Combining benefits of an adrenergic and a muscarinic blocker in a single formulation – A pharmacokinetic evaluation

A pharmacokinetic bioequivalence study was conducted in Asian subjects, to compare a fixed dose combination capsule single oral dose of alpha adrenoceptor blocker—Alfuzosin hydrochloride 10 mg extended release and muscarinic antagonists—Solifenacin succinate 5 mg against individually administered Xatral XL 10 mg tablets (Alfuzosin) of Sanofi Synthelabo Limited, United Kingdom (UK) and Vesicare 5 mg tablets (Solifenacin) of Astellas Pharma Limited, UK under fed conditions. Blood samples were collected pre-dose up to 72 h post dose for determination of plasma Alfuzosin and Solifenacin concentrations and calculation of the pharmacokinetic parameters. ANOVA was performed on the log (natural)-transformed pharmacokinetic parameters. A 90% confidence interval for the ratios of the test and reference product averages (least square means) were calculated for alfuzosin and solifenacin. The 90% confidence intervals obtained for alfuzosin for Cmax, AUC0−t and AUC0−∞ were 102.74–122.75%, 95.84–116.96% and 95.82–116.76%, respectively. The 90% confidence intervals obtained for Solifenacin for Cmax, and AUC0−72 were 89.55–97.91% and 90.47–99.38%, respectively. Based on the results, the fixed dose combination was concluded to be bioequivalent to individually administered products.