| Abstract: | A direct fluorometric high‐performance liquid chromatography (HPLC) method was developed and validated for the analysis of ibuprofen enantiomers in mouse plasma (100 μl) and tissues (brain, liver, kidneys) using liquid–liquid extraction and 4‐tertbutylphenoxyacetic acid as an internal standard. Separation of enantiomers was accomplished in a Chiracel OJ‐H chiral column based on cellulose tris(4‐methylbenzoate) coated on 5 μm silica‐gel, 250 x 4.6 mm at 22 °C with a mobile phase composed of n‐hexane, 2‐propanol, and trifluoroacetic acid that were delivered in gradient elution at a flow rate of 1 ml min?1. A fluorometric detector was set at: λexcit. = 220 nm and λemis. = 290 nm. Method validation included the evaluation of the selectivity, linearity, lower limit of quantification (LLOQ), within‐run and between‐run precision and accuracy. The LLOQ for the two enantiomers was 0.125 μg ml?1 in plasma, 0.09 μg g?1 in brain, and 0.25 μg g?1 in for liver and kidney homogenates. The calibration curves showed good linearity in the ranges of each enantiomers: from 0.125 to 35 μg ml?1 for plasma, 0.09–1.44 μg g?1 for brain, and 0.25–20 μg g?1 for liver and kidney homogenates. The method was successfully applied to a pharmacokinetic study of ibuprofen enantiomers in mice treated i.v. with 10 mg kg?1 of racemate. |
