ENTRAPMENT OF WATER-SOLUBLE MATERIAL INTO BIODEGRADABLE MICROCAPSULE PREPARED BY SOLVENT EVAPORATION

Preparation of biodegradable microcapsule using a poly lactic acid as wall material was performed by (W/O/W) emulsion solvent evaporation me thod. Fractional entrapment of the core material and the average diame ter of the microcapsule are independent of the composition of the inne r aqueous phase, such as salt concentration, pH and viscosity. On the other hand, by changing the salt concentration of the outer aqueous ph ase and the hold up of dispersion phase in the (W/O) emulsion, it is p ossible to increase the fractional entrapment of the core material wit h the increase in (W/O/W) emulsion stability and amount of wall materi al. The entmpment effect is controlled by preparation conditions.