pH-Sensitive Polymeric Poly (ϵ-caprolactone) Core- Chitosan/Alginate Shell Particle System for Oral Insulin Delivery

Oral administration of the drugs is considered as one of the most convenient and comfortable routes. However, an effective oral delivery of insulin still remains a challenging and elusive goal, due to bioavailability problem. The aim of our work is to develop a pH sensitive polymeric system for the oral delivery of insulin based on a poly (ϵ-caprolactone) (PCL) core and shells of chitosan (CS) and alginate (ALG). The particles were prepared based on the double emulsion (water/oil/water) solvent evaporation method. The effect of blending Pluronic127 (F127) into the hydrophobic PCL matrix to improve its water permeability by increasing specific surface area. ALG have been chosen to provide the needed pH-sensitivity to the system. However, to coat the PCL surface with this anionic ALG layer a cationic CS layer has been added. The influence of each of the CS and ALG layers on the nanoparticle's physiochemical properties as well as on the encapsulation efficiency and the drug release behavior of the nanoparticles was investigated. The results showed that CS and ALG shells increased the stability of the nanoparticles. The in vitro release studies using two different pH environments (1.2 and 6.8) to simulate the physiological conditions in the gastrointestinal tract (GIT) showed that, the particles have pH-responsive release patterns. The kinetics studies showed that, the insulin release from all the particles formulations obey the Korsmeyer- Peppas kinetic model.