Determination of Ibuprofen in Rabbit Plasma by High-Performance Liquid Chromatography

The aim of the present study was to develop and validate a procedure based on high-performance liquid chromatography (HPLC) for determination of ibuprofen in rabbit plasma. Separation of ibuprofen and naproxen (internal standard, IS) was achieved on an Ace C18 column (5 mu m, 250x4.6 mm i.d.) using UV detection with lambda=225 nm. The mobile phase consisted of 20 mM phosphate buffer (pH 7) containing 0.1% trifluoroacetic acid (TFA)-acetonitrile (65:35. v/v). The analysis was performed in less than 10 min with a flow rate of 1 mL/min. Excellent linearity was found between 0.5 and 40 mu g/mL. Intra- and inter-day precision values for ibuprofen in plasma were less than 4.97, and accuracy (relative error) was better than 7.20%. The recoveries for all samples were >92.8%. The limits of detection (LOD) and quantification (LOQ) of ibuprofen were 0.10 and 0.25 mu g/mL, respectively. The described HPLC method has adequate sensitivity and specificity to study pharmacokinetics of ibuprofen in rabbits, and could be adapted also to clinical pharmacokinetic study.