Controlled release of diclofenac sodium from sodium alginate beads crosslinked with glutaraldehyde1

Abstract

Controlled release sodium alginate (Na–Alg) beads containing diclofenac sodium (DS) have been prepared by precipitation of Na–Alg in alcohol followed by crosslinking with glutaraldehyde (GA) in acidic medium. Preparation of the beads was optimized by considering the percentage entrapment efficiency, swelling capacity of beads in water and their release data. The percentage entrapment efficiency was found to vary between 30 and 71 depending upon the conditions of their preparations. The beads produced at higher temperatures and longer times of exposure to the crosslinking agent have shown the lower entrapment efficiency, but extended release of DS from the beads. The scanning electron microscopic studies indicated nonporous smooth surfaces and the differential scanning calorimetric data indicated the molecular level dispersion of the drugs in the beads.