ABSTRACT
An HPLC method for the determination of 18alpha-glycyrrhetinic acid and 18beta-glycyrrhetinic acid in rat plasma was established, which was used subsequently to determine the pharmacokinetic profiles of both epimers of glycyrrhetinic acid in rats. alpha-glycyrrhetinic acid, beta-glycyrrhetinic acid, and a mixture of alpha-glycyrrhetinic and beta-glycyrrhetinic acids were administered to rats via gastric infusion. Blood samples were collected at different time intervals and extracted by liquid-liquid extraction. Separation was achieved by using a Kromasil C18 column (150 mm x 4.6 mm, 5 microm) with the mobile phase composed of acetonitrile--4 mmol x L(-1) ammonium acetate solution (46 : 54, v/v) at a flow rate of 1.0 mL x min(-1), and the detection wavelength was set at 250 nm. The pharmacokinetic parameters were calculated using the software DAS 2.0. In a combined administration, the main pharmacokinetic parameters of beta-glycyrrhetinic acid are significantly different from that of alpha-glycyrrhetinic acid (P < 0.05), while no significant difference was obtained when administrated individually. Compared to the single administration, significant differences (P < 0.05) on the values of AUC(0-t) and AUC(0-infinity) of beta-glycyrrhetinic acid were observed when this chemical was administrated together with alpha-glycyrrhetinic acid. In contrast, the pharmacokinetic parameters of alpha-glycyrrhetinic acid were not affected even under the co-administration. Here, a sensitive, specific, rapid and reproducible HPLC method was developed for the pharmacokinetic studies of alpha-glycyrrhetinic acid and beta-glycyrrhetinic acid in rat plasma.
ABSTRACT
We described the first results of a quantitative ultra performance liquid chromatographytandem mass spectrometry method for a novel antimicrobial peptide （phylloseptin, PSN-1）. Chromatographic separation was accomplished on a Waters bridged ethyl hybrid （BEH） C18 （50mm× 2.1 mm, 1.7 μm） column with acetonitrile-water （25：75, v/v） as isocratic mobile phase. Mass spectrometry detection was performed in the positive electrospray ionization mode and by monitoring of the transitions at m/z 679.6/120, 509.6/120 （PSN-1） and m/z 340.7/165 （Thymopentin, IS）. Protein precipitation was investigated and the recovery was satisfactory （above 82%）. The method was shown to be reproducible and reliable with intra-day precision below 5.3%, inter-day precision below 14.2%, and linear range from 0.02 to 2 lag/mL with r〉0.994. The method was successfully applied to a pharmacokinetic study of PSN-1 in rats after intravenous administration.
ABSTRACT
We described the first results of a quantitative ultra performance liquid chromatographytandem mass spectrometry method for a novel antimicrobial peptide (phylloseptin,PSN-1).Chromatographic separation was accomplished on a Waters bridged ethyl hybrid (BEH) C18 (50 mm × 2.1 mm,1.7 μm) column with acetonitrile-water (25∶75,v/v) as isocratic mobile phase.Mass spectrometry detection was performed in the positive electrospray ionization mode and by monitoring of the transitions at m/z 679.6/120,509.6/120 (PSN-1) and m/z 340.7/165 (Thymopentin,IS).Protein precipitation was investigated and the recovery was satisfactory (above 82％).The method was shown to be reproducible and reliable with intra-day precision below 5.3％,inter-day precision below 14.2％,and linear range from 0.02 to 2 μg/mL with r＞0.994.The method was successfully applied to a pharmacokinetic study of PSN-1 in rats after intravenous administration.
ABSTRACT
AIM:To determine four bioactive components in Tongda Granule ( Radix Paeoniae alba,Flos Carthami,Radix Scutellariale,etc. ),namely hydroxy safflower yellow A,peoniflorin,ferulic acid,and baicalin. METHODS:The isolation was performed on an Alltech Apollo C18 (250 mm ? 4. 6 mm,5 ?m) with the mobile phase consisting of methanol-0. 2% (w)phosphoric acid for gradient elution. The flow rate was 1. 0 mL/min and the column temperature was set at 30 ℃. RESULTS:This method was successfully applied to determining four bio-active components in Tongda Granule. The standard curves were linear over the ranges of 5. 20 -104 mg/L for hydroxy safflower yellow A(r =0. 999 1),25. 6 -512 mg/L for peoniflorin (r =0. 999 6),7. 72 -154. 4 mg/L for ferulic acid (r =0. 999 5),32. 5 -650 mg/L for baicalin (r = 0. 999 5),respectively. The average recoveries were 101. 1% ,99. 6% ,98. 9% and 101. 9% ,RSD were 2. 3% ,1. 8% ,2. 6% and 1. 3% ,respectively. CONCLUSION:The method is simple and can be used as a quality control method for Tongda Granule.