Study of the bioequivalence of three oral formulations of ibopamine in healthy volunteers.

Ibopamine (SK & F 100168-A), a new chemical entity, is capable of eliciting positive inotropic effects accompanied by vasodilating, diuretic and saliuretic activity after oral administration. The relative bioavailability and bioequivalence of 3 oral presentations of Ibopamine was examined after a single oral dose. Thirty healthy subjects (15 males and 15 females) received the 3 formulations at one-week intervals according to "single-blind assayer" latin-square crossover design. Two tablets of 100 mg ibopamine (SIMES formulations), 2 tablets of 100 mg ibopamine (UK formulation) and 1 tablet of 200 mg ibopamine (US-Tiltab formulation) were used. In a 4th occasion, all volunteers received again the 200 mg-tablet of the US-Tiltab formulation in order to assess the intra-individual variability of its oral bioavailability. Free epinine plasma levels were measured before and 10, 20, 30, 45, 60, 90, 105 min and 2, 2.5, 3, 4, 6, 8 and 24 h after each oral administration. Free epinine was assayed by HPLC/electrochemical detection method. The amount of drug absorbed as measured by the area under the curve, AUC0-8 h, and the rate of absorption, as measured by Cmax and tmax, were compared by examining the symmetric 95% confidence intervals. If the symmetric 95% confidence interval with respect to AUC is between 80% and 120%, two formulations are considered bioequivalent.(ABSTRACT TRUNCATED AT 250 WORDS)