Fast and Sensitive Chiral Analysis of Amphetamines and Cathinones in Equine Urine and Plasma Using Liquid Chromatography Tandem Mass Spectrometry

A simple, rapid, sensitive and reproducible method for enantiomer analysis of methamphetamine, amphetamine, cathinone and methcathinone was developed and validated. The compounds were extracted from equine plasma and urine using a fast liquid-liquid extraction procedure. Only one milliliter plasma and one hundred microliter urine sample is needed for analysis. The extraction procedure had good recovery (>70%) and the matrix effect was negligible. Enantiomer differentiation and confirmation were achieved using liquid chromatography with chiral stationary phase and mass spectrometry detection. The method demonstrated excellent reproducibility with intra-day and inter-day precision of lower than 5%. The lower limits of detection for all of the compounds studied here were at low pg/mL level for both plasma and urine. This is the first report of the analysis of four chiral compounds in equine plasma and urine. Routine application was demonstrated for (S)- and (R)-enantiomer differentiation.

Metabolic profiling of four synthetic stimulants,including the novel indanyl-cathinone 5-PPDi,after human hepatocyte incubation

Synthetic cathinones are new psychoactive substances that represent a health risk worldwide.For most of the 130 reported compounds,information about toxicology and/or metabolism is not available,which hampers their detection(and subsequent medical treatment)in intoxication cases.The principles of forensic analytical chemistry and the use of powerful analytical techniques are indispensable for stab-lishing the most appropriate biomarkers for these substances.Human metabolic fate of synthetic cathinones can be assessed by the analysis of urine and blood obtained from authentic consumers;however,this type of samples is limited and difficult to access.In this work,the metabolic behaviour of three synthetic cathinones(4-CEC,4-CPrC and 5-PPDi)and one amphetamine(3-FEA)has been evalu-ated by incubation with pooled human hepatocytes and metabolite identification has been performed by high-resolution mass spectrometry.This in vitro approach has previously shown its feasibility for obtaining excretory human metabolites.4-CEC and 3-FEA were not metabolised,and for 4-CPrC only two minor metabolites were obtained.On the contrary,for the recently reported 5-PPDi,twelve phase I metabolites were elucidated.Up to our knowledge,this is the first metabolic study of an indanyl-cathinone.Data reported in this paper will allow the detection of these synthetic stimulants in intoxi-cation cases,and will facilitate future research on the metabolic behaviour of other indanyl-based cathinones.

Abuse-related effects of synthetic cathinones：importance of DAT/SERT relationships

OBJECTIVE Wide spread abuse of synthetic cathinones found in bath salts preparations has resulted in regulation of some cathinones internationally.Chemists skirt these laws by altering the chemical structures of first-generation cathinones(ie,MDPV,methylone,and mephedrone),resulting in second-generation cathinones(eg,α-PVP,α-PPP,MDPPP,and MDPBP).Although MDPV is a more effective reinforcer than cocaine,little is known about the reinforcing effectiveness of secondgeneration cathinones.To test the hypothesis that synthetic cathinones with higher selectivity for DAT relative to SERT are more effective reinforcers.METHODS Monoamine transporter inhibition was determined using synaptosomes prepared from rat brains.The relative reinforcing effectiveness of intravenously self-administered MDPV,MDPBP,MDPPP,α-PVP,α-PPP,and cocaine were directly compared through evaluations of (1)dose-response curves under a progressive ratio(PR)schedule of reinforcement and (2)demand curves obtained for each drug in male Sprague-Dawley rats.RESULTS Rank order selectivity for DAT/SERT wasα-PVP>MDPV>α-PPP≈MDPBP>MDPPP>cocaine.Comparisons of the maximum number of infusions obtained under a PR schedule of reinforcement(α-PVP>MDPV>α-PPP>MDPBP≈MDPPP>cocaine)and the essential value obtained for each drug in demand analyses(α-PVP>MDPV>α-PPP≈MDPBP≈MDPPP>cocaine)suggest relative reinforcing effectiveness is related to DAT/SERT selectivity.CONCLUSION These data provide evidence that DAT/SERT selectivity accounts for select synthetic cathinones functioning as more effective reinforcers than cocaine and may predict the abuse-related effects of novel synthetic cathinones in humans.

Molecular docking of amphetamine,cathine and cathinone with dihydrofolate reductase:a computational analysis of inhibition of dihydrofolate reductase by khat alkaloids

Interaction of amphetamine,cathine and cathinone with the enzyme dihydrofolate reductase was studied by molecular docking using AutoDock 4.2 as the docking software application.AutoDock 4.2 software serves as a valid and acceptable docking application to study the interactions of small compounds with proteins.Interactions of amphetamine,cathine and cathinone with dihydrofolate reductase were compared to those of methotrexate,a known inhibitor of the enzyme.The calculated free energy of binding(ΔG binding)shows that the three ligands(ΔG=-6.87 to-7.21 kcal/mol;Ki=9.15 to 5.18μM)bind with affinity slightly lower than methotrexate(ΔG=-8.78 kcal/mol;Ki=363 nM).Binding interactions of the three ligands with active site residues of the enzyme are also predicted.All the ligands appear to bind in a similar conformation making extensive VDW contacts in the active site of the enzyme.Hydrogen bonding and pi-pi interaction with key active site residues is also observed.Thus,a probable inhibition of dihydrofolate reductase by khat alkaloids can be explained on the basis of this in silico binding and khat alkaloids can be considered as potential lead compounds in the development of new inhibitors of dihydrofolate reductase which is a potential target of anti-cancer drugs.The results of these studies can serve as a starting point for further computational and experimental studies.