An HPLC-ESI-MS method for analysis of loureirin A and B in dragon's blood and application in pharmacokinetics and tissue distribution in rats

A sensitive HPLC-ESI-MS method for the simultaneous determination of loureirin A (LA) and loureirin B (LB) in rat plasma and tissues was developed, and the pharmacokinetic and tissue distribution characteristics of LA and LB were investigated after gavage administration. The samples were pretreated by protein precipitation with ethyl acetate and then separated on a Welch Ultimate XB-C18 column with water-acetonitrile (42:58, v/v) containing 0.1% glacial acetic acid as the mobile phase. The analytes were detected with no interference in multiple reaction monitoring (MRM) mode on an electrospray ionization ion trap mass spectrometer. The analytes showed good linearity over a wide concentration range and the lowest limit of quantification (LLOQ) was 5 ng/mL for LA and 2 ng/mL for LB in matrices. The pharmacokinetic curves of both analytes were best fitted to one-compartment model. It suggested that the analytes absorbed and distributed very quickly in rats. Tissue distribution results showed that the analytes had a wide distribution in tissues and the highest levels for LA and LB were observed in liver followed by kidney, lung, spleen, heart and cerebrum. This work provided the pharmacokinetics and tissue distribution characteristics of LA and LB, which would be instructive for their clinical regiment design.

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