A rapid and selective LC method for simultaneous determination of cyclosporin a and its major metabolite (AM1) in human serum at room temperature

A simple and highly selective isocratic reverse-phase high performance liquid chromatography (RP-LC) method at room temperature is developed in order to determination of Cyclosporine A (CyA) and its major metabolite (AM1) in serum samples of kidney transplanted patients. The method uses a phenyl column stationary phase, acetonitrile–water–methanol 47:50:3 as mobile phase and 215 nm detector wavelength, at room temperature. The solid phase extraction procedure using cyano disposable extraction column was carried out to separtate the CyA and AM1 with recovery 99±6 and 98±10, respectively. A linear correlation was found at the range of 40–1000 ng ml−1 for CyA and 25–500 ng ml−1 for AM1. The average intra and inter-day variations were 5.03 and 7.89% for CyA, 5.92 and 8.12% for AM1, respectively. The detection limit of 20 ng ml−1 was found for CyA and 12.5 ng ml−1 for AM1. Also, the clinical application of the method using serum concentration against time profile from kidney transplantated patients is reported.