Pharmacokinetic and bioequivalence study of two brands of valsartan tablets in healthy male volunteers

Abstract

Valsartan (CAS 137862-53-4) is an antihypertensive drug belonging to the family of angiotensin II receptor antagonists acting at the AT₁ receptor, which mediates all known effects of angiotensin II on the cardiovascular system. In the present study, the pharmacokinetic parameters of two oral formulations of valsartan tablets were compared in a randomized, single oral dose, two-treatment crossover design in 24 healthy male volunteers under fasting conditions. After an overnight fast, the volunteers received 80 mg valsartan. Blood samples were collected up to 48 h and drug concentrations were determined by a reverse-phase HPLC method with fluorescence detection. Various pharmacokinetic parameters were determined from the plasma concentration-time curves of both formulations. The obtained values for test and reference products were 3 067.7 ± 1 281.7 and 3 304.3 ± 1 196.4 ng/ml for C_max; 17 834.4 ± 7 083.8 and 18319.1 ± 7 800.7 ng · h/ml for AUC_0–48; 18825.7 ± 7 553.2 and 19 172.2 ± 8 307.2 ng · h/ml for AUC_0–∞, respectively. The 90% confidence intervals obtained by analysis of variance were 86.84–100.87% for C_max and 93.43–115.54% for AUC_0–t, which are within the acceptance range of 80–125%. Therefore it can be concluded that both products are bioequivalent in terms of rate and extent of drug absorption and therefore interchangeable.

Key words

Angiotensin II receptor antagonist - Antihypertensive - CAS 137862-53-4 - Valsartan, bioavailability, bioequivalence

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