PLGA-based nanoparticles for oral insulin delivery: synthesis and in-vitro evaluations

Significant advances in biotechnology and biochemistry have led to the discovery of a large number of bioactive molecules and vaccines based on peptides, proteins and oligonucleotides. However, the development of appropriate carrier systems remains a major challenge for the pharmaceutical scientists, in particular when such carriers are designed to cross the epithelial and/or endothelial barriers such as the gastrointestinal tract (GIT) epithelia (1,2). Thus, huge challenges have been devoted to improve the absorption of peptide and protein drugs through the GIT (3,4).There is an increased interest in developing biodegradable nanoparticles since they offer a suitable means of divers delivering of small molecular weight drugs, peptides, proteins and genes by either localized or targeted delivery to the desired cells/tissue (5,6). Recently, it was shown that oral application of polymeric nanoparticles containing insulin is useful in prolonging the duration of drug effect, and accordingly, enhanced oral absorption of insulin was reported upon its administration as polymeric nanocapsules. To achieve such aim, different polymers have been utilized to formulate biodegradable nanoparticles, among which poly (D, L- lactide-co-glycolide) (PLGA) and poly lactic acid (PLA) approved biocompatible and biodegradable polymers have been extensively studied.