Research paper Influence of organic acids on drug release pattern of verapamil hydrochloride pellets

The main objective of the present study was to deve lop a multiple-unit, extended release drug delivery system for verapamil hydrochloride and to evaluate the influence of organic acids on drug release from pellets. Organic acids such as fumaric and malic acid were u sed as a pH-adjuster inside the pellet core for the maintenance of constant acidic micro-environment. The core vera pamil pellets were prepared by extrusion- spheroniz ation technique. The physical properties and in vitro dru g release studies were carried out to evaluate the influence of organic acids as formulation ingredient. Influence of processing variables was also studied. Spherical pellets with acceptable physical properties were observed when organic acids were used. The dissolution studies cle arly indicated increase in dissolution in presence of or ganic acids. The dissolution rate of the drug from pellets containing fumaric acid was high even in the elevat ed pH corresponding to intestine, which may be due to creation of microenvironmental pH inside the pellet core and thus, maintenance of constant acidic pH inside the pellet.