In vitro determination of verapamil hydrochloride tablet dissolution

Overview

Three different products containing 240 mg of verapamil hydrochloride in a coated tablet withsustained release were compared using the blinded dissolution test. The amount of the activesubstance released from the tablet and its dynamics differed significantly with all three productsafter 3 hours of dissolution. With product C (Isoptin SR, a proprietary product manufactured byKnoll), 92,2 % of the active substance was released after seven hours. With generic products A andB, the amounts were higher and lower, respectively. The dynamics of release of the active substancewas linear only with the proprietary product. Irregular and non-linear rates of active substancerelease from the tablet may result in clinically suboptimal efficacy and safety of generic products.

Key words:
dissolution test – verapamil – sustained release – UV spectrophotometry