RESUMO
A new method was developed to analyze three cardiovascular drugs in rat plasma, Mexiletine hydrochloride (MXL), Methoxamine hydrochloride (MTX), and Metaraminol bitartrate (MTR), by high-performance liquid chromatography (HPLC) using 9,10-anthraquinone-2-sulfonyl chloride (ASC) as the derivatization reagent. The derivatization modes and conditions for this method were optimized. The quantitative analysis was achieved using a C18 column at room temperature (25 degrees C), with various volume ratios of methanol-water as the mobile phase and a detection wavelength at 256 nm. Analytical linearity was obtained for the method over the concentration range of 0.04-8.0 microg mL(-1) for all the three drugs. The lower limit of quantification (LLOQ) was 0.04 microg mL(-1). This method was successfully applied to the analysis of the three drugs in rat plasma and their pharmacokinetic studies. The t1/2 values of the three drugs in rats were found to be 5.38+/-0.61, 4.49+/-0.53, and 3.70+/-0.19 h for MXL, MTX, and MTR, respectively.