In vitro and toxicological assessment of dexamethasone sodium phosphate loaded pH sensitive Pectin-g-poly(AA)/PVP semi interpenetrating network

Herein, we developed and characterized pH responsive semi interpenetrating network (semi-IPN) of Pectin-gpoly(AA)/PVP by free radical polymerization. These hydrogels were developed to overcome hurdles associated with; i) mechanical strength of formed system which was dealt by the use of combination of natural (pectin) and synthetic (PVP) polymers and ii) oral administration of drugs requiring action in distal part of gastrointestinal tract which was addressed by employing pectin and acrylic acid which conferred pH sensitivity due to carboxylic group in their structure. Structurally and morphologically, developed semi-IPN hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Chemically, they were evaluated for swelling and release kinetics. Semi-IPN hydrogels restricted the swelling of system and therefore the release of dexamethasone sodium phosphate (DSP) at pH 1.2 but released it in controlled manner at pH 7.4 by non-Fickian diffusion. Biologically, acute toxicity testing of developed semi-IPN hydrogels, revealed biocompatibility and safety of hydrogels after oral administration. Conclusively, prepared semi-IPN hydrogels showed good mechanical properties, swelling, biocompatibility, pH dependent DSP release for possible treatment of inflammatory bowel diseases.