Study On The Chemical Basis And Pharmacokinetics Of Huangqin Tang

Huangqin Tang (HQT), a well-known Chinese medicine formula, is a3:2:2:2by weight combination of four herbal medicines, Radix Scutellariae (Scutellaria baicalensis Georgi), Radix Paeoniae Alba (Paeonia lactiflora Pall.), Radix Rhizoma Glycyrrhizae(Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L.) and Jujubae Fructus (Ziziphus jujuba Mill.). HQT was used for the treatment of colds and gastrointestinal diseases with the symptoms of fever, abdominalgia and diarrhea for thousands years in Asia countries. Recently, its gastrointestinal toxicity reduction and the anti-tumor efficacy enhancement of some anti-cancer drugs are reported both in preclinical models and in clinical studies. To full reveal its mechanism of action in vivo and provide valuable data for its clinical use, this study investigated the pharmacokinetic properties of HQT.Typically, the present study firstly conducted qualitative and quantitative analysis to clarify the chemical basis of HQT and establish the quality control method. Then, perfused intestine-liver preparation was established for in situ absorption and metabolism study of HQT. Lastly, rat models were used for the in vivo analysis of metabolism and pharmacokinetic study of the major constituents. Comparative studies at different doses, administration frequency in both physiological and pathological models were conducted to investigate the fate of the major constituents and finally clarify the PK property of HQT.1Chemical investigation and quality control of HQTFirstly, qualitative analysis of HQT was carried out by HPLC fingerprinting and LC-IT-MSn method. In the fingerprint analysis,10batches of HQT were homogeneous with the similarity between0.990and1.000.26common peaks in the chemical profile of HQT were detected.12major compounds were identified and confirmed by LC-IT-MSn.Besides, quantification analysis was established for full quality assurance of HQT. HPLC method was used to determination of the major compounds in HQT. It was found that the total flavoids in different batches of HQT was quite consistent. Further principal component analysis as well proved the batch-to-batch homogeneity of HQT samples.Moreover, a novel pharmacological model established on single animal was used for simultaneous evaluation of antipyretic, analgesic and anti-inflammatory effects of HQT samples. Only little pharmacodynamic differences between different batches of HQT samples were found, proving the quality homogeneity of HQT and indicating the suitability of utilizing these samples for further pharmacokinetics study.2In situ absorption and metabolism of major constituents in HQTPerfused intestine-liver preparation was applied for the absorptive and metabolic fingerprint analysis of HQT. The established chemical fingerprint method was successfully used for the clarification of chemical changes after the in situ process of HQT. Revealed in the chemical fingerprint,25peaks could be pass the intestine and liver and10of them were confirmed by comparison with standards. Besides, some significant metabolites were found. These compounds were deduced as potential QC markers, DM markers, and PK markers as well, which were considered as the therapeutic basis of HQT and also supported the further pharmacokinetics study.3In vivo pharmacokinetic property of HQTAn LC-MS method for simultaneous determination of flavonoids and terpenoids in rat plasma was developed and validated. The results of specificity, linearity, intra-day and inter-day precisions, accuracy, and stability for LC-MS assay are suitable for the quantification of paeoniflorin, baicalin, wogonoside, baicalein, wogonin, oroxylin A, glycyrrhizic acid and glycyrrhetinic acid in rat plasma. This method was successfully applied for the PK property study of HQT at different dose. Besides, the PK properties of HQT in pathological models, including ulcerative colitis model and fever model in rats, were also explored.The flavonoids of HQT showed good PK property in rat plasma. The dose, administration frequency, and pathological condition could greatly affect the PK behavior of major constituents when treated rats with HQT. It was worth noting that flavonoid glycosides and flavonoid aglycones possessed similar PK properties.As a conclusion, the present study successfully revealed the material basis of HQT from the points of chemistry and the pharmacokinetics. Multi-components were selected as potential markers based on the chemical and in-situ analysis of HQT. By in-vivo PK study of HQT, it is also of significance to identify several QC marker, DM marker and PK marker of HQT.