Abstract:
OBJECTIVE To develop an HPLC method to determine the concentration of methotrexate(MTX) in human plasma. METHODS Theophyline was used as the internal standard. The analytical column was Agilent Eclipse XDB-C
18(4.6 mm×250 mm, 5 μm). The mobile phase was phosphate buffer solution with pH 6.6-methanol(82∶18). The UV determine wavelength of MTX was 306 nm and theophyline was 254 nm. The flow rate was 1.0 mL·min
-1, and the column temperature was 30 ℃. RESULTS The calibration curves of MTX were linear at a concentration range from 0.03 to 1.65 μmol·L
-1(r=0.999 9) and 1.65 to 66.08 μmol·L
-1(r=0.995 8). The intra-day and inte-day precision were both less than 5%. The average method recovery was 97.6% and the average extraction recovery was 68.5%, with a lowest limit of 0.03 μmol·L
-1. CONCLUSION The method is sensitive, accurate, wide linear range, suitable for plasma concentration monitoring of MTX.