Pharmacokinetics, safety and tolerability of three dosage regimens of buccal adhesive testosterone tablets in healthy men suppressed with leuprorelin.

We used a randomised, double-blind, crossover design to evaluate the pharmacokinetics, safety and tolerability of three doses of buccal adhesive testosterone tablets (BATT). Twenty-four healthy men, whose endogenous testosterone was suppressed to </=5.38 nmol/l with leuprorelin acetate, took BATT (10, 20 or 30 mg) daily for 10 days. There was a 4-day washout between treatments. Substantial testosterone absorption occurred from BATT, and mean serum testosterone, free testosterone and dihydrotestosterone (DHT) concentrations over 24 h showed circadian variation. Steady state was reached by day 5. Average 24-h concentrations for the three BATT doses were within the normal range for eugonadal men: testosterone 11.67-14.57 nmol/l, free testosterone 0.026-0.33 nmol/l and DHT 1.66-2.03 nmol/l. On all three doses, peak testosterone and free testosterone was reached 8-9 h after tablet application; DHT peaked about 1-2 h later, and declined more slowly. Hormone concentrations increased with BATT dose, but increases were less than dose-proportional. There was no evidence of testosterone accumulation. BATT was well tolerated.