Determination of Mycophenolic Acid Concentration in Human Plasma and Its Application to Therapeutic Drug Monitoring in Renal Transplantation Patient

OBJECTIVE To establish a HPLC method for the determination of mycophenolic acid in human plasma and monitoring mycophenolic acid concentration in renal transplantation patients.METHODS The plasma was mixed with 20 μL H3PO4.Mycophenolic acid was extracted from plasma with ether and nalidixic acid as internal standard.The content of mycophenolic acid was detected by ultraviolet detector at 254 nm with Kromasil 100-5C8(4.6 mm×150 mm,5 μm) column.The mobile phase consisted of methol-acetonitrile-0.05 mol·L-1KH2PO4(adjusted to pH 2.8 with H3PO4)(12∶38∶50)at a flow rate of 0.5 mL·min-1.The column temperature was 25 ℃.RESULTS The linear range was 0.191～24.45 mg·L-1(r=0.999 8).The lowest determination concentration was 0.191 mg·L-1(S/N=10).The average method recovery was 89.7%～101.5%,and extract recovery was over 85% for the low,middle,high control samples.The relative standard deviation obtained for inter-and intra-assay precisions were less than 10%.The MPA plasma concentration in 83.2% renal transplantation patient was below 2 mg·L-1.CONCLUSION This method is convenient,sensitive and reproducible,suitable for the determination of mycophenolic acid in human plasma for pharmacokinetics and monitoring mycophenolic acid concentration in renal transplantation patient.