pH sensitive N-succinyl chitosan grafted polyacrylamide hydrogel for oral insulin delivery

pH sensitive PAA/S-chitosan hydrogel was prepared using ammonium persulfate (APS) as an initiator and methylenebisacrylamide (MBA) as a crosslinker for oral insulin delivery. The synthesized copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) study; morphology was observed under scanning electron microscope (SEM). The PAA/S-chitosan with similar to 38% of insulin loading efficiency (LE) and similar to 76% of insulin encapsulation efficiency (EE), showed excellent pH sensitivity, retaining similar to 26% of encapsulated insulin in acidic stomach pH 1.2 and releasing of similar to 98% of insulin in the intestine (pH 7.4), providing a prolonged attachment with the intestinal tissue. The oral administration of insulin loaded PAA/S-chitosan hydrogel was successful in lowering the blood glucose level of diabetic mice. The bioavailability of insulin was similar to 4.43%. Furthermore, no lethality or toxicity was documented after its peroral administration. Thus, PAA/S-chitosan hydrogel could serve as a promising oral insulin carrier in future. (C) 2014 Elsevier Ltd. All rights reserved.