Development of a method for the analysis of drugs of abuse in vitreous humor by capillary electrophoresis with diode array detection (CE-DAD).

This work presents the development of an analytical method based on capillary electrophoresis with diode array detection for the analysis of drugs of abuse and biotransformation products in vitreous humor. Composition of the background electrolyte, implementation of an online pre-concentration strategy and sample preparation procedures were objects of study. The complete electrophoretic separation of 12 analytes (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), ketamine, cocaine, cocaethylene, lidocaine, morphine, 6-monoacetylmorphine and heroin) and the internal standard N-methyl-1-(3,4-methylenedioxyphenyl)-2-butamine (MBDB) was obtained within 13min of run. The method was validated presenting good linearity (r(2)>0.99), recovery ≥90%, precision better than 12% RSD and acceptable accuracy in the range of 86-118% at three concentration levels (50, 100 and 500ng/mL). LODs and LOQs in the order of 1-5ng/mL and 5-10ng/mL, respectively, were obtained. After validation, the method was applied to eighty-seven vitreous humor samples and the results were compared to those obtained by a liquid chromatography tandem mass spectrometry (LC-MS/MS) screening method, routinely used by the forensic toxicology laboratory of the Sao Paulo State Police, Brazil. Cocaine was detected in 7.1%, cocaethylene in 3.6%, lidocaine in 2.4% and ketamine in 1.2% of the total number of analyzed samples.

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS.

In this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ's (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its metabolites was further confirmed by MS/MS experiments.

Cocaina e cocaetileno: influência do etanol nas concentraçöes de cocaína em sangue humano post mortem / Cocaine and cocaethylene: influence of the etanol in cocaine concentrations post mortem human blood

O uso concomitante de cocaína (COC) e etanol ocorre com muita frequência e sabidamente aumenta o risco de morbidade e de mortalidade relacionadas à intoxicaçäo cocaínica. Decorrente da interaçäo, aparece de um produto de transesterificaçäo da COC, o cocaetileno (CE), que apresenta mecanismos de açäo tóxica semelhantes que, por vezes, porém, superam os da de COC. O CE apresenta 'DL IND. 50' menor que a do precursor, sendo, portanto, importante na letalidade atribuída a COC. Para estudar o papel do etanol como agente de interaçäo nas intoxicaçöes letais de COC e estabelecer sua influência nos teores do toxicante encontrados post mortem, foi validado um método para quantificaçäo desse agente, de seus produtos de biotransformaçäo benzoilecgonina (BE) e éster metilecgonina (EME) e do "biomarcador" dessa interaçäo, o CE, em sangue total com posterior aplicaçäo a 36 casos de óbito em que a cocaína ocorreu como fármaco único, e a 18 em que houve interaçäo com o etanol. A análise estatística dos resultados pelo teste de MANOVA caracterizou os grupos como estatísticamente diferentes, quando se consideram as três variáveis concomitantemente. A análise de cada um dos parâmetros (COC, BE e EME) em separado, todavia, näo é suficiente para discriminar os dois grupos. A relaçäo BE/COC, entretanto, é significativamente maior na intoxicaçäo por cocaína como fármaco único do que naquela verificada na interaçäo COC/etanol