Development and Validation of a UPLC-MS/MS for Determination of Loureirin D in Rat Plasma and Its Application to...

Loureirin D is a bioactive dihydrochalcone isolated from Dracaena resin with very high therapeutic value. A sensitive and high-throughput ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the quantitative analysis of loureirin D in rat plasma with only 50 μL of sample per assay. Sample extraction was protein precipitation using acetonitrile, and isoscoparin was used as internal standard (IS). Separation was achieved on the BEH C18 column with a gradient mobile phase of 0.1% (v/v) aqueous formic acid and acetonitrile. Detection was achieved with negative-ion electrospray ionization (ESI) detector in the multiple reaction monitoring (MRM) mode. The method was validated and proved to be linear in the concentration range of 2-2400 ng/mL (r ≥ 0.995), intraday and interday precision (RSD) was < 15%, and accuracy was 93.3%-110.1%. The extraction recovery was 88.7%-94.4%, and the matrix effects were 87.3%-92.9%. UPLC-MS/MS was used in pharmacokinetics in the rats after administration of loureirin D. The AUC_(0-t) after intravenous administration (1 mg/kg) was 2074.7 ± 180.3 ng · h/mL, and AUC_(0-t) after oral administration (5 mg/kg) was 563.4 ± 61.4 ng · h/mL; the absolute oral bioavailability was 5.4%. Pharmacokinetics showed rapid absorption, large V_z/F (52.7 ± 10.7 L/kg), high CL_z/F (8.8 ± 0.9 L/h/kg), and extensive first-pass metabolism.