Objective:To establish a practical RP-HPLC method to determine the concentration of cyclosporin A in patient's whole blood.Methods: CsA was extracted from whole blood with ether and separated,using a C_(18) column and a mobile phase of acetonitrile-methanol(80∶20).The column temperature was maintained at 70 ℃ and CsA was detected at 210 nm.Results: A good linear relationship was obtained between the concentration of CsA from 50 ng/mL to 1 600 ng/mL,r=0.9998.The average recovery rate of CsA was 97.6%,and the...