Study in the stabilization of proteins encapsulated in PLGA delivery system: Effects of additives on protein encapsulation, release, and stability

Abstract

Therapeutic proteins/peptides face severe stability impairment in biotechnology drug delivery systems prepared by the W/O/W solvent evaporation method. Screening of protein stabilizers for poly (D, l-lactide-co-glycolide) (PLGA) nanoparticles can improve the low encapsulation efficiency and undesirable release behavior of proteins caused by PLGA carriers, which is a crucial step to achieve a high proportion of continuous release of encapsulated protein in the target time and give full play to the therapeutic effect. Therefore, model proteins were selected for stability testing to simulate the specific destabilization pathways. Through the comprehensive study of protein conformation, recovery rate, encapsulation rate, and drug release behavior, the effects of additives on the stability of protein were synthetically characterized, and their action links and mechanisms were also further studied. The results showed that different denaturation environments were intertwined during the preparation and release of peptide-loaded NPs, jointly inducing protein denaturation and incomplete release behavior. After optimization with stabilizers, urea and lactose increased the encapsulation efficiency of proteins to more than 95% (P < 0.001). Except for the P188, all other stabilizers showed great potential for optimizing the release and stability of the encapsulated protein as a whole, increasing the release proportion of protein from 44% to 60 %-75% (P < 0.0001). The improvement of the drug release curve demonstrated the long-term stabilizing effect of the above-mentioned co-solubilizing additives on the therapeutic protein.