Preparation and characterization of microencapsulated proteinase inhibitoraprotinin

Preparation of microcapsules through interfacial cross-linking of soluble s tarch/hydroxyethyl starch and bovine serum albumin (BSA) with terephthaloyl chloride is described. The proteinase inhibitor aprotinin, either native o r active site protected, was microencapsulated, being;incorporated in the a queous phase. The influence of aqueous phase pH, BSA, and terephthaloyl chl oride concentrations as well as stirring rate on microcapsule morphology an d size was studied. The polycondensation pH was shown to be the determining factor for tough microcapsule production with a high encapsulation yield. The size of the microcapsules ranged between 10-30 and 50-100 mu m at stirr ing speed 1500 and 500 rpm,respectively. Fourier transform infrared spectro scopic studies were performed on microcapsules: prepared under various cond itions. A correlation was established between spectral changes and microcap sule morphology and size. The optimal conditions for microcapsule degradati on by a-amylase were found. Active site-protected aprotinin was shown to fu lly retain its activity after microencapsulation.