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A sensitive and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was successfully applied to the determination of 10 alkaloids in beagle dog plasma following a single oral dose of Xiatianwu capsules and enteric-coated capsules, with theophylline serving as the internal standard (IS).Plasma samples were preprocessed using liquid-liquid extraction (LLE) with ethyl acetate ahead to separation using a gradient elution procedure on a Waters ACQUITY UPLC HSS T3 column (1.8 μm, 100 × 2.1 mm). The mobile phase was composed of 0.1% formic acid solution and acetonitrile at the flow rate of 0.3 ml/min. Multiple reaction monitoring (MRM) was used to determine the analytes in the positive ion mode.The calibration curves for 10 analytes demonstrated a high degree of linearity (r ≥ 0.9920). The lower limit of quantification (LLOQ) values for 10 alkaloids were all more than 1.074 ng/ml, and matrix effects varied from 94.25% to 106.15%. The mean extraction recovery of quality control samples at low (LQC), medium (MQC) and high (HQC) concentrations, as well as IS, was all more than 76.60%. The intra-day and inter-day precision (RSD) also satisfied the requirement. Simultaneously, the variation of assay accuracies (RE) was between 13.05% and 9.38%.The test was validated in accordance with regulatory bioanalytical guidelines and was found to be suitable for use in a pharmacokinetic investigation of these compounds in beagle dogs after oral administration of Xiatianwu general capsules and enteric-coated capsules. The C

A selective and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established and validated for the determination of ziyuglycoside I, 3

Uncaria rhynchophylla (Miq.) Miq. ex Havil (U. rhynchophylla), a traditional Chinese medicine that has been officially included in the Chinese Pharmacopeia, is used to treat cardiovascular and central nervous system diseases. The major alkaloids isolated from U. rhynchophylla are two pairs of epimer including rhynchophylline (RIN) and isorhynchophylline (IRN), along with corynoxeine (CN) and isocorynoxeine (ICN). An ultra-performance liquid chromatography with tandem mass spectrometry method (UHPLC-MS/MS), which was highly accurate, stable and sensitive, was established and validated for the simultaneous determination of four alkaloid compounds (RIN, IRN, CN, ICN) in rat plasma samples after oral administration of RIN, IRN, CN, ICN and U. rhynchophylla extract. In this study, the biotransformation and pharmacokinetics of RIN, IRN, CN and ICN were determined for the first time. An ACQUITY UPLC®HSS T3 column (1.8 µm, 2.1 mm × 100 mm) was used to complete the chromatographic separation within 3 min. The isocratic mobile phase was composed of 0.1 % formic acid water (v/v) and acetonitrile, and the flow rate was 0.2 mL/min. The multireaction monitoring mode was adopted, and the tandem mass spectrometry in the positive ion mode was detected by the electrospray ionization source. The method was fully verified and linear at a wide concentration (r 0.9913), and the linear concentration range was 0.1552-124.5 ng/mL. The intraday and interday precisions of the four analytes were lower than 8.20 % and 13.42 %, respectively. The accuracy range was - 2.64 % and 13.63 %. The extraction recoveries of the analytes exceeded 83.74 %, and the matrix effect range was 98.43-103.7 % in the plasma samples. The four alkaloids can be quickly absorbed into the blood (T

A novel analytical method involving high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) was developed for simultaneous determination of 11 phenolic acids and 12 triterpenes in Sanguisorba officinalis L. Chromatographic separation was conducted with gradient elution mode by using a DiamonsilTM C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.1% acetic acid water (A) and methanol (B). The drift tube temperature of ELSD was set at 70 °C and the nitrogen cumulative flow rate was 1.6 L/min. The method was fully validated to be linear over a wide concentration range (R2 ≥ 0.9991). The precisions (RSD) were less than 3.0% and the recoveries were between 97.7% and 101.4% for all compounds. The results indicated that this method is accurate and effective for the determination of 23 functional components in Sanguisorba officinalis L. and could also be successfully applied to study the influence of processing method on those functional components in Sanguisorba officinalis L.

A sensitive, specific, and accurate ultra high-performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous quantification of purpurin, munjistin, mollugin, and alizarin from Qianzhi capsules in rat plasma. Chromatographic separation was performed on an Agilent Eclipse Plus C18 RRHD column with a mobile phase consisting of methanol and 5 mM ammonium acetate/water with gradient elution. The analytes were quantified on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring mode and switching the electrospray ion source polarity with positive electrospray ionization in a single run. Samples were pretreated by liquid-liquid extraction with cyclohexane. The intra- and interday precision and accuracy of the assay were within acceptable ranges. Matrix effects for all of the analytes were between 90.16 and 100.21%. The average recovery ranged from 75.38 to 88.96%. This method was successfully applied to study the pharmacokinetic parameters of the four compounds in rat plasma after oral administration of Qianzhi capsules. Four quinones could be rapidly absorbed into blood (tmax , 0.80-1.93 h) and eliminated relatively slowly (t1/2 , 8.07-11.97 h). The results might be helpful for guiding the clinical application of Qianzhi capsules in the future.

In this study, the constituents of a Corydalis bungeana Turcz extract were qualitatively analyzed using gradient elution with a mobile phase of 0.2% acetic acid and acetonitrile. We obtained comprehensive insight into the constituents of C. bungeana Turcz extracts through the quantitative analysis of 14 compounds by comparison with authentic reference standards, and tentatively identified an additional 44 compounds through electrospray ionization mass spectrometry (ESI&ndash, MS) and tandem MS detection. The separation was successfully achieved using an Agilent SB-C18 column (1.8 &micro, m, 150 &times, 2.1 mm, Agilent, Santa, CA, USA). A tandem quadrupole spectrometer was operated in either full-scan mode or multiple reaction monitoring (MRM) for the qualitative and quantitative analyses of the constituents, respectively. Validation data (inter-day and intra-day combined) for accuracy and precision ranged from &minus, 4.80% to 4.73%, and 0.30% to 4.97%, respectively. An ultrahigh performance liquid chromatographic&ndash, ESI&ndash, tandem MS (UHPLC&ndash, MS/MS) method for qualitative of C. bungeana Turcz (C. bungeana) extract and the quantification of 14 alkaloids, namely, A&ndash, N, was developed and validated. Quantitative analysis involved gradient elution with a mobile phase of 0.1% acetic acid and methanol for 45 min. The separation was successfully achieved using a Waters SB-C18 column (1.8 &micro, m, 100 mm &times, 2.1 mm, Waters, Milford, Massachusetts, USA). The repeatability and stability of the method also met USFDA criteria with CV values lower than 5%. The limit of detection of the 14 alkaloids ranged from 9.74 to 13.00 ng/mL, whereas the linearities of the standard curves were between 0.9991 and 0.9995. In total, 15 commercial samples from 11 different sources were analyzed.

This study has developed a sensitive and simple ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of corydaline, dehydrocorydaline, tetrahydropalmatine, protopine, palmatine, tetrahydroberberine, columbamine, berberine, coptisine and berberrubine in beagle dog plasma after the oral administration of the Corydalis yanhusuo W.T. Wang and Yuanhuzhitong tablets. Chromatographic separation was achieved on an Agilent Eclipse Plus C18 RRHD column (1.8 &micro, m, 50 &times, 2.1 mm) using a gradient elution program with a mobile phase consisting of acetonitrile and water containing 0.1% formic acid at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection was conducted by multiple reaction monitoring (MRM) mode via an electrospray ionization source in the positive mode. The calibration curves of all analytes showed good linear (r2 &gt, 0.9800). The intra-day and inter-day precisions were less than 15% and the accuracies were within &plusmn, 15%. The extraction recoveries conformed to the acceptable range. And there was no interference of endogenous substances in the sensitive assay method. All analytes were proven to be stable during sample storage and analysis procedures. The pharmacokinetic study indicated that the Yuanhuzhitong tablets could get a better absorption than Corydalis yanhusuo W.T. Wang.

Pharmacokinetic studies were conducted on rats for protopine, corynoline, 7'-(3',4'-dihydroxyphenyl)-N-[(4-methoxyphenyl)-ethyl]propenamide, acetylcorynoline, and 8-oxocorynoline, five main active components from Corydalis bungeana Turcz (C. bungeana Turcz). An ultra high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the simultaneous determination of the pharmacokinetic characteristics of these components in rat plasma. Chromatographic separation was achieved on an Agilent SB-C18 column (1.8 μm, 150 × 2.1 mm) using a gradient elution program with a mobile phase consisting of acetonitrile and water containing 0.1% acetic acid at a flow rate of 0.3 mL/min. The analytes were detected in the multiple reaction monitoring mode with positive electrospray ionization. Lower limits of quantification were >0.680 ng/mL and matrix effects ranged from 91.26 to 100.38%. The mean extraction recoveries of quality control samples were less than 79.32%, and the precision and accuracy were within the acceptable limits. All analytes were proven to be stable during sample storage and analysis procedures. The validated method was successfully applied to the pharmacokinetic study of five alkaloid components after oral administration of C. bungeana Turcz extract to rats. The obtained results may be helpful to reveal the mechanism of action and to guide the clinical application of C. bungeana Turcz.

Aralia elata (Miq.) Seems (A. elata) grow in Northeast China and the total saponins of A. elata is used to auxiliary treatment for the acute hepatitis, chronic hepatitis and the transaminase on the high side. Aralia-saponinV and Aralia-saponinVI are the major bioactive saponins in A. elata leaves. A selective and sensitive UHPLC-MS/MS method was developed and validated for the determination and pharmacokinetic study of Aralia-saponinV and Aralia-saponinVI indwelling the extract in rat plasma in this article. The sample pretreatment involved a one-step extraction of 0.2mL plasma with methanol. Shengmaxinside C was used as internal standard (I.S.). The separation was carried out on an Agilent SB-C18 column (1.8μm, 50mm×2.1mm) at 30°C with a mobile phase of acetonitrile-5mM ammonium acetate (90:10, v/v) at a flow rate of 0.2mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion-pairs (m/z) monitored for Aralia-saponinV, Aralia-saponinVI and I.S. were 1103.2/941.2, 1119.2/957.0 and 707.0/647.1, respectively. The current UHPLC-MS/MS assay method was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability, and it was suitable for the pharmacokinetic studies of the two saponins after oral administration of extract of A. elata leaves. The lower limits of quantification were 5.70ng/mL for Aralia-saponinV and 6.15ng/mL for Aralia-saponinVI. Intra-day and inter-day precisions were less than 7.4% and the accuracy range was from 1.19% to 8.60%. The mean extraction recoveries of analytes and I.S. from rat plasma were all more than 89.5%. This paper described a simple, sensitive and validated UHPLC-MS/MS method for simultaneous determination of Aralia-saponinV and Aralia-saponinVI in rat plasma after oral administration of the extract of A. elata leaves, and investigated on their pharmacokinetic studies as well.

A rapid and sensitive Ultra High Performance Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (UHPLC-ESI-MS/MS) method was developed and validated to simultaneously determine the concentration of seven phenolic acids (syringic acid, ferulic acid, caffeic acid, vanillic acid, p-coumaric acid, 3,4-dihydroxybenzoic acid and 4-hydroxybenzoic acid) in rat plasma after oral administration of Echinacea purpurea extract. After mixing with the internal standard (IS), butylparaben, plasma samples were prepared by liquid–liquid extraction with ethyl acetate. The separation was performed using the Agilent Eclipse Plus C18 column (1.8 μm, 2.1 mm × 50 mm) with a gradient system consisting of solution A (0.1% acetic acid in water) and solution B (methanol) at a flow rate of 0.3 mL/min. The detection was accomplished by a multiple reaction monitoring (MRM) mode with electrospray ionization (ESI). The method was validated in terms of linearity, precision, accuracy, extraction recovery, matrix effect and stability. This method was successfully applied to study the pharmacokinetic properties of the seven compounds after oral administration of Echinacea purpurea extract in rats.

Rosmarinus officinalis L. is commonly used as a spice and flavoring agent. Diterpenes are the main active compounds of R. officinalis. An Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-ESI-MS/MS) method was developed for the determination of carnosol, rosmanol, and carnosic acid isolated from R. officinalis in rat plasma, and applied to a pharmacokinetic study after oral administration of R. officinalis extract. Sample preparation involved a liquid-liquid extraction of the analytes with ethyl acetate. Butylparaben was employed as an internal standard (I.S.). Chromatographic separation was carried out on a C18 column (ACQUITY UPLC® HSS T3, 1.8 μm, 2.1 mm × 100 mm) with a gradient system consisting of the mobile phase solution A (0.1% formic acid in water) and solution B (acetonitrile) at the flow rate of 0.3 mL/min. The quantification was obtained using multiple reaction monitoring (MRM) mode with electrospray ionization (ESI). The UHPLC-MS/MS assay was validated for linearity, accuracy, precision, extraction recovery, matrix effect and stability. This study described a simple, sensitive and validated UHPLC-MS/MS method for the simultaneous determination of three diterpene compounds in rat plasma after oral administration of R. officinalis extract, and investigated on their pharmacokinetic studies as well.

Cucurbitacin B (CuB) and cucurbitacin E (CuE) are tetracyclic triterpene compounds from Cucurbitaceae, and the main bioactive compounds of cucurbitacins tablets that used to treatment of chronic hepatitis. Pharmacological research has been very comprehensive, and there are few studies on pharmacokinetics, especially about CuE. An Ultra High Performance Liquid Chromatography-tandem Mass Spectrometry (UHPLC-MS/MS) method with high selectivity, simplicity and sensitivity has been used for quantitative analysis of Cucurbitacin B (CuB) and cucurbitacin E (CuE). Plasma samples were pretreatment by Liquid-liquid extraction (LLE) method with dichloromethane. The chromatographic separation was achieved on a C18 column (Agilent Eclipse Plus, 1.8μm, 50×2.1mm) using gradient elution with water - methanol at a flow rate of 0.3mL/min and the column temperature was set at 30°C. The method was validated according to FDA guidelines. Lower limit of quantification (LLOQ) was 1.60ng/mL for CuB and 1.58ng/mL for CuE. Correlation coefficients of CuB and CuE were more than 0.99 in rat plasma. All values of intra-day and inter-day precision (RSD%) were not exceeded 15%, the accuracy (RE%) were within -5.57 to 5.20% for CuB and -3.33 to 7.37% for CuE. The mean extraction recoveries were more than 80%. Pharmacokinetic parameters were also evaluated by UHPLC-MS/MS method. The results suggestion that this method was successfully applied to pharmacokinetic study of CuB and CuE in rat plasma after oral administration cucurbitacin tablets.

Corynoline and acetycorynoline are active compounds of Corydalis bungeana Turcz. with various pharmacological effects such as sedation, anti-leptospira and liver injury protection effects. A specific, simple and sensitive UHPLC–ESI–MS/MS method was developed and validated for the pharmacokinetic study of corynoline and acetycorynoline in rat plasma. Corynoline and acetycorynoline were extracted from plasma samples by liquid–liquid extraction. The analysis was carried out on an Agilent SB-C18 column (1.8 μm, 50 mm × 2.1 mm) with the mobile phase of acetonitrile–0.1% formic acid (80:20, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source in positive mode. The current UHPLC–ESI–MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability. The lower limits of quantification were 0.10 ng/mL for corynoline and 0.353 ng/mL for acetycorynoline. Intra-day and inter-day precision were less than 12.3% and accuracy ranged from 0.18% to 14.9%. The mean extraction recoveries of analytes and internal standard (IS) from rat plasma were all more than 76.2%. This validated method was successfully applied to pharmacokinetic study in rats after oral administration of corynoline, acetycorynoline and the extract of Corydalis bungeana Turcz.

Hernandezine, a novel anticancer AMPK activator, is a major active constituent of Thalictrum Ranunculaceae. A simple, specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantification of hernandezine in rat plasma and tissues after intravenous administration. Sample preparation was carried out through a protein-precipitation extraction with acetonitrile using tetrandrine as internal standard (IS). The chromatographic separation was achieved by using an Agilent ZORBAX Eclipse Plus C18 column with a mobile phase of acetonitrile and water (containing 10mM ammonium acetate) in an isocratic elution way. The mass spectrometry (MS) analysis was conducted in positive ionization mode with multiple reaction monitoring (MRM) transitions at m/z 653.4→411.2 for hernandezine and m/z 623.3→381.3 for tetrandrine (IS). Calibration curves were linear over the ranges of 20.0-4000ng/ml f or both plasma samples and tissue samples (r>0.991). The lower limit of quantification (LLOQ) was 20.0ng/ml. The intra-day and inter-day precision (RSD%) were less than 14.0%, while the accuracy was ranged from 85.2% to 114.9%. Finally, this developed method was successfully applied in the pharmacokinetics and tissue distribution study of hernandezine after intravenous administration.

Ethnopharmacological relevance Coptidis rhizoma (CR) is the dried rhizome of the ranunculaceous plant CR. For decades in China, this plant has been used to treat hypertension, hyperlipidemia, and chronic diarrhea and has been officially included in the Chinese Pharmacopoeia. The present paper presents a review of the pharmacokinetics of CR. Aim of the study The pharmacokinetic studies and differences of 10 alkaloids among Coptis deltoidea C. Y. cheng et Hsiao, Coptis chinensis Franch and Coptis teeta Wall. Are seldom reported. This study is the first to determine corydaline, dehydrocorydaline, tetrahydropalmatine, palmatine, magnoflorine, jatrorrhizine, berberine, worenine, berberrubine, and coptisine, which adopted an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, simultaneously. Materials and methods Chromatographic separation was performed within 8 min by using an Agilent SB-C18 column (150 mm × 2.1 mm, 1.8 μm) with gradient mobile phase consisting of 0.3% acetic acid water (v/v) and acetonitrile at a flow rate of 0.3 mL/min. Multiple reaction monitoring mode was used to detect the tandem mass spectrum in the positive ionization mode by electrospray ionization source. Results The method was fully validated to be linear over a wide concentration (r > 0.9916), and the linear concentration range was 0.195–2260 ng/mL. Intra- and interday precisions were below 14.19% and 18.56% for the 10 analytes, respectively. The accuracy ranged from −9.30% to 6.31%. The extraction recovery of the 10 alkaloids and internal standard ranged from 79.76% to 95.37%. Pharmacokinetic comparative study showed that the Cmax and AUC0-∞ values of dehydrocorydaline, tetrahydropalmatine, palmatine, magnoflorine, jatrorrhizine, berberine, worenine, berberrubine, and coptisine increased significantly (p Conclusion This validated method was successfully applied for the pharmacokinetics study of beagle plasma after oral administration of three CR extract types.

A ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight alkaloids: tetrahydropalmatine (A); palmatine (B); magnoflorine (C); columbamine (D); berberine (E); worenine (F); berberrubine (G) and coptisine (H) in rat plasma, which are the active components in Coptis deltoidea C. Y. cheng et Hsiao (CCY) and Coptis chinensis Franch (CF). The chromatographic separation of analytes was successfully achieved on an Agilent SB-C18 column (1.8 µm, 150 mm × 2.1 mm) using a programme with a mobile phase consisting of acetonitrile and water containing 0.3% acetic acid at a flow rate of 0.25 mL/min. The analytes were detected with a triple quadrupole tandem MS in multiple reaction monitoring (MRM) mode and an electrospray ionization (ESI) source in positive mode. The validated method showed good linearity over a wide concentration range (r2 > 0.991), and lower limits of quantification (LLOQ) less than 1.1 ng/mL for all analytes, and matrix effects ranged from 85.2% to 106.8%. The mean extraction recoveries were no less than 86.4%, and the precision and accuracy were within the acceptable limits. All analytes were proven to be stable during sample storage and analysis procedures. The method validation results demonstrated that the proposed method was sensitive, specific, and reliable, which could lay a foundation for the pharmacokinetic study of eight analytes after oral administration of CCY and CF in subsequent studies.

A specific ultra-performance liquid chromatography tandem mass spectrometry method has been described for the simultaneous determination of caffeine, tolbutamide, metoprolol and dapsone in rat plasma, which are the four probe drugs of the four cytochrome P450 (CYP450) isoforms CYP1A2, CYP2C9, CYP2D6 and CYP3A4. The chromatographic separation was achieved using a Waters Acquity UPLC BEH HILIC C18 column (2.1 3 50 mm, 1.7 mm). The mobile phase consisted of acetonitrile and water (containing 0.1% formic acid) (15:85, v/v). The triple quadrupole mass spectrometric detection was operated by positive electrospray ionization. Phenacetin was chosen as internal standard. Plasma samples were extracted with dichloromethane – butanol (10:1, v/v). The recoveries ranged from 67.5% to 98.5%. The calibration curves in plasma were linear in the range of 2.5 –1,000 ng/mL for caffeine and dapsone, 5– 5,000 ng/mL for tolbutamide and 2.5 –250 ng/mLfor metoprolol, with correlation coefficient (r 2 ) of 0.9936, 0.9966, 0.9990 and 0.9998, respectively. The method was successfully applied to pharmacokinetic studies of the four probe drugs of the four CYP450 isoforms and used to evaluate the effects of breviscapine on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats.

A selective and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the determination of ziyuglycoside I (I), 3&beta, 19&alpha, dihydroxyurs-12-en-28-oic-acid 28-&beta, d-glucopyranosyl ester (II), 3&beta, [(&alpha, l-arabinopyranosyl) oxy]-urs-12,18(19)-dien-28-oic acid &beta, d-glucopyranosyl ester (III), rosamultin (IV), 1&beta, hydroxyeuscaphic acid (V) and alpinoside (VI) in rats after oral administration of Sanguisorba officinalis L. (S. officinalis) extract. The 3&beta, d-glucopyranosyl ester, 3&beta, d-glucopyranosyl ester, rosamultin, 1&beta, hydroxyeuscaphic acid and alpinoside in rat plasma were the first report in the pharmacokinetics study in the present study. The analytes were quantified using the multiple reaction monitoring (MRM) mode with the electrospray ion source in positive electrospray ionization. Plasma was extracted with ethyl acetate via liquid&ndash, liquid extraction. Bifendate was used as internal standard (IS). The current method was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery, matrix effect and stability. The lower limits of quantification of ziyuglycoside I, 3&beta, hydroxyeuscaphic acid and alpinoside were 6.1, 4.9, 1.3, 3.8, 1.5 and 5.7 ng/mL, respectively. Intra-day and inter-day precision and the accuracy of the assay were in range from &minus, 9.48 to 12.74%. The extraction recoveries of analytes and bifendate (IS) from rat plasma ranged from 77.17% to 92.48%. Six compounds could be rapidly absorbed into blood (Tmax, 0.58&ndash, 1.58 h), and then eliminated relatively slowly (t1/2, 6.86&ndash, 11.63 h). The pharmacokinetic results might contribute to further guide the clinical application of S. officinalis.

A sensitive, specific method has been developed for simultaneous determination of neoeriocitrin and naringin in rat plasma using liquid chromatography-tandem mass spectrometry. With hesperidin as the internal standard, plasma samples were prepared by protein precipitation with methanol. Analysis was carried out on an ACQUITY UPLC BEH C(18) column using acetonitrile-water (20:80, v/v) as the mobile phase. Detection was performed by means of electrospray ionization mass spectrometry in negative ion mode with multiple reaction monitoring. Linear calibration curves of neoeriocitrin and naringin were obtained over the concentration ranges of 15.0-960 ng/mL and 12.0-1200 ng/mL, respectively. The intra- and inter-day precisions were within 9.7% and 7.6% for neoeriocitrin and 7.8% and 12.9% for naringin. The accuracy was from -4.3% to 0.43% for neoeriocitrin and from -3.8% to 3.0% for naringin. The validated method was successfully applied to the pharmacokinetic study of neoeriocitrin and naringin in rats after oral administration of a Chinese compound formulation, gushudan.

Ethnopharmacological relevance Gentianella acuta (Michx.) Hulten belonging to the family of Gentianaceae is an annual plant mainly distributed in north of China, Mongolia plateau, Siberia and Far East areas of Russia. The whole herb was used as folk medicine to treat hepatitis, jaundice, headache and fever in Mongolia native medicine. Xanthones are the main active compounds of G. acuta and possess a lot of pharmacological and biological activities Aim of the study A selective and sensitive UHPLC–MS/MS method was developed and validated for the determination and pharmacokinetic study of swertianolin, norswertianolin, bellidifolin and demethylbellidifolin (DMB) in rat plasma after oral administration of G. acuta extract. Materials and methods Sample preparation involved a liquid–liquid extraction of the analytes with ethyl acetate. Butylparaben was employed as an internal standard. LC separation was achieved on an Agilent SB-C18 RRHD column (1.8 μm, 150 mm×2.1 mm) at 30 °C with an isocratic mobile phase consisting of acetonitrile–water (0.1% formic acid) (90:10, v/v ). The detection was accomplished by multiple-reaction monitoring (MRM) scanning with electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion-pairs ( m/z ) monitored for swertianolin, norswertianolin, bellidifolin, DMB and I.S. were 435.1/272.0, 420.8/258.9, 273.0/258.0, 258.9/214.9 and 193.0/92.0, respectively. Results The current UHPLC–MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability and was suitable for pharmacokinetic studies of the four xanthones after oral administration of G. acuta extract. The time to reach the maximum plasma concentration ( T max ) was 0.40±0.12 h for swertianolin, 0.27±0.07 h for norswertianolin, 1.00±0.18 h for bellidifolin and 0.94±0.15 h for demethylbellidifolin. The elimination half-time ( t 1/2 ) of swertianolin, norswertianolin, bellidifolin and DMB, was 19.7±9.64 h, 11.3±4.51 h, 19.9±8.11 h and 24.9±8.19 h, respectively. Conclusion This study described a simple, sensitive and validated UHPLC–MS/MS method for simultaneous determination of four xanthones in rat plasma after oral administration of G. acuta extract, and investigated on their pharmacokinetic studies as well.

Ethnopharmacological relevance Semen Cassiae, called Juemingzi in China, is the seed of the annual Cassia obtusifolia L., of the leguminosae family. It has been used as healthy drinks to alleviate constipation and improve eyesight for many years in China. Aim of the study A simple sensitive UHPLC–MS/MS method has been developed and validated for the simultaneous determination and pharmacokinetic study of chrysophanol, emodin, aloe-emodin, rhein, physcion, obtusifolin and aurantio-obtusin in rat plasma. Materials and methods Chromatographic separation was accomplished on a C 18 column with a 5 min gradient elution. A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source and operating in the negative ionization mode. The samples were prepared by LLE with ethyl acetate after being spiked with an internal standard (butylparaben). Results The current UHPLC–MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability. The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.9900. The lower limit of quantification (LLOQ) of each analyte was lower than 5 ng/mL. Intra-day and inter-day precisions were less than 14.99%. The relative errors of accuracies were in the range of −14.60% to 5.11%. The mean recoveries and matrix effects of anthraquinones were higher than 65.54% and 93.26%, respectively. After oral administration 1.25 g/kg of Semen Cassiae extract, the maximum plasma concentration ( C max) was 1189.25±333.40 ng/mL for chrysophanol, 38.48±3.15 ng/mL for emodin, 79.20±34.76 ng/mL for aloe-emodin, 152.70±23.91 ng/mL for rhein, 461.85±266.77 ng/mL for physcion, 243.59±22.71 ng/mL for obtusifolin and 1950.44±638.86 ng/mL for aurantio-obtusin, respectively. The time to reach the maximum plasma concentration ( T max ) was 0.333±0.071 h for chrysophanol, 0.333±0.059 h for emodin, 0.333±0.009 h for aloe-emodin, 0.333±0.09 h for rhein, 0.167±0.002 h for physcion, 0.5±0.074 h for obtusifolin and 0.333±0.06 h for aurantio-obtusin, respectively. Conclusion The proposed method was further applied to investigate the pharmacokinetics of seven anthraquinones after oral administration of Semen Cassia extract to rats.

To investigate the influence of scutellarin on the activities of CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 in rats in vivo.Scutellarin and saline were intravenously administered to male Wistar rats via the caudal vein for 7 days consecutively. On the 8th day, the rats were treated with probe drugs of caffeine (10 mg/kg), tolbutamide (10 mg/kg), metoprolol (20 mg/kg), dapsone (10 mg/kg) by intraperitoneal injection, and the blood samples were collected at different times. The probe drugs in the blood samples were measured by ultra performance liquid chromatography mass spectrometer (UPLC-MS/MS) and the changes of the pharmacokinetics parameters of the drugs were observed to evaluate the effects of scutellarin on the four CYP450 isoforms in rats.The activity of CYP1A2 in rats was inhibited significantly after treatment with scutellarin by increased caffeine t1/2 (21.76%, P0.05), T(max) (43.05%, P0.05), C(max) (43.92%, P0.01) and AUC(0-infinity) (50.88%, P0.01) in the scutellarin-treated group compared with those of the blank control. The activity of CYP2C11 in rats was inhibited significantly after treatment with scutellarin by increased tolbutamide t1/2 (16.74%, P0.01), T(max) (116.87%, P0.05), C(max) (63.78%, P0.01) and AUC(0-infinity) (70.61%, P0.01) in the scutellarin-treated group compared with those of the blank control. The activity of CYP3A1/2 in rats was inhibited significantly after treatment with scutellarin by increased dapsone t1/2 (45.28%, P0.05), T(max) (81.55%, P0.05), C(max) (155.58%, P0.01)and AUC(0-infinity) (176.35%, P0.01) in the scutellarin-treated group compared with those of the blank control. The pharmacokinetic parameters of metoprolol were not significantly changed in the scutellarin-treated group compared with those of the blank control.Scutellarin could significantly inhibit CYP1A2, CYP2C11 and CYP3A1/2 activities in rats in vivo, but had no effects on the activity of CYP2D1.

Chiisanogenin existing in many Acanthopanax species has been reported to possess anti-inflammatory, antibacterial and antiplatelet aggregatory activities.To develop and validate a rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry method for the determination of chiisanogenin in rat plasma and to investigate its pharmacokinetics after oral administration of chiisanogenin or the extract of Acanthopanax sessiliflorus fruits.The sample pretreatment involved a one-step extraction of 0.2 mL plasma with diethyl ether. Acetaminophen was used as the internal standard. The separation was carried out on an ACQUITY UPLC™ BEH C₁₈ column with a mobile phase of acetonitrile-5 mM ammonium acetate (90:10, v/v) at a flow rate of 0.2 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source.A high sample throughput was achieved with an analysis time of 1.1 min per sample. The calibration curve was linear (r² ≥ 0.99) over the concentration range of 5-500 ng/mL with a lower limit of quantification (LLOQ) of 5 ng/mL. The intra-day and inter-day precision (relative standard deviation, R.S.D.) values were below 11% and the accuracy (relative error, R.E.) was within 8% at all three quality control (QC) levels.The method was successfully applied to the pharmacokinetic study of chiisanogenin in rat after oral administration of chiisanogenin and the extract of Acanthopanax sessiliflorus fruits. Other constituents in the extract affected the pharmacokinetic behavior of chiisanogenin.

A method was developed for the quantitative determination of protocatechuic acid in rat plasma by high performance liquid chromatography (HPLC). With added p-hydroxybenzoic acid as internal standard, the plasma samples were extracted with a solvent mixture of methanol and acetonitrile ( 1: 5, v/v). The analyte was determined by HPLC with a Diamondsil C18 column and a mobile phase of acetonitrile-water (adjusted to pH 2.5 with H3PO4, 9: 91, v/v) at a flow rate of 1. 2 mL/min. The UV detection wavelength was 260 nm. The assay exhibited a good linearity in the concentration range from 0. 050 to 3. 20 mg/L with a correlation coefficient of 0. 997 8. The limit of quantification was 0. 050 mg/L. The relative standard deviations of intra-day and inter-day determination were both less than 7. 0% and the accuracy ranged from - 1. 4% to 2. 6%. The extraction recoveries of protocatechuic acid from rat plasma samples at three concentration levels were 83. 4%, 87. 3%, and 91. 1%, respectively. The developed method was applied to a pharmacokinetic study. The main pharmacokinetic parameters in rats after a single oral dose of 10 mL/kg body weight were as follows: Cmax of (3. 16 +0. 03) microg/mL, tmax of (0. 50 +/- 0. 00) h, AU0--t of (39. 9 +/- 5. 9) microg x mL(-1) x h, AUC--infinity of (54. 8 +/- 8. 1) microg x mL(-1) x h and t1/2 of (3. 87 +/- 0. 25) h. The method was proved to be simple, sensitive and accurate, thus suitable for the pharmacokinetic study of protocatechuic acid in rat plasma.