Phase Transited Asymmetric Membrane Capsule: A Means for Achieving Delayed and Controlled Osmotic Flow

Abstract

In the present study, a phase transited nondisintegrating polymeric capsular system in achieving delayed as well as improved osmotic flow for the model drug cefadroxil was developed. Asymmetric membrane capsule (AMC) was prepared by precipitation of asymmetric membrane (AM) on the fabricated glass mold pins via wet phase inversion process. Effect of different formulation variables were studied based on 23 factorial design, namely, level of osmogen, ethylcellulose, pore former, apart from studying the effect of varying osmotic pressure on drug release. Scanning electron microscopy showed an outer dense non-porous region and an inner lighter porous region for the prepared AMC. Statistical test (Dunnett multiple comparison test) was applied for in vitro drug release (n=6) at P < 0.05. The best formulation in the design closely corresponded to the extra design checkpoint formulation by a similarity factor (f2) of 98.91, and a difference factor (f1) of 2.17. The drug release was independent of agitation intensity but dependent on the osmotic pressure of the dissolution medium. The release kinetics followed Higuchi model, and mechanism of release was Fickian diffusion.