Pharmacokinetics of deramciclane and N-desmethylderamciclane after single and repeated oral doses in healthy volunteers

Objective: To study the pharmacokinetics and accumulation of deramciclane and its metabolite N-desmethylderamciclane after 60 mg twice daily doses for 4 weeks. Methods: Sixteen healthy male subjects, age range of 20 - 29 years, participated in this randomized, double-blind, parallelgroup, placebo-controlled study. Ten subjects first received a single 60 mg dose of deramciclane followed by 60 mg deramciclane b.i.d. between days 4 and 31. Six subjects received matching placebo in a similar manner. Pharmacokinetics of deramciclane and N-desmethylderamciclane were determined on days 1, 10, 17, 24 and 31. Plasma prolactin concentrations were measured before drug administration and 4 hours after on the same days. Safety was monitored using repeat laboratory determinations and ECG recordings. Results: The mean (SD) AUC 0 - ∞ of deramciclane was 1,251 (385) ng x h/ml after the first dose. The AUC τ calculated for the dosing interval was significantly higher at week I (p = 0.048) than the AUC 0 - ∞ after the first dose but thereafter there was no further accumulation of deramciclane. The mean accumulation indices at weeks 1, 2, 3 and 4 varied between 2.3 and 2.7 with no tendency to increase over time. The mean apparent elimination half-life of deramciclane was 24.9 (3.5) hours after the first dose and 29.3 (9.3) hours after 4-week repeated dosing; this difference was not statistically significant. The accumulation index of N-desmethylderamciclane increased from week 1 to week 2 but remained stable thereafter. The treatment was well tolerated. Plasma prolactin levels were not influenced by deramciclane administration. Conclusions: Deramciclane administration, 60 mg twice daily for 4 weeks to healthy male volunteers, is well tolerated, and there is no evidence of continuous accumulation of the drug during maintenance treatment. Deramciclane at a dose of 60 mg b.i.d. does not antagonize dopamine receptors to a significant degree.