Shuming Li

Simultaneous determination of five phenolic components and paeoniflorin in rat plasma by liquid chromatography-tandem mass spectrometry and pharmacokinetic study after oral administration of Cerebralcare granule(®).

A simple, sensitive and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed for simultaneous determination and pharmacokinetic study of six active components, protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule(®) for the first time. The method involves a simple liquid-liquid extraction with ethyl acetate. The separation was performed on a Luna C18 column (2.0×100mm i.d., 3.0μm, particle, Phenomenex, USA) with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.2ml/min. Electrospray ionization (ESI) in negative ion mode and selective reaction monitoring (SRM) was used for the quantification of six active components and internal standard (IS, Chloroamphenicol). The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.9914. The lower limits of quantification (LLOQ) were 1.0ng/ml for protocatechuic acid, 1.0ng/ml for chlorogenic acid, 1.0ng/ml for caffeic acid, 5.0ng/ml for ferulic acid, 1.5ng/ml for rosmarinic acid and 6.0ng/ml for paeoniflorin, respectively. The intra- and inter-day precisions (R.S.D.%) were less than 6.60% and 11.68%, and accuracy (RE %) between -3.26% and 1.13% (n=6). The developed method was applied for the first time to the pharmacokinetic study of protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid, rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule(®).

Determination of ginsenoside Rc in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

Ginsenoside Rc (GRc) is a potential pharmacologically active ingredient isolated from ginseng (Panax ginseng C.A. Meyer, Araliaceae). A simple, rapid and sensitive method for determination of GRc in rat plasma was developed based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analyte and internal standard (IS), ginsenoside Rb(1) (GRb(1)), were extracted from plasma with n-butanol and chromatographied on a C(18) column eluted with a mobile phase of methanol and water containing 0.1% formic acid. The detection was performed by positive ion electrospray ionization in selective reaction monitoring mode (SRM), monitoring the transitions m/z 1101.6→789.3 and m/z 1131.7→364.7 for GRc and IS, respectively. The assay was linear over the concentration range of 5-5000 ng/mL with a limit of quantitation (LOQ) of 5 ng/mL. The accuracy was between 86.7% and 114.9%, and the precision was less than 9.7%. This method was successfully applied to investigate the pharmacokinetic study of GRc in rats after intravenous (2mg/kg) and oral (20mg/kg) administration, and the result showed that the ginsenoside was poorly absorbed with an absolute bioavailability being approximately 0.17%.

Simultaneous determination of caffeic acid and its major pharmacologically active metabolites in rat plasma by LC-MS/MS and its application in pharmacokinetic study.

A simple, sensitive and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination and pharmacokinetic study of caffeic acid (CA) and its active metabolites. The separation with isocratic elution used a mobile phase composed of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection of target compounds was done in selected reaction monitoring (SRM) mode. The SRM detection was operated in the negative electrospray ionization mode using the transitions m/z 179 ([M - H](-) ) → 135 for CA, m/z 193 ([M - H](-) ) → 134.8 for ferulic acid and isoferulic acid and m/z 153 ([M - H](-) ) → 108 for protocatechuic acid. The method was linear for all analytes over the investigated range with all correlation coefficients 0.9931. The lower limits of quantification were 5.0 ng/mL for analytes. The intra- and inter-day precisions (relative standard deviation) were <5.86 and <6.52%, and accuracy (relative error) was between -5.95 and 0.35% (n = 6). The developed method was applied to study the pharmacokinetics of CA and its major active metabolites in rat plasma after oral and intravenous administration of CA.

Identification of metabolites of Radix Paeoniae Alba extract in rat bile, plasma and urine by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC–Q-TOF/MS) was developed to identify the absorbed parent components and metabolites in rat bile, plasma and urine after oral administration of Radix Paeoniae Alba extract (RPAE). A total of 65 compounds were detected in rat bile, plasma and urine samples, including 11 parent compounds and 54 metabolites. The results indicated that glucuronidation, hydroxylation and methylation were the major metabolic pathways of the components of RPAE. Furthermore, the results of this work demonstrated that UPLC–Q-TOF/MS combined with MetaboLynx™ software and mass defect filtering (MDF) could provide unique high throughput capabilities for drug metabolism study, with excellent MS mass accuracy and enhanced MSE data acquisition. With the MSE technique, both precursor and fragment mass spectra can be simultaneously acquired by alternating between high and low collision energy during a single chromatographic run.

Simultaneous determination and pharmacokinetic study of four phenolic acids in rat plasma using UFLC–MS/MS after intravenous administration of salvianolic acid for injection

HIGHLIGHTSDevelopment of a sensitive and selective ultra‐fast liquid chromatography‐tandem mass spectrometry (UFLC–MS/MS) method.Application of UFLC–MS/MS for the determination of RA, sal D, LA and sal B in SAFI in rat plasma.The first pharmacokinetic study of salvianolic acid for injection (SAFI).Investigation of dose‐dependent pharmacokinetics of SAFI. ABSTRACT A simple, sensitive and selective ultra‐fast liquid chromatography‐tandem mass spectrometry (UFLC–MS/MS) method was established for simultaneous determination and pharmacokinetic study of rosmarinic acid (RA), salvianolic acid D (Sal D), lithospermic acid (LA) and salvianolic acid B (Sal B) in rat plasma after intravenous administration of salvianolic acid for injection (SAFI). Three doses of administration, containing 14, 28 and 56 mg/kg, were investigated in this study. Plasma samples were pretreated using protein precipitation (PP) with pre‐cooled acetonitrile. Chromatographic separation was achieved on a CORTECS™ UPLC C18 column (1.6 &mgr;m, 2.1 × 100 mm) with a mobile phase composed of 0.1% formic acid aqueous (V/V) and 0.1% formic acid acetonitrile (V/V). Analytes were detected using electrospray ionization (ESI) source in negative ionization mode and quantified in multiple reaction monitoring (MRM) mode. The validated method is stable and reliable. No significant difference of half lives (t1/2) of four analytes at three doses was observed. Area under the curve (AUC0‐∞) and peak concentration (Cmax) of the four analytes demonstrated a linear increase in across the doses with the linear correlation r of each analyte at three doses were greater than 0.95. It indicated that the pharmacokinetic behavior of SAFI is positively related to dose at the range of 14–56 mg/kg.

UFLC–MS/MS determination and pharmacokinetic studies of six Saikosaponins in rat plasma after oral administration of Bupleurum Dropping Pills

A rapid and sensitive ultra fast liquid chromatography tandem mass spectrometry method (UFLC-MS/MS) was developed and validated for the simultaneous determination of six Saikosaponins (SSs) (SSa, SSb1, SSb2, SSd, SSc, SSf) of Bupleurum Dropping Pills (BDP) in rat plasma using chloramphenicol as the internal standard (IS). The SSs were separated using an ACQUITY UPLC(®) BEH C18 column (50 mm × 2.1mm, 1.7 μm) and detection of these compounds were done by using a Qtrap 5500 mass spectrometer coupled with negative electrospray ionization (ESI) source under the multiple reaction monitoring (MRM) mode. According to regulatory guidelines, the established method was fully validated and results were showed within acceptable limits. The lower limit of quantifications (LLOQs) of all analytes were 0.2 ng/mL. The validated method was successfully applied into a pharmacokinetic study of orally administered BDP in rats.

Salvianolic acids T and U: a pair of atropisomeric trimeric caffeic acids derivatives from root of Salvia miltiorrhiza.

Two new trimeric caffeic acids, named salvianolic acids T and U (1 and 2), were isolated from the underground part of Salvia miltiorrhiza. Their structures, consisting of three caffeic acid units, were determined based on extensive 1D- and 2D-spectroscopic analyses and electronic circular dichroism (ECD) calculations.

Simultaneous Determination and Pharmacokinetic Study of Protocatechuic Aldehyde and Its Major Active Metabolite Protocatechuic Acid in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry.

A very simple and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS-MS) method was developed for simultaneous determination and pharmacokinetic study of protocatechuic aldehyde (PAL) and its active metabolite protocatechuic acid (PCA). The method involves a simple liquid-liquid extraction with ethyl acetate. The separation was performed on a Hypersil GOLD C18 column (2.1 × 150 mm, 3.0 µm; particle, Thermo, USA) with isocratic elution using a mobile phase consisted of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection of target compounds was done by using low-energy collision dissociation tandem mass spectrometry (CID-MS-MS) using the selective reaction monitoring scan mode. The method was linear for all analytes over the investigated range for all correlation coefficients greater than 0.9950. The lower limits of quantification were 2.0 ng/mL for PAL and PCA. The intra- and interday precisions (relative standard deviation, RSD %) were <6.84 and 5.54%, and the accuracy (relative error, RE %) was between -2.85 and 0.74% (n = 6). The developed method was applied to study the pharmacokinetics of PAL and its major active metabolite PCA in rat plasma after oral and intravenous administration of PAL.

Comparison of the effectiveness of whole-brain radiotherapy plus temozolomide versus whole-brain radiotherapy in treating brain metastases based on a systematic review of randomized controlled trials.

Temozolomide (TMZ) combination with whole-brain radiotherapy (WBRT) has been tested by many randomized controlled trials in the treatment of brain metastases (BMs) in China and other countries. We performed an up-to-date meta-analysis to determine (i) the log odds ratios (LORs) of objective response (ORR) and adverse effects (AEs) for all-grade, and (ii) the T value of mean overall survival in patients with BMs treated with WBRT combined with TMZ versus WBRT alone. PubMed, Chinese National Knowledge Infrastructure, and WanFang Data were searched for articles published up to 28 January 2015. Eligible studies were selected according to the PRISMA statement. ORR, AEs, and 95% confidence intervals were calculated using random-effects models. Eighteen studies were included in our analysis. A total of 1028 participants were enrolled. Summary LORs of ORR were 1.0239 (P<0.0001) on comparing WBRT plus TMZ with WBRT ORR (n=17). The overall mean difference of mean overall survival (n=17) between TMZ plus WBRT and WBRT was 2.2505 weeks (P=0.02185). There was a significant difference between WBRT plus TMZ and WBRT alone with a LOR of AEs for all-grade of (i) 0.923 for gastrointestinal toxicity and (ii) 0.7978 for myelosuppression. Sensitivity analysis and subgroup analysis were also performed. The 18 eligible randomized controlled trials demonstrated that the combination of WBRT and TMZ significantly improves the ORR and is statistically insignificant in prolonging the survival of patients with BMs. In addition, an increase in the incidence of gastrointestinal toxicity and myelosuppression was significant for all-grade.

Identification of a major metabolite of danshensu in rat urine and simultaneous determination of danshensu and its metabolite in plasma: application to a pharmacokinetic study in rats

Danshensu, as the effective component of Salvia miltiorrhiza (Danshen), has been widely used in clinical studies for treatment of cardiovascular diseases in China. A new metabolite, 4-hydroxy-3-methoxyphenyllactic acid was isolated from the urine of rats, and its chemical structure was identified by ultraviolet (UV), Infrared Spectroscopy (IR), mass spectrometry (MS) and nuclear magnetic resonance (NMR). Furthermore, a selective and sensitive high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the simultaneous quantification of danshensu and its major metabolite, 4-hydroxy-3-methoxyphenyllactic acid, in rat plasma after oral and intravenous administration of danshensu. The separation was performed on a Hypersil Gold C18 column (150 × 2.1 mm i.d., 3.0 µm, Thermo, San jose CA, USA) with gradient elution using a mobile phase composed of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. Linear detection responses were obtained for danshensu and 4-hydroxy-3-methoxyphenyllactic acid ranging from 5 to 10000 ng/mL and 5 to 4000 ng/mL, respectively. The lower limits of quantification (LLOQs) for the two compounds were both 5 ng/mL. The intra-and inter-day precision (R.S.D %) were within 5.61% for the two analytes. The average recoveries of the analytes were greater than 72.43%. The method was proved to be stable during all sample storage, preparation and analytic procedures. This method was successfully applied to the pharmacokinetic studies of danshensu and 4-hydroxy-3-methoxyphenyllactic acid after oral and intravenous administration of danshensu in rats.