A Fast and Validated High Throughput Bar Adsorptive Microextraction (HT-BAµE) Method for the Determination of Ketamine and Norketamine in Urine Samples

Application of a bar adsorptive microextraction based methodology for doping control of alkylamine stimulants in urine matrices

To comply with 'World Anti-Doping Agency' (WADA) guidelines, doping control laboratories must continuously adjust their analytical procedures. Therefore, sample preparation continues to play a critical step in modern analytical strategies, namely by replacing the tedious, time and solvent consuming commonly employed (e.g. liquid-liquid extraction). The present contribution proposes, for the first time in doping control, bar adsorptive microextraction (BAμE) as an alternative analytical technique for the qualitative determination of six alkyl amine stimulants (AAs; 1,3-dimethylbutylamine, 1,4-dimethylpentylamine, heptaminol, isometheptene, octodrine and tuaminoheptane) in urine matrices followed by derivatization prior to gas chromatography coupled to mass spectrometry, operating in the selected ion monitoring mode acquisition (GC-MS(SIM)). After selecting the most selective coating phase, i.e., a mixed-mode reversed phase/strong anion exchange sorbent (P2), assays performed under optimized experimental conditions [microextraction - BAμE(P2), 1 h (1,000 rpm), pH 11, 10 % NaCl; back-extraction - methanol (150 μL), 30 min, under sonication], allowed remarkable recoveries ranging from 48.7 % (heptaminol, 200 ng/mL) to 83.1 % (1,4-dimethylpentylamine, 200 ng/mL). The validation assessment assays of the proposed methodology showed suitable limits of identification (5.0-35.0 ng/mL), appropriate linear dynamic ranges (5.0-200.0 ng/mL) and good determination coefficients (r2 > 0.9937), as well as excellent selectivity, robustness, accuracy and precision. To check whether the methodology is fit-for-purpose, four previously analysed proficiency urine samples were successfully tested, in which were unequivocally detected and identified some of the target AAs. The present methodology showed to be a remarkable alternative in comparison to other dedicated analytical approaches to screen AAs in urine matrices, since it is cost-effective, user- and eco-friendly, requiring low volume of urine sample (1 mL). The great potential of this analytical technology in doping control lies in a very effective microextraction combined with the minimization of potential interferents, presenting itself as an added value to be applied to other types of substances and complex matrices.

Simple Analytical Strategy for Screening Three Synthetic Cathinones (α-PVT, α-PVP, and MDPV) in Oral Fluids

Synthetic cathinones are analogue compounds of the plant based stimulant cathinone. Its use, abuse, and related consumption complications have steadily increased in the last years. For this reason, there is a need for innovative analytical approaches that enable its rapid screening in biological matrices (e.g., oral fluids). The present work proposes a new analytical methodology by combining bar adsorptive microextraction followed by microliquid desorption and gas chromatography coupled to mass spectrometry (BAµE-µLD/GC-MS) for screening three synthetic cathinones (α-PVP, α-PVT, and MDPV) in oral fluids. The optimization of the BAµE-µLD/GC-MS methodology was successfully applied for the analysis of the target compounds in oral fluids. The results show average recoveries between 43.1 and 52.3% for the three synthetic cathinones. Good selectivity was also noticed. The developed methodology presents itself as an alternative tool to screen these compounds in oral fluids. To the best of our knowledge, this is the first work that combines a microextraction sorption-based technique followed by GC-MS analysis for the screening of synthetic cathinones in oral fluids.

Effects of long-term alcohol exposure on the pharmacokinetic profiles of ketamine and norketamine in rats

BACKGROUND

Alcohol abuse has become a serious health issue worldwide. Ketamine can reduce addiction risk among patients with alcohol use disorders. This study aimed to determine the effects of alcohol on the pharmacokinetics of ketamine during long-term alcohol exposure.

METHOD

An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of ketamine and norketamine was developed and validated. A total of 15 rats were given 40% alcohol for 3 weeks. The pharmacokinetics of ketamine were measured at time zero, 1 week, 2 weeks, and 3 weeks after alcohol exposure. The metabolic capability of liver CYP450 was evaluated using three probe drugs: metoprolol, phenacetin, and tolbutamide.

RESULTS

During drinking of 40% alcohol, the AUC(0-t), AUC(0-∞), and Cmax of ketamine and norketamine significantly increased, while V and CL significantly decreased with time (p < 0.001). The pharmacokinetic changes of norketamine were highly consistent with ketamine. Additionally, the concentration ratio of norketamine/ketamine in sample time also decreased over time. However, there were no pharmacokinetic changes of three probe drugs, which indicated there was no significant change of liver CYPs activities.

CONCLUSION

Alcohol significantly increases plasma concentration of ketamine and norketamine. The effect of alcohol on pharmacokinetics of ketamine should be considered in clinical therapy.

Application of Microextraction-Based Techniques for Screening-Controlled Drugs in Forensic Context-A Review

The analysis of controlled drugs in forensic matrices, i.e., urine, blood, plasma, saliva, and hair, is one of the current hot topics in the clinical and toxicological context. The use of microextraction-based approaches has gained considerable notoriety, mainly due to the great simplicity, cost-benefit, and environmental sustainability. For this reason, the application of these innovative techniques has become more relevant than ever in programs for monitoring priority substances such as the main illicit drugs, e.g., opioids, stimulants, cannabinoids, hallucinogens, dissociative drugs, and related compounds. The present contribution aims to make a comprehensive review on the state-of-the art advantages and future trends on the application of microextraction-based techniques for screening-controlled drugs in the forensic context.