Development and Analysis of Risedronate Sodium Loaded Multi-particulate Drug Delivery System Using Superabsorbent Polymer

Abstract

In this study biocompatible and sustained released multiparticulate systems comprising superabsorbent polymer particles were prepared to reduce the local irritant effect of risedronate sodium. SAP based on 2-hydroxyethyl methacrylate, itaconic acid and polyvinyl pyrrolidone /chitosan were prepared by solution polymerization and fractioned to form SAP particles. Ethylene glycol dimethacrylate, potassium persulfate and N,N,N,N tetramethylethylene diamine were used as crosslinker, initiator and activator, respectively. Various concentrations of polymer and monomers were used in the formulations. Crosslinking was confirmed by Fourier transform infrared spectroscopy. The dynamic swelling studies were carried at pH 1.2, 5.5 6.5 and 7.5, which indicated a direct relationship of concentration of IA and media pH to swelling. By increasing the IA content or decreasing HEMA content porosity increased and a direct relationship was found in the case of gel fraction with HEMA and PVP contents. Furthermore, the values of volume fraction of polymer, molecular weight between crosslinks and solvent interaction parameters were determined. Risedronate sodium loading efficiency was determined which was dependent on IA and PVP contents. Drug release study was performed at buffers of pH 1.2 and 7.4 and result showed pH dependent drug release. The release mechanism was best described by zero order kinetics at pH 1.2 and Higuchi kinetics at pH 7.4. n value of almost all formulations was between 0.5 and 1.0, hence drug release followed non-Fickian release mechanism. A balanced, single dose, parallel study design was utilized to perform in vivo studies on rabbits. Cmax, Tmax and AUCo-∞ of formulations S1 and F1 were shifted to new values that proved the sustained release behavior. The bioavailability of drug was improved when administered in the form of multi-particulate formulation