PROCESSING FACTORS AFFECTING PARTICLE-SIZE AND IN-VITRO DRUG-RELEASE OF SUSTAINED-RELEASE IBUPROFEN MICROSPHERES

Ibuprofen microspheres were prepared using an aqueous dispersion metho d. The method was adapted so that two processing factors, cooling time and stirring rate, could be altered. The subsequent effects of alteri ng these parameters on the characterisation of the microspheres and th e drug release kinetics were investigated. Particle size analysis show ed that both stirring rate and cooling time significantly affected the mean particle size although the effects were independent of each othe r. In vitro release data were fitted to several models, the Higuchi sq uare root of time model (with appropriate limits) giving the best fit for the release data. Increasing the cooling time or decreasing the st irring rate decreased the release of drug from the system. By using th is method of manufacture, which allows alteration of processing parame ters, it would be relatively straightforward to produce microspheres w ith tailored in vitro release characteristics.