Two 2-aminoimidazole-based inhibitors, LY3031207 (1) and LY3023703 (2), of the microsomal prostaglandin E synthase-1 (mPGES-1) enzyme were found to cause drug-induced liver injury (DILI) in humans. ...We studied imidazole ring substitutions to successfully mitigate reactive metabolite (RM) formation. These studies support the conclusion that RM formation may play a role in the observations of DILI and the consideration of 2-aminoimidazoles as structure alerts, due to the high likelihood of bioactivation to generate RMs.
Mass balance and metabolism studies using radiolabeled substances are well recognized as an important part of the drug development process. In this study, we directly assessed the use of fluorine ...nuclear magnetic resonance (
F NMR) to achieve quantitative mass balance, metabolism, and distribution information for fluorinated compounds, without the need for radiolabeled synthesis or study. As a test case, the disposition of pefloxacin, a fluoroquinolone antibiotic, was evaluated in rats using quantitative
F NMR in parallel with a radiolabeled study. Urine, bile, and feces samples were collected over specific periods after oral administration of either 25 mg/kg
Cpefloxacin or 25 mg/kg pefloxacin and were subsequently profiled by radioactivity or
F NMR, respectively. The percentage of dose excreted in each matrix was comparable between the two methods, with the total dose recovered by radioactivity and
F NMR determined to be 86.8% and 81.8%, respectively. In addition, plasma samples were collected to determine the exposure of pefloxacin and its circulating metabolites. The plasma exposure of pefloxacin determined by
F NMR was within 5% to that calculated by a validated liquid chromatography-tandem mass spectrometry bioanalytical method. By both methods, pefloxacin was identified as the major circulating entity, with pefloxacin glucuronide as the major circulating metabolite. Quantitative analysis of metabolites in excreta was generally comparable between the two methods. In selected tissues, both methods indicated that the parent drug accounted for most of the drug-related material. In summary, we have demonstrated that
F NMR can be used as an alternative method to conventional radiolabeled studies for compounds containing fluorine without the need for radiolabeled synthesis/study.
The synthesis of the radiolabeled glucagon receptor antagonist 1‐14C was accomplished based on decarboxylative iodination of acid 2 followed by “reattachment” of 14C carboxylic function. The method ...allowed a significant reduction in the number of steps in preparation of the radiolabeled compound. Iodide 4, obtained by the halodecarboxylation, was converted to cyanide 5‐14C, which was hydrolyzed to provide the radiolabeled acid 2‐14C. Coupling with β‐alanine fragment and hydrolysis of ester 6‐14C completed the synthesis of the target molecule 1‐14C. The resulting compound was utilized in a mass balance and metabolism study where hepatic oxidation followed by a trace amount of sulfate conjugation and elimination was the main clearance pathway for 1 in humans.
The synthesis of the radiolabeled glucagon receptor antagonist 1‐14C was accomplished based on decarboxylative iodination of acid 2 followed by “reattachment” of 14C carboxylic function to form 2‐14C. Coupling with β‐alanine fragment completed the synthesis of the target molecule. The resulting compound was utilized in a mass balance and metabolism study.
Synthesis of deuterium‐labeled CB1 receptor antagonist 2‐d9 was accomplished in three steps by alkylation of 2‐nitrophenylacetonitrile with cyclopentyl‐d9 bromide, reductive cyclization of the ...resulting secondary nitrile into the 3‐cyclopentyl indole‐d9 and its N‐sulfonylation with corresponding p‐amidosulfonyl chloride. Another, structurally related, CB1 receptor antagonist 1 was radiolabeled with carbon‐14 by oxidative cleavage of 3‐cyclopentyl indole followed by the ring closure of o‐acyl substituted N‐formylaniline with potassium cyanide‐14C, in situ reduction‐elimination of the intermediate amino alcohol, and N‐sulfonylation of the resulting 3‐cyclopentyl indole‐2‐14C.
Synthesis of deuterium‐labeled CB1 receptor antagonist was accomplished in three steps from cyclopentyl‐d9 bromide, through the 3‐cyclopentyl indole‐d9 and its N‐sulfonylation. Another, structurally related, CB1 receptor antagonist was radiolabeled with carbon‐14 by the ring closure of o‐acyl substituted N‐formylaniline with potassium cyanide‐14C, in situ reduction‐elimination of the intermediate amino alcohol, and N‐sulfonylation of the resulting 3‐cyclopentyl‐2‐14C‐indole.
Novel dual GIP and GLP-1 receptor agonist, tirzepatide (TZP), is being developed as a potential weekly treatment for type 2 diabetes (T2DM), weight management and nonalcoholic steatohepatitis. The ...absorption, metabolism and excretion of a single subcutaneous (SC) dose of 14C-tirzepatide was investigated in Sprague Dawley rat and cynomolgus monkey. In addition, tissue distribution of 14C-tirzepatide was assessed in quantitative whole-body autoradiography (QWBA) study in pigmented Long Evans rat following a single SC dose.
14C-Tirzepatide was prepared by incorporating four 14C’s in the mini-PEG linker between the peptide backbone and the di-acid chain to provide a specific activity of ∼ 40 µCi/mg. Following a single SC dose of 14C-tirzepatide in rat (3 mg/kg) and monkey (0.5 mg/kg), total radioactivity recovery was > 97% over the course of study (336 hours for rat and 672 hours for monkey). The dosed radioactivity was similarly excreted via urine and feces in rats and monkeys. Metabolism of 14C-tirzepatide was characterized in plasma and excreta. Parent drug was the major component in circulation accounting for approximately 87% of total radioactivity in rat and 84% in monkey. Tirzepatide was primarily metabolized via catabolism of the peptide backbone and β-oxidation of the di-acid chain.
Following a single SC dose of 14C-tirzepatide in rats (3 mg/kg), radioactivity was distributed to tissues as early as the first collection time point at 1-hour post dose. The tissues with the highest radioactivity concentrations were observed in the dose site, kidney, cecum, urinary bladder, intervertebral ligaments, arterial wall, lungs, and liver, generally at 12 to 48 hours post dose.
Disclosure
J. Martin: Employee; Self; Eli Lilly and Company. K. Cassidy: Employee; Self; Eli Lilly and Company. B. Czeskis: None. J. Alberts: Employee; Self; Eli Lilly and Company. Y. Lao: Employee; Spouse/Partner; Eli Lilly and Company. J. Gluff: None. A.M. Niedenthal: None.
Mass balance and metabolism studies using radiolabeled substances are well recognized as an important part of the drug development process. In this study, we directly assessed the use of fluorine ...nuclear magnetic resonance ( super(19) F NMR) to achieve quantitative mass balance, metabolism, and distribution information for fluorinated compounds, without the need for radiolabeled synthesis or study. As a test case, the disposition of pefloxacin, a fluoroquinolone antibiotic, was evaluated in rats using quantitative super(19) F NMR in parallel with a radiolabeled study. Urine, bile, and feces samples were collected over specific periods after oral administration of either 25 mg/kg super(14) Cpefloxacin or 25 mg/kg pefloxacin and were subsequently profiled by radioactivity or super(19) F NMR, respectively. The percentage of dose excreted in each matrix was comparable between the two methods, with the total dose recovered by radioactivity and super(19) F NMR determined to be 86.8% and 81.8%, respectively. In addition, plasma samples were collected to determine the exposure of pefloxacin and its circulating metabolites. The plasma exposure of pefloxacin determined by super(19) F NMR was within 5% to that calculated by a validated liquid chromatography-tandem mass spectrometry bioanalytical method. By both methods, pefloxacin was identified as the major circulating entity, with pefloxacin glucuronide as the major circulating metabolite. Quantitative analysis of metabolites in excreta was generally comparable between the two methods. In selected tissues, both methods indicated that the parent drug accounted for most of the drug-related material. In summary, we have demonstrated that super(19) F NMR can be used as an alternative method to conventional radiolabeled studies for compounds containing fluorine without the need for radiolabeled synthesis/study.
Mass balance and metabolism studies using radiolabeled substances are well recognized as an important part of the drug development process. In this study, we directly assessed the use of fluorine ...nuclear magnetic resonance (19F NMR) to achieve quantitative mass balance, metabolism, and distribution information for fluorinated compounds, without the need for radiolabeled synthesis or study. As a test case, the disposition of pefloxacin, a fluoroquinolone antibiotic, was evaluated in rats using quantitative 19F NMR in parallel with a radiolabeled study. Urine, bile, and feces samples were collected over specific periods after oral administration of either 25 mg/kg 14Cpefloxacin or 25 mg/kg pefloxacin and were subsequently profiled by radioactivity or 19F NMR, respectively. The percentage of dose excreted in each matrix was comparable between the two methods, with the total dose recovered by radioactivity and 19F NMR determined to be 86.8% and 81.8%, respectively. In addition, plasma samples were collected to determine the exposure of pefloxacin and its circulating metabolites. The plasma exposure of pefloxacin determined by 19F NMR was within 5% to that calculated by a validated liquid chromatography-tandem mass spectrometry bioanalytical method. By both methods, pefloxacin was identified as the major circulating entity, with pefloxacin glucuronide as the major circulating metabolite. Quantitative analysis of metabolites in excreta was generally comparable between the two methods. In selected tissues, both methods indicated that the parent drug accounted for most of the drug-related material. In summary, we have demonstrated that 19F NMR can be used as an alternative method to conventional radiolabeled studies for compounds containing fluorine without the need for radiolabeled synthesis/study.
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