Congcong Wen

Brain metabolomics in rats after administration of ketamine

In this study, we developed a brain metabolomic method, based on gas chromatography-mass spectrometry (GC/MS), to evaluate the effect of ketamine on rats. Pattern recognition analysis, including both principal component analysis and partial least squares-discriminate analysis revealed that ketamine induced metabolic perturbations. Compared with the control group, the levels of glycerol, uridine, cholesterol in rat brain of the ketamine group (50 mg/kg, 14 days) decreased, while the urea levels increased. Our results indicate that metabolomic methods based on GC/MS may be useful to elucidate ketamine abuse through the exploration of biomarkers.

Determination of CUDC-101 in rat plasma by liquid chromatography mass spectrometry and its application to a pharmacokinetic study.

CUDC-101 is a multi-targeted, small-molecule inhibitor of histone deacetylase (HDAC), epidermal growth factor receptor tyrosine kinase (EGFR/ErbB1), and human epidermal growth factor receptor 2 tyrosine kinase (HER2/neu or ErbB2) with potential antineoplastic activity. A sensitive and selective liquid chromatography mass spectrometry method for determination of CUDC-101 in rat plasma was developed. After addition of carbamazepine as internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm × 150 mm, 5 μm) column with acetonitrile-0.1% formic acid in water as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; selective ion monitoring (SIM) mode was used for quantification using target fragment ions m/z 435 for CUDC-101 and m/z 237 for the IS. Calibration plots were linear over the range of 5-2000 ng/mL for CUDC-101 in rat plasma. Mean recoveries of CUDC-101 in rat plasma were in the range of 84.0-90.5%. RSD of intra-day and inter-day precision were both <14%. The method was successfully applied to pharmacokinetic study of CUDC-101 after intravenous administration of single dosage 5 mg/kg in rats.

Determination of chidamide in rat plasma by LC‐MS and its application to pharmacokinetics study

A sensitive and selective liquid chromatography mass spectrometry method for determination of chidamide in rat plasma was developed. After addition of linezolid as internal standard, protein precipitation by acetonitrile-methanol (9:1, v/v) was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 × 150 mm, 5 µm) column with acetonitrile-0.1% formic acid as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; selective ion monitoring mode was used for quantification using target fragment ions m/z 391.5 for chidamide and m/z 338.5 for the IS. Calibration plots were linear over the range of 10-2000 ng/mL for chidamide in rat plasma. The lower limit of quantification for chidamide was 10 ng/mL. The mean recovery of chidamide in plasma was in the range of 86.6-92.1%. The coefficients of variation of intra-day and inter-day precision were both <12%. This method is simple and sensitive and was applied successfully in a pharmacokinetic study of chidamide to rats.

Metabolic changes in rat urine after acute paraquat poisoning and discriminated by support vector machine

Paraquat is quick-acting and non-selective, killing green plant tissue on contact; it is also toxic to human beings and animals. In this study, we developed a urine metabonomic method by gas chromatography-mass spectrometry to evaluate the effect of acute paraquat poisoning on rats. Pattern recognition analysis, including both partial least squares discriminate analysis and principal component analysis revealed that acute paraquat poisoning induced metabolic perturbations. Compared with the control group, the levels of benzeneacetic acid and hexadecanoic acid of the acute paraquat poisoning group (intragastric administration 36 mg/kg) increased, while the levels of butanedioic acid, pentanedioic acid, altronic acid decreased. Based on these urinary metabolomics data, support vector machine was applied to discriminate the metabolomic change of paraquat groups from the control group, which achieved 100% classification accuracy. In conclusion, metabonomic method combined with support vector machine can be used as a useful diagnostic tool in paraquat-poisoned rats.

Validated UPLC-MS/MS method for determination of hordenine in rat plasma and its application to pharmacokinetic study.

Hordenine is an active compound found in several foods, herbs and beer. In this work, a sensitive and selective UPLC-MS/MS method for determination of hordenine in rat plasma was developed. After addition of caulophylline as internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used as sample preparation. Chromatographic separation was achieved on a UPLC BEH HILIC (2.1 mm × 100 mm, 1.7 μm) with acetonitrile (containing 10mM ammonium formate) and water (containing 0.1% formic acid and 10 mM ammonium formate) as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used for quantification using target fragment ions m/z 166.1 → 121.0 for hordenine and m/z 205.1 → 58.0 for IS. Calibration plots were linear over the range of 2-2000 ng/mL for hordenine in rat plasma. Mean recoveries of hordenine in rat plasma were in the range of 80.4-87.3%. RSD of intra-day and inter-day precision were both <8%. The accuracy of the method ranged from 97.0% to 107.7%. The method was successfully applied to pharmacokinetic study of hordenine after oral and intravenous administration.

Pharmacokinetics and tissue distribution model of cabozantinib in rat determined by UPLC-MS/MS

Cabozantinib (XL184) is a novel small molecule inhibitor of receptor tyrosine kinases (RTKs) targeted at mesenchymal-epithelial transition factor (MET). In order to study the pharmacokinetics and tissue distribution in rat, a specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed with midazolam as internal standard. The calibration curves in plasma and tissues were linear in the range of 5-5000ng/mL (r(2)>0.99). The recoveries were better than 80.4% and matrix effects ranged from 96.9% to 105.1%. Then, the developed UPLC-MS/MS method was applied to determine the concentration of XL184 in blood and tissues. The pharmacokinetics of four different dosages (iv 5, 10mg/kg and ig 15, 30mg/kg) revealed that XL184 was eliminated slowly, the t1/2 was longer than 10h and the absolute bioavailability was 25.6±8.3%. The concentration distribution of XL184 in tissues was liver>lung>kidney>spleen>heart. Based on the concentration-time of XL184 in tissues, a BP-ANN distribution model was developed with good performance, and can be used to predict the concentration of XL184 in tissues.

Urine metabolomics in rats after administration of ketamine

In this study, we developed a urine metabonomic method, based on gas chromatography–mass spectrometry (GC-MS), to evaluate the effect of ketamine on rats. Pattern recognition analysis, including both principal component analysis and partial least squares discriminate analysis revealed that ketamine (50 mg/kg) induced metabolic perturbations. Compared with the control group, at day 7, the level of alanine, butanoic acid, glutamine, butanedioic, trimethylsiloxy, L-aspartic acid, D-glucose, cholesterol, acetamide, and oleic acid of the ketamine group was increased, while the level of 2,3,4-trihydroxybutyric acid, benzeneacetic acid, threitol, ribitol, xylitol, and glycine decreased. At day 14, the level of alanine, ethanedioic acid, L-proline, glycerol, tetradecanoic acid, l-serine, l-phenylalanine, L-aspartic acid, d-glucose, cholesterol, heptadecanoic acid, and acetamide in rat urine of the ketamine group was increased, while the 2,3,4-trihydroxybutyric acid, benzeneacetic acid, d-ribose, threitol, ribitol, glycine, pyrazine, and oleic acid levels decreased. Our results indicate that metabonomic methods based on GC-MS may be useful to elucidate ketamine abuse, through the exploration of biomarkers.

Pharmacokinetic study of dendrobine in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry.

Dendrobine, considered as the major active alkaloid compound, has been used for the quality control and discrimination of Dendrobium which is documented in the Chinese Pharmacopoeia. In this work, a sensitive and simple ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for determination of dendrobine in rat plasma is developed. After addition of caulophyline as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 (2.1 ×100 mm, 1.7 µm) column with acetonitrile and 0.1% formic acid as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring mode was used for quantification using target fragment ions m/z 264.2 → 70.0 for dendrobine and m/z 205.1 → 58.0 for IS. Calibration plots were linear throughout the range 2-1000 ng/mL for dendrobine in rat plasma. The RSDs of intra-day and inter-day precision were both <13%. The accuracy of the method was between 95.4 and 103.9%. The method was successfully applied to pharmacokinetic study of dendrobine after intravenous administration. Copyright

Determination of N-methylcytisine in rat plasma by UPLC-MS/MS and its application to pharmacokinetic study.

In this work, a sensitive and selective UPLC-MS/MS method for determination of N-methylcytisine in rat plasma is developed. After addition of hordenine as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH HILIC (2.1 mm×100mm, 1.7μm) with acetonitrile (containing 10mM ammonium formate) and water (containing 0.1% formic acid and 10mM ammonium formate) as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used for quantification using target fragment ions m/z 205.1→58.0 for N-methylcytisine, and m/z 166.1→121.0 for IS. Calibration plots were linear throughout the range 2-2000ng/mL for N-methylcytisine in rat plasma. Mean recoveries of N-methylcytisine in rat plasma ranged from 86.1% to 94.8%. RSD of intra-day and inter-day precision were both<13%. The accuracy of the method was between 94.5% and 109.4%. The method was successfully applied to pharmacokinetic study of N-methylcytisine after either oral or intravenous administration. For the first time, the absolute bioavailability of N-methylcytisine was reported as high as 55.5%.

Serum Metabolomics in Rats after Acute Paraquat Poisoning

Paraquat is one of the most widely used herbicides in the world and is highly toxic to humans and animals. In this study, we developed a serum metabolomic method based on GC/MS to evaluate the effects of acute paraquat poisoning on rats. Pattern recognition analysis, including both principal component analysis and partial least squares-discriminate analysis revealed that acute paraquat poisoning induced metabolic perturbations. Compared with the control group, the level of octadecanoic acid, L-serine, L-threonine, L-valine, and glycerol in the acute paraquat poisoning group (36 mg/kg) increased, while the levels of hexadecanoic acid, D-galactose, and decanoic acid decreased. These findings provide an overview of systematic responses to paraquat exposure and metabolomic insight into the toxicological mechanism of paraquat. Our results indicate that metabolomic methods based on GC/MS may be useful to elucidate the mechanism of acute paraquat poisoning through the exploration of biomarkers.