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One of the many issues of designer drugs of abuse like synthetic cannabinoids (SCs) such as JWH-018 is that details on their metabolism has yet to be fully elucidated and that multiple metabolites exist. The presence of isomeric compounds poses further challenges in their identification. Our group has previously shown the effectiveness of gas chromatography-electron ionization-tandem mass spectrometry (GC-EI-MS/MS) in the mass spectrometric differentiation of the positional isomers of the naphthoylindole-type SC JWH-081, and speculated that the same approach could be used for the metabolite isomers. Using JWH-018 as a model SC, the aim of this study was to differentiate the positional isomers of its hydroxyindole metabolites by GC-MS/MS. Standard compounds of JWH-018 and its hydroxyindole metabolite positional isomers were first analyzed by GC-EI-MS in full scan mode, which was only able to differentiate the 4-hydroxyindole isomer. Further GC-MS/MS analysis was performed by selecting m/z 302 as the precursor ion. All four isomers produced characteristic product ions that enabled the differentiation between them. Using these ions, MRM analysis was performed on the urine of JWH-018 administered mice and determined the hydroxyl positions to be at the 6-position on the indole ring. GC-EI-MS/MS allowed for the regioisomeric differentiation of the hydroxyindole metabolite isomers of JWH-018. Furthermore, analysis of the fragmentation patterns suggests that the present method has high potential to be extended to hydroxyindole metabolites of other naphthoylindole type SCs in identifying the position of the hydroxyl group on the indole ring. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

This paper describes highly sensitive HPLC methods for the determination of amphetamine (AP) and methamphetamine (MP) in abusers' plasma and hair samples. AP and MP were derivatized with the fluorescent reagent, DIB-Cl, to yield a highly fluorescent DIB-derivatives of AP and MP, which were then analyzed by HPLC with fluorescence detection at excitation and emission wavelengths of 325 and 430 nm, respectively. The separation was achieved on an ODS column with isocratic mobile phases composed of acetoniltrile and citrate buffer (55:45, v/v) for plasma samples and of acetonitrile-methanol-citrate buffer (45:20:37.5, v/v/v) for hair samples. The limits of detection were less than 0.87 ng/mL and 0.12 ng/mg in plasma and hair samples, respectively, for both AP and MP. The methods were then applied to the determination of MP and its metabolite AP in plasma obtained from two cases of illegally ingested MP and in one of the cases' hair received later. Case I was treated with dialysis; samples before and after dialysis were analyzed by the described method. After dialysis for 5 h, the total plasma levels of AP and MP decreased from 720 to 190 ng/mL. For case II, MP and AP levels were monitored for 3 days after digestion. Total plasma levels decreased from 57 ng/mL in the day of digestion to 11 ng/mL after 3 days. In hair samples, AP and MP could also be detected in very low concentrations., (Copyright 2003 John Wiley & Sons, Ltd.)

Background: We sought to evaluate the parameters of CO2 transport during the administration of acetazolamide in order to assess the role of carbonic anhydrase in CO2 transport., Materials and Methods: The partial pressure of carbon dioxide in tissue (PtCO2), arterial blood (PaCO2) and end-tidal gas (PETCO2) were monitored to study the correlation between PaCO2, PtCO2 and PETCO2 in spontaneously breathing healthy volunteers after the intravenous administration of acetazolamide 6 mg kg-1., Results: At 60 min after the administration of acetazolamide, the PtCO2 peaked at more than 60 mmHg, and although it decreased by 90 min, it then remained stable above the baseline value. The PaCO2 did not change and the PETCO2 decreased significantly. The changes in PtCO2 were greater than those of either PaCO2 or PETCO2. The minute ventilation increased progressively throughout the study., Conclusions: We concluded that gastrotonometry represents a new method for monitoring the dramatic increase in PtCO2 induced by drugs such as acetazolamide clinically, and that it could be a warning against acetazolamide administration in severe patients without keeping a ventilation and circulation reserve.