Crystallization of a non-steroidal anti-inflammatory drug from ethanol-water solution in presence of polymers: physicochemical characterization and release behaviour from suppositories.
Altered crystallization condition has been designed and adopted to a model non-steroidal anti-inflammatory drug, while crystallizing from ethanol-water solution in absence and presence of polymers such as Eudragit RS and ethylcellulose. To minimize the gastro-intestinal side effects nimesulide was considered as a model drug candidate for the development of suppository formulation. Physicochemical characteristics of the crystals were evaluated by Scanning Electron Microscopy (SEM). X-ray diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FT-IR). Smoothness and sharpness of the crystal have been decreased with increased concentration of a polymer. A little change in crystal habit and geometry has also been observed. Crystals are discrete in nature and more than 90% were in the range of 20-90 micron. The X-ray diffractions of nimesulide crystallized in absence of polymer and physical mixture of drug-polymer revealed fewer high intensity reflections when compared with the drug crystallized in presence of Eudragit RS, which testified a slight decreased ordering of crystal lattice in the latter. In presence of ethylcellulose, slightly increased ordering of crystal lattice was observed. No strong interactions were noticed as revealed by FT-IR spectroscopy. Drug dissolution rate from suppository formulations containing nimesulide crystallized in presence of polymer was found to delay as compared with the suppository prepared by nimesulide crystallized in absence of polymer.