Preparation and evaluation of bioactive and compatible starch based superabsorbent for oral drug delivery systems

Abstract

Novel types of highly swelling hydrogels (superabsorbent) were prepared by grafting crosslinked poly acrylic acid-co-2-hydroxyethylmetacrylate (PAA-co-HEMA) chains onto starch through a free radical polymerization method. The effect of grafting variables (i.e., concentration of methylenebisacrylamide (MBA), acrylic acid/2-hydroxy methymetacrylate (AA/HEMA) weight ratio, ammonium persulfate (APS), starch, neutralization percent, were systematically optimized to achieve a hydrogel with a maximum swelling capacity. The superabsorbent (SAP) formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The controlled-release behavior of diclofenac sodium (DS) from SAP was investigated and showed that the release profiles of DS from superabsorbent polymer were slow (less than 6 %) in simulated gastric fluid (SGF, pH1.6) over 3h, but nearly all of the initial drug content was released in simulated intestinal fluid (SIF, pH7.4) within 8h after changing media. Overall, the results demonstrated that biodegradable superabsorbent could successfully deliver a drug to the intestine without losing the drug in the stomach, and could be potential candidates for an orally administrated drug delivery system.