Использование ингибиторов протеаз в составе полиэлектролитных микрочастиц для увеличения биодоступности капсулируемых белков при пероральном применении

Abstract

Protein protease inhibitors (aprotinin, soybean Bowman – Birk inhibitor, and soybean Kunitz trypsin inhibitor) possessing different specificity with respect to trypsin, chymotrypsin, and elastase were encapsulated together with a cargo protein in polyelectrolyte microparticles using the layer-by-layer (LBL) deposition techniques. The most efficient inclusion of the inhibitors occurred at the stage of formation of insoluble protein complex with polyanion. The simultaneous immobilization of the inhibitor and protein did not influence the physicochemical properties of microparticles, specifically their pH-sensitive behavior under conditions modeling the passage via various parts of the human gastrointestinal tract after peroral administration. The most effective protection against the action of proteolytic enzymes of pancreatic juice and small intestine was achieved for the simultaneous release of a cargo protein and inhibitor from the microparticles. Soybean Bowman-Birk inhibitor, which is most similar to insulin in respect of the physicochemical properties, as well as the extract from soybean enriched with protease inhibitors, were the most suitable agents for the protection of human insulin or rapidly acting analogs of insulin (lispro and aspart). These findings suggest that the simultaneous microencapsulation of both protein and the protein protease inhibitor is a promising way to increase the protein bioavailability upon peroral administration of polyelectrolyte microparticles.