Development of a Practical and Efficient Synthesis of CP-945,598-01, a CB1 Antagonist for the Treatment of Obesity

Self-optimisation of the final stage in the synthesis of EGFR kinase inhibitor AZD9291 using an automated flow reactor

Self-optimising flow reactors combine online analysis with evolutionary feedback algorithms to rapidly achieve optimum conditions.

Excretion, metabolism, and pharmacokinetics of 1-(8-(2-chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl)-4-(ethylamino)piperidine-4-carboxamide, a selective cannabinoid receptor antagonist, in healthy male volunteers

The disposition of 1-(8-(2-chlorophenyl)-9-(4-chlorophenyl)-9H- purin-6-yl)-4-(ethylamino)-piperidine-4-carboxamide (CP-945,598), an orally active antagonist of the cannabinoid CB1 receptor, was studied after a single 25-mg oral dose of [(14)C]CP-945,598 to healthy human subjects. Serial blood samples and complete urine and feces were collected up to 672 h after dose. The mean total recovery of radioactivity was 60.1 ± 12.8 from the urine and feces, with the majority of the dose excreted in the feces. The absorption of CP-945,598 in humans was slow with T(max) at 6 h. Less than 2% of the dose was recovered as unchanged drug in the combined excreta, suggesting that CP-945,598 is extensively metabolized. The primary metabolic pathway of CP-945,598 involved N-de-ethylation to form an N-desethyl metabolite (M1), which was then subsequently metabolized by amide hydrolysis (M2), N-hydroxylation (M3), piperidine ring hydroxylation (M6), and ribose conjugation (M9). M3 was further metabolized to oxime (M4) and keto (M5) metabolites. M1, M4, and M5 were the major circulating metabolites, with AUC((0-48)) values 4.7-, 1.5-, and 1.1-fold greater than that of CP-945,598. M1, M2, and M9 accounted for 5.6, 33.6, and 6.30% of the dose, respectively, in excreta. The results from in vitro experiments with recombinant isoforms suggested that the oxidative metabolism of CP-945,598 to M1 is catalyzed primarily by CYP3A4/3A5. The molecular docking study showed that the N-ethyl moiety of CP-945,598 can access to the heme iron-oxo of CYP3A4 in an energetically favored orientation. Together, these data suggest that CP-945,598 is well absorbed and eliminated largely by CYP3A4/3A5-catalyzed metabolism.

Excretion, metabolism, and pharmacokinetics of CP-945,598, a selective cannabinoid receptor antagonist, in rats, mice, and dogs

1-(8-(2-Chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl)-4-(ethylamino)piperidine-4-carboxamide (CP-945,598) is an orally active antagonist of the cannabinoid CB-1 receptor that progressed into phase 3 human clinical trials for the treatment of obesity. In this study, we investigated the metabolic fate and disposition of CP-945,598 in rats, Tg-RasH2 mice, and dogs after oral administration of a single dose of [(14)C]CP-945,598. Total mean recoveries of the radioactive dose were 97.7, 97.8, and 99.3% from mice, rats, and dogs, respectively. The major route of excretion in all three species was via the feces, but on the basis of separate studies in bile duct-cannulated rats and dogs, this probably reflects excretion in bile rather than incomplete absorption. CP-945,598 underwent extensive metabolism in all three species, because no unchanged parent compound was detected in the urine across species. The primary metabolic pathway of CP-945,598 involved N-deethylation to form an N-desethyl metabolite (M1). M1 was subsequently metabolized by amide hydrolysis, oxidation, and ribose conjugation to numerous novel and unusual metabolites. The major circulating and excretory metabolites were species-dependent; however, several common metabolites were observed in more than one species. In addition to parent compound, M1, M3, M4, and M5 in rats, M1, M3, and M4 in mice, and M1 and M2 in dogs were identified as the major circulating metabolites. Gender-related differences were also apparent in the quantitative and qualitative nature of the metabolites in rats. An unprecedented metabolite, M4, formed by deamidation of M1 or M3 (N-hydroxy-M1), but not by decarboxylation of M2, was identified in all species. M4 was nonenzymatically converted to M5.