A sensitive and selective LC-MS/MS method was developed and validated for the determination of aconitine in microdialysate and rat plasma. Extraction of plasma sample was conducted by use of 1% trichloracetic acid and acetonitrile solution with 10 ng/mL internal standard (propafenone) spiked. Microdialysates were analyzed without sample purification. After sample preparation, 2 microL were injected and separated with an isocratic mobile phase consisting of acetonitrile:0.1% formic acid (60:40, v/v) at a flow rate of 0.3 mL/min. The Agilent G6410A triple quadrupole LC/MS system was operated under the multiple-reaction monitoring mode (MRM) using the electrospray ionization technique in positive mode. Overall, the assay exhibited good precision and accuracy. The diffusion properties of aconitine investigated in in vitro microdialysis experiments revealed unfavourable concentration dependence avertable by keeping a constant pH 5.77 using isotonic phosphate buffer solution as perfusate. The mean relative recoveries were 48.23% [coefficient of variation (CV 4.47%)] and 55.38% (CV 2.89%) for retrodialysis and recovery experiments, respectively. The in vivo recovery of aconitine was 34.48% (CV 3.05%) and was stable over the 6 h study period. Following characterization of aconitine both in vitro and in vivo microdialysis, the developed setting is suitable for application in pharmacokinetics and pharmacodynamics studies.
(c) 2009 John Wiley & Sons, Ltd.