Disposition and Metabolism of [14C]Brasofensine in Rats, Monkeys, and Humans

Mingshe Zhu; Daisy B. Whigan; Shu Y. Chang; Randy C. Dockens

doi:10.1124/dmd.107.016139

Abstract

Brasofensine is an inhibitor of the synaptic dopamine transporter. These studies were conducted to characterize the pharmacokinetics, absolute bioavailability, disposition, and metabolism of brasofensine after i.v. and/or p.o. administrations of [¹⁴C]brasofensine in rats (1.5 mg/kg i.v., 4 mg/kg p.o.) and monkeys (4 mg i.v., 12 mg p.o.) and humans (50 mg p.o.). Brasofensine was rapidly absorbed after p.o. administration in rats and monkeys, with peak plasma concentrations occurring 0.5 to 1 h but 3 to 8 h for brasofensine in humans. Plasma terminal elimination half-lives were ∼2 h in rats, ∼4 h in monkeys, and ∼24 h in humans. Total body clearance and steady-state volume of distribution values were 199 ml/min/kg and 24 l/kg, respectively, in the rat and 32 ml/min/kg and 46 l/kg, respectively, in the monkey. Absolute bioavailability was 7% in rats and 0.8% in monkeys. After a single p.o. dose, urinary excretion of radioactivity accounted for 20% of the administered dose in rats, 70% in monkeys, and 86% in humans, with the remainder excreted into the feces. Brasofensine had extensive first-pass metabolism following p.o. administration in humans, monkeys, and rats. It primarily underwent O- and N-demethylation and isomerization. Some of the desmethyl metabolites were further converted to glucuronides. These primary metabolites and glucuronides of demethyl brasofensine (M1 and M2) were major circulating metabolites in humans and were also observed in rat and monkey plasma.

Footnotes

Part of this work was presented at the 9th North American ISSX Meeting, Nashville, TN, October 24–28, 1999.
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.107.016139.
ABBREVIATIONS: brasofensine, BMS-204756, (+)-(E)-(1R,2R,3S)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carbaldehyde O-methyloxime; BMS-205912, (+)-(Z)-(1R,2R,3S)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carbaldehyde O-methyloxime; BMS-180448, (3S-trans)-N-(4-chlorophenyl)-N′-cyano-N″-(6-cyano-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-yl)guanidine; BMS-217380, N,N-diethyl-2-[4-(phenylmethyl-14C)phenoxy]ethanamine, monohydrochloride; BMS-181101, 5-fluoro-3-[3-[4-(5-methoxy-4-pyrimidinyl)-1-piperazinyl]propyl]-1H-indole; ODME, O-desmethyl brasofensine; ODMZ, O-desmethyl BMS-205912; NDME, N-desmethyl brasofensine; BMS, Bristol-Myers Squibb; LE, Long Evans; BDC, bile duct–cannulated; LC/MS, liquid chromatography/mass spectrometry; MS/MS, tandem mass spectrometry; QC, quality control; LLQ, lower limit of quantitation; CSF, cerebrospinal fluid; HPLC, high-performance liquid chromatography; AUC_INF, area under the plasma concentration-time curve from 0 to infinity; CL_T, total body clearance; Vd_ss, steady-state volume of distribution; AUMC, area under the first moment curve; MRT, mean residence time(s); amu, atomic mass unit(s).
- Received April 4, 2007.
- Accepted September 26, 2007.