Abstract
Some physical and dynamical factors affecting the second emulsification were investigated in ethyl cellulose microcapsules containing aspirin prepared by a multiple (WI/O/WII) emulsion method. Furthermore, the dissolution rates of aspirin from microcapsules were measured. The following results were obtained ; In the second emulsification at preparation, the mean length diameter of microcapsules decreased initially and was leveled off later with an increase in the gelatin concentration in outer aqueous phase. The yield of microcapsules decreased as the revolution number of agitation became higher. The change in the serum concentration of aspirin after administration of aspirin microcapsules was apparently different from the plain powder, showing delayed release properties at the early time periods and a flatter response decay at the later time periods.
