Quantitative determination of fluorinated caffeic acid phenethyl ester derivative from rat blood plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

The quantitative determination of caffeic acid phenethyl ester (CAPE) and its fluorinated derivative (FCAPE) from rat plasma using ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) is reported. CAPE and FCAPE were extracted using ethyl acetate in the presence of methyl caffeate (MC) as internal standard. Separation was achieved using a C(18) column (2.1 mm x 50 mm, 1.7 microm) and gradient elution with water and acetonitrile containing 0.2% and 0.1% formic acid, respectively. A non-linear response over a broad concentration range (1-1000 ng/ml, r(2)>0.995 using a quadratic regression model and 1/concentration weighting) was obtained. The inter-day and intra-day variability for CAPE and FCAPE were found to be less than 14.2% and 9.5%, respectively. Data are presented to illustrate the practicality of the method for the pharmacokinetic evaluation of CAPE and FCAPE after intravenous administration to rats.