Comparative Bioavailability of Two Tablet Formulations of Dipyridamole in Healthy Volunteers

The bioavailability of two dipyridamol tablet formulations of (Dipyridamole from Tolidaru and Persantin from Boehringer) was compared in 14 healthy male volunteers who received a single dose of 25 mg of the test (T) and the reference (R) products in a randomized balanced 2- way crossover design. Plasma samples were obtained over a 16 h interval and dipyridamole concentrations determined by HPLC with ultraviolet detection. The maximum plasma concentration (C_max), area under the plasma concentration time curve up to the last measurable concentration (AUC_0-t), as well as infinity (AUC_0-∞), and the absorption rate (C_max/AUC_0-∞) were analyzed statistically under the assumption of a multiplicative model. The time to maximum concentration (T_max) was analyzed assuming an additive model. The parametric confidence intervals (90%) of the mean values of the pharmacokinetic characteristics for T/R ratio were in each case well within the bioequivalence acceptable range of 80-125%. The test formulation was found bioequivalent to the reference formulation by the Schuirmann’s two one-sided t tests and by Wilcoxon Mann Whitney two one-sided tests procedure. Therefore, the 2 formulations were considered to be equivalent.