems or organs of the subject.

[0008] In some embodiments, the 1,2-HOPO chelator has the structure: [ka] (In the formula, R is a hydroxy group or [ka] and R1 and R2 are selected from the group consisting of H, --CH3, --CH2CH3, and --CH2--φ, and X is either hydrogen, an alkali metal ion, or a quaternary ammonium ion.

[0009] In some embodiments, the 1,2-HOPO chelator is [ka] , [ka] , and [ka] wherein l, m, and n are integers between 1 and 20. In some embodiments, m is 3. In some embodiments, n is 4. In some embodiments, l and n are 3 and m is 4. In some embodiments, the 1,2-HOPO chelator is 3,4,3-LI-1,2-HOPO. In some embodiments, the subject has an excess of one or more of gadolinium, lead, yttrium, scandium, cadmium, or tin.

[0010] In some embodiments, a method for prophylactically treating metal exposure in a subject is provided. The method comprises administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelating agent. In some embodiments, the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. In some embodiments, the metal is a heavy metal. In some embodiments, the heavy metal is selected from the group consisting of gadolinium, lead, tin, cadmium, yttrium, scandium, and plutonium. In some embodiments, the metal is an actinide, a lanthanide, or a mixture thereof.

[0011] In some embodiments, a method is provided comprising administering a 1,2-HOPO chelating agent to a subject before or after administering an MRI contrast agent to the subject. In some embodiments, the subject is identified as a subject scheduled to receive an MRI contrast agent. In some embodiments, the contrast agent comprises Gd. In some embodiments, the amount of contrast agent is 100-600 μmol / kg. In some embodiments, the 1,2-HOPO chelating agent is administered before the subject receives the MRI contrast agent. In some embodiments, the 1,2-HOPO chelating agent is administered after the subject receives the MRI contrast agent. In some embodiments, the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. In some embodiments, the subject has severe renal impairment.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS Those skilled in the art will readily appreciate the foregoing aspects and others from the following description of exemplary embodiments when read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows the structures of 5-LIO(Me-3,2-HOPO) (“5LIO”) and 3,4,3-LI(1,2-HOPO) (“343LI”).

[0014] [Figure 2] FIG. 2 shows the structure of diethylenetriaminepentaacetic acid (DTPA).

[0015] [Figure 3] FIG. 3 shows the total body content and distribution of 238Pu for 7 days after a single time-delayed ip chelation treatment.

[0016] [Figure 4]Figure 4 shows the daily cumulative excretion of 238Pu after a single delayed ip chelation treatment at 1 hour (A), 5 hours (B), 16 hours (C), 24 hours (D), 3 days (E), or 7 days (F) after contamination. Young adult female Swiss-Webster mice were intravenously injected with plutonium citrate (238Pu); as indicated by the arrows, saline or various treatments (3,4,3-Li(1,2-HOPO) (30 μmol / kg), 5-Li(Me-3,2-HOPO) (100 μmol / kg), or Ca-DTPA (30 μmol / kg)) were administered ip at 1 hour, 5 hours, 16 hours, 24 hours, 3 days, or 7 days after contamination; mice were euthanized 7 days after treatment. Excretion from each group of five mice was pooled. Because data are calculated from cumulative recovered excretion, standard deviations are not available.

[0017] [Figure 5] Figure 5 shows the daily excretion of Pu in feces (left panels A, C, E, G) and urine (right panels B, D, F, H) after delayed ip chelation treatment with a single dose of 3,4,3-LI(1,2-HOPO) (A and B), 5-LI(Me-3,2-HOPO) (C and D), DTPA (E and F), or saline (G and H) at 1, 5, 16, 24, 3, or 7 days after contamination.

[0018] [Figure 6] Figures 6A-C show the total body content and distribution of 238Pu 3 days after a contamination event preceded by a single prophylactic chelation treatment.

[0019] [Figure 7] Figure 7 shows the daily excretion of Pu in feces (top panels A and B) and urine (bottom panels C and D) after a single prophylactic ip chelation treatment with 3,4,3-LI(1,2-HOPO) (left panels A and C) or po chelation treatment (right panels B and D).

[0020] [Figure 8A]Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8B] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8C] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8D] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8E] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8F] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8G] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8H] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8I] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8J] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8K]Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8L] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8M] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8N] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8O] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8P] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). [Figure 8Q] Figures 8A-8Q show the results from Example 9. Results are plotted as percentage of recovered dose (percent RD). DETAILED DESCRIPTION OF THE INVENTION

[0021] Detailed Description of Various Embodiments A major radiological accident can result not only in large-scale external exposure of the population but also in the uncontrolled spread of radionuclides and internal contamination. Emergency response planning for radiological and nuclear incidents must consider not only the need for post-exposure treatment of contaminated individuals, but also the need for preventative measures to protect contaminated areas and patient-facing professionals in the aftermath of such events. In addition to meeting desirable criteria for post-exposure treatment, such as safety, ease of administration, and broad-spectrum effectiveness and challenge levels against multiple radionuclides, an ideal preventative measure must be fast-acting with minimal or no performance-degrading side effects; compatible with current military chemical, biological, radiological, nuclear, and explosive countermeasures; and require minimal logistical burden.

[0022] Hydroxypyridinone-based actinide efflux agents show promise as elimination strategies for a variety of radionuclides of concern, including the actinides plutonium and americium. Several results presented herein explore the range of plutonium efflux efficacy for two chelators, 3,4,3-LI(1,2-HOPO) and 5-LI0(Me-3,2-HOPO), from an initial preexposure time point through 7 days after administration via parenteral or oral treatment (i.e., well beyond the first few hours of emergency response). Despite delayed treatment after a contamination event, both ligands clearly enhanced plutonium efflux throughout the 7-day posttreatment period studied. Furthermore, significant preventive efficacy was observed for 3,4,3-LI(1,2-HOPO) using early treatment, 48 hours before plutonium challenge. This study provides new insights into the indications and use of experimental actinide efflux agents.

[0023] Rapid elimination from the body is essential to mitigating both the immediate and future biological effects resulting from radioactive contamination. Adverse health effects include tissue damage and the development of various cancers, which depend on factors such as the amount of contaminant and the duration of contamination. Internal contamination (i.e., deposition of radionuclides within the body through routes including ingestion, inhalation, and absorption through wounds) is particularly dangerous because it can result in localized radiation effects, systemic effects, or a combination.

[0024] To enhance emergency preparedness in the United States in response to potential nuclear accidents and terrorist threats, the U.S. Food and Drug Administration (FDA) approved two forms of diethylenetriaminepentaacetic acid (DTPA)—calcium (Ca-DTPA) and zinc (Zn-DTPA)—in 2004 to promote the excretion of plutonium, americium, and curium after internal contamination. DTPA is the first and only approved drug for treating internal contamination with the above-mentioned radioactive elements, but its effectiveness is limited to certain forms, routes of administration, and dosages of these elements. The effectiveness of the drug is hindered when the isotope is mixed with other substances; as a result of reduced absorption of the drug in the gastrointestinal tract, the drug must be administered intravenously or by inhalation via nebulization, depending on the route of contamination; and the drug must be ingested in large quantities. Experiments have also shown that Ca-DTPA does not significantly chelate plutonium after its deposition in organs, which explains the need for treatment as soon as possible after contamination. However, as demonstrated in rats and dogs, although the large molar percentage of parenterally administered DTPA can reside in the blood and extracellular fluids, it is not excreted from the body by the liver. Only a small fraction may reach the intracellular spaces responsible for efficacy. Furthermore, side effects of DTPA include the loss of essential metals such as zinc and magnesium from the body, further highlighting the need for alternative excretion therapies.

[0025] Addressing the limitations of Ca-DTPA and Zn-DTPA, the octadentate hydroxypyridinone chelator 3,4,3-LI(1,2-HOPO) has demonstrated efficacy with high potency and low toxicity via parenteral and oral routes of administration—a desirable quality in drug development. The study not only considered gender differences by testing efficacy in both male and female mice, but also elucidated the ability of 3,4,3-LI(1,2-HOPO) to form stable, excretable complexes with DTPA-chelated radioactive elements, including uranium, neptunium, and europium, at physiological pH. Its efficacy and safety have been demonstrated in multiple animal models, meeting the standards set out in the FDA's Animal Efficacy Regulations, and have been approved, as efficacy testing in humans is ethically unfeasible. 3,4,3-LI (1,2-HOPO), a promising candidate for treating internal radionuclide contamination, received Investigational New Drug (IND) designation from the FDA in August 2014 and is awaiting phase I clinical trials.

[0026] The experiments described herein confirm the potential for delayed and prophylactic treatment of internal plutonium contamination by intraperitoneal injection or oral administration. Realistically, it will not be possible to treat a large proportion of the population after a radiological incident until after the first 24 hours of emergency response; similarly, prophylaxis is essential for first responders and the military. An ideal prophylaxis should provide broad protection against multiple isotopes and levels of challenge. In some embodiments, it is also desirable for the prophylaxis to be safe, effective, rapidly acting, easy to administer, induce minimal or no performance-limiting side effects, be compatible with current military chemical, biological, radiological, and nuclear (CBRN) countermeasures, and / or impose a minimal logistical burden. Consequently, the current limitations of DTPA-based products and the lack of available drugs for use before exposure to radiological agents highlight the importance and urgency of developing new, effective elimination therapies, such as 3,4,3-LI(1,2-HOPO). Additionally, other embodiments and applications for the chelators are provided herein, such as use for reducing risks associated with MRI contrast agents.

[0027] The following disclosure provides a series of brief definitions, then provides further details regarding various embodiments for treatment, prevention, and the like, including the chelators provided herein, and then provides a series of examples regarding the various embodiments.

[0028] definition The term "emergency" includes: (a) any accidental release of radioisotopes into the environment resulting from any nuclear accident; (b) any accidental release of harmful nuclides into the environment; (c) nuclear fallout (including fallout occurring in the normal course of experimental, diagnostic or therapeutic purposes); (d) any kind of accidental uptake and retention of radionuclides by human or animal subjects; (e) any other kind of exposure to volatile radionuclides; and (f) any kind of radiological accident.

[0029] The term "pharmaceutically acceptable salts" as used herein refers to, inter alia, the pharmaceutical compositions of a compound. When referring to a pharmaceutically acceptable salt (including 3,4,3-LI(1,2-HOPO)), it refers to any pharmaceutically acceptable salt of the compound, preferably an acid addition salt of the compound.

[0030] The terms "pure," "purified," "substantially purified," and "isolated," as used herein, refer to a compound of the embodiments that is free of other distinct compounds with which the compound would be associated in its natural state if found in its natural state. In certain embodiments described herein as "pure," "purified," "substantially purified," or "isolated," the compound may comprise at least 0.5% to 1%, 1% to 5%, 5% to 10%, 10% to 20%, 20% to 50%, 50% to 70%, 70% to 90%, 90% to 95%, 95% to 99%, and 99% to 100%. In some embodiments, the amount of the compound is at least 50% or 75% by weight of the total mass of a given sample. "Functional purity" is a measure of the amount of a particular compound in a sample or product relative to other compounds in the sample that may adversely affect the function of the particular compound in the sample or product. Thus, other components in the sample that do not interfere with the activity of the compound (eg, water) are not used in determining the purity of the sample or product.

[0031] The terms "derivative," "variant," or other similar terms refer to a compound that is an analog of another compound.

[0032] The term "and / or" indicates both the "and" and "or" alternatives in certain circumstances. However, unless otherwise specified herein, use of the term "or" or "and" includes a description of both alternatives. Thus, the use of the term "or" should not be construed as excluding the "and" alternative unless further context indicates that the "and" alternative should be excluded (this definition does not apply to terms in the claims). Unless otherwise indicated, the use of the singular and plural forms of a term includes both alternatives (singular or plural) and both combinations of alternatives (singular and plural).

[0033] The term "inhibition," as used herein, refers to any statistically significant reduction in the adverse effects of a metal, including complete blocking of activity. For example, "inhibition" can refer to a reduction in the adverse effects of a metal by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%.

[0034] The term "patient" includes human and other mammalian subjects receiving either prophylactic or therapeutic treatment.

[0035] The terms "treat" or "prevent" do not require complete treatment or complete prevention under all conditions. A delay in the onset of a disorder or its symptoms or a reduction in the number of symptoms may be appropriate "prevention" in some embodiments. Similarly, a reduction in the severity of symptoms of a disorder may also be an effective treatment of the disorder. "Prophylactic treatment" refers to administration of a compound prior to exposure to a harmful compound (e.g., a metal such as plutonium or an MRI imaging agent). Treatment may also be responsive to exposure (e.g., response therapy). Treatment may also include correction, exenteration, and / or decontamination.

[0036] "Therapeutically effective amount" refers to the amount of a chelator (such as 3,4,3-LI(1,2-HOPO), 5-LI0(Me-3,2-HOPO), and / or DTPA) that elicits the biological or medical response in a tissue system, animal, or human sought by a researcher, veterinarian, physician, or other clinician, where the response includes alleviation of symptoms of the disease or disorder being treated. The particular amount of chelator required to elicit the biological or medical response is The efficacy of the chelating agent will depend on several factors, including, but not limited to, the disease or disorder being treated, the chelating agent being administered, the method of administration, and the condition of the patient.

[0037] "Mammal," as used herein, refers to any animal that is considered a mammal. Preferably, the mammal is a human.

[0038] The term "pharmaceutical product or drug," as used herein, refers to a chemical compound or composition capable of inducing a desired therapeutic effect when properly administered to a patient. Other chemical terms herein are used in accordance with conventional usage in the art, as exemplified by The McGraw-Hill Dictionary of Chemical Terms (Parker, S., Ed., McGraw-Hill, San Francisco (1985)), which is incorporated herein by reference.

[0039] The term "heavy metal" refers to one or more transition metals, metalloids, metallic elements in Groups 13, 14, and 15 of the periodic table, actinides, and / or lanthanides. Heavy metals include, for example, gadolinium, lead, tin, cadmium, yttrium, scandium, and plutonium.

[0040] How to use a chelator Previous studies have shown that excretion of radionuclides is enhanced after prompt or slightly delayed treatment with chelating agents (most often within the first 24 hours of a contamination event). The scenario for human contamination with actinides involves numerous unknowns, but unfortunately, widespread implementation of treatment or rapid availability to large populations after an incident seems unlikely.

[0041] One of the experiments provided in the Examples below established the effective range of excretion well beyond the initial 24-hour emergency response, with up to a 7-day delay in administering treatment. In this case, extending the autopsy time point to 7 days after treatment was useful for comparing plutonium excretion patterns over several days (i.e., until the rate of actinide excretion had significantly slowed). When preparing for a nuclear emergency, additional considerations must be taken into account, including the need for pre-event prophylaxis, particularly for the military and first responders. Another study described below employed a different experimental protocol to explore the potential prophylactic activity of actinide excretors. 238 Treatment was administered either parenterally or orally prior to Pu challenge (delayed up to 48 hours before contamination). In this study, the necropsy time point was set at 3 days after contamination, regardless of treatment time.

[0042] When provided after contamination, despite delayed treatment, parenteral 3,4,3-LI(1,2-HOPO), 5-LI(Me-3,2-HOPO), and DTPA all significantly increased the efficacy of DTPA throughout the 7-day posttreatment period studied. 238 Pu excretion was clearly enhanced.

[0043] However, the behavior of the two HOPO ligands differed in that the known and confirmed enhanced excretion persisted over several days for 3,4,3-Li(1,2-HOPO) and DTPA, but was not observed with 5-LiO(Me-3,2-HOPO). Furthermore, the observed enhancement of excretion after treatment with 5-LiO(Me-3,2-HOPO) or DTPA was not observed. 238 The rate of Pu excretion slowed earlier than that after 3,4,3-LI(1,2-HOPO) injection.

[0044] 238 The superiority of 3,4,3-LI(1,2-HOPO) in enhancing Pu excretion rate was also demonstrated in the following prophylactic protocol: 5-LI(Me-3,2-HOPO) and DTPA when administered within 6 hours before contamination. 238 The decrease in Pu content Although the efficacy of 3,4,3-LI(1,2-HOPO) was significantly higher, 238 Even early treatment, 48 hours before Pu challenge, was effective.

[0045] Formed with 3,4,3-LI(1,2-HOPO) or DTPA 238 While Pu complexes are relatively rapidly cleared and completely eliminated from the body within 24 hours, the persistent enhanced excretion profile in treated animals has been suggested to be due to cellular uptake and delayed clearance of the ligand. 14 The pharmacokinetics and biodistribution profile of C-labeled 3,4,3-Li(1,2-HOPO) were recently characterized in a juvenile Swiss-Webster mouse model. After parenteral injection, the radiolabeled compound rapidly distributed within highly vascularized tissues, with peak concentrations observed in the kidney and liver as early as 1 hour after administration. However, this high concentration remained constant, and more significantly, approximately 40% of the administered dose remained in various tissues and organs after 24 hours. These results are a good indicator of the longer residence time of 3,4,3-Li(1,2-HOPO), which correlates well with both its duration of action after treatment and the magnitude of its protective window. Similarly, clearance of the radiolabeled ligand after oral administration was more rapid, as most of the compound remained unabsorbed and was readily excreted by 24 hours. Nevertheless, significant retention of the ligand within the first 6 hours after oral administration again demonstrates the shorter but consequential protective activity of 3,4,3-Li(1,2-HOPO) after oral administration.

[0046] In feces and urine in Figure 5 238Pu emissions were promoted by either HOPO ligand, as evidenced by the figure. 238 The biliary route as the primary route of Pu excretion is dramatically different from the pattern of enhanced urinary excretion resulting from treatment with DTPA. These differences have been previously discussed and are likely based on the physicochemical parameters (solubility, lipophilicity, and ionization constants, etc.) of the respective ligands and actinide complexes. Furthermore, Pu excretion after either parenteral or oral administration is significantly enhanced. 14 The biliary route is the primary mode of excretion for 3,4,3-Li(1,2-HOPO) in mice, as evidenced by the high fecal accumulation of C-labeled 3,4,3-Li(1,2-HOPO). Thus, the excretion pathway for the radionuclide appears to be ligand-driven. In one case of prophylactic parenteral treatment with 3,4,3-Li(1,2-HOPO) 1 hour before contamination, 238 Of particular interest is the fact that Pu urinary excretion was described to be three times higher than fecal levels. 14 The deposition profile of the C-labeled ligand also showed higher urinary excretion at early time points, within 4 hours of ligand administration, which was attributed to a longer colonic transit time associated with biliary excretion. Thus, the excretion pattern observed in the early prophylaxis cases suggests that the 3,4,3-LI(1,2-HOPO) ligand was available as soon as it entered the systemic circulation. 238 It is suggested that it chelates a fraction of Pu, thereby preventing this fraction from reaching the site of radionuclide deposition.

[0047] As detailed above and demonstrated in the examples below, 238Enhanced Pu elimination was observed after parenteral treatment with 3,4,3-LI(1,2-HOPO), 5-LI0(Me-3,2-HOPO), or DTPA delayed up to 7 days after contamination, with roughly equivalent efficacy for the latter two ligands, but with a large and significant reduction in whole-body and tissue content for 3,4,3-LI(1,2-HOPO). However, elimination efficacy clearly decreased with increasing treatment delay. Another attribute of the 3,4,3-LI(1,2-HOPO) ligand demonstrated in the studies presented herein is its high elimination efficacy when administered prophylactically as early as 48 hours before exposure. On the other hand, 3,4,3-LI(1,2-HOPO), a lead hydroxypyridinonate chelator under investigation, significantly reduced Pu excretion from contaminated mice, even when a single treatment was delayed 7 days after exposure. 238 It is noteworthy that this study confirms that extracorporeal treatment should be performed with as short a delay as possible after contamination, promoting significant removal of Pu. Furthermore, the long spectrum of preventive activity revealed here opens new perspectives in the indication and use of this extracorporeal treatment. Extensive nonclinical studies have highlighted the safety of hydroxypyridinonate chelators and the absence of serious toxicity concerns, and for now, 3,4,3-LI(1,2-HOPO) can be considered useful for prophylactic use, with treatment decisions based on suspicion or prevention of potential contamination rather than knowledge, which may require lengthy triage, evaluation, and decision-making procedures in emergency situations. These results therefore complement the available efficacy data set for hydroxypyridinonate ligands in general, and 3,4,3-LI(1,2-HOPO) in particular, and, in combination with parallel clinical safety analyses, 238 This will help define treatment options for Pu excretion.

[0048] Various applications of the above aspects are provided below.

[0049] How to use In some embodiments, a method for treating heavy metal exposure in a subject is provided, comprising administering a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelator to a subject having an excess amount of one or more of gadolinium, lead, tin, yttrium, scandium, and / or cadmium, resulting in excretion, elimination, or reduction of the gadolinium, lead, tin, and / or cadmium from the subject.

[0050] In some embodiments, the subject may be exposed to, and / or in contact with, and / or be exposed to or contaminated with, one or more actinides and / or lanthanides, or mixtures thereof. In some embodiments, the subject has an excess amount of one or more of gadolinium, lead, yttrium, scandium, cadmium, or tin. In some embodiments, the subject has an excess amount of gadolinium. In some embodiments, the subject has an excess amount of lead. In some embodiments, the subject has an excess amount of yttrium. In some embodiments, the subject has an excess amount of scandium. In some embodiments, the subject has an excess amount of cadmium. In some embodiments, the subject has an excess amount of tin. The excess amount may be an amount above normal baseline or background levels. In some embodiments, the excess amount may be an amount that is unhealthy for the subject. In some embodiments, the excess amount is at least 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1000, or 10,000 percent or more of the amount of heavy metal present in an unexposed individual. That is, the excess amount is at least 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1000, or 10,000 percent higher than the baseline resulting from a standard environment. In some embodiments, such as in the case of Gd, the average dose of different imaging agents is 0.1 mmol / kg, or 7 mmol, in a 70 kg adult, which is approximately 1 g of Gd per patient. For some MRI scans, patients ingest about 1 g of chelated Gd, and a few percent of the Gd remains in the body. Therefore, reducing the amount of Gd remaining in the body below this level may be beneficial to the subject. For lead (Pb), the excess may be at even lower levels since lead is more toxic.

[0051] In some embodiments, the method is a prophylactic method. A method for prophylactically treating a subject against metal exposure can include administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelating agent.

[0052] In some embodiments, the chelating agent can be any chelating agent provided herein. In some embodiments, the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. In some embodiments, the 3,4,3-LI-1,2-HOPO compound can be used for the treatment of heavy metal exposure either before or after exposure. In some embodiments, the treatment of heavy metal exposure either before or after exposure to heavy metals can be used. 3,4,3-LI-1,2-HOPO can be used in the preparation of a medicament for the treatment of heavy metal exposure. In some embodiments, a composition can include 3,4,3-LI-1,2-HOPO for the treatment of heavy metal exposure, either pre- or post-exposure. In some embodiments, a composition can include 3,4,3-LI-1,2-HOPO for the neutralization of contrast agents from MRI, such as gadolinium-based contrast agents. In some embodiments, 3,4,3-LI-1,2-HOPO can be used to prepare a medicament for the reduction and / or removal of gadolinium-based contrast agents (GBCAs).

[0053] In some embodiments, the subject is or may be exposed to one or more heavy metals. In some embodiments, the subject is scheduled to undergo or is about to undergo MRI. In some embodiments, the MRI procedure requires the administration of a gadolinium-based contrast agent (GBCA) (such as gadoterate (Dotarem), gadodiamide (Omniscan), gadobenate (Multihans), gadopentetate (Magnevist), gadoteridol (Prohans), gadofosveset (Abrava, formerly Vasovist), gadoversetamide (OptiMARK), gadoxetate (Eovist), or gadobutrol (Gadavist)). In some embodiments, one or more negative effects from an MRI contrast agent can be reduced by the use (prophylactic or otherwise) of one or more chelators provided herein, particularly 3,4,3-LI-1,2-HOPO. In some embodiments, the contrast agent comprises Gd. In some embodiments, effects include: 1) pain - tingling; burning, soreness, and / or tingling (paresthesia); deep bone pain; typically seen in the limbs or joints, occasionally in an MRI scan area such as the head; 2) skin changes - tight skin, rash, hyperpigmentation, etc.; most often seen in the limbs; 3) muscle problems - spasms - small, localized, rapid contractions and weakness; 4) eye problems - decreased vision, dry eyes, bloodshot eyes; 5) cognitive symptoms; 6) ear, nose, and throat - ringing in the ears, swallowing, and voice problems; 7) hypothermia; 8) hair loss; 9) itchy skin; 10) balance problems; 11) swelling of the limbs (edema); and / or 12) occasionally Perception of a localized, sometimes more generalized feeling, typically an electric, vibrating, twitching sensation just below the skin.

[0054] In some embodiments, the administering step results in the excretion, elimination, or reduction of the amount of actinides and / or lanthanides from one or more systems and / or organs of the subject. In some embodiments, the heavy metals present in the subject are reduced by at least 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, or 100 percent. In some embodiments, when applied prophylactically, the heavy metals clear the subject more quickly and do not need to accumulate substantially within the subject, which is beneficial. In some embodiments, the heavy metals are present in the subject for 10, 20, 30, 40, 50, 60, 70, 80, or 90% less time than if the subject had not received the chelator. In some embodiments, the heavy metal is excreted from the subject at a rate that is 1.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000, 10,000 times or more faster than if the subject had not received the chelator.

[0055] In some embodiments, a chelator as described herein is administered to a subject exposed to or at risk of exposure to a heavy metal 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 hours or more before.

[0056] In some embodiments, the metal is a heavy metal. Any heavy metals provided herein may have adverse health effects that are reduced by one or more chelators provided herein in a preventative manner. In some embodiments, the heavy metal is selected from at least one of the group consisting of gadolinium, lead, tin, cadmium, yttrium, scandium, and plutonium. In some embodiments, the preventative chelator can be used to protect against heavy metals, actinides, lanthanides, or mixtures thereof.

[0057] In some embodiments, the 1,2-HOPO chelator has the structure: [ka] is defined by

[0058] During the ceremony, R is a hydroxy group or [ka] and R1 and R2 are selected from the group consisting of H, --CH3, --CH2CH3, and --CH2--φ, and X is either hydrogen, an alkali metal ion, or a quaternary ammonium ion.

[0059] In some embodiments, the 1,2-HOPO chelator is [ka] , [ka] , and [ka] wherein l, m, and n are integers between 1 and 20.

[0060] In some embodiments, m is 3 and / or n is 4. In some embodiments, l and n are 3 and m is 4. In some embodiments, the 1,2-HOPO chelator is 3,4,3-LI-1,2-HOPO.

[0061] Suitable 3,2-HOPO chelating agents include those having the following structure: Examples of chelating agents include, but are not limited to, chelating agents having the formula:

[0062] Modes of Administration and Pharmaceutical Formulations Suitable modes of administration of the pharmaceutical compositions include oral, topical, aerosol, inhalation by spray, parenteral, subcutaneous, intravenous, intramuscular, interperitoneal, rectal, and vaginal administration. The term parenteral as used herein includes, but is not limited to, subcutaneous injection techniques as well as intravenous, intrathecal, intramuscular, and intrasternal injections. Injection or infusion techniques are included. A particular mode of administration is one that delivers the chelating agent to the actual site(s) or potential site(s) of radionuclide contamination in a subject. The pharmaceutical composition may be in solid, semi-solid, and / or liquid form. In some embodiments, any of the above formulations may be used for any of the metal (including gadolinium, lead, tin, and / or cadmium) and / or prophylactic uses provided herein.

[0063] Pharmaceutically acceptable carriers described herein (e.g., vehicles, adjuvants, excipients, and diluents) are well known and readily available to those skilled in the art. In some embodiments, the carrier is chemically inert to the compounds of the chelating agent and has no adverse side effects or toxicity under the conditions of use. In some embodiments, the pharmaceutically acceptable carrier is pyrogen-free. Pharmaceutically acceptable carriers that can be used include, but are not limited to, water, glucose, lactose, acacia gum, gelatin, mannitol, starch paste, magnesium trisilicate, talc, corn starch, keratin, colloidal silica, potato starch, and urea.

[0064] The amount of chelating agent that can be combined with a pharmaceutically acceptable carrier to produce a single dosage form varies depending on the subject being treated and the particular mode of administration. Suitable dosage levels of the chelating agent include about 1 mg / kg body weight / day to about 500 mg / kg body weight / day. In some embodiments, suitable dosage levels are about 20 mg / kg body weight / day to about 100 mg / kg body weight / day. In some embodiments, suitable dosage levels of 3,4,3-LI-1,2-HOPO are about 10 μmol / kg body weight to about 100 μmol / kg body weight. In some embodiments, suitable dosage levels of 5-LIO-Me-3,2-HOPO are about 30 μmol / kg body weight to about 200 μmol / kg body weight. Dosage unit forms generally contain about 20 mg to about 100 mg of the chelating agent. Additionally, pharmaceutical compositions can be administered intermittently (i.e., daily, twice weekly, or weekly). It is understood, however, that the specific dosage level for a particular subject will depend on a variety of factors, including the activity of the particular compound used, the age, weight, general health, sex, and diet of the subject, the time and route of administration and excretion rate of the chelating agent, the combination of chelating agents used in the treatment, and the severity of the particular disease or condition for which treatment is sought.

[0065] Pharmaceutical compositions suitable for oral administration include, but are not limited to, (a) liquid formulations; (b) capsules, sachets, tablets, lozenges, and troches (each containing a predetermined amount of the active ingredient as a solid or granules); (c) powders; (d) suspensions; and (e) suitable emulsions. Liquid formulations may contain diluents (such as water and alcohol) and, optionally, a pharmaceutically acceptable surfactant. Capsule forms may be, for example, conventional hard-shell or soft-shell gelatin types containing surfactants, lubricants, and inert fillers. Tablet forms may contain one or more of lactose, sucrose, mannitol, corn starch, potato starch, alginic acid, microcrystalline cellulose, acacia, gelatin, guar gum, colloidal silicon dioxide, croscarmellose sodium, talc, magnesium stearate, calcium stearate, zinc stearate, stearic acid, and the like. Tablets may further comprise one or more coloring agents, diluents, buffers, disintegrating agents, moisturizing agents, preservatives, or flavoring agents.

[0066] The pharmaceutical composition, alone or in combination with other suitable components, can be made into an aerosol formulation for inhalation administration. These aerosol formulations can be placed in an acceptable pressurized propellant (such as dichlorodifluoromethane, propane, and nitrogen) or in a non-pressurized preparation (such as a nebulizer or atomizer). When the subject's site(s) of infection are pulmonary, the preferred mode of administration is inhalation of an oral or nasal aerosol formulation. In particular, the aerosol formulation can contain particles of a respirable size (including, but not limited to, an average particle size of 5 μm to 500 μm).

[0067] The pharmaceutical composition can be an injectable preparation.The requirements of effective carriers for injectable compositions are well known to those skilled in the art (see, for example, Pharmaceutics and Pharmacy Practice, J.B. Lippincott Company, Philadelphia, Pa., edited by Banker and Chalmers, pages 238-250 (1982) and ASHP Handbook on Injectable Drugs, Toissel, 4th edition, pages 622-630 (1986)).In certain embodiments, the injectable composition is administered intravenously.The preparations suitable for parenteral administration include aqueous and non-aqueous isotonic sterile injection solutions, which may contain antioxidants, buffers, bacteriostatic agents, and solutes that make the formulation isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions, which may contain suspending agents, solubilizers, thickeners, stabilizers, and preservatives.

[0068] The pharmaceutical composition may further comprise an excipient. Excipients that can be used include one or more carriers, surfactants, thickeners or emulsifiers, solid binders, dispersing or suspending aids, solubilizers, colorants, flavoring agents, coatings, disintegrants, lubricants, sweeteners, preservatives, isotonicity agents, and combinations thereof. The selection and use of suitable excipients is discussed in detail in Remington: The Science and Practice, edited by Gennaro. of Pharmacy, 20th Edition, (Lippincott Williams & Wilkins 2003), the disclosure of which is incorporated herein by reference.

[0069] In some embodiments, octadentate 3,4,3-LI-1,2-HOPO is highly effective in chelating Pu, Np, Th, Am, and Cf in vivo, and its effectiveness Its efficacy far exceeds that of the current actinide chelating standard, CaNa3-DTPA, at low dosages. For example, the clearance efficiency of 3,4,3-LI-1,2-HOPO for circulating Pu from mouse tissues in five different protocols ranges from 100-fold (skeleton) to 240-fold (soft tissue) that of CaNa3-DTPA. Furthermore, the optimal active dose of 3,4,3-LI-1,2-HOPO for removing newly deposited Pu from mice is 2.5% of the clinically used dose of CaNa3-DTPA. Tetradentate 5-LiO-Me-3,2-HOPO has potential therapeutic value for Pu, U, Am, and Np, and its clearance efficiency for circulating Pu from mouse tissues ranges from 5-fold (skeleton) to 15-fold (liver) that of CaNa3-DTPA.

[0070] Orally active. Both compounds are orally active actinide chelators: when orally administered to mice or beagle dogs after Pu injection, 3,4,3-LI-1,2-HOPO and 5-LI-Me-3,2-HOPO are able to remove up to 80% and 60% of the injected Pu, respectively. Furthermore, 14 Pharmacokinetic studies using C-labeled ligands indicate that both compounds are stable to metabolic degradation and are significantly more effective than CaNa3-DTPA for removing newly deposited Pu, Np, Am, and U from mice.

[0071] Ligand combinations. Octadentate 3,4,3-LI(1,2-HOPO), HOPO(1), is highly effective for the in vivo chelation of Pu(IV) and Am(III). Tetradentate 5-LI(Me-3,2-HOPO), HOPO(2), is structurally suitable for the chelation of Np(V) and U(VI).

[0072] Application of chelating agents for specific MRI contrast agents In some embodiments, one or more chelating agents provided herein can be used to reduce the risks associated with gadolinium-based contrast agents. In some embodiments, the chelator can be administered before, with, or after the use of a gadolinium-based contrast agent. Since their introduction into clinical practice in the United States in 1988, gadolinium-based contrast agents (GBCAs) have had a profound impact on magnetic resonance imaging (MRI). It is estimated that GBCAs are used in more than half of the 30 million MRI scans performed each year in the United States. The contrast agents are considered safe, with a reported associated adverse event rate of 14.4 per 100,000 doses worldwide. The first serious adverse event reported by nephrologists linking GBCA administration to nephrogenic systemic fibrosis (NSF) occurred 18 years after use, prompting the U.S. Food and Drug Administration (FDA) to issue a warning in 2006. Although the exact pathophysiology of NSF remains unknown, dissociation of Gd ions from chelating ligands is accepted as the primary etiology. Considering the time it takes for chelates to dissociate in vivo, this dissociation is more likely to occur in patients with renal failure than in those with normal renal function, due to the decreased excretion rate in these patients. While most cases of NSF reported in the literature are associated with the administration of nonionic linear gadodiamide (Omniscan), reports also describe substantial incidents with another nonionic linear agent, gadoversetamide (OptiMARK), and with the ionic linear agent, gadopentetate dimeglumine (Magnevist). NSF has been almost completely eliminated since 2009, likely due to effective screening of patients with renal disease and the avoidance of GBCAs in patients with substantial renal disease, or the use of more stable GBCAs, which have resulted in very few or no NSF cases. However, in the past two years, numerous studies have been published on Gd deposition in neural tissue in patients with normal renal function. This deposition was first postulated by MR imaging studies in which gradual increases in signal intensity within the globi pallidi and / or dentate nucleus on unenhanced T1-weighted images in patients with normal renal function were associated with multiple GBCA administrations.As with NSF, the drug most commonly associated with this finding was gadodiamide, but this finding was also associated with other drugs (gadopentetate dimethicone). It has also been shown using α-glucan (containing glutamic acid).

[0073] Currently, there are nine FDA-approved GBCAs, all of which are hydrophilic. These GBCAs differ in their stability, ability to enhance proton relaxation rates, and distribution, with macrocyclic agents thought to form more kinetically stable complexes. However, gadobutrol (Gadavist), one of the most stable macrocyclic agents, has also been shown to produce cerebral deposition. These findings suggest that all GBCAs should be evaluated individually, and that all may release some level of Gd, despite their molecular structure. Gd, a lanthanide heavy metal, is highly toxic as a free ion and is slowly excreted through interactions with endogenous ligands and metal-binding sites (particularly those associated with calcium, zinc, and iron). Free Gd 3+ When administered (in animal models), only 1%-3% is excreted daily, with the remainder deposited primarily in the liver, kidneys, and bone. The free ion disrupts cellular processes and inhibits stretch-activated ion channels, making it one of the most effective calcium antagonists. Due to numerous recent reports of Gd tissue deposition, the FDA is currently evaluating the risk and potential adverse effects of brain deposition, and several clinical trials (ClinicalTrials.gov) are currently recruiting patients to evaluate long-term Gd retention and associated adverse effects at the time of this filing.

[0074] However, no viable options exist for removing internalized Gd. The only practical treatment to mitigate the health effects of Gd deposition would be treatment with chelating agents that form excretable complexes. However, Gd, like other heavy metals, is one of the most difficult elements to eliminate from the body.

[0075] The mechanism of action of 3,4,3-LI(1,2-HOPO) is a chelation mechanism in which the compound binds to the targeted actinide to form a stable complex that can be excreted via excretory pathways. Chelation may be clinically effective if the affinity of the chelator for the targeted actinide metal ion is higher than that of potential biological ligands (such as proteins and bone matrix) and if the affinity of the chelator for the targeted actinide metal ion is more specific than its affinity for divalent essential metal ions. A quantitative tool for predicting the efficacy of a chelator and confirming its potential for actinide chelation is the determination of the stability constants of the corresponding actinide complexes in vitro. As outlined in Example 2 below, these constants can be calculated using the logarithm of Pu(IV) (Logβ 110 >41.5) or Cm(III)(Logβ 110 = 21.8). This constant supports a chelation mechanism with 3,4,3-LI(1,2-HOPO). The protonation and stability constants (Logβ 110 = 20.5), suggesting that 3,4,3-LI(1,2-HOPO) forms some of the most stable Gd complexes known at physiological pH. This high affinity should translate into high in vivo Gd removal rates, which are comparable to those observed with other elements such as Eu(III), Am(III), and Cm(III) in mouse models.

[0076] In some embodiments, chelation treatment with 3,4,3-LI(1,2-HOPO) can enhance the long-term clearance of Gd deposits. In some embodiments, this treatment can enhance clearance of Gd deposits by 10, 20, 30, 40, 50, 100%, or more.

[0077] In some embodiments, another method for reducing the potential health effects of Gd release from administered GBCAs is by preventing deposition.

[0078] 3,4,3-LI(1,2-HOPO) is administered as a single dose before or simultaneously with the contrast agent. In some embodiments, 1, 2, 3, 4, 5, or more doses of the chelator can be administered prior to or overlapping with the administration of the Gd-containing compound.

[0079] There are risks associated with administering GBCAs to patients with severe renal dysfunction (eGFR<30). Patients with normal renal function were initially thought to be free of GBCA-derived Gd retention risk; however, some Gd from each dose of contrast agent may be retained in the body of all patients exposed to GBCAs. The FDA (including its National Center for Toxicological Research (NCTR)) and several academic and industrial research groups are actively working to understand the Gd retention mechanism and determine the extent of adverse health effects. However, there are currently no viable options for removing Gd deposits associated with GBCA administration or for preventing Gd deposition. Therefore, the development of a pre- or post-GBCA injection clearance strategy is an important research need that has the potential to change the paradigm of clinical MR imaging practice. Thus, in some embodiments, the chelators provided herein can be administered to subjects at risk for or already suffering from severe renal dysfunction. This can be prophylactic or symptomatic treatment.

[0080] 3,4,3-LI(1,2-HOPO) has been shown to be up to 30 times more potent than DTPA in eliminating actinide ions in animal studies, and has the advantages of being orally available and highly effective as a prophylactic treatment. 14 Recent absorption, distribution, metabolism, and excretion studies performed using C-labeled 3,4,3-LI(1,2-HOPO) have revealed that the ligand can penetrate the blood-brain barrier, as trace amounts of the ligand were found in rat brains several days after administration. This property is particularly relevant for targeting Gd deposited in the brain.

[0081] In some embodiments, any one or more of the chelators provided herein (e.g., 3,4,3-LI(1,2-HOPO)) can be used in combination with a Gd-based imaging agent (either before, with, or after administration of the imaging agent) to reduce the risk of Gd retention in the host. The amount of 3,4,3-LI(1,2-HOPO) administered is sufficient to reduce the residual Gd level to a desired amount. In some embodiments, the amount of Gd remaining in the host is reduced by 1.1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 98, 99%, or more (e.g., 100%). The chelating agent can be administered to reduce the risk, symptoms, or duration of NSF or other disorders associated with the use of Gd-based imaging agents in a subject. Metal poisoning can severely affect mental and physical development. Even low levels of heavy metal exposure can cause damage over time, especially in children. There is a significant risk to the developing brain, and this damage can be irreversible. At higher levels, it can damage the kidneys and nervous system in both children and adults. In some embodiments, specific symptoms may include: 1) pain - tingling; burning, soreness, and / or tingling (paresthesia); deep bone pain; typically seen in the limbs or joints, occasionally in an MRI site such as the head; 2) skin changes - tight skin, rash, hyperpigmentation, etc.; most often seen in the limbs; 3) muscle problems - spasms - small, localized, rapid contractions and weakness; 4) eye problems - reduced vision, dry eyes, bloodshot eyes; 5) cognitive symptoms; 6) ear, nose, and throat - tinnitus, swallowing, and voice problems; 7) hypothermia; 8) hair loss; 9) itchy skin; 10) balance problems; 11) swelling of the limbs (edema); and / or 12) a sensation of an electric shock-like, vibrating, or twitching sensation typically just under the skin, sometimes localized and sometimes a more generalized feeling.

[0082] In some embodiments, the chelating agent need not be administered to a subject, but instead is administered to reduce the amount of heavy metals in one or more fluids (gas or liquid). as a catalyst for the purification of said one or more fluids.

[0083] It is to be understood that the invention is not limited to the particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the invention, since the scope of the invention will be limited only by the appended claims.

[0084] Where a range of values ​​is provided, it is understood that each intervening value between the upper and lower limit of that range is also specifically disclosed to the tenth of the unit of the lower limit, unless the context clearly indicates otherwise. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded within the range, and each range where either, both, or neither of these smaller limits is included within the invention, subject to any specifically excluded limit in the stated range. When a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0085] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited.

[0086] It must be noted that as used herein and in the appended claims, the singular forms "a," "and," and "the" include the plural forms unless the context clearly dictates otherwise. Thus, for example, reference to "a chelating agent" includes a plurality of such chelating agents, and so forth.

[0087] Having described the invention, the following examples are provided to illustrate the invention and are not intended to be limitations of the invention. [Example]

[0088] Example 1 Two sets of studies aimed at investigating the administration time window of 3,4,3-Li(1,2-HOPO) and 5-LiO(Me-3,2-HOPO) are presented herein. Enhanced plutonium excretion is described as early as 48 hours after contamination for prophylactic intraperitoneal or oral treatment, and as late as 7 days after challenge for delayed intraperitoneal treatment. To ensure consistency between these studies and previously reported studies, soluble plutonium citrate ( 238 We performed contamination with Pu and selected young adult female Swiss-Webster mice as the animal model. The advantages of these procedures are that only small amounts of radioactive contaminants are required to obtain accurate counting statistics in tissue and fecal samples, large inventory of radionuclides is avoided, and the amount of radioactive material handled is reduced.

[0089] 2. Materials and Methods 2.1 Contaminant and ligand solutions Pu nitrate in 4M HNO3 ( 238 A stock solution of Pu was prepared from Eckert and Ziegler Isotope Products (Valencia, CA, USA). The contaminant dose was 0.74 kBq (1.16 ng) in 0.008 M sodium citrate and 0.14 M NaCl (pH 4). 238 The solution consisted of a 0.2 mL aliquot of a solution containing Pu. The ligands 3,4,3-LI(1,2-HOPO) and 5-LIO(Me-3,2-HOPO) were prepared by Synthetech, Inc. (Albany, OR, USA) and Albany Molecular Research, Inc. (Albany, NY, USA), respectively, as previously described

[19] . DTPA was obtained from Sigma-Aldrich (St. Louis, MO, USA) and formulated as Ca-DTPA using CaCO3 and NaOH. This Ca-DTPA is similar to the pharmaceutical product previously available commercially from Hameln Pharmaceuticals GmbH (Hameln, Germany). Ligand solutions were prepared by incorporating the selected dosage (30 μmol / kg for Ca-DTPA, 30 or 100 μmol / kg for 3,4,3-LI(1,2-HOPO), and 100 or 200 μmol / kg for 5-LI(Me-3,2-HOPO)) in 0.5 mL of 0.14 M NaCl and adjusting the pH to 7.4–8.4 with 1 N NaOH. All solutions were filter-sterilized (0.22 μm) before administration. The concentration of each solution was verified by high-performance liquid chromatography according to a modified version of a published method.

[0090] 2.2 Animals and general procedures All procedures and protocols used in the described in vivo studies were reviewed and approved by the Lawrence Berkeley National Laboratory Animal Care and Use Committee and were performed in an AAALAC-accredited facility. Animals used were young adult (86 ± 6 days old for delayed treatment experiments and 90 ± 3 days old for preventive treatment experiments) female (30.7 ± 4.0 g for delayed treatment experiments and 30.8 ± 1.6 g for preventive treatment experiments) Swiss-Webster mice (Simonsen Laboratories, Gilroy, CA, USA). The overall body and tissue composition of these mice, plasma, extracellular fluid, and red blood cell volume (intact or bled to 25–40% of the mouse's total blood volume) of the mice were previously determined. Mice were maintained under a 12-h light-dark cycle with controlled temperature (18–22°C) and relative humidity (30–70%) and were provided with water and food ad libitum. Each group of mice was housed in a plastic stock cage lined with a 0.5 cm layer of highly absorbent, low-ash pelleted cellulose bedding (ALPHA-dri®) to separate urine and feces. Intravenous (iv) injection into a warmed lateral tail vein, intraperitoneal (ip) injection, oral administration (po, via gastric intubation), and euthanasia were performed under isoflurane anesthesia. Treatment dose volumes were adjusted based on mouse weight (a volume of 0.5 mL was used for a 35 g mouse). To examine the effects of delayed treatment, groups of five mice were administered a single dose of plutonium citrate ( 238 Pu) was injected iv, and the ligand solution or control saline solution was administered ip once after the following contamination treatment times: 1 hour, 5 hours, 16 hours, 24 hours, 3 days, and 7 days. Feces were collected daily for 7 days. Animals were euthanized 7 days after treatment. To examine the effects of prophylactic treatment, groups of five mice were first administered a single dose of the ligand solution or control saline solution ip or po at the following pre-contamination treatment times: -1 hour, -6 hours, -16 hours, -24 hours, -30 hours, -40 hours, and -48 hours. Mice were then administered a single dose of plutonium citrate ( 238Pu) was injected intravenously, and feces were collected daily for 3 days. Three days (72 hours) after contamination, the animals were euthanized. Mice were euthanized by cervical dislocation in their respective cages, and urine excreted at the time of death was collected, immediately wrapped in plastic, and frozen for subsequent dissection.

[0091] Tissue sampling and processing After partial thawing of frozen mice, the liver and kidneys were dissected, and the remaining abdominal tissues (including the ATR, intact gastrointestinal (GI) tract, reproductive organs, spleen, bladder, and abdominal fat) were removed. The liver, kidneys, ATR, and partially eviscerated carcasses were maintained as separate samples. Fecal samples were manually separated from urine-soiled cellulose bedding and processed as group samples (one group per cage). All samples were dried at 100°C and dry-ashed at 575°C. The ashed samples were treated with concentrated HNO3. These acidified solutions were then homogenized in dilute HNO3 and mixed with Ultima Gold (Perkin Elmer, Shelton, CT, USA) for detection of radionuclides by liquid scintillation counting (Packard Tri-Carb model B4430, Perkin Elmer).

[0092] Data Management and Analysis Radioactive contaminants in all experiments 238 Pu was used and therefore controlled as a metabolic balance study in which all tissues and excretions were analyzed for radioactivity; the mean recoveries of radioactive chemicals were all above 95% injected dose (ID). Experimental data were presented as the percentage of radionuclides (injected 238The data are reported as a percentage of Pu (%ID) and values ​​are arithmetic means ± SD. When comparing values ​​between groups in excretion studies, the term "significant" is used in the statistical sense, indicating p<0.01 by one-way analysis of variance (ANOVA) followed by appropriate post-hoc analysis. Dunnett's multiple comparison test was used to compare groups of animals treated with chelators with matched saline-administered controls, while Tukey's just significant difference (HSD) multiple comparison test was used for pairwise comparisons between all chelator-treated groups. Both tests were set at the 99% confidence interval level. All statistical analyses were performed using GraphPad Prism 5 (GraphPad Software, Inc., San Diego, CA, USA).

[0093] result Enhanced plutonium excretion by single parenteral or oral administration of one of the experimental efflux agents, 3,4,3-Li (1,2-HOPO) or 5-Li (Me-3,2-HOPO), was investigated in young adult female Swiss-Webster mice, depending on the administration time of the treatment. In the first study, chelation treatment was administered parenterally once after the challenge event at various times, ranging from 1 hour to 7 days after contamination, and mice were euthanized 7 days after treatment. In the second study, a single prophylactic treatment was administered either parenterally or orally at various times, ranging from 48 hours to 1 hour before contamination, and mice were euthanized 3 days after the contamination event. In both studies, the primary efficacy endpoint was the reduction in radionuclide body content at the time of euthanasia compared with saline-treated controls. For parenteral treatment cases, comparisons could also be drawn with DTPA-treated groups. The in vivo portion of both studies was performed without incident. As expected from previously reported results, the dose levels of the experimental ligands 3,4,3-LI(1,2-HOPO) and 5-LIO(Me-3,2-HOPO) did not produce any discernible adverse effects.

[0094] Delayed parenteral chelation treatment For studies in which mice were treated between 1 hour and 7 days after contamination and euthanized 7 days after treatment, total body mass at different necropsy times was measured.238 The results of Pu content and distribution were subjected to statistical analysis and are shown in Figure 3. At treatment time points ranging from 1 hour to 16 hours after contamination, a single parenteral dose of either 3,4,3-LI(1,2-HOPO) or 5-LI(Me-3,2-HOPO) significantly reduced Pu content compared to saline-treated controls. 238 Pu excretion rate significantly increased, and the total body burden and tissue content were clearly reduced. However, only in the 3,4,3-LI(1,2-HOPO) chelated group at the aforementioned time points. 238 The Pu content was reduced, which was significantly better than the reduction observed after DTPA treatment. Furthermore, 3,4,3-LI(1,2-HOPO) reduced the Pu content when treatment was administered at delayed time points, from 24 hours to 7 days after contamination. 238 It was the only chelation option that significantly enhanced Pu excretion. 3,4,3-LI(1,2-HOPO) also significantly enhanced Pu excretion at all treatment time points tested. 238 It was the only ligand that significantly reduced Pu skeletal content. Elimination efficacy increased with increasing treatment delay. Both decreased.

[0095] Figure 3 shows the results 7 days after a single delayed ip chelation treatment. 238 The total content and distribution of Pu in the body are shown. 238 Pu) was injected iv; saline or treatment (3,4,3-LI(1,2-HOPO) (30 μmol / kg), 5-LI(Me-3,2-HOPO) (100 μmol / kg), or Ca-DTPA (30 μmol / kg)) was administered ip 1, 5 (A), 16, 24 (B), 3, or 7 days (C) after contamination; mice were euthanized 7 days after treatment. Data are shown for groups of 5 mice each injected. 238 The percentage of Pu dose (%ID, mean ± SD) is shown. Groups with significantly lower retention than control mice were * or ** (p<0.05 or p<0.01, one-way ANOVA with post-hoc Dunnett's multiple comparison test), whereas the groups with significantly lower retention than Ca-DTPA-treated mice #or ## (p<0.05 or p<0.01, one-way ANOVA with post-hoc Tukey HSD multiple comparison test).

[0096] Nevertheless, as shown in Figure 4, the excretion rates followed different kinetics depending on the time elapsed between contamination and treatment. For 5-LiO (Me-3,2-HOPO) or 3,4,3-Li (1,2-HOPO), respectively, rapid chelation treatment with a HOPO ligand (1 h after contamination) promoted immediate elimination of over 80% of the injected dose, whereas the excretion rate remained slower than that observed in control animals until 2 or 3 days after treatment. Delayed treatment (7 days after contamination) promoted less pronounced enhancement of excretion; however, the excretion rates observed 7 days after treatment with either HOPO ligand were still comparable to or faster than those observed in control animals. While 3,4,3-Li(1,2-HOPO) demonstrated significantly better efficacy than 5-LiO(Me-3,2-HOPO) at all time points, the excretion rates also differed significantly between the two ligands: after the initial, rapid effect of the ligand, observed within 24 hours of treatment, 5-LiO(Me-3,2-HOPO) showed no significant prolonged effect, in contrast to 3,4,3-Li(1,2-HOPO) or DTPA. The cumulative excretion patterns shown in Figure 4 visually demonstrate these differences. For treatment time points between 16 hours and 7 days, the prolonged effect of DTPA was evident over several days after treatment, and the excretion pattern was curvilinear, reaching excretion levels similar to (and in one case even higher than) 5-LiO(Me-3,2-HOPO) by day 4 after treatment. Similarly, the long-term efficacy of 3,4,3-LI(1,2-HOPO) was evident over the 7-day fecal collection period of this study, with 3,4,3-LI(1,2-HOPO) not only being the most effective; 238 It also emerged as the treatment option that most rapidly reduced Pu contamination.

[0097] The daily fecal and urinary excretion rates for each chelation treatment were also examined and are shown in Figure 5. These panels demonstrate that, unlike DTPA treatment, both 3,4,3-LI(1,2-HOPO) and 5-LIO(Me-3,2-HOPO) were systematically excreted, primarily via the biliary route, with only trace amounts in urine, regardless of the treatment time after contamination. The fecal (left panels A, C, E, G) and urinary (right panels B, D, F, H) excretion rates after delayed ip chelation treatment with a single 3,4,3-LI(1,2-HOPO) (A and B), 5-LIO(Me-3,2-HOPO) (C and D), DTPA (E and F), or saline (G and H) at 1, 5, 16, 24, 3, or 7 days after contamination were also measured. 238 Daily excretion of Pu. Young adult female Swiss-Webster mice were given Pu citrate ( 238 Mice were injected intravenously with 3,4,3-Li(1,2-HOPO) (30 μmol / kg), 5-Li(Me-3,2-HOPO) (100 μmol / kg), or Ca-DTPA (30 μmol / kg) at 1, 5, 16, 24, 3, or 7 days after contamination; saline or treatment (3,4,3-Li(1,2-HOPO) (30 μmol / kg), 5-Li(Me-3,2-HOPO) (100 μmol / kg), or Ca-DTPA (30 μmol / kg)) was administered intravenously at 1, 5, 16, 24, 3, or 7 days after contamination; mice were euthanized 7 days after treatment. Daily pooling was performed. Data were calculated from group recovered excretion amounts, so standard deviations were not available.

[0098] 3.2 Prophylactic Parenteral or Oral Chelation Treatment For this study, mice were treated prophylactically between 1 hour and 48 hours before contamination and 3 days after contamination. 238 The results of the total body content and distribution of Pu were subjected to statistical analysis and are shown in Figure 6. As shown in panel A of Figure 6, parenteral administration of 5-LIO(Me-3,2-HOPO) or DTPA resulted in a very short prophylactic time window (1 hour and 6 hours, respectively). 238The 3,4,3-LI(1,2-HOPO) group was effective in significantly reducing Pu body and tissue burden. In contrast, 3,4,3-LI(1,2-HOPO) showed significant preventive activity even when injected once 48 hours before contamination (Panel B of Figure 6). All animals showed significantly lower Pu body, skeletal, liver, soft tissue, and kidney burdens in the parenteral 3,4,3-LI(1,2-HOPO) group compared with the corresponding saline- and DTPA-treated groups. 238 The results showed a highly significant reduction in Pu content. As expected, the excretion efficacy decreased with increasing delay between treatment and contamination. Nevertheless, the efficacy level observed after 3,4,3-LI(1,2-HOPO) injection 48 hours before contamination (up to 50% within 3 days) was significantly higher than that observed after 3,4,3-LI(1,2-HOPO) injection 48 hours before contamination. 238 The preventive efficacy of 3,4,3-LI(1,2-HOPO) and 5-LI(Me-3,2-HOPO) after oral administration was also examined (Figure 6, Panel C). Groups treated with either ligand during the 6-hour preventive time window showed significant improvements in whole body, skeletal, and liver damage compared to the saline control group. 238 The Pu content was significantly reduced. However, the poor oral bioavailability of 3,4,3-LI(1,2-HOPO) reflected the lack of elimination effectiveness for earlier treatment.

[0099] As mentioned above, Figure 6 shows the results of the 3-day post-contamination event preceded by a single prophylactic chelation treatment. 238 The total content and distribution of Pu in the body are shown. 238Mice were injected iv with 3,4,3-LI(1,2-HOPO) (30 μmol / kg ip or 100 μmol / kg po), 5-LI(Me-3,2-HOPO) (100 μmol / kg ip or 200 μmol / kg po), or Ca-DTPA (30 μmol / kg ip)) ip (A for 5-LI(Me-3,2-HOPO) and DTPA and B for 3,4,3-LI(1,2-HOPO)) or po (C) 1, 6, 16, 24, 30, 40, or 48 hours before contamination; mice were euthanized 3 days after contamination. Data are for groups of 5 mice each injected. 238 The percentage of Pu dose (%ID, mean ± SD) was expressed as the percentage of Pu dose. * or ** (p<0.05 or p<0.01, one-way ANOVA with post-hoc Dunnett's multiple comparison test), whereas the groups with significantly lower retention than Ca-DTPA-treated mice # or ## (p<0.05 or p<0.01, one-way ANOVA with post-hoc Tukey HSD multiple comparison test). In panel B, all individual tissue content bars are ** , ## (-1 hour to -24 hours) or ** (-30 hours to -48 hours) should be indicated, but the symbol has been omitted for clarity.

[0100] Finally, daily fecal and urinary excretion following prophylactic administration of parenteral or oral 3,4,3-LI(1,2-HOPO) is shown in Figure 7. All panels show a rapid loss of excretion enhancement beyond day 1 post-challenge. For all treatment regimens except one, 238 Pu excretion was also mainly in the feces. However, in the case of parenteral treatment with 3,4,3-LI(1,2-HOPO) immediately before contamination (-1 hour time point), Pu was detected in the urine. 238 Pu levels were three times higher than fecal excretion. For the results in Figure 7, young adult female Swiss-Webster mice were given plutonium citrate ( 238Pu) i.v. injection; 3,4,3-LI(1,2-HOPO) (30 μmol / kg i.p. or 100 μmol / kg i.p. injection) 1, 6, 16, 24, 30, 40, or 48 h before contamination. Mice were euthanized 3 days after contamination. The excreta of groups of five mice each were pooled daily. Data were calculated from the group recovered excretion, so standard deviations are not available.

[0101] Example 2 Recent studies in humans and animals aimed at determining Gd release levels from GBCAs have primarily been performed using MR imaging as the method of choice for Gd detection. While MRI is a noninvasive technique, enhanced resolution has primarily been achieved when Gd is chelated, which shortens the hydrogen-proton relaxation time and limits the sensitivity of free Gd detection. A few earlier studies have described the biodistribution of radiolabeled GBCAs in mice and rats, improved measurement precision, and demonstrated a broader than expected range of Gd release. However, these studies have focused on low-energy gamma emitters detected by gamma counting. 153 Gd isotopes were used. Here, α-emitters 148 Gd is then used. 148 Gd is detected by liquid scintillation counting (a much more sensitive method) according to published protocols. Furthermore, the combination of radiotracer determination and MR measurements allows us to reliably distinguish free from chelated Gd in vivo. Finally, access to the high-affinity chelator 3,4,3-LI(1,2-HOPO) promises ex vivo elimination unmatched by any other existing and available ligand.

[0102] Free 148 Gd and chelation 148Comparative preclinical studies will be conducted in an established mouse model injected with Gd. The objectives of these studies are to determine the in vivo clearance of Gd by 3,4,3-Li(1,2-HOPO) and the effect of prophylactic 3,4,3-Li(1,2-HOPO) on GBCA MR image enhancement. For each of the following studies, feces and several tissues will be collected and analyzed to determine metal levels. Most details of the technical methods used have been published and include the ligand solution, animals, animal injection procedures, necropsy procedures, fecal collection, sample preparation, radioactivity analysis, and data management. A baseline study including an animal control group will also be conducted. The series of studies will involve Swiss-Webster mice before and after administration of Gd in different chemical forms: 148 The efficacy of 3,4,3-LI(1,2-HOPO) in increasing the excretion rate of Gd will be investigated: in the form of a citrate solution to mimic the free ion or chelated with either the linear DTPA-BMA (gadodiamide) or macrocyclic DO3A (gadoterate) ligands. MR images will also be acquired to examine the effect of 3,4,3-LI(1,2-HOPO) treatment on the efficacy of injected GBCAs. Details of the experimental procedure are described below.

[0103] Test System: Young Adult Swiss-Webster Mice. The majority of previous radionuclide elimination efficacy studies using 3,4,3-Li (1,2-HOPO) were conducted using laboratory mice. Mice are commonly used for metabolism and toxicity studies because they are an appropriate small-scale acute model for larger mammals. While Pu metabolism and chelation have been studied in this animal, other factors also needed to be considered, leading to the use of mice in some studies. The animals selected for the preliminary studies were young adult female Swiss-Webster mice (an outbred strain with stable size and docile behavior). Mice were used at 11–15 weeks of age and weighing 30 ± 3 g. At that age, the mouse skeleton is nearly mature, with long bones reaching 98% of their maximum length. Animal models with mature skeletons more closely resemble adults with regard to the degree and extent of bone remodeling. There are important considerations in interpreting the results of chelation therapy that significantly affect metal biokinetics and deposition kinetics in sites such as the skeleton. A final important advantage inherent in metal chelator studies using radioactive tracers is the generation of much smaller amounts of radioactive waste.

[0104] Test Challenge: Complexed with citrate 148 GdDTPA-BMA (gadodiamide) or DO3A (gadoterate). 3+Ions may exhibit different biokinetics depending on their chemical form. Therefore, parameters and variables to consider in efficacy studies should include appropriate control and comparison groups. Gadodiamide and gadoterate are used as reference GBCAs because DTPA-BMA exhibits one of the lowest Gd complex stability constants and is a linear agent responsible for the majority of observed brain deposition, while DO3A is one of the most stable macrocyclic chelators. Metal solutions are formulated according to published protocols to mimic clinically relevant GBCA dose levels and administered via intravenous injection to female young adult Swiss-Webster mice. Systematic injection of soluble radiotracers has been shown to contaminate animals with highly reproducible isotope loading, which is important for assessing chelator efficacy in a precise manner. 148 Gd is obtained commercially from the U.S. Department of Energy National Isotope Development Center. All ligands and imaging agents are commercially available. Table 1 summarizes the study design.

[0105] Treatment Regimen. Treatment with the chelator 3,4,3-LI (1,2-HOPO) is administered parenterally (intraperitoneally - i.p. - injection) or orally (po, gastric intubation) at eight time points ranging from 24 hours to 1 hour before or after Gd contamination. Both parenteral and oral treatment regimens are optimized for actinide elimination in multiple dosing regimens starting 24 hours after metal contamination. The parenteral and oral dose levels selected (100 μmol / kg and 600 μmol / kg, respectively) are based on previous optimization studies using this particular mouse model. As summarized in Table 1, each 148For the Gd morphology study, 72 female and 72 male animals are randomly assigned to one of 18 treatment groups (4 animals / group, statistical justification provided in the Vertebrate Animal Use section). Mice are group-housed in disposable stock cages lined with absorbent, low-ash pelleted cellulose bedding to facilitate urine and feces separation. All animals in these studies are monitored for adverse health effects and are euthanized 72 hours after Gd injection. Urine and feces are collected daily from contamination until necropsy. A complete necropsy is performed, and all samples are collected for thermal and chemical processing and subsequent analysis by liquid scintillation counting.

[0106] Endpoints and Success Criteria. Efficacy can be based on direct measurement of radiotracer excretion via feces and / or urine at various time points after administration of the excretion agent. In animal efficacy studies, a reduction in metal content after administration of a chelating agent is generally interpreted as prevention of Gd toxicity. In these preventive efficacy studies, metal excretion efficacy is assessed based on direct measurement of radiotracer excretion at a single time point, 72 hours after contamination. Successful excretion is characterized as a significant decrease in radiotracer body content and a significant increase in body excretion compared to control groups (contaminated and vehicle-treated animals). MR imaging is performed on the prophylactic 3,4,3-LI(1,2-HOPO)-treated group within a 4-hour window after Gd injection (to examine the effect of 3,4,3-LI(1,2-HOPO) on MR images) and on the group immediately prior to necropsy (to correlate MR images with radionuclide distribution results).

[0107] These studies therefore provide clear evidence of the potential elimination efficacy of 3,4,3-LI(1,2-HOPO) for Gd and expand the indications for 3,4,3-LI(1,2-HOPO) as an elimination agent to include Gd. [Table 1]

[0108] Example 3 Subjects who will receive a Gd-containing MRI contrast agent are identified. Subjects with severe renal dysfunction are A subject with a Gd-based MRI contrast agent is administered an effective prophylactic dose of 3,4,3-LI(1,2-HOPO) (between 1 micromol / kg and 1000 micromol / kg) and then receives an amount of Gd-based MRI contrast agent. Two days after the MRI, the amount of Gd-based contrast agent in the subject is lower than if the subject had not received the chelating agent.

[0109] Example 4 A subject is identified who will receive an MRI contrast agent containing Gd. The subject is administered the Gd-based MRI contrast agent. Within seven days of administration, the subject is administered an effective amount of 3,4,3-LI(1,2-HOPO). Over the following days, the amount of Gd contrast agent in the subject is lower than if the subject had not received the chelating agent.

[0110] Example 5 A subject is identified who is expected to be in an environment where he or she may be exposed to heavy metals, including one of lead, tin, cadmium, scandium, and yttrium. The subject is administered an effective prophylactic dose of 3,4,3-LI(1,2-HOPO) (between 1 micromol / kg and 1000 micromol / kg). The subject can then be exposed to heavy metals within the next two days with an enhanced ability to chelate and excrete the heavy metals from the subject.

[0111] Example 6 A subject exposed to gadolinium, lead, tin, and / or cadmium is identified. The subject is administered an effective amount of 3,4,3-LI(1,2-HOPO) (between 1 micromol / kg and 1000 micromol / kg). Over the next several days, the amount of gadolinium, lead, tin, and / or cadmium in the subject is lower than if the subject had not received the chelating agent. Alternatively, 3,4,3-LI(1,2-HOPO) can be administered 1, 2, 3, 4, 5, 6, or 7 days after the subject's exposure to gadolinium, lead, tin, and / or cadmium.

[0112] Example 7 Subjects chronically exposed to lead from environmental contamination are identified. They are administered an effective dose of 3,4,3-LI(1,2-HOPO) (between 1 and 1000 micromoles / kg). Repeated administration of the chelating agent is given as needed. Over the next several days, the amount of lead in the subject's body is lower than if the subject had not received the chelating agent.

[0113] Example 8 A subject who has previously undergone one or more MRI scans using Gd is identified. The subject is administered one or more doses of an effective amount of 3,4,3-LI(1,2-HOPO) (between 1 micromol / kg and 1000 micromol / kg). Over the next few days, the amount of Gd in the subject is lower than if the subject had not received the chelating agent.

[0114] Example 9 This example evaluates the metal removal efficacy of various molecules, including 3,4,3-LI(1,2-HOPO) and DTPA. A summary of the arrangements tested (compounds, how much, for how long the compounds were administered before or after contamination, etc.) is shown in Table 9.1. [Table 9.1]

[0115] The results of the various study designs in Table 9.1 are detailed in Figures 8A–8Q. Data are plotted as percent recovered dose (%RD), and the isotopic content of whole animals and specific tissues is determined at specific time points (4 days after metal challenge), while fecal excretion is determined daily until necropsy. Results demonstrate the effectiveness of 3,4,3-LI(1,2-HOPO) in removing Gd-153 from mice when injected both prophylactically and after exposure. Indeed, even doses administered prophylactically up to 24 hours were excreted at high and nearly quantitative levels. When administered as late as 48 hours after exposure, 3,4,3-LI(1,2-HOPO) was highly effective in removing Gd-153, with Gd-153 removal rates similar to those achieved with DTPA treatment only 1 hour after exposure. 3,4,3-LI(1,2-HOPO) is more effective than DTPA at clearing Gd-153 from the kidney, an important feature for patients with pre-existing conditions such as renal dysfunction. The excretion route of 3,4,3-LI(1,2-HOPO) is almost exclusively fecal, which is also notably different from that of DTPA (urinary). An additional significant advantage of 3,4,3-LI(1,2-HOPO) is its ability to remove Gd-153 from the skeleton. Figures 8A-8C show a summary of the results. Figure 8D shows a comparative analysis of the recovered dose from the body versus excreta. Figures 8E-8P show the analysis of each tissue type, including brain (Figure 8E), thymus (Figure 8F), heart (Figure 8G), lung (Figure 8H), spleen (Figure 8I), kidney (Figure 8J), abdominal remnant tissue (ART, Figure 8K), all other soft tissues (SOFT, Figure 8L), liver (Figure 8M), and skeleton (SKEL, Figure 8N). Figures 8O and 8P show total urinary and fecal excretion at necropsy. Figure 8Q shows daily excretion. As can be seen throughout the various figures, excretion of Gd in vitro was observed both before and after exposure to Gd. It can be discharged.

[0116] While the present invention has been described in conjunction with preferred specific embodiments thereof, it is to be understood that the foregoing description is intended to be illustrative and not to limit the scope of the invention. Other aspects, advantages, and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.

[0117] All patents, patent applications, and publications mentioned herein are incorporated by reference in their entirety.

[0118] According to a preferred embodiment of the present invention, for example, the following is provided: (Section 1) 1. A method for treating heavy metal exposure in a subject, comprising administering a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelator to a subject having an excess amount of one or more of gadolinium, lead, tin, yttrium, scandium, or cadmium, wherein the administering step results in excretion, elimination, or reduction of the amount of gadolinium, lead, tin, or cadmium from the subject. (Section 2) Item 10. The method according to item 1, wherein the subject has been exposed to, contacted with, or contaminated with one or more actinides and / or lanthanides, or a mixture thereof. (Section 3) Item 10. The method according to item 1, wherein the administering step results in the excretion, elimination, or reduction of the amount of actinide and / or lanthanide from one or more systems or organs of the subject. (Section 4) The 1,2-HOPO chelating agent has the structure: [ka] (In the formula, R is a hydroxy group or [ka] and The method of claim 1, wherein R1 and R2 are selected from the group consisting of H, --CH3, --CH2CH3, and --CH2--φ, and X is either hydrogen, an alkali metal ion, or a quaternary ammonium ion. (Section 5) The 1,2-HOPO chelating agent is [ka] , [ka] , and [ka] (wherein l, m, and n are integers between 1 and 20). (Section 6) Item 6. The method according to item 5, wherein m is 3. (Section 7) Item 6. The method according to item 5, wherein n is 4. (Section 8) Item 6. The method according to item 5, wherein l and n are 3 and m is 4. (Section 9) Item 1. The method according to item 1, wherein the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. (Section 10) Item 10. The method of claim 1, wherein the subject has an excess amount of one or more of gadolinium, lead, yttrium, scandium, cadmium, or tin. (Section 11) A method for prophylactically treating metal exposure in a subject, comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising a 1,2-HOPO chelating agent. (Section 12) Item 12. The method according to item 11, wherein the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. (Section 13) Item 12. The method according to item 11, wherein the metal is a heavy metal. (Section 14) Item 14. The method according to item 13, wherein the heavy metal is selected from the group consisting of gadolinium, lead, tin, cadmium, yttrium, scandium, and plutonium. (Section 15) 15. The method of claim 14, wherein the metal is an actinide, a lanthanide, or a mixture thereof. (Section 16) A method comprising administering to a subject a 1,2-HOPO chelating agent before or after administering to the subject an MRI contrast agent. (Section 17) Item 17. The method according to item 16, wherein the subject is identified as a subject who is scheduled to receive the MRI contrast agent. (Section 18) Item 17. The method according to item 16, wherein the contrast agent comprises Gd. (Section 19) Item 19. The method according to item 18, wherein the amount of the contrast agent is 100 to 600 μmol / kg. (Section 20) Item 17. The method according to item 16, wherein the 1,2-HOPO chelating agent is administered to the subject before the subject receives the MRI contrast agent. (Section 21) Item 17. The method according to item 16, wherein the 1,2-HOPO chelating agent is administered to the subject after the subject has received the MRI contrast agent. (Section 22) Item 17. The method according to item 16, wherein the 1,2-HOPO chelating agent is 3,4,3-LI-1,2-HOPO. (Section 23) Item 17. The method according to item 16, wherein the subject has severe renal dysfunction.

Claims

[Claim 1] The invention described in the specification.

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