Quantitative analysis and pharmacokinetic study of phellopterin in rat plasma by UPLC-MS/MS

Phellopterin, a naturally derived furanocoumarin, is widely distributed in medicinal plants like Angelica dahurica and Toddalia asiatica, as well as in citrus fruits. In this experiment, an UPLC-MS/MS bioanalytical method over the concentration range of 0.725-290 ng mL-1 was established for the quantitative analysis and pharmacokinetic study of phellopterin in rat plasma. Following protein precipitation with acetonitrile, the samples were separated by gradient elution on a UPLC system, using acetonitrile-0.1% formic acid as the mobile phase. Quantification was performed using multiple reaction monitoring (MRM) method in electrospray positive-ion mode (ESI+), with the ion transitions of m/z 301.1 -> 233.4 for phellopterin and m/z 209.1 -> 194.1 for the internal standard, fraxetin. The accuracy of phellopterin ranged from 87.9 to 112.4%, with the precision between 4.1 and 12.2%. The matrix effect was 92.4-97.4%, and the recovery was over 77.9%. The optimized UPLC-MS/MS bioanalytical method was successfully used to study the pharmacokinetics of phellopterin in rats. The AUC(0-t) values were 74.2 +/- 7.9 ng mL-1*h for intravenous and 37.1 +/- 5.3 ng mL-1*h for oral administration, while the corresponding half-lives (t1/2z) were 1.1 +/- 0.2 h and 3.1 +/- 0.7 h, respectively. The bioavailability of phellopterin was determined to be 16.7%.