CONTROLLED-RELEASE SALBUTAMOL SULFATE MICROCAPSULES PREPARED BY EMULSION SOLVENT EVAPORATION TECHNIQUE AND STUDY ON THE RELEASE AFFECTED PARAMETERS

Microcapsules of salbutamol sulphate with ethylcellulose were prepared using an emulsion-solvent evaporation technique and by the use of two different stirrer types, propeller and magnet. Different amounts of drug were added in order to obtain various drug to polymer ratios. The physical properties, loading efficiency and dissolution rate depended on the emulsion-solvent evaporation technique and on the drug to polymer ratio. Tween 80 was used as a dispersing agent. For a given drug to polymer ratio the percentage amount of Tween 80 affected the release of salbutamol sulphate and the size distribution of microcapsules. In order to further investigate the type of drug release mechanism taking place, the dissolution data were plotted according to the four different kinetic models. In vitro dissolution studies showed that first-order and square-root of time (Higuchi model) release characteristics were exhibited.