[Thoughts and experimental exploration on pharmacokinetic study of herbal medicines with multiple-components and targets].

The pharmacokinetic research of traditional Chinese medicines (TMC) is an inalienable part of the chain of TCM modernization and plays an important role in the TCM novel drug development. However, the researching method and system that is consistent with the specific characteristics of TCM, i.e., multiple-components and targets, is still lacking. Furthermore, the current understanding of the critical scientific questions of TCM pharmacokinetics remains still unclear. This review makes a brief summary of our recent developments on the pharmacokinetic exploration of TCMs, mainly including integral pharmacokinetic study of multiple components, herbalome analysis both in vitro and in vivo, mechanism based compatibility study for herbal components interactions, and the representative pharmacokinetic study for single herbal compound. Furthermore, the critical scientific questions of TCM pharmacokinetics are discussed based on understanding the requirements of novel drug developments from TCM.

Simultaneous quantitation of dicaffeoylquinic acids in rat plasma after an intravenous administration of mailuoning injection using liquid chromatography-mass spectrometry.

A high-performance liquid chromatography electrospray ionization mass spectrometry method is developed and validated for the simultaneous quantitation of three major phenolic acids including 1,5-dicaffeoylquinic acid (1,5-DCQA), 3,4-dicaffeoylquinic acid (3,4-DCQA), and 3,5-dicaffeoylquinic acid (3,5-DCQA) in rat plasma. All analytes and internal standard (bergeninum) are extracted from plasma samples by liquid-liquid extraction with isopropanol. The chromatographic separation is accomplished on a stainless-steel column with a gradient 0.1% formic acid-acetonitrile solution as mobile phase at a flow rate of 0.2 mL/min with an operating temperature of 40 degrees C. The selected ion monitoring is performed at m/z 515.2 for 1,5-DCQA, 3,4-DCQA, and 3,5-DCQA, and m/z 327 for the internal standard bergeninum. Linear detection responses are obtained at a concentration range from 0.020 to 5.0 microg/mL for 1,5-DCQA, and 0.039 to 10.0 microg/mL for 3,4-DCQA and 3,5-DCQA. The lower limits of quantitation for 1,5-DCQA, 3,4-DCQA, and 3,5-DCQA are 20, 39, and 39 ng/mL, respectively. The intra- and inter-day precisions (RSD%) are within 11.0%, and the deviations of the assay accuracies are within +/- 12.0% for all analytes. The recoveries are greater than 84.0%. All analytes are proved to be stable during the sample preparation and analytic procedures. The method is successfully applied to the pharmacokinetic study of 1,5-DCQA, 3,4-DCQA, and 3,5-DCQA following an intravenous dose of 10 mL/kg mailuoning injection to rats.

Quantitative determination of ophiopogonin d by liquid chromatography/electrospray ionization mass spectrometry and its pharmacokinetics in rat.

A sensitive and rapid liquid chromatography-mass spectrometric method for the determination of ophiopogonin D in rat plasma was developed and validated. Chromatographic separation was performed on a C (18) column using a step gradient program with the mobile phase of 0.5 mmol/L ammonium chloride solution and acetonitrile. Ophiopogonin D was quantified using an electrospray negative ionization mass spectrometry in the selected ion monitoring (SIM) mode using digoxin as an internal standard. Good linearity was obtained in the concentration range of 2.5 - 480.0 ng/mL ( R2 = 0.9984). The lower limit of quantification (LLOQ) and lower limit of detection (LLOD) were 2.5 ng/mL and 1.0 ng/mL, respectively. Both the intra- and inter-day precision was less than 8.9 % and the accuracy was within 97.5 - 107.3 %. The pharmacokinetic study of ophiopogonin D in rats was then defined using the method after intravenous dosing (77.0 microg/kg). The plasma concentration-time profile for ophiopogonin D was best fitted to an open two-compartment model with a clearance of 0.024 +/- 0.010 L/min/kg and a terminal half life of 17.29 +/- 1.70 min. A comparison of the pharmacokinetics of ophiopogonin D as a pure compound and as a component of 'SHENMAI' injection revealed a significantly smaller clearance of ophiopogonin D (0.007 +/- 0.002 L/min/kg) for the latter formulation, consistent with an inhibition by one or more other components in the formulation.

Characterization of metabolites of tanshinone IIA in rats by liquid chromatography/tandem mass spectrometry.

The metabolism of tanshinone IIA was studied in rats after a single-dose intravenous administration. In the present study, 12 metabolites of tanshinone IIA were identified in rat bile, urine and feces with two LC gradients using LC-MS/MS. Seven phase I metabolites and five phase II metabolites of tanshinone IIA were characterized and their molecular structures proposed on the basis of the characteristics of their precursor ions, product ions and chromatographic retention time. The seven phase I metabolites were formed, through two main metabolic routes, which were hydroxylation and dehydrogenation metabolism. M1, M4, M5 and M6 were supposedly tanshinone IIB, hydroxytanshinone IIA, przewaquinone A and dehydrotanshinone IIA, respectively, by comparing their HPLC retention times and mass spectral patterns with those of the standard compounds. The five phase II metabolites identified in this research were all glucuronide conjugates, all of which showed a neutral loss of 176 Da. M9 and M12 were more abundant than other identified metabolites in the bile, which was the main excretion path of tanshinone IIA and the metabolites. M12 was the main metabolite of tanshinone IIA. M9 and M12 were proposed to be the glucuronide conjugates of two different semiquinones and these semiquinones were the hydrogenation products of dehydrotanshinone IIA and tanshinone IIA, respectively. This hydrogenized reaction may be catalyzed by the NAD(P)H: quinone acceptor oxidoreductase (NQO). The biotransformation pathways of tanshinone IIA were proposed on the basis of this research.

Simultaneous determination of tanshinone IIA and its three hydroxylated metabolites by liquid chromatography/tandem mass spectrometry.

A rapid and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the simultaneous determination of tanshinone IIA and its three hydroxylated metabolites, tanshinone IIB, hydroxytanshinone IIA and przewaquinone A, in a rat liver microsome was developed and fully validated. A single step of liquid-liquid extraction with ethyl acetate was utilized in this method. Chromatographic separation of the sample matrix from the analytes and the internal standard diazepam was performed using a Shim-pack VP-ODS analytical column. Detection was performed on a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization source and operated in selected reaction monitoring (SRM) mode. The method was linear in the concentration range of 1-500 ng/mL for all analytes. The intra- and inter-day precisions (RSD %) were within 15% and deviations of the assay accuracies were within 15.0% for all analytes. The analytes proved to be stable during sample storage, preparation and analyses. This validated method was successfully applied to the enzyme kinetic study of tanshinone IIA in liver microsome. The elimination of tanshinone IIA and formation of tanshinone IIB and hydroxytanshinone IIA in the liver microsome all exhibited a sigmoidal kinetics profile. The formation of przewaquinone A shows a typical hyperbolic profile. In addition, this method has now been applied in the analysis of other bio-samples including plasma, urine, bile and feces.