Mechanism study on the effect of different surfactants on dissolution rate of recrystallized prednisolone in various concentrations

The effects of re-crystallization of prednisolone as a poorly water-soluble drug in aqueous surfactant solutions on its dissolution rate were investigated. A significant enhancement was observed for crystal dissolution rate in hydrophilic surfactants such as tween 80 and sodium lauryl sulfate （SLS）. Differential scanning calorimetry （DSC） and Fourier transform infrared spectroscopy （FT-IR） indicated the existence of both form Ⅰ and Ⅱ ofprednisolone in SLS treated crystals. The FT-IR results also showed that, only form Ⅱ could be detected in prednisolone crystals without surfactant and prednisolone form Ⅲ was produced in tween 80 treated crystals. These results were also confirmed by X-ray （XRD） diffraction and scanning electron microscopy （SEM）. In general, the results indicated that the presence of hydrophilic surfactants could generate forms Ⅱ and Ⅲ of the crystals. These forms would give rlse to the increase of prednisolone＇s dissolution rate owing to their physicochemical instability and more hydrophilic property in comparison with stable polymorph of form Ⅰ.