Preparation and Characterization of Microencapsulated Proteinase Inhibitor Aprotinin

N. V. Larionova¹, N. F. Kazanskaya¹, N. I. Larionova^1*, G. Ponchel², and D. Duchene²

¹School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-5417; E-mail: nilar@enzyme.chem.msu.ru

²Laboratory of Physico-Chemistry, Pharmacotechnique, and Biopharmacy, UMR CNRS 8612, School of Pharmacy, University of Paris-Sud, 92290 Chatenay-Malabry, France

^* To whom correspondence should be addressed.

Received April 8, 1999

---

Preparation of microcapsules through interfacial cross-linking of soluble starch/hydroxyethyl starch and bovine serum albumin (BSA) with terephthaloyl chloride is described. The proteinase inhibitor aprotinin, either native or active site protected, was microencapsulated, being incorporated in the aqueous phase. The influence of aqueous phase pH, BSA, and terephthaloyl chloride concentrations as well as stirring rate on microcapsule morphology and 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 µm at stirring speed 1500 and 500 rpm, respectively. Fourier transform infrared spectroscopic studies were performed on microcapsules prepared under various conditions. A correlation was established between spectral changes and microcapsule morphology and size. The optimal conditions for microcapsule degradation by alpha-amylase were found. Active site-protected aprotinin was shown to fully retain its activity after microencapsulation.

---

KEY WORDS: microencapsulation, proteinase inhibitor, aprotinin, starch, biodegradation

---