RESUMO
A sensitive and robust liquid chromatography-tandem mass spectrometry [LC-MS/MS] method was developed and validated for the determination of corosolic acid [CRA] in rat plasma. The plasma samples were prepared by a simple protein precipitation treatment. Chromatographic separation was performed on an Agela MG-C[18] column [50 mm x 4.6 mm; i.d., 5 microm] at 30[degree]C. The mobile phase consisting of methanol-10 mM ammonium acetate-formic acid [80:20:0.1, v/v/v; pH=3.8] was delivered with a flow rate of 0.6 ml/min and a running time of 2.5 min. Quantification was performed with positive electrospray ionization [ESI] in the multiple-reaction monitoring [MRM] mode at m/z 490 - m/z 205 for CRA, and m/z 471 - m/z 203 for TEOA [internal standard, IS], respectively. Linearity was evaluated over the concentration range of 1.00-1000 ng/ml with a lower limit of quantification [LLOQ] of 1.00 ng/ml. The validated method was successfully applied to the pharmacokinetic study of CRA after the drug was orally administered in Sprague-Dawley rats.