Liquid chromatography-tandem mass spectrometric analysis of stobadine in human plasma

A rapid, sensitive, and specific high performance liquid chromatography procedure for the determination of stobadine in human plasma using electrospray tandem mass spectrometry (MS/MS) detection was developed. Multiple reaction monitoring (MRM) transitions at 202.9 > 160 (stobadine) and 166 > 103 (phenylalanine, I.S.) were selected to quantify stobadine by the internal standard method. Linear correlations (r: 0.9971-0.9981) of the calibration curves over the concentration range 20-500 ng mL(-1) with lowest limit of quantitation (LOQ) of 10 ng mL(-1) were established. An overall recovery of 94.3% of stobadine from plasma was attained using the SPE technique, The developed tandem mass spectrometry method was proven to be accurate and reproducible as a percent relative error (%RE) ranging from -3.5% to 3.0% and %RSD in the range of 1.4-8.3% were determined. Samples of stobadine in plasma were stable at -20degreesC for at least 5 weeks. The slope of the calibration curves was 0.00146 +/- 0.000087, indicating good stability and the between-day precision and accuracy of the MS/MS method. The validation data suggest the utility of the described method in planned clinical studies of stobadine in humans.