Preparation and in-vitro characterization of liner and star-shaped poly lactide-glycolide smart nanoparticles for oral insulin delivery

Abstract

Background Biodegradable nanoparticles, as drug delivery paradigms, have been extensively used for delivery of wide ranges of small molecules as well as macromolecules such as peptides, proteins and genes. The morphological modification may improve the physicochemical characteristics of the biodegradable polymers. Aims In the present research we report the synthesis and characterization of linear, poly (D, L-lactide-co-glycolide) (PLGA), poly ethylene glycol (PEG-PLGA) and star-branched -cyclodextrin-PLGA (-CD-PLGA) copolymers containing insulin as a model peptide drug. Methods Linear and star-branched copolymers of PLGA were synthesized by bulk melt polymerization of the lactones (lactide and glycolide) in the presence of the PEG or -CD using Sn-octoate as a catalyst. Nanoparticles were prepared by a modified (w1/o/w2) double emulsion method. Bovine insulin was successfully encapsulated into the linear and star-branched PLGA nanoparticles with retention of insulin stability. Nanoparticles preparation process was optimized to reduce the burst effect and provide in-vitro sustained release. Results The average particle size of samples was 120- 355 nm. The cumulative amount of 65-84% insulin was released from the samples after 24 days. The yield of encapsulation of insulin was superior to 95 %. Conclusion Upon these findings, we suggest that the novel PLGA nanoparticles could be used as a carrier for prolonged delivery of protein-peptide drugs.