[Pharmacokinetics of 8-O-acetylharpagide and harpagide after oral administration of Ajuga decumbens extract in beagle dog].

8-O-acetylharpagide and harpagide are two kinds of effective component of Ajuga decumbens extract. A sensitive LC-MS/MS method has been established for pharmacokinetics of 8-O-acetylharpagide and harpagide in beagle dog after oral administration of from A. decumbens extract. Female beagle dogs received orally 12.9, 25.7 mg x kg(-1) p. o. Concentrations of 8-O-acetylharpagide and harpagide in plasma were determined by LC-MS/MS method at different time points and all pharmacokinetic parameters were estimated by non-compartment analysis. The mobile phase consisted of 0.1% formic acid in water (A) and acetonitrile (B), which was run at a flow rate of 0.3 mL x min(-1). Chromatographic separation was achieved on an Agilent ZORBAX XDB-C18 column (2.1 mm x 50 mm, 3.5 microm) using a gradient elution of 5% B at 0-2 min, 95% B at 2. 1-5 min and 5% B at 5. 1-10 min. All analytes, including the IS, were monitored under positive ionization conditions and quantified in MRM mode with transitions of m/z 429.2-369.2 for 8-O-acetylharpagide, m/z 387.2-207.2 for harpagide, and m/z 149.2-103.1 for IS. High purity nitrogen was employed as both the nebulizing and drying gas. Other parameters of the mass spectrometer were optimized as follows: drying gas flow 10.0 L x min(-1); drying gas temperature 300 degrees C; capillary voltage 4 000 V. Results showed that 8-O-acetylharpagide and harpagide showed a dose-dependence profile. T(max) of 8-O-acetylharpagide is 1.7 h, and T(max) of harpagide is 1.57 h, which was higher than T(max) of 8-O-acetylharpagide and harpagide after oral administration of from A. decumbens extract in rats. The different pharmacokinetic parameters may be due to the species differences of rat and beagle dog.