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
