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Abstract A sensitive and robust LC-MS/MS method has been developed and validated to simultaneous determine the concentrations of tumulosic acid, dehydrotumulosic acid, polyporenic acid C, cinnamic acid, Atractylenolide I, Atractylenolide II, Atractylenolide III, glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin and isoliquiritin in plasma from rats who received Ling-Gui-Zhu-Gan Decoction extract oral administration. The samples were prepared by a liquid-liquid extraction procedure using ethyl ether as the extraction solvent and schisandrin as the internal standard. Chromatographic separation was achieved using a Thermo Hypersil GOLD C 18 column (2.1 mm × 100 mm, 1.9 µm) and a gradient mobile phase consisting of acetonitrile-water with 0.1% formic acid. All of the analytes were quantified using negative and positive multiple reaction monitoring mode. The method was validated for selectivity, linearity, accuracy, precision, recovery, matrix effect and sample stability under various storage conditions, whose values are all fell in the acceptable limits. We report the lowest limit of quantification for tumulosic acid, dehydrotumulosic acid and polyporenic acid C as 2 ng/mL. This is the first study for simultaneous determination of so many analytes in rat plasma after oral administration of Ling-Gui-Zhu-Gan Decoction. This validated method was successfully used to study the pharmacokinetics of multiple compounds in rat plasma after oral administration of Ling-Gui-Zhu-Gan Decoction. Graphical abstract fx1 Highlights • Simultaneous determination of eleven compounds in rat plasma by UPLC-MS/MS. • The pharmacokinetic study of LGZGD is reported. • The lowest limit of quantification for tumulosic acid, dehydrotumulosic acid and polyporenic acid C as 2 ng/mL. • Rapid, sensitive, selective and accurate. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare intestinal permeability between enantiomers of 2-(2-hydroxypropanamido) benzoic acid (( R) -/( S) -HPABA), a marine-derived antiinflammatory drug, using an in situ single-pass intestinal perfusion (SPIP) model in rats. Concentrations, isolated regions of small intestine, and p-glycoprotein (P-gp) inhibitor were performed to investigate their influences on the intestinal absorption of ( R) -/( S) -HPABA. In addition, a molecular docking method was performed to illustrate our prediction. The absorption rate coefficients ( K a) and permeability values ( P eff) of ( R) -/( S) -HPABA were calculated. The permeability of ( S)-HPABA was significantly ( P < 0.01) higher than that of ( R)-HPABA in jejunum, and ileum permeability of ( R) -/( S) -HPABA appeared best in ileum; the investigated concentrations ranged from 20 to 80 μg/mL, K a and P eff values of ( R) -/( S) -HPABA increased linearly; in the presence of P-gp inhibitor (verapamil), P eff values of two enantiomers were increased significantly; and the effect of P-gp on absorption of ( R)-HPABA is stronger than that of ( S)-HPABA in ileum segment. Based on these results, carrier-mediated transport or passive transport combined with carrier-mediated transport seems to be the mechanism for intestinal absorption of ( R) -/( S) -HPABA, and ( R) -/( S) -HPABA may be recognized as the P-gp substrate. In addition, the intestinal permeability of ( S)-HPABA is higher than that of ( R)-HPABA. [ABSTRACT FROM AUTHOR]

Dictamnine, a furoquinoline alkaloid isolated from the root bark of Dictamnus dasycarpus Turcz. (Rutaceae), is reported to have a wide range of pharmacological activities. In this study, the in vitro metabolic profiles of dictamnine in mouse, rat, dog, monkey, and human liver microsomes were investigated and compared. Dictamnine was incubated with liver microsomes in the presence of an NADPH-regenerating system, resulting in the formation of eight metabolites (M1–M8). M1 is an O -desmethyl metabolite. M5 and M6 are formed by a mono-hydroxylation of the benzene ring of dictamnine. M8 was tentatively identified as an N -oxide metabolite. The predominant metabolic pathway of dictamnine occurs through the epoxidation of the 2,3-olefinic to yield a 2,3-epoxide metabolite (M7), followed by the ring of the epoxide opening to give M4. Likewise, cleavage of the furan ring forms M2 and M3. Slight differences were observed in the in vitro metabolic profiles of dictamnine among the five species tested. A chemical inhibition study with a broad and five specific CYP450 inhibitors revealed that most of the dictamnine metabolites in liver microsomes are mediated by CYP450, with CYP3A4 as the predominant enzyme involved in the formation of M7, the major metabolite. These findings provide vital information to better understand the metabolic processes of dictamnine among various species. [ABSTRACT FROM AUTHOR]

Highlights: [•] Simultaneous determination of puerarin glucuronide, puerarin and daidzin in rat plasma. [•] An UPLC–MS/MS method was developed and applied for pharmacokinetic study. [•] Comparative pharmacokinetics was performed in rats under different physiological states. [•] Blood stasis syndrome had effect on pharmacokinetics of puerarin glucuronide, puerarin and daidzin. [•] Pharmacokinetics of the three constituents changed when Gegen was used in combination with Sanqi. [Copyright &y& Elsevier]

TM-2 (13-( N-Boc-3- i-butylisoserinoyl-4,10-β-diacetoxy-2-α-benzoyloxy-5-β-20-epoxy-1,13-α-dihydroxy-9-oxo-19-norcyclopropa[g]tax-11-ene) is a novel semisynthetic taxane derivative. Our previous study suggested that TM-2 is a promising antitumor analogue. In this paper, the metabolism of TM-2 was investigated in rats following intravenous administration. Two different types of mass spectrometry-hybrid linear trap quadrupole orbitrap (LTQ-Orbitrap) mass spectrometry and triple-quadrupole tandem (QQQ) mass spectrometry-were employed to acquire structural information of TM-2 metabolites. A total of 17 components were identified as the metabolites of TM-2 in bile, feces, and urine samples. Accurate mass measurement using LC-LTQ-Orbitrap-MS was used to determine the accurate mass data and elemental composition of metabolites thereby confirming the proposed structures of the metabolites. The metabolites proposed were mainly oxidates of TM-2, including methoxy, hydroxyl, dihydroxy, and trihydroxyl analogues. The major metabolic pathway of TM-2 was the hydroxylation of the taxane ring or the lateral chain. These important metabolic data serve as a useful resource to support further research of TM-2. [ABSTRACT FROM AUTHOR]

Abstract A selective, sensitive and fully validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of dihydromyricetin, dihydroquercetin, myricetin and quercetin in rat plasma after intragastric administration of Hoveniae Semen total flavonoids. Baicalin was selected as the internal standard. Analytes were extracted from the rat plasma by protein precipitation with acetonitrile and separated on a C18 chromatographic column (Agilent ZORBAX Eclipse Plus, 4.6 mm × 100 mm, 3.5 μm) using the mobile phase containing acetonitrile (A) and 0.1% formic acid-water (B) by gradient elution at 0.5 mL/min flow rate. A tandem mass spectrometer equipped with an electrospray ionization (ESI) source was used to detect analytes. The analytes were measured by multiple reaction monitoring (MRM) in the negative ionization mode. The lower limit of quantification of dihydromyricetin, dihydroquercetin, myricetin and quercetin were 0.70, 8.16, 1.62 and 0.56 ng/mL, respectively. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and the compounds were stable in rat plasma under all tested conditions. The approach was successfully applied to study pharmacokinetic characteristics of the four bioactive flavonoids in plasma after administering Hoveniae Semen total flavonoids intragastrically to rat. Further investigation was carried out to assess pharmacokinetic comparability of the four bioactive flavonoids after intragastric administration of Hoveniae Semen total flavonoids to mixture of flavonoids. Highlights • Pharmacokinetics of 4 main flavonoids in Hoveniae Semen were determined. • Only 6.5 min was in need for one analytical run. • The pharmacokinetic of Hoveniae Semen was firstly studied. • Comparative pharmacokinetics of Hoveniae Semen total flavonoids and a mixture of flavonoids were firstly investigated. [ABSTRACT FROM AUTHOR]

Abstracts 2-(2-Hydroxypropanamido) benzoic acid (HPABA) is a potential anti-inflammatory agent isolated from the marine fungus Penicillium chrysogenum . In vivo tissue distribution and excretion of HPABA were unknown. Therefore, the purpose of this paper was to establish an UHPLC–MS/MS method for the determination of HPABA and proceed to apply for the study of tissue distribution and excretion in rats. The results obtained indicated that HPABA in tissues was rapidly distributed and cleared. The highest level was found in intestine and stomach, followed by kidney, liver, lung and heart. These observations showed that HPABA was well distributed into abundant blood-supply tissues, suggesting that the blood flow or perfusion rate of organs plays a major role. A small amount of HPABA was detected in brain indicated that the ability of it in crossing the blood brain barrier (BBB) was very weak in rats. Excretion studies demonstrated that HPABA was mainly excreted by kidney. The total cumulative excretion of HPABA were 54.3% and 44.1% in male and female rats, respectively. In addition, gender-related differences in the excretion and distribution profile of HPABA were observed in rats. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) method was developed and fully validated for simultaneous determination of puerarin, 3′-hydroxy puerarin, 6″- O -xylosyl puerarin, 3′-methoxy puerarin, mirificin, puerarin-7- O -glucoside, daidzin, daidzein, daidzein-7- O -glucoside, ginsenoside-Rd, notoginsenoside-R1, ginsenoside-Re, ginsenoside-Rg1, ginsenoside-Rb1 in rat plasma after intravenous injection of 5 mL/kg Gegen-Sanqi compatibility solution (containing Pueraria flavonid 10.8 mg/mL and Panax notoginsenosidum 5.4 mg/mL). After addition of internal standard (IS) baicalin, the analytes and IS were recovered from rat plasma by protein precipitation using acetonitrile containing 0.1% formic acid. Chromatographic separation was performed on a Capcell pak MG C18 column (3.0 mm × 75 mm, 3.0 μm) at 35 °C with a flow rate of 0.75 mL/min. Mass spectrometry was conducted using multiple reaction monitoring in positive mode. The method was linear for all of the analytes over 1000 times concentration range with correlation coefficients greater than 0.99. The precision and accuracy of the LC–MS/MS assay based on the three analytical quality control (QC) levels were well within the acceptance criteria from FDA guidance for bioanalytical method validation. Method recoveries were higher than 75% and the matrix effects were minimal. All analytes were stable under tested conditions. It was the first time to study the pharmacokinetics of daidzein-7- O -glucoside in rat plasma. To the best of our knowledge, this is the first study for simultaneous determination of so many analytes in rat plasma after intravenous injection of Gegen-Sanqi compatibility solution. It was expected that the present work would provide some helpful references for the apprehension of the mechanism of action and further clinical efficacy studies of Gegen-Sanqi herb-pair. [ABSTRACT FROM AUTHOR]

In Hedera helix hederacoside C, hederacoside D, and ɑ-hederin are three major bioactive saponins and play pivotal roles in the overall biological activity. In this study, a specific and sensitive ultra-high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the quantification of three major bioactive saponins in rat plasma. Chromatographic separation was performed on a reversed-phase Thermo Hypersil GOLD C18 column (2.1 mm × 50 mm, 1.9 μm) using a gradient mobile phase system of acetonitrile-water containing 0.1% formic acid. The assay was successfully applied to study the pharmacokinetic behavior of the three analytes in rats after oral and intravenous administration of a mixture of saponins (hederacoside C, hederacoside D, and ɑ-hederin). Further research was performed to compare the pharmacokinetic behavior of the three analytes after the oral administration of a mixture of saponins and an extract of saponins from Hedera helix, and results showed that double peaks were evident on concentration-time profile for each of the three saponins. The difference in the pharmacokinetic characteristics of three saponins between a mixture of saponins and an extract of saponins from Hedera helix was found in rat, which would be beneficial for the preclinical research and clinical use of Hedera helix. [ABSTRACT FROM AUTHOR]

A simple and rapid ultra high performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) method was developed for the simultaneous determination of Atractylenolide I, II and III in rat plasma. Plasma samples were processed by liquid–liquid extraction with ethyl acetate, using schisandrin as internal standard (IS). Chromatographic separation was accomplished on a Thermo Hypersil GOLD C 18 column (2.1 mm × 50 mm, 1.9 μm) with mobile phase consisting of acetonitrile and 0.1% formic acid–water (50:50, v/v ). The detection was carried out by ESI-MS (positive ionization mode) and low-energy collision dissociation tandem mass spectrometric analyses using the multiple-reaction monitoring (MRM) scan mode. The quantification was performed using the transitions of the protonated molecule → product ion at m / z 231.0 → 185.1 for Atractylenolide I, at m / z 233.1 → 187.1 for Atractylenolide II and at m / z 249.1 → 231.1 for Atractylenolide III, respectively. Method validation revealed excellent linearity over investigated range together with satisfactory intra- and inter-day precision, accuracy, matrix effects and extraction recoveries. This method was successfully applied to the comparative pharmacokinetic study of Atractylenolide I, II and III in rat plasma after intragastric administration of Baizhufuling extract and Atractylodis extract. [ABSTRACT FROM AUTHOR]

An ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) method was developed to investigate the in vivo metabolism of 2-(2-hydroxypropanamido) benzoic acid (HPABA), a marine-derived anti-inflammatory drug, for the first time. Plasma, urine, feces and bile samples were collected from male and female rats after a single intragastric administration of HPABA at a dose of 100 mg/kg. Besides the parent drug, a total of 13 metabolites (3 phase I and 10 phase II metabolites) were detected and tentatively identified through comparing their mass spectrometry profiles with those of HPABA. Results demonstrated that metabolic pathways of HPABA in rats included decarboxylation, hydroxylation, dehydrogenation, glucuronidation, glycine conjugation and N-acetyl conjugation. In summary, this work provided valuable information regarding the metabolism of HPABA in rats, which would contribute to better understanding of its safety and mechanism of action. [ABSTRACT FROM AUTHOR]

Highlights: [•] The report describes the validation of a high precision and accuracy UPLC–MS/MS method for the simultaneous determination of limonin, dictamnine, obacunone and fraxinellone in rat plasma. [•] The pharmacokinetic study of Cortex Dictamni in rats is firstly reported. [•] Extraction performed with a simple liquid–liquid extraction. [•] Sensitivity, specificity and high throughput. [Copyright &y& Elsevier]