Pharmaceutical studies on chitosan matrix: controlled release of aspirin from chitosan device

Abstract

Chitosan (β-d-glucosaminan) is chemically prepared from chitin (N-acetyl-β-d-glucosaminan) which is an unutilized natural resource. We now report on the suitability of the chitosan matrix for use as vehicles for the controlled release of drugs. Salicylic acid and aspirin were used as model drugs in this study. The permeation of salicylic acid in the chitosan membranes was determined in a glass diffusion cell with two compartments of equal volume. Drug release studies on the devices were conducted in a beaker containing 5% sodium hydroxide solution. Partition coefficient (Kd) value for acetate membrane (472) is much greater than that for fluoro-perchlorate chitosan membrane (282). Higher Kd value for acetate chitosan membrane appears to be inconsistent with the bulk salicylic acid concentration. The permeability constants of fluoro-perchlorate and acetate chitosan membranes for salicylic acid were 3.139×10−7 cm2/sec. and 4.255×10−7 cm2/sec, respectively. It was also found that release rate of 30% salicylic acid in devices was 3.792×10−2 mg/cm2/min up to 60 min and that of 30% aspirin in the devices was 4.739×10−2 mg/cm2/sec up to 60 min. As the loading dose of aspirin in a chitosan device increased, water up-take of chitosan device increased, but in case of salicylic acid it decreased. The release rate increased with increase in the molecular volume of the drugs. These results suggest that the release mechanism may be controlled mainly by diffusion through pores.