FORMULATION AND EVALUATION OF SOLID DISPERSION OF TADALAFIL

Tadalafil is used for the treatment of the erectile dysfunction (ED) and pulmonary arterial hypertension. It is having low aqueous solubility thus it shows poor bioavailability of about 28% by after oral administration. To improve its solubility and dissolution profile solid dispersions (SDPs) of Tadalafil was prepared by physical mixing and solvent evaporation method using polyvinyl pyrollidone-K30 (PVP-30) as a hydrophilic polymeric carrier in different proportions with respect to drug (drug to polymer ratio 1:1 to 1:5). Drug and polymer compatibility studies were performed using FTIR study. The best suitable ratio and method was selected on the basis of enhanced aqueous solubility of drugs. Further selected SDPs were evaluated for various parameters like DSC analysis, percentage yield, percent drug content, saturation solubility, percent drug dissolution and stability studies. FTIR study indicated no incompatibility between Tadalafil and PVP-K30. SDPs prepared with drug to polymer ratio 1:3 and solvent evaporation method was found to be best as they shown significant increased (up to 10 fold) in aqueous solubility in comparison with that of others. DSC study also suggested the depression in the crystalline nature of Tadalafil. Selected SDPs exhibited good stability up to 3 months at 25 ± 2°C /60 ± 5% RH. Based on the results it can be concluded that, SDPs shown remarkable increase in the aqueous solubility and dissolution of Tadalafil and it may improve oral bioavailability of drug as compared with plain drug.