Steady state bioequivalence study of dipyridamole ER and acetyl salicylic acid 200 mg + 25  mg capsules in adult healthy male and female volunteers under fasting condition

The aim of the study was to evaluate the steady state pharmacokinetics and establish bioequivalence between the test (dipyridamole ER and acetyl salicylic acid 200 mg + 25 mg capsules of Dr. Reddy’s Laboratories Limited, India) against equal doses of reference (AGGRENOX® retard capsule of Boehringer Ingelheim Pharma GmbH & Co., KG 55216 Ingelheim am Rhein, Germany) formulations in 72 healthy adult male and female volunteers under fasting conditions. This was an open-label, block randomized, multiple dose, two-period, two-sequence, cross-over study separated by a washout period of 8 days. On day 5 of each period, post-dose blood samples were collected up to 12 h and analyzed for dipyridamole, salicylic acid and acetyl salicylic acid using a validated LC-MS/MS method. The 90% CI for dipyridamole (AUC(0–τ).ss, Cmax.ss and Cmin.ss) and for salicylic acid (AUC(0–τ).ss, Cmax.ss and %ptf) lie within the accepted bioequivalence range of 80.00–125.00%, thus permitting one to conclude for bioequivalence. In conclusion, both the formulations were well tolerated and the test product was bioequivalent to the reference product in terms of the rate and extent of absorption at steady state.