Sustained release coprecipitates of ibuprofen(IBF) with
polyacrylic resin Ⅱ were prepared by dissolving the drug and the
polymer in ethanol followed by the addition of a non solvent with agitation . Two different and novel approaches were employed to prepare the coprecipitates at different drug to polymer ratios. Using these precipitates, matrix type tablets were also prepared by direct compression method. Scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and infrared(IR) absorption spectroscopy were carried out for the characterization of the coprecipitates. The investigation focuses on the influence of the concentration of
polyacrylic resin Ⅱ, the pH of the
dissolution media , and the preparation methodology of the coprecipitates on IBF release rate from the IBF polyacrylic resin Ⅱ matrix tablets. In vitro dissolution experiments were performed in dissolution media with different pH environments. Generally, in all the formulations prepared at various drug to polymer ratios, the polyacrylic resin Ⅱ could considerably prolong the drug release in polymer concentration dependent manners. Increasing pH of the dissolution media also played an important role in enhancing the cumulative percentage release of the drug. It was also investigated that the cumulative percentage of IBF released from the formulations prepared by method B was higher than that prepared by method A. Moreover, formulations prepared by method A exhibited comparatively linear release profiles.