Simultaneous analysis of 12 bioactive constituents in Gegen Qinlian pill by HPLC-DAD

In this study, a novel and simple high performance liquid chromatography with diode array detection （HPLC-DAD） method for the simultaneous qualitative and quantitative determination of 12 bioactive components in Gegen Qinlian pill was developed. The separation was performed on a Kromasil C18 column （250 mm×4.6 ram, 5.0 μm） by gradient elution with acetonitrile and 0.02 mol/L ammonium acetate （containing 0.3% triethylamine, and adjusted pH to 4.3 using 1% glacial acetic acid） as the mobile phase at a flow rate of 0.7 mL/min. Three different detection wavelengths （250, 280, 346 nm） were set at the maximum UV absorption wavelengths of these components. Twelve components （puerarin, daidzin, baicalin, wogonoside, liquiritin, berberine, palmatine, jatrorrhizine, glycyrrhizin, baicalein, wogonin and daidzein） were identified and determined using the developed method. All calibration curves showed good linear regression （r〉0.9995） within tested ranges. The injection precision, intra-day precisions and analysis repeatability were evaluated with the RSD values, which were no more than 0.97%, 1.69% and 1.71%, respectively. The recoveries were ranged from 97.4% to 100.2% with RSD values less than 1.87%. This readily available, low-cost and reliable HPLC-DAD method would improve the quality control of Gegen Qinlian pill.

Non-isothermal kinetic analysis of thermal dehydration of La_2(CO_3)_3·3.4H_2O in air

The single phase La2（CO3）3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2（CO3）3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2（CO3）3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2（CO3）3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction（FnFnFn model）. The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.

Ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry method for the simultaneous determination of itraconazole and hydroxy itraconazole in human plasma

A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid-liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.

Simultaneous determination of fourteen components of Gumiganghwal-tang tablet in human plasma by UPLC-ESI-MS/MS and its application to pharmacokinetic study

Gumiganghwal-tang is a traditional herbal medicine widely used for its anti-inflammatory,analgesic,and antipyretic effects.However,the safety and efficacy of its active ingredients based on an in vivo pharmacokinetic(PK)study have yet been investigated.We have established a sensitive and accurate UPLC-ESI-MS/MS method and conducted a PK study on 14 constituents of Gumiganghwal-tang through human plasma analysis.Analytical conditions were optimized according to the physicochemical properties of the 14 compounds to facilitate efficient separation and eliminate overlap or interference between peaks.KINETEX-C18 and Inertsil-C8 columns were used as UPLC stationary phases,and acetonitrile and aqueous formic acid were used as mobile phases.All the analytes were quantified with a triple quadrupole mass spectrometer using electrospray ionization in multiple reaction monitoring mode.The chromatograms of 14 bioactive compounds showed excellent elution and sensitivity,and each peak was selectively separated and quantified without interference with each other or impurities.The established analytical method was based on international guidelines and was successfully used to perform PK studies of 14 herbal ingredients in humans after oral administration with Gumiganghwal-tang tablets.The oral absorption of most active components of Gumiganghwal-tang was relatively rapid and remained considerably long in the body to be quantified in plasma up to 48 h after administration.

Simultaneous Determination of Bufadienolides and Qualitative Evaluation for Venenum Bufonis by High Performance Liquid Chromatography

A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides（resibufogenin, einobufagin, cinobufaginol, arenobufagin, bufalin, bufotalin, gamabufotalin, cinobufotalin, ψ-bufaranogin, desacetylcinobufagin, telocinobufagin and resibufogenol） in Venenum Bufonis. The chromatographic separation was performed on a Dikma C18 analytical column via gradient elution with an aqueous solution of acetonitrile and 0.3% acetic acid at a flow rate of 0.8 mL/min. The method was validated to be acceptable in consideration of linearity（r2 〉 0.9992） and recovery（ranged from 98.9% to 102.0%）. The limits of detection of the bufadienolides were from 0.48 ng for bufalin to 6.00 ng for cinobufotalin. The intra-day and inter-day precisions of the method were evaluated and were less than 3.0%. The method was successfully used to analyze 19 batches of Venenum Bufonis, and the similarity values between batches were calculated by Similarity Evaluation System for Chromatographic Fingerprint of TCM（Version 2004A, Chinese Pharmacopoeia Committee, Beijing）. The results show that the contents of bufadienolides in the medicine and the similarity values based on these bufadienolides varied significantly from batch to batch. This proposed method could be utilized to qualify and control Venenum Bufonis to ensure its safety and efficacy in application.

Rapid Quantification of Chinese Medicine Zuo Jin Pill via RRLC

A rapid method based on rapid resolution liquid chromatography（RRLC） coupled with a diode array detector（DAD） was developed for the simultaneous determination of six major constituents（magnoflorine,jatrorrhizine,coptisine,palmatine,berberine and evodiamine） in traditional Chinese medicine（TCM） Zuo Jin Pill（ZJP）.The satisfactory chromatographic separation was carried on an Eclipse Plus C18 column（1.8 μm i.d.,150 mm×4.6 mm） by linear gradient elution with a mobile phase of acetonitrile-acetate buffer.All the calibration curves show good linearity（r2 0.9998）.The detection limits and quantification limits ranged in 1.4―12 ng and 4.8―30 ng,respectively.The intra-and inter-day precisions were less than 0.63% with accuracies 98.60%―100.78%,and the recoveries were from 99.45% to 100.46%.Furthermore,hierarchical cluster analysis（HCA） was used to evaluate the variation of the herbal prescription.The results demonstrate that this analytical method is simple,sensitive and reliable for rapidly analyzing six major bioactive compounds in ZJPs and is helpful to comprehensively evaluating the quality of this TCM.

Screening Method for 23 Alkaloids in Human Serum Using LC/MS/MS with a Pentafluorophenyl Column in Dynamic Multiple Reaction Monitoring Mode

Alkaloids are nitrogen-containing organic compounds, generally basic, and found in plants, fungi, and bacteria. Some alkaloids are used in medicine, but some compounds are highly toxic. Accidental ingestion, homicide, and suicide have occurred due to plants containing alkaloids. The identification of toxic components in biological samples is important for the diagnosis and/or treatment of poisoning cases in forensic and emergency medicine. Alkaloids have a wide variety of structures, such as isoquinoline alkaloid, indole alkaloid, tropane alkaloid, and diterpene alkaloid;therefore, there are few reports of simultaneous analysis methods. We have established a method for the simultaneous analysis of 23 alkaloids in human serum with a liquid chromatograph-tandem mass spectrometer (LC/MS/MS). A liquid-liquid extraction which was modified from the first step of the QuEChERS AOAC method was used for serum pretreatment. The separation of the compounds was performed using a pentafluorophenyl (PFP) column, CAPCELL CORE PFP (2.1 mm I.D. × 100 mm, 2.7 μm) in gradient mode. Mobile phase A consisted of 10 mM ammonium formate and 0.1% formic acid in ultrapure water, and mobile phase B was 10 mM ammonium formate and 0.1% formic acid in methanol. Simultaneous analysis was performed in dynamic multiple reaction monitoring mode. The separation of 23 alkaloids was satisfactory, as PFP columns exhibited different retention behaviors than alkyl phase columns. The PFP column effectively retained polar aromatic compounds;therefore, it was suitable for alkaloid analysis. The validated method was applied to a forensic case of aconite poisoning. The present method was useful in LC/MS/MS screening for 23 alkaloids in human serum.

Development and validation of a HPLC-UV-ESI-MS method for the simultaneous quantitation of ten bioactive compounds in Dahuang Fuzi Tang

AIM: To develop a high performance liquid chromatography(HPLC) coupled with electrospray ionization mass spectrometry(ESI-MS) and ultraviolet(UV) detector method for the acid-alkaline simultaneous determination of ten bioactive compounds, and analyze the effect of compatible medicinal plants on the concentration of components in Dahuang Fuzi Tang(DFT). METHOD: The chromatographic separation was performed on a Hypersil BDS C18 analytical column by gradient elution with acetonitrile and formate buffer(containing 0.15% formic acid, V/V) at 25 °C with a flow rate of 1.0 mL ·min–1 and UV detection at 280 nm. Four of the ten compounds in DFT were identified and their MS fragments were elucidated by HPLC-ESI-MS, and the contents of the six compounds were determined by HPLC-UV. RESULTS: All calibration curves showed good linear regression(r2 ≥ 0.9990). The limits of detection and limits of quantification were 0.021–0.155 μg·mL –1 and 0.076–0.520 μg·mL –1, respectively. Overall precision RSD(intra-day and inter-day) were less than 2.96%, and the average recoveries were 98.35%–101.45%, with RSD ranging from 1.54% to 3.01% for the analytes. CONCLUSION: The developed method can be applied for the quality control and provide analytical evidence on the chemical basis and combinational principles of DFT.