The synthesis of [1-14 C]2-(1H-tetrazol-5-yl)acetic acid.

Tetrazoles are a common heterocyclic functionality in many biologically active molecules. [1-14 C]2-(1H-Tetrazol-5-yl)acetic acid was required as an intermediate in the synthesis of a development candidate as part of a discovery phase program to complete metabolic profiling studies. [1-14 C]2-(1H-Tetrazol-5-yl)acetic acid was prepared in 4 steps overall and in 3 radiochemical steps from K14 CN in an overall 32% radiochemical yield.

The syntheses of isotopically labelled CB-1 antagonists for the treatment of obesity.

BMS-725519, BMS-811064, and BMS-812204 are potent and selective central cannabinoid receptor antagonists that have been investigated for the treatment of human obesity. To further understand their biotransformation profiles, radiolabelled and stable-labelled products were required. This paper describes the utility of [14 C]1,1-carbonyldiimidazole as a radiolabelling reagent for the syntheses of carbonyl-labelled [14 C]BMS-725519, [14 C]BMS-811064, and [14 C]BMS-812204. The syntheses of stable-labelled [13 C6 ]BMS-725519 and [13 CD313 CD2 ]BMS-812204 synthesized from of [13 C6 ]4-chloroacetophenone and [13 CD313 CD2 ]iodoethane, respectively, are also described.

The syntheses of [(14) C]BMS-823778 for use in a human ADME clinical study and of [(13) CD3 (13) CD2 ]BMT-094817, a stable-isotope labeled standard of a newly detected human metabolite.

Type 2 diabetes is a significant worldwide health problem. To support the development of BMS-823778 as an inhibitor of 11ß-hydroxysteroid dehydrogenase type 1 for type 2 diabetes, the synthesis of carbon-14-labeled material was required for use in a human adsorption, distribution, metabolism, and excretion (ADME) study. The HCl salt form of [(14) C]BMS-823778 was synthesized in two steps from commercially available [2-(14) C]acetone. The radiochemical purity of the synthesized [(14) C]BMS-823778 after dilution with unlabeled clinical-grade BMS-823778 was 99.5% having a specific activity of 7.379 µCi/mg. One result of the human ADME study was the detection of a new human metabolite, BMT-094817. To support the quantification of BMT-094817 in clinical samples, it was necessary to synthesize [(13) CD3 (13) CD2 ]BMT-094817 for use as a liquid chromatography/mass spectrometry standard. [(13) CD3 (13) CD2 ]BMT-094817 was prepared in five labeled steps from [(13) CD3 ]iodomethane.

The synthesis of (14)C-labeled, (13)CD2-labeled saxagliptin, and its (13)CD2-labeled 5-hydroxy metabolite.

(14)C-labeled saxagliptin, (13) CD2-labeled saxagliptin, and its (13) CD2-labeled 5-hydroxy metabolite were synthesized to further support development of the compound for biological studies. This paper describes new syntheses leading to the desired compounds. A total of 3.0 mCi of (14)C-labeled saxagliptin was obtained with a specific activity of 53.98 µCi/mg (17.13 mCi/mmol). The radiochemical purity determined by HPLC was 99.29%, and the overall radiochemical yield was 3.0% based upon 100 mCi of [(14)C]CH2 I2 starting material. By following similar synthetic routes, 580.0 mg of (13)CD2-labeled saxagliptin and 153.1 mg of (13)CD2-labeled 5-hydroxysaxagliptin metabolite were prepared.

Metabolism and disposition of [14C]brivanib alaninate after oral administration to rats, monkeys, and humans.

Brivanib [(R)-1-(4-(4-fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[1,2,4]triazin-6-yloxy)propan-2-ol, BMS-540215] is a potent and selective dual inhibitor of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) signaling pathways. Its alanine prodrug, brivanib alaninate [(1R,2S)-2-aminopropionic acid 2-[4-(4-fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[2,1-f][1,2,4]triazin-6-yloxy]-1-methylethyl ester, BMS-582664], is currently under development as an oral agent for the treatment of cancer. This study describes the in vivo biotransformation of brivanib after a single oral dose of [(14)C]brivanib alaninate to intact rats, bile duct-cannulated (BDC) rats, intact monkeys, BDC monkeys, and humans. Fecal excretion was the primary route of elimination of drug-derived radioactivity in animals and humans. In BDC rats and monkeys, the majority of radioactivity was excreted in bile. Brivanib alaninate was rapidly and completely converted via hydrolysis to brivanib in vivo. The area under the curve from zero to infinity of brivanib accounted for 14.2 to 54.3% of circulating radioactivity in plasma in animals and humans, suggesting that metabolites contributed significantly to the total drug-related radioactivity. In plasma from animals and humans, brivanib was a prominent circulating component. All the metabolites that humans were exposed to were also present in toxicological species. On the basis of metabolite exposure and activity against VEGF and FGF receptors of the prominent human circulating metabolites, only brivanib is expected to contribute to the pharmacological effects in humans. Unchanged brivanib was not detected in urine or bile samples, suggesting that metabolic clearance was the primary route of elimination. The primary metabolic pathways were oxidative and conjugative metabolism of brivanib.

Disposition of [1'-(14)C]stavudine after oral administration to humans.

The disposition of stavudine, a potent and orally active nucleoside reverse transcriptase inhibitor, was investigated in six healthy human subjects. Before dosing humans with [1'-(14)C]stavudine, a tissue distribution study was performed in Long-Evans rats. Results from this study showed no accumulation of radioactivity in any of the tissues studied, indicating that the position of the (14)C-label on the molecule was appropriate for the human study. After a single 80-mg (100 microCi) oral dose of [1'-(14)C]stavudine, approximately 95% of the radioactive dose was excreted in urine with an elimination half-life of 2.35 h. Fecal excretion was limited, accounting for only 3% of the dose. Unchanged stavudine was the major drug-related component in plasma (61% of area under the plasma concentration-time curve from time zero extrapolated to infinite time of the total plasma radioactivity) and urine (67% of dose). The remaining radioactivity was associated with minor metabolites, including mono- and bis-oxidized stavudine, glucuronide conjugates of stavudine and its oxidized metabolite, and an N-acetylcysteine (NAC) conjugate of the ribose (M4) after glycosidic cleavage. Formation of metabolite M4 was shown in human liver microsomes incubated with 2',3'-didehydrodideoxyribose, the sugar base of stavudine, in the presence of NAC. In addition, after similar microsomal incubations fortified with GSH, two GSH conjugates, 3'-GS-deoxyribose and 1'-keto-2',3'-dideoxy-3'-GS-ribose, were observed. This suggests that 2',3'-didehydrodideoxyribose underwent cytochrome P450-mediated oxidation leading to an epoxide intermediate, 2',3'-ribose epoxide, followed by GSH addition. In conclusion, absorption and elimination of stavudine were rapid and complete after oral dosing, with urinary excretion of unchanged drug as the predominant route of elimination in humans.