Characterization of microparticles prepared by the solvent evaporation method, use of alcohol-soluble cellulose acetate butyrate as a carrier

Abstract

Context: Cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are used in solid pharmaceutical dosage forms for controlling drug delivery. The property of cellulose acetate butyrate (CAB) varies according to butyryl, acetyl and hydroxyl level. These polymers are soluble in flammable organic solvents such as acetone. CAB-553-0.4, however, is characterized by its solubility in a less harmful organic solvents such as low molecular weight alcohol. Aims: To evaluate the use of CAB-553-0.4 as a new carrier for the preparation of microparticles by solvent evaporation method and comparing the result to the well-known carrier i.e., ethylcellulose (EC). Methods: The polymer organic phase containing carbamazepine or propranolol HCl was dispersion in an aqueous media containing polyvinyl alcohol (PVA). Percent of encapsulation efficiency, EE%, was calculated and in vitro drug release from the microparticles was investigated. Results: EE% of EC microparticles was relatively high (71%) for carbamazepine and low for propranolol HCl. However, the EE% of propranolol HCl increased by two folds when CAB used as a carrier. EE% of carbamazepine was decreased by increasing the volume of the aqueous phase from EC- and unchanged from CAB-microparticles. The optimum concentration of PVA was 0.25% w/v and the EE% was decreased with increasing temperature. Carbamazepine release from EC- and CAB-microparticles was similar, however, propranolol HCl release was slower from CAB- microparticles than EC microparticles. Conclusions: CAB-553-0.4 is an interesting carrier for the formulation of microparticles, loaded with a water-soluble drug, by solvent evaporation.