OBJECTIVETo establish an UPLC-MS/MS method for simultaneous determination protocatechuic acid, isoorientin and scutellarin in rat tissues after a single intravenous administration of Compound Hongcao for injection, and investigate the distribution character of the three compounds.

METHODThree compounds were simultaneously determined by UPLC with Waters Acquity UPLC BEH C18 column. The mobile phase, consisting of acetonitrile and 0.1% aqueous formic acid, was programmed as a linear gradient. The flow rate was 0.35 mL x min(-1). The compounds were ionized in the electrospray ionization ion source of the mass spectrometer and detected in the multiple reaction model. The tissue samples were homogenated and the suspension were extracted with methanol for further use.

RESULTThe relationship between the concentration and the peak areas of the three compounds were all linear (r > 0. 99). The precisions, accuracy, extract recoveries and stability of the analytes meet the requirements. The method has been successfully applied to tissue distribution studies of the three compounds. The present study demonstrates that the higher tissues concentration of three components were obtained in kidney, lung and heart after a single intravenous administration of ones.

CONCLUSIONThe present study demonstrates that the three compounds have unequal distribution character. It was showed that the three compounds were mainly distributed in abundant blood-supply tissues such as kidney, lung and heart. It was also found that protocatechuic acid, isoorientin and scutellarin exceretion rapidly and have no long-term accumulation. The method was shown to be effective, convenient, and suitable for simultaneous study the distribution of the three compounds in rat.