Determination of tadalafil in pharmaceutical preparation by HPLC using monolithic silica column.

The simple, reliable and reproducible HPLC and extraction methods were developed for the analysis of tadalafil in pharmaceutical preparation. The column used was monolithic silica column, Chromolith Performance RP-18e (100mm x 4.6mm, i.d.). The mobile phase used was phosphate buffer (100mM, pH 3.0)-acetonitrile (80:20, v/v) at the flow rate of 5mLmin(-1) with UV detection at 230nm at ambient temperature. Extraction of tadalafil from tablet was carried out using methanol. Linearity was observed in the concentration range from 100 to 5000ngmL(-1) for tadalafil with a correlation coefficient (R(2)) 0.9999 and 100ngmL(-1) as the limit of detection. The values of linearity range, correlation coefficient (R(2)) and limit of detection were 50-5000ngmL(-1), 0.9999-50ngmL(-1), respectively for sildenafil. Parameters of validation prove the precision of the method and its applicability for the determination of tadalafil in pharmaceutical tablet formulation. The method is suitable for high throughput analysis of the drug.