A method for the pretreatment and qualitative detection of 26 trace cathinone new psychoactive substances in wastewater was established and applied in actual wastewater cases. The effluent samples were eluted on the Oasis PRiME HLB solid phase extraction column by ultra-pure water drenching and methanol solution, then dried with nitrogen at 40 ℃, and finally re-dissolved with 0.1% formic acid-acetonitrile solution (95∶5), and detected by liquid chromatography-tandem mass spectrometry, The effluent sample was determined by high-performance liquid chromatography-Tandem mass spectrometry (HPLC-MS/MS) using selected reaction monitoring (SRM) mode and separated on chromatographic column UPLC BEH C18(100 mm×2.1 mm, 1.7 μm） at 35 ℃ with a mobile phase consisting of acetonitrile-0.1% formic acid in aqueous solution gradient elution. After methodological validation, the lower quantification of 26 cathinone new psychoactive substances could reach 1.50−3.00 ng/L. Among these, 21 analytes fell within the concentration range of 1.50−375.0 ng/L, while 5 were detected in the range of 3.00−750.0 ng/L, the correlation coefficient was 0.99, within-and between-batch precision was less than 7.71% and 13.91%, respectively, and the extraction recoveries were higher than 92.64% . The method is simple, accurate, and sensitive, and can be used for cathinone detection and abuse monitoring.

Type 2 diabetes (T2D) is often accompanied with an induction of retinaldehyde dehydrogenase 1 (RALDH1 or ALDH1A1) expression and a consequent decrease in hepatic retinaldehyde (Rald) levels. However, the role of hepatic Rald deficiency in T2D progression remains unclear. In this study, we demonstrated that reversing T2D-mediated hepatic Rald deficiency by Rald or citral treatments, or liver-specific Raldh1 silencing substantially lowered fasting glycemia levels, inhibited hepatic glucogenesis, and downregulated phosphoenolpyruvate carboxykinase 1 (PCK1) and glucose-6-phosphatase (G6PC) expression in diabetic db/db mice. Fasting glycemia and Pck1/G6pc mRNA expression levels were strongly negatively correlated with hepatic Rald levels, indicating the involvement of hepatic Rald depletion in T2D deterioration. A similar result that liver-specific Raldh1 silencing improved glucose metabolism was also observed in high-fat diet-fed mice. In primary human hepatocytes and oleic acid-treated HepG2 cells, Rald or Rald + RALDH1 silencing resulted in decreased glucose production and downregulated PCK1/G6PC mRNA and protein expression. Mechanistically, Rald downregulated direct repeat 1-mediated PCK1 and G6PC expression by antagonizing retinoid X receptor α, as confirmed by luciferase reporter assays and molecular docking. These results highlight the link between hepatic Rald deficiency, glucose dyshomeostasis, and the progression of T2D, whilst also suggesting RALDH1 as a potential therapeutic target for T2D.

Body is equipped with organic cation transporters (OCTs). These OCTs mediate drug transport and are also involved in some disease process. We aimed to investigate whether liver failure alters intestinal, hepatic and renal Oct expressions using bile duct ligation (BDL) rats. Pharmacokinetic analysis demonstrates that BDL decreases plasma metformin exposure, associated with decreased intestinal absorption and increased urinary excretion. Western blot shows that BDL significantly downregulates intestinal Oct2 and hepatic Oct1 but upregulates renal and hepatic Oct2. In vitro cell experiments show that chenodeoxycholic acid (CDCA), bilirubin and farnesoid X receptor (FXR) agonist GW4064 increase OCT2/Oct2 but decrease OCT1/Oct1, which are remarkably attenuated by glycine-β-muricholic acid and silencing FXR. Significantly lowered intestinal CDCA and increased plasma bilirubin levels contribute to different Octs regulation by BDL, which are confirmed using CDCA-treated and bilirubin-treated rats. A disease-based physiologically based pharmacokinetic model characterizing intestinal, hepatic and renal Octs was successfully developed to predict metformin pharmacokinetics in rats. In conclusion, BDL remarkably downregulates expressions of intestinal Oct2 and hepatic Oct1 protein while upregulates expressions of renal and hepatic Oct2 protein in rats, finally, decreasing plasma exposure and impairing hypoglycemic effects of metformin. BDL differently regulates Oct expressions via Fxr activation by CDCA and bilirubin.

In this paper, chemical derivatization-high performance liquid chromatography was used to determine the potential genotoxic impurities chloroacetyl chloride and chloroacetic acid, respectively, in the raw material of azintamide.Derivatization was carried out using 2-nitrophenylhydrazine followed by the determination.Separation was performed on a Thermo Syncronis C18 column (250 mm × 4.6 mm, 5 μm), with mobile phase consisting of 0.1% phosphoric acid in water (A) and acetonitrile(B) by gradient elution, at a flow rate of 1 mL/min.The column temperature was 40 °C and the detection wavelength was 226 nm.The blank solvent, derivatization reagent, and azintamide did not interfere with the peak of the test substance, and the target component was well separated from the others.For impurities chloroacetyl chloride and chloroacetic acid, the limits of detection (LOD) were 7.5 ng/mL and 15 ng/mL respectively. There was a good linear relationship between the integral area and the concentration in the range of 30-300 ng/mL.The sample recovery rate was in the range of 87.37% ~ 109.75%.The two methods established in this study have good specificity, good precision, high sensitivity and simple operation, which can be used for the trace determination of potential genotoxic impurities chloroacetyl chloride and chloroacetic acid in the raw material of azintamide.

OBJECTIVE：To establish a method for the content determination of potential genotoxic impurity maleic hydrazide in azintamide raw material. METHODS ：HPLC-FLD method was adopted. The determination was performed on Thermo Syncronis C18 column with mobile phase consisted of 0.2 mol/L acetic acid-methanol （gradient elution ）. The column temperature was set at 30 ℃，the excitation wavelength was 315 nm and emission wavelength was 389 nm. The flow rate was 1 mL/min，and the sample size was 20 μL. RESULTS：The blank solvent and azintamide did not interfere with the determination of maleic hydrazide. The linear range of maleic hydrazide was 19.5-300 ng/mL（r＝0.999 9）. The limit of detection was 4.5 ng/mL and the limit of quantification was 19.5 ng/mL. The recovery ranged from 98.79％ to 103.76％（RSDs were lower than 3.00％，n＝9）. RSDs of precision and stability （24 h）tests were no more than 5.63％，and those of durability tests were less than 2.00％（n＝6）. Maleic hydrazide was not detected in 3 batches of azinamide raw material. CONCLUSIONS ：The method is specific ，sensitive and accurate. It can be used for the trace determination of maleic hydrazide in azintamide or other matrix.

In this study,we developed a novel on-line solid phase extraction (SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS)-based analytical method for simulta-neously quantifying 12 illicit drugs and metabolites (methamphetamine,amphetamine,morphine,co-deine,6-monoacetylmorphine,benzoylecgonine,3,4-methylenedioxymethamphetamine,3,4-methylenedioxyamphetamine,cocaine,ketamine,norketamine,and methcathinone) and cotinine(COT) in wastewater samples.The analysis was performed by loading 2 mL of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step (5％ methanol) to eliminate interference with a total run time of 13 min.The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process.Typical analytical characteristics used for method validation were sensitivity,linearity,precision,repeatability,recovery,and matrix effects.The limit of detection (LOD) and limit of quantification (LOQ)of each target were set at 0.20 ng/L and 0.50 ng/L,respectively.The linearity was between 0.5 ng/L and 250 ng/L,except for that of COT.The intra-and inter-day precisions were ＜10.45％ and 25.64％,respec-tively,and the relative recovery ranged from 83.74％ to 162.26％.The method was used to analyze various wastewater samples from 33 cities in China,and the results were compared with the experimental re-suits of identical samples analyzed using off-line SPE.The difference rate was between 19.91％and-20.44％,and the error range could be considered acceptable.These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples.

The conventional equilibrium dialysis and ultrafiltration methods cannot be used to determine the protein binding of some peptides because of their non-specific adsorption on the semipermeable membrane or poor stability in the plasma. The method of dextran-coated charcoal adsorption combined with LC-MS/MS were used. Based on the kinetic principle of initial rate of candidate drugs absorbed to dextran-coated charcoal, seven phosphorylated peptides with the same amino acid sequence and different configurations in rat plasma were selected as the study model using; the protein binding in rat plasma were determined; the amino acid distribution rules affecting the changes in protein binding rates of peptide candidate drugs were summarized. The results suggest that the dextran charcoal adsorption method, as a supplementary method for the determination of plasma protein binding, is suitable for peptides or organic drug candidates that cannot be determined by traditional techniques.

A quantitative analysis method based on solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) for simultaneous determination of illicit drugs and their metabolites in wastewater was established. Samples filtered at pH of 2 and spiked with internal standard were loaded to Oasis Prime MCX cartridges for solid-phase extraction. The samples were washed with 4 mL of methanol and eluted with 4 mL of 5% ammonia in acetonitrile before reconstituting with 0.1% formic acid/water solution. ZORBAX Eclipse Plus C18 column was used for chromatography, and gradient elution was performed with 0.1% formic acid/water solution and acetonitrile as mobile phase. The samples were then detected by electrospray ionization (ESI) in positive ion mode, and multiple reaction monitoring mode (MRM) was adopted for quantitative analysis. All analytes had a good linear relationship (r ≥ 0.993 2) within the range of their respective standard curve; the limit of quantification was 1 ng/L (except amphetamine at 2.5 ng/L); the extraction recovery ranged from 82.13% to 99.96%; and the intra- and inter-day precisions were less than 9.43%. The method is accurate, reliable and reproducible, and is suitable for the quantitative determination of illicit drugs and their metabolites in wastewater and can provide an analytical method for real-time monitoring of drug abuse.

To develop a rapid and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for the determination of endogenous glutathione in rat plasma. Glycyltyrosine was used as the internal standard(IS)and 4-(N-maleimido)phenyl trimethylammonium iodide(MPTA)was used as the derivation reagent. Chromatographic separation was achieved on a Zorbax HILIC PLUS column(4. 6 mm×100 mm, 3. 5 μm)and the mobile phase consisted of acetonitrile and 0. 1% formic acid(75 ∶25)pumped at a flow rate of 1. 0 mL/min. Detection was carried out on a triple quadrupole tandem mass spectrometer by selected reaction monitoring(SRM)in the can meet positive ion mode. The linearity ranged from 3. 000 to 2 000 ng/mL(r=0. 997 1); and the limit of detection of glutathione in rat plasma was 10 pmol/L. Matrix effect, stability, precision and accuracy of the method met the requirements. The proposed method was proved to be selective and sensitive, which is suitable for the quantification of endogenous glutathione in rat plasma.

GC-MS and LC-MS are the main techniques used for the structural identification of new psychoactive substances at present. However, they are hard to give accurate structure information because of the hardly available corresponding reference standards and the quickly changing status of these compounds. This leads tremendous obstacle on the rapid identification of new psychoactive substances. Nuclear magnetic resonance spectroscopy is one of the most effective methods for structures identification. Therefore, NMR is especially suitable for the analysis and identification of new psychoactive substances even with rapid structural changes. This article summarizes the NMR applications for the structural analysis of new psychoactive substances including synthetic cannabinoids, synthetic cathinones, piperazines, phenethylamines, ketamine & phencyclidine-type substances, and fentanyls. It is found that the NMR signals of the main frame structure of each kind of the new psychoactive substances are basically the same. Hence, these frame structure NMR signals can provide scientific evidence for the rapid identification of new psychoactive substances. This article also look ahead the prospect for the application of LC-NMR and DOSY in new psychoactive substances, which provides new ideas for the screening of new psychoactive substances.