RESUMO
Carbohydrate biopolymer of biocompatible biodegradable chitosan, currently become one of the most usable polymer in medical and pharmaceutical sciences. In this regard a large number of protein and peptide drugs are used as therapeutic agents which can be exposed to temperature stresses either in transporting or storage. These stresses can make the protein structure unstable, change the active structure and disrupt its therapeutic function that limits their using as successful drug. In order to overcome these disadvantages associated with protein drugs, different materials such as natural or synthetic polymers are used to make protein loaded biocompatible nano and microspheres. In this research, molecular dynamics simulations were used to study the effects of chitosan with different degree of deacetylation on the stability of Interferon αII structure at high temperature and compare its results with those of commonly used biocompatible synthetic polymers of Poly Ethylene Glycol and Poly Lactic-Co-Glycolic Acid. In these simulations, the conformational changes at high temperatures (343 K) and in the presence and absence of polymers were compared to data related to protein in normal temperature (300 K). In brief, and according to the results, it can be said that low deacetylated chitosan and poly lactic co-glycolic acid are more successful in terms of protein stability at high-temperature. It is also observed that Poly Ethylene Glycol has penetrated into the protein and shows some instability of protein conformation. Eventually, according to the findings of this study, low deacetylated chitosan and Poly Lactic-Co-Glycolic Acid are the preferable copolymers for using in protein delivery systems of this drug.
