A liquid chromatography-tandem mass spectrometry method for preclinical pharmacokinetics and tissue distribution of hydrolyzable tannins chebulinic acid and chebulagic acid in rats

A simple and sensitive liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of chebulinic acid and chebulagic acid in rat plasma and tissues and well used in the pharmacokinetic and tissue distribution studies after intraperitoneal injection administration. Samples were processed with methanol by protein precipitation, and chromatographic separation was performed on an Agilent Zorbax SB-C-18 column (50 x 2.1 mm, 1.8 mu m) with a mobile phase consisting of methanol and water containing 0.1% formic acid (60:40, v/v). Quantification was performed by selected reaction monitoring with m/z 977.1 -> 806.8 for chebulagic acid, m/z 979.0 -> 808.7 for chebulinic acid and m/z 851.2 -> 704.9 for the internal standard. Good linearity was observed over their respective concentration range. The pharmacokinetic study showed that both compounds reached their peak concentration values (605.8 +/- 35.6 ng/mL for chebulinic acid and 1327.1 +/- 118.6 ng/mL for chebulagic acid) at the same time of 0.9 h following intraperitoneal injection administration. The two compounds could be detected in blood-abundant tissues. The kidney had the highest concentrations (462.6 +/- 138.5 ng/g for chebulinic acid and 1651.7 +/- 167.7 ng/g for chebulagic acid) at 1 h post-dose, followed by the heart, liver, spleen and lung.