Spherical crystals of celecoxib to improve solubility, dissolution rate and micromeritic properties.

Celecoxib spherical agglomerates were prepared with polyvinylpyrrolidone (PVP) using acetone, water and chloroform as solvent, non-solvent and bridging liquid, respectively. The agglomerates were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), IR spectroscopic studies and scanning electron microscopy (SEM). The IR spectroscopy and DSC results indicated the absence of any interactions between drug and additives. XRD studies showed a decrease in crystallinity in agglomerates. The crystals exhibited significantly improved micromeritic properties compared to pure drug. The loading efficiency (% or mg drug per 100 mg crystals) was in the range of 93.9 +/- 2.3 and 97.3 +/- 1.3% (n = 3) with all formulations. The aqueous solubility and dissolution rate of the drug from crystals was significantly (p < 0.05) increased (nearly two times). The solubility and in vitro drug release rates increased with an increase in PVP concentration (from 2.5 to 10%). The SEM studies showed that the crystal posseses a good spherical shape with smooth and regular surface.