Jianli Liu

Distribution study of tryptanthrin in rat tissues by HPLC and its relationship with meridian tropism of indigo naturalis in traditional Chinese medicine

The aim of the present study is to characterize the distribution of tryptanthrin (TRYP) in rat tissues following oral administration at a dose of 100 mg/kg and its relationship with meridian tropism (MT) of indigo naturalis (IN) in traditional Chinese medicine (TCM). For quantitative analysis in biological samples, a sensitive, inexpensive and accurate high-performance liquid chromatographic method was developed and validated with 2-hydroxy acetophenone as internal standard, a Shimadzu C18 column and water-acetonitrile (55:45, v/v) as mobile phase. Acceptable intra-day and inter-day precision at high, medium and low concentration was acquired with RSD ranging from 0.87 to 5.22% and from 1.25 to 6.47%, respectively. Good assay and extraction recoveries were obtained with a single and relatively fast step to precipitate protein. The extraction recovery of TRYP ranged from 87.5 to 94.5 %. TRYP concentration was highest in the liver and remained for a much longer time than in other tissues. It could also be detected in kidney, lung, heart and spleen, but not in brain under the experimental conditions. The results confirmed the traditional knowledge of TCM that MT of IN belongs to the liver meridians and demonstrated that TRYP is one of the active constituents of the MT of IN.

Simultaneous determination of 10 kinds of biogenic amines in rat plasma using high-performance liquid chromatography coupled with fluorescence detection

We describe a simple, rapid, selective and sensitive HPLC method coupled with fluorescence detection for simultaneous determination of 10 kinds of biogenic amines (BAs: tryptamine, 2-phenethylamine, putrescine, cadaverine, histamine, 5-hydroxytryptamine, tyramine, spermidine, dopamine and spermine). BAs and IS were derivated with dansyl chloride. Fluorescence detection (λex /λem = 340/510 nm) was used. A satisfactory result for method validation was obtained. The assay was shown to be linear over the ranges 0.005-1.0 μg/mL for tryptamine, 2-phenethylamine and spermidine, 0.025-1.0 μg/mL for putrescine, 0.001-1.0 μg/mL for cadaverine, 0.25-20 μg/mL for histamine, 0.25-10 μg/mL for 5-hydroxytryptamine and dopamine, and 0.01-1.0 μg/mL for tyramine and spermine. The limits of detection and the limits of quantification were 0.3-75.0 ng/mL and 1.0-250.0 ng/mL, respectively. Relative standard deviations were ≤5.14% for intra-day and ≤6.58% for inter-day precision. The recoveries of BAs ranged from 79.11 to 114.26% after spiking standard solutions of BAs into a sample at three levels. Seven kinds of BAs were found in rat plasma, and the mean values of tryptamine, 2-phenethylamine, putrescine, cadaverine, histamine, spermidine and spermine determined were 52.72 ± 7.34, 11.45 ± 1.56, 162.56 ± 6.26, 312.75 ± 18.11, 1306.50 ± 116.16, 273.89 ± 26.41 and 41.51 ± 2.07 ng/mL, respectively.

Preparation and properties of new nickel ion affinity chromatography medium

With the chloromethylated crosslinking polystyrene microspheres (chlorine ball) as the matrices, N,N⁃dimethylformamide (DMF) as the solvent, activated by N,N⁃diisopropyleth⁃ ylamine (DIEA), the synthesized Lys(Boc) ⁃OEt and ethyl chloroacetate were coupled to the matrices. After hydrolysis, the carboxyl group was released and chelated with Ni, and a new nickel ion affinity chromatographic medium was prepared. The affinity medium was applied to purify the His⁃Lys⁃Tyr and Phe⁃His⁃Thr tri⁃peptides. The results showed that the peptides con⁃ taining histidine were retained on the affinity medium and separated with other substances.

[Determination of 11 sulfonamide residues in aquaculture water and sediments by high performance liquid chromatography coupled with post-column derivatization].

An analytical method was developed for the determination of 11 sulfonamide compounds in aquaculture water and sediments by high performance liquid chromatography (HPLC) coupled with post-column derivatization. The filtered water sample was purified and concentrated with HLB cartridge, while the sediment sample was extracted with a mixture of methanol and EDTA-McIlvaine buffer (1:1, v/v), and then purified and enriched through HLB solid-phase extraction. The sulfonamides were separated on a C18 column by HPLC and on-line derivatized with a fluorescamine and detected with a fluorescence detector. The parameters of post-column derivatization system were optimized, and the fluorescamine solution concentration, velocity of reagent solution and reaction temperature were 0.2 g/L, 0.15 mL/min and 50 °C, respectively. The calibration curves of the method showed good linearity in the range of 0.01-1.0 mg/L, with the correlation coefficients (r2) all above 0.99995. The recoveries were 79.3%-100.7% and 74.6%-95.3% with RSD values of 2.2%-11.0% and 2.6%-10.3% for the 11 sulfonamides in aquaculture water and sediments, respectively. The respective limits of detection (LODs, S/N = 3) were 0.9-5.5 ng/L and 0.3-1.3 µg/kg and the limits of quantification (LOQs, S/N = 10) were 3.0-18.1 ng/L and 1.0-4.4 µg/kg. The method can be applied to the determination of sulfonamides in the aquaculture environment, and it has a good practicability.

On the ideal quality control specification of compound prescription

Effectiveness, safety and quality controllability are the three basic and most important premises for evaluating the quality of drugs. Having undergone clinical tests and been verified in thousands of years, the effectiveness and safety of compound prescription, the chief form of medication in TCM, have been proved reliable. Sometimes due to the lack of quality controllability, incorrect drug or method of preparing being used, so poor therapeutic effect can be seen, though diagnosis and prescription are correct. Quality uncontrollability is also one of the important reasons that causes difficulty for TCM preparation to enter international market. In order to ensure the effectiveness and safety of TCM compound prescription and the entering of TCM preparation into international market, strict quality control specifications should be defined. Although wide attention has been paid to this task, how to define the specifications is still under discussion. ……