High-performance liquid chromatographic determination of licochalcone A and its metabolites in biological fluids.

A high-performance liquid chromatographic method has been developed for the analysis of the novel antiparasitic agent, licochalcone A (Lica), and three of its glucuronic acid conjugates in plasma and urine. The high-performance liquid chromatography assay was performed using gradient elution and UV detection at 360 nm. The proposed technique is selective, reliable and sensitive. The limits of quantification for Lica are 0.2 microg/ml in plasma and 0.14 microg/ml in urine, 1.2 microg/ml for the 4'-glucuronide in plasma and 1.4 microg/ml in urine, and 2.0 microg/ml for the 4-glucuronide in plasma and 3.2 microg/ml in urine. The reproducibility of the analytical method according to the statistical coefficients is 7% or below. The accuracy of the method is good, that is, the relative error is below 10%. The stability of Lica and its glucuronides in urine and plasma samples has been assessed during storage in the autosampler and freezer. The applicability of the assay for determining Lica and its intact glucuronide conjugates in biological fluids was shown using a single dose study in rat.