Determination of 3‐hydroxy pterocarpan, a novel osteogenic compound in rat plasma by liquid chromatography–tandem mass spectrometry: application to pharmacokinetics study

A rapid, sensitive and selective LC-MS/MS method for the quantitative analysis of 3-hydroxy pterocarpan (S006-1709) in female rat plasma has been developed and validated. A Discovery RP₁₈ column was used for the chromatographic elution using acetonitrile and 0.1% acetic acid in water as mobile phase (80:20 v/v) at the flow rate of 0.5 mL/min. MS/MS analysis was performed using a triple quadrupole mass spectrometer with electrospray ionization in negative ion mode using biochanin as an internal standard (IS). Extraction of S006-1709 and IS from rat plasma was done by liquid-liquid extraction method using diethyl ether. The LC-MS/MS method was sensitive with 1.95 ng/mL as the limit of detection and 3.9 ng/mL as the lower limit of quantification. The method was linear in the concentration range of 3.9-1000 ng/mL. The percentage bias for intraday and interday accuracy was not greater than 4.2 and the %RSD for intraday and interday precision was not greater than 13.2. The recoveries of S006-1709 and IS were 73.9-79.3 and 85.7%, respectively. S006-1709 was found to be stable in various stability studies. The validated LC-MS/MS method was successfully applied for the oral pharmacokinetics study of S006-1709 at 10 mg/kg in female Sprague-Dawley rats.