Surface engineered and ligand anchored nanobioconjugate: An effective therapeutic approach for oral insulin delivery in experimental diabetic rats

The present study was designed to enhance intestinal absorption of insulin by nanobioconjugate formulated with PEGylation and Concanavalin A based targeted synergistic approach. The attempts were aimed at maximizing bioavailability and therapeutic efficacy of insulin by incorporating it in Concanavalin A anchored PEGylated nanoconstructs. The Con A anchored PEGylated PLGA diblock copolymer was synthesized by modified surface functionalization method, and was then characterized by FTIR and H-1 NMR spectrum analysis. The nanoparticles from synthesized polymers were prepared and characterized for mean size and distribution by laser diffraction spectroscopy. The physicochemically characterized (by SEM and TEM) formulations were evaluated for optimum particle size, polydispersity index, zeta potential and entrapment efficiency 196.3 +/- 14.5 nm, 0.15 +/- 0.04, -25.6 +/- 1.68 and 44.6 +/- 13.5% respectively. The insulin encapsulation efficiency and in vitro release were assessed by bicinchoninic protein assay (BCA). The in vitro results corroborated in vivo studies carried out in experimentally created diabetic albino rats. The nano-encapsulated insulin was discovered to meet the requirements by achieving better stability, improved absorption and enhanced oral bioavailability elucidated by in vivo and in vitro bioassays. (C) 2015 Elsevier B.V. All rights reserved.