Design and characterization of hollow/porous floating beads of captopril for pulsatile drug delivery

Abstract

The present study was aimed to design and characterize hallow/ porous floating beads of captopril for pulsatile drug delivery for the treatment of hypertension. Captopril, an antihypertensive agent, is one of the most commonly prescribed drugs for the treatment of patients with hypertension and congestive heart failure.The floating pulsatile concept was applied to increase the gastric residence of the dosage form, having lag phase followed by a burst release.To overcome the limitations of the various approaches for imparting buoyancy, hollow/porous beads were prepared. A preliminary study was done for selection of the polymer (low methoxy pectin and gellan gum) combination. Based on the preliminary studies, an optimized concentration of polymers was selected for formulation design with varying the concentration of sodium bicarbonate. The obtained floating beads were studied for physical characterization, in vitro release, in vivo gamma-scintigraphy study and stability study. Formulation F1E floating beads had a porosity of 38.41% and hollow with bulk density <1. The entrapment efficiency for formulation F1E was 83.10%, and the particle size of the beads was 1.124 mm. The floating beads showed a two-phase release pattern, with initial lag time in acidic medium followed by rapid pulse release in the phosphate buffer medium with in vitro release of 96.77% for almost 8 h. The in vivo gastric residence of batch F1E was subjected to gamma-scintigraphy imaging on rabbits to determine the retention of drug (beads) for up to 6 h. This approach suggested use of hollow sodium bicarbonate microparticles as promising floating-pulsatile drug delivery systems for site- and time-specific release of antihypertensive drugs.