LC-MS/MS determination of bakkenolide D in rats plasma and its application in pharmacokinetic studies

A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for determination of bakkenolide D (BD), which was further applied to assess the pharmacokinetics of BD. In the LC-MS/MS method, the multiple reaction monitoring mode was used and columbianadin was chosen as internal standard. The method was validated over the range of 1-800 ng/mL with a determination coefficient >0.999. The lower limit of quantification was 1 ng/mL in plasma. The intra- and inter-day accuracies for BD were 91-113 and 100-104%, respectively, and the inter-day precision was <15%. After a single oral dose of 10 mg/kg of BD, the mean peak plasma concentration of BD was 10.1 ± 9.8 ng/mL at 2 h. The area under the plasma concentration-time curve (AUC0-24 h ) was 72.1 ± 8.59 h ng/mL, and the elimination half-life (T1/2 ) was 11.8 ± 1.9 h. In case of intravenous administration of BD at a dosage of 1 mg/kg, the AUC0-24 h was 281 ± 98.4 h⋅ng/mL, and the T1/2 was 8.79 ± 0.63 h. Based on these results, the oral bioavailability of BD in rats at 10 mg/kg is 2.57%.