*Corresponding Author E-mail: gadepalli_raj@yahoo.com
A simple high-performance liquid chromatographic method for the determination of tadalafil in human plasma has been developed. Separation was achieved by Reverse phase chromatography on a Grace Genesis C18 (150 x 4.6 mm, 5μ) column with mobile phase A containing Triethylamine buffer (pH adjusted to 2.5 ±0.05 with Orthophosphoric acid) and mobile phase B containing Acetonitrile 95% (95:5 (Acetonitrile:water)) as eluent at a flow rate 1.2ml/min. UV detection was performed at 225nm. Lower limit of quantitation was 4.997ng/ml. Maximum between-run precision was 2.085%. Mean extraction recovery was found to be 97.38 to 97.45%. Stability study showed that after three freeze-thaw cycles the loss of three quality control samples were less than 10%. Samples were stable at room temperature for 48h and at −20° for 2months. Before injecting onto HPLC system, the processed samples were stable for at least 6h. The method can be used to perform bioequivalence study in human.
