Development and Characterization of Nimesulide Nanosponges: Solvent Evaporation vs Ultrasonic-Assisted Synthesis

This study was designed to compare solvent evaporation and ultrasonic assisted synthesis in the preparation of Nimesulide nanosponges, using polyvinyl-alcohol and Eudragit L100 as a polymer/copoly-mer, and dichloromethane as a cross linker. Twelve formulations of Nimesulide were prepared, six with each method by varying the ratios of both polymer and co-polymer. The resulting nanosponges were evaluated, characterized by pre-formulation studies, production yield (%), differential scanning calorimeter, X-ray dif-fraction, Fourier transformation infrared spectroscopy, scanning electron microscopy, entrapment efficiency (%), actual drug content (%), and in vitro dissolution studies. Formulation with high amount of co-polymer in both methods, solvent evaporation and ultrasonic assisted method, showed crystalline structures with enhanced dissolution rates in basic mediums. Drug entrapment in solvent evaporation method was more, i.e up to 74% than that of ultrasonic assisted method, i.e. up to 61% correspondence to enhanced dissolution rates by solvent evaporation method, and increased solubility due to drug-polymer complex formation. Formulations of solvent evaporation method showed more production yields and better drug entrapment. The nanosponges prepared by both methods showed enhanced dissolution rates in basic medium, while the rates observed by solvent evaporation method formulations were higher than formulations of ultrasonic assisted method.