Pharmacokinetics of Maxing Shigan decoction in normal rats and RSV pneumonia model rats by HPLC-MS/MS / 中国中药杂志

To establish a LC-MS/MS method to determine the concentrations of liquiritin, glycyrrhizin, glycyrrhetinic acid, amygdalin, amygdalin prunasin, ephedrine, pseudoephedrine and methylephedrine of Maxing Shigan decoction in rat plasma, and study the differences on their pharmacokinetic process in normal rats and RSV pneumonia model rats. After normal rats and RSV pneumonia model rats were orally administered with Maxing Shigan decoction, the blood was collected from retinal vein plexus of different time points. Specifically, tetrahydropalmatine was taken as internal standard for determining ephedrine, while chloramphenicol was taken as internal standard for determining other components. After plasma samples were pre-treated as the above, the supernatant was dried with nitrogen blowing concentrator and then redissolved with methylalcohol. The chromatography was eluted with mobile phase consisted of acetonitrile and 0.1% formic acid solution in a gradient manner. ESI sources were adopted to scan ingredients in ephedra in a positive ion scanning mode and other ingredientsin a negative ion scanning mode. The multiple-reaction monitoring (MRM) method was developed the plasma concentration of each active component. The pharmacokinetic parameters of each group were calculated by using Win-Nonlin 4.1 software and put into the statistical analysis. The result showed the plasma concentration of the eight active ingredients, i.e., liquiritin, glycyrrhizin, glycyrrhetinic acid, amygdalin, amygdalin prunasin, ephedrine, pseudoephedrine and methylephedrine within the ranges of 1.04-1040, 1.04-1040, 0.89-445, 1.05-4200, 1.25-2490, 0.3-480, 0.3-480, 0.3-480 microg x L(-1), with a good linearity and satisfactory precision, recovery and stability in the above ingredients. After modeling, except for glycyrrhetinic acid whose pharmacokinetic parameters were lacked due to the data missing, all of the rest components showed significant higher Cmax, AUC(0-1) and lower clearance rate (CL) than that of the normal group, indicating the increase in absorption in rats in the pathological state by reducing the clearance rate. The method is accurate and sensitive and so can be used to determine the plasma concentrations of the eight active ingredients in Maxing Shigan decoction. RSV pneumonia-infected rats absorbed more ingredients in Maxing Shigan decoction.

Pharmacokinetic study on combined application of gastrodin and puerarin in rats / 中国中药杂志

To establish a HPLC method for simultaneously determining plasma concentrations of gastrodin (Gas) and its metabolites hydroxybenzyl alcohol (HBA), puerarin (Pur) and internal standard (IS) p-hydroxyphenylethanol (Tyr) in rats and studying the pharmacokinetic process and interactions of gastrodin and puerarin after single and combined intravenous injection and oral administration. With Tyr as the internal standard, plasma samples were processed with methanol for protein precipitation, supernatant was dried with N2, and residues were re-dissolved with acetonitrile-0.05% phosphoric acid (20: 80). Chromatography was carried out on an Agilent ZORBAX SB-Aq C18 column (4.6 mm x 250 mm, 5 μm), with acetonitrile-0.05% phosphoric acid as the gradient mobile phase for the gradient elution. The UV detector wavelength was set at 221 nm for Gas HBA and IS and 250 nm for Pur. After the single or combined administration of Gas and Pur, their plasma concentrations in rats were detected. WinNonlin 5.2 pharmacokinetic software and SPSS 17. 0 software were used to respectively calculate pharmacokinetic parameters of each group, make a statistical analysis and compare the pharmacokinetic processes of Gas and Pur after the single or combined administration. According to the results, the absolute recoveries between low, media and high concentrations of Gas, HBA and Pur and IS as well as Tyr were more than 77.20%, with a good linearity (r > 0.999 6, n = 5) for Gas, HBA and Pur within concentration ranges of 0.10-101, 0.03-7.58 and 0.05-5.98 mg xL ('1) respectively. The lower limits of quantification for Gas, HBA and Pur were 0.10, 0.03, 0.05 mg x L(-1), respectively. Their in-ra-day and inter-day precisions were less than 12% with the accuracy between 85. 1% -1 10. %. All of the three substances and IS were stable during the whole analysis process. The findings showed significant differences in the main in vivo pharmacokinetic parame-ers in rats (AUC, C.(max) T,½ T.(max) MRT) after the single and combined administration of Gas and Pur. Either after the oral adminis-ration or after the intravenous injection, parameters showed a lower clearance rate ( L) longer mean residence time ( RT) and higher relative bioavailability, especially after the oral administration. Specifically, the relative bioavailability of the combined oral ad-inistration of Pur was 10. 7 times of that of the single administration, while that of Gas was 1. times of that of the single administra-ion. The combined administration of Gas and Pur can promote the absorption, decrease the elimination rate and prolong the mean resi-ence time. The method is simple and accurate and can be applied in the simultaneous determination of plasma concentrations of Gas, HBA and Pur in rats and the pharmacokinetic studies.