Development of Risedronate Sodium-loaded Nanosponges by Experimental Design: Optimization and in vitro Characterization

Abstract

The present investigation focussed on the development of a novel strategy to enhance the bioavailability of risedronate sodium, which has poor and erratic absorption. Nanosponges were statistically developed by full 32 factorial design using Design of Experiment software considering concentration of polymer and stabilizer as independent variables and particle size and entrapment efficiency as experimental responses by utilizing the modified quasi-emulsion solvent diffusion technique. Optimized formulation showed 67.27±1.05 % entrapment efficiency, 155.8±2.17 nm particle size and –35.4 mV of zeta potential. The data from in vitro release study showed burst release for initial 2 h followed by slow and sustained release up to 24 h, which followed a diffusion-controlled release mechanism by the Higuchi model. Scanning electron microscopy study showed uniformly discrete spherical particles with porous surface without any agglomeration. Stability study demonstrated no significant changes in particle size, entrapment efficiency and in vitro release, which indicated that the nanosponge formulation was stable. In conclusion, it appeared that the nanosponges were a suitable nanocarrier system that could play a significant role in improving osteoporotic condition.