Effect of DA-8031, a novel oral compound for premature ejaculation, on male rat sexual behavior

Abstract

Objectives: DA-8031 is a potent and selective serotonin transporter inhibitor developed for the treatment of premature ejaculation. The aim of the present study was to investigate the effects of DA-8031 on male sexual behavior in a rat model. Methods: Sexual behavior was examined after an acute oral administration of 10, 30 or 100mg/kg of DA-8031 in copulation studies with female rats. Pharmacokinetic parameters were calculated after oral administration of DA-8031 at a dose level of 30mg/kg. Results: DA-8031 treatment produced a dose-dependent increase in ejaculation latency time and showed statistical significance at 30 and 100mg/kg dosage levels compared with the vehicle (P<0.05). In addition, DA-8031 treatment reduced the mean number of ejaculations in a dose-dependent manner. No changes in post-ejaculatory interval, numbers of mounts, intromissions or ejaculations were observed at any dose. In pharmacokinetic study, the blood concentration of DA-8031 peaked at 0.38±0.14h after oral administration, and then rapidly declined with a half-life of 1.79±0.32h. Conclusions: Treatment with DA-8031 delays the ejaculation latency time without affecting the initiation of mounting behavior or post-ejaculatory interval in rats. Furthermore, DA-8031 is rapidly absorbed and eliminated after oral administration in rats. These preclinical findings provide a clue for the clinical testing of DA-8031 as an "on-demand" agent for premature ejaculation. © 2013 The Japanese Urological Association.