Abstract
A solid dispersion (SD) approach has been performed to enhance the dissolution rate of insoluble drugs by improving their aqueous solubility. An insoluble drug, nimesulide (Nims), was chosen as a model for non-steroidal anti-inflammatory drugs. It was dispersed in a water-soluble carrier poloxamer 407. Different methods were employed to prepare such dispersion, namely: Solvent method (SM), Melting method (MM) and Kneading method (KM) in different drug: carrier ratios. Nims solid dispersions were characterized for their physicochemical properties using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and the powder X-ray diffractometry (XRD). In addition to dissolution studies, the results revealed that Nims was converted to its amorphous state. The dissolution rate of the prepared solid dispersion systems was determined in phosphate buffer pH 7.4. The solubility of drug from different systems was also determined in water. This study revealed that, the presence of the hydrophilic carrier allows improving the drug solubility. The dissolution rate was enhanced in the following order KM > MM > SM. The enhancement of dissolution rate may be due to increase in wettability, dispersibillity as well as particle size reduction of the drug.