Application of gelatin for encapsulating aspirin into ethyl cellulose microcapsule in an O/W emulsion

The application of gelatin protective colloid for microencapsulating aspiri n in ethylcellulose was demonstrated using an oil-in-water emulsification/s olvent evaporation technique. The gelatin concentration, alcohol co-solvent amount, and ethylcellulose viscosity were investigated by analyzing the re covered weight, particle size distribution, drug loading efficiency, aspiri n release rate, surface characteristics, and release kinetics. Results show ed that recovery increased with greater concentrations of gelatin (up to 1% ). Adding co-solvent (ethanol) also changed the microcapsule particle size distribution. Higher recovery and release rates were obtained when the etha nol content in polymer solvent was at 25% and the viscosity of ethylcellulo se was low (45 cps). The release rate followed Higuchi matrix release kinet ics, suggesting a monolithic system with aspirin uniformly distributed over the microcapsule.