Determination of Ibuprofen Enantiomers in Plasma by HPLC-Chiral Stationary Phase

OBJECTIVE To establish a method for the determination of plasma levels of enantiomers of ibuprofen. METHODS Ibuprofen was extracted from samples with Hexane-isopropanol(100∶5). HPLC was performed on Chirobiotic column with methanol-aceticacid-triethylamine(100∶0.04∶0.02) as mobile phase. Detection wavelength was 226 nm. Indomethacin was used as the internal standard. RESULTS Under this chromatographic condition, R-ibuprofen, S-ibuprofen and indomethacin had no interference within each other. The calibration curve was linear in the range of 0.01-5 mg·L^-1 for R-ibuprofen and S-ibuprofen. The relative recoveries of R-ibuprofen and S-ibuprofen were 99.1%-102.2% and 99.3%-102.4% respectively. The absolute recoveries of R-ibuprofen and S-ibuprofen were 66.8-72.9 and 66.3-71.4 respectively; RSD range of intraday were 4.2%-5.4% and 3.6%-5.1%. RSD ranges of interday were 5.9%-7.3% and 6.2%-7.9% respectively. CONCLUSION This method is accurate, rapid, with high sensitivity and good repeatability. It is applicable for the determination and pharmacokinetic study of the enantiomers of ibuprofen in plasma.