Formulation and Evaluation of Megesterol Proniosomal Systems

Over 40% of old and new drug molecules are implicated with poor oral bioavailability due to poor drug solubility in aqueous environment of gastro-intestinal lumen. Chemical methods to improve drug solubility are again limited, because any drastic change in the chemistry of molecules might result into loss of pharmacophore and thus loss of biological activity. Megesterol acetate, a synthetic derivative of the naturally occurring steroid hormone used to manage various disorders that affect women. Magesterol does not appear to be well absorbed from the gut. This may be related to its relative insolubility (2μg/ml) micronized formulations are more completely absorbed than are nonmicronized preparations. Liposomal drug products have shown improved oral bioavailability. The various proniosomal systems developed were span 20: megesterol (50:50%), span 20: megesterol (70:30%), span 20 50% and 50% megesterol+cholesterol (50:50), and span 20, 70% and 30% megesterol+cholesterol (50:50). Out of all the compositions the one with 70% span 20 and 30% megesterol:cholesterol (50:50) exhibited slower release. All other compositions have enhanced the release to significant extent.