Hair testing for cocaine and metabolites by GC/MS: criteria to quantitatively assess cocaine use.

A simple, rapid and sensitive method has been developed and validated for the determination of cocaine and its main metabolites (benzoylecgonine and cocaethylene) in human hair. The method involved solid-phase extraction with an Oasis HLB extraction cartridge and subsequent analysis by GC/MS. The limit of detection was 0.01 ng mg(-1) for cocaine, 0.04 for benzoylecgonine and 0.03 for cocaethylene. The method validation included linearity (with a correlation coefficient >0.99 over the range 0.2-50 ng mg(-1) ), intra- and inter-day precision (always lower than 12%) and accuracy (mean relative error always below 17%) to meet the bioanalytical acceptance criteria. The procedure was further applied to 40 hair samples from self-reported cocaine users arrested by the police who provided a positive urine-analysis for cocaine, and was demonstrated to be suitable for its application in forensic toxicology. New approaches were raised to detect false-negative results that allow a better interpretation of hair testing results.

Validation of ELISA screening and LC-MS/MS confirmation methods for cocaine in hair after simple extraction.

This article describes an easy and innovative extraction procedure for cocaine and its primary metabolite, benzoylecgonine (BE), from hair consisting of sonication with H(2)O/0.1% formic acid for 4 h. The same extract was used for screening with an enzyme-linked immunoassay (ELISA) and confirmation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For the ELISA screening test a cutoff of 0.5 ng/mg was used according to the Society of Hair Testing recommendations. LC-MS/MS limits of detection (LODs) were established to be 10 pg/mg and 1 pg/mg for cocaine and BE, respectively. Linearity was obtained over a range of 0.2-5 ng/mg for BE (target analyte) in the ELISA screening test, while in the LC-MS/MS method the range was 0.10-10 ng/mg for cocaine and 0.01-10 ng/mg for BE. Intra- and interbatch coefficients of variation and mean relative errors were less than 20% for all analytes and concentrations studied. The validated ELISA and LC-MS/MS methods were applied to 48 hair samples and the results of both methods were compared; ELISA demonstrated a sensitivity and specificity of 89.2% and 10.8%.

Cocaine and opiates use in pregnancy: detection of drugs in neonatal meconium and urine.

In this study, the case of a newborn with symptoms of hyperexcitability was analyzed. After it was confirmed in the hospital that the mother had consumed drugs during pregnancy using an enzyme multiplied immunoassay technique, samples of the newborn's urine and meconium were sent to our laboratory to observe the evolution in the distribution of cocaine and opiates during the days following birth. For urine analysis, screening was done with an immunoassay technique, and the confirmation was done by gas chromatography-mass spectrometry (GC-MS) according to a published method. A GC-MS method for simultaneous analysis of cocaine, benzoylecgonine, codeine, morphine, and 6-acetylmorphine in meconium is described. GC-MS confirmation of urine and meconium results showed consumption of cocaine and codeine during pregnancy and also showed the levels of drugs gradually declined, totally disappearing by the third day.

HPLC-DAD determination of opioids, cocaine and their metabolites in plasma.

High performance liquid chromatography with diode array detection (HPLC-DAD) was used to develop a method for the simultaneous determination of morphine, codeine, 6-acetylmorphine (6AM), cocaine, benzoylecgonine (BEG), cocaethylene, methadone and its metabolite, 2-ethylidene-1,5-dimethyldiphenylpyrrolidine (EDDP), in plasma. Following solid-phase extraction with Bond Elut Certify cartridges, chromatography was performed on an X-Terra RP8 column (250 mm x 4.6 mm i.d., 5 microm particle size), using acetonitrile-phosphate buffer pH 6.53 as mobile phase and elution in the gradient mode. The detector response was linear at concentrations over the range 0.1-10 microg/mL in plasma, and the correlation coefficients for the eight drugs studied were all higher than 0.99. The average extraction recoveries from plasma ranged from 60% for BEG to 95% for methadone. The precision was acceptable, with coefficients of variation oscillating between 2.55% and 6.45%. The accuracy was found to be within satisfactory limits (+/- 8.1%). Finally, the method was applied to 21 plasma samples from fatal overdoses, obtaining positive results for two or more drugs.

A new GC-MS method for the determination of five amphetamines in human hair.

A new gas chromatography-mass spectrometry method for the simultaneous identification and quantitation of amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethamphetamine (MDEA) in hair is proposed. Hair was hydrolyzed in 1 M NaOH at 40 degrees C, subjected to extraction with 4:1 (v/v) methylene chloride/isopropanol, and derivatized with pentafluoropropionic anhydride (PFPA) and ethyl acetate. Calibration curves for the five analytes were constructed over the concentration range 0.5-25.0 ng/mg, using their pentadeuterated analogues as internal standards. The limits of detection and quantitation obtained were 0.045 and 0.151 ng/mg for AP; 0.014 and 0.048 ng/mg for MA; 0.013 and 0.043 ng/mg for MDA; 0.017 and 0.057 ng/mg for MDMA; and 0.007 and 0.023 ng/mg for MDEA. The accuracy of the method was found to be in the range +/- 9%, and the coefficients of variation were less than 8%. Overall, 24 hair specimens tested positive for one or more amphetamines, with average concentrations of 0.88 ng/mg for AP, 10.14 ng/mg for MA, 1.30 ng/mg for MDA, and 8.87 ng/mg for MDMA. Only one specimen tested positive for MDEA with a concentration of 0.84 ng/mg.

Influence of concomitant drugs on methadone elimination half-life in patients under a maintenance treatment.

Methadone elimination half-life was determined in 18 patients under maintenance treatments and found to range from 2.05 to 49.6 h. A study of potential correlations between this parameter and the presence of concomitant drugs, inhibitors or inducers of cytochrome P450, revealed an increase or decrease of methadone elimination half-life, respectively. Twenty-four-hour urinary excretion of methadone was determined in three patients, who were found to release 22.3-49.8% of the dose taken. The amount excreted varied with the chemical form (unaltered drug or its main metabolite) in the three cases. No statistically significant correlation was found between urine pH and the elimination half-life (p < 0.50).

Use of solid-phase microextraction (SPME) for the determination of methadone and EDDP in human hair by GC-MS.

Solid-phase microextraction (SPME) is a new extraction technique with many advantages: small sample volume, simplicity, quickness and solvent-free. It is mainly applied to environmental analysis, but is also useful for the extraction of drugs from biological samples. In this paper the use of SPME is proposed for the determination of methadone and its main metabolite EDDP in hair by GC-MS. The hair samples were washed, cut into 1-mm segments, and incubated with Pronase E for 12 h. A 100-micron polydimethylsiloxane (PDMS) film fibre was submerged for 30 min in a diluted solution of the hydrolysis liquid (1:4 with borax buffer) containing methadone-d3 and EDDP-d3 as internal standards. Once the microextraction was concluded the fibre was directly inserted into the CG injection port. Linearity was found for methadone and EDDP in the range studied, 1.0-50 ng/mg hair, with correlation coefficients higher than 0.99. Interassay relative standard deviation (R.S.D) was determined to be less than 13.30% for methadone and less than 8.94% for EDDP, at 3.0 and 30.0 ng/mg. Analytical recoveries were close to 100% for both compounds on spiked samples. The method was applied to the analysis of real hair samples from eight patients of a methadone maintenance programme. The concentration of methadone in hair ranged from 2.45 to 78.10 ng/mg, and for EDDP from 0.98 to 7.76 ng/mg of hair.

Evaluation of cocaine, amphetamines and cannabis use in university students through hair analysis: preliminary results.

The evaluation of drug abuse in a defined population was performed through toxicological hair analysis. Hair samples from university students ranging from 18 to 25 years of age were anonymously collected and screened for cocaine, amphetamines and cannabinoids by radioimmunoassay (RIA). Positive results (cut-off values adopted were 2 ng/mg for cocaine and amphetamines and 0.5 ng/mg for cannabinoids) were confirmed by GC/MS. Preliminary results showed 19% of positive results for cocaine on 200 samples analysed. No confirmed positive results were obtained for amphetamine analysis. RIA technique demonstrated its unsuitability for cannabinoids preliminary screening on hair, giving a high percent of false positive results.

Determination of colchicine in biological fluids by reverse-phase HPLC. Variation of colchicine levels in rats.

A reverse-phase HPLC method for the determination of colchicine in biological fluids is proposed. Blood, liver and kidney colchicine concentrations were determined in rats at different times following intraperitoneal (i.p.) injection of 10 mg/kg of the drug. Colchicine was extracted from the samples studied using dichloromethane at pH 8. The dry extract was redissolved in the mobile phase and analyzed with simultaneous detection at 254 and 350 nm.

Quantitation of cocaine and its major metabolites in human saliva using gas chromatography-positive chemical ionization-mass spectrometry (GC-PCI-MS).

An analytical method for the simultaneous determination of cocaine (COC) and its major metabolites, ecgonine methyl ester (EME) and benzoylecgonine (BEG), in saliva was developed. The method involves liquid-liquid extraction in Toxitubes A, derivatization with 99:1 (v/v) N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS) and gas chromatography-mass spectrometry (GC-MS) determination. The detector response thus obtained is linear over the range 25-1000 ng/mL, with a reproducibility better than 93% and a recovery close to 100% for the three analytes. The limits of detection achieved were 0.9 ng/mL for EME, 2.2 ng/mL for cocaine, and 0.2 ng/mL for BEG, and the limits of quantitation were 3.0 ng/mL for EME, 7.4 ng/mL for cocaine, and 0.8 ng/mL for BEG. The proposed method was applied to 48 saliva samples from cocaine users, 96% of which were positive for the drug and/or its metabolites. Saliva is thus a suitable biological fluid for determining cocaine, EME, and BEG by GC-PCI-MS.

Solid-phase microextraction in the determination of methadone in human saliva by gas chromatography-mass spectrometry.

Solid-phase microextraction (SPME) with a 100-microm polydimethylsiloxane film fiber was applied to the determination of methadone and 2-ethylidine-3,3-diphenylpyrrolidine (EDDP) by GC-MS in human saliva and compared with liquid-liquid extraction. A shorter extraction time of 30 min with the fiber was obtained, speeding up the total analysis time. Linearity was found for SPME from 0.05 to 2.0 microg/mL (r = 0.9976 for methadone; r = 0.9988 for EDDP) with precision between 0.7 and 4.3% for saliva spiked with 0.2 and 1.5 microg/mL of methadone and EDDP. The limit of detection using SPME was 0.04 microg/mL for methadone and 0.008 microg/mL for EDDP. Analytical recoveries of SPME and liquid-liquid extraction ranged from 98.8 to 103.6%. The use of deuterated internal standard by both methods have yielded comparable results. Thus, the SPME method is highly accurate, precise, and useful for determination of methadone and EDDP in saliva.

Use of solid-phase microextraction (SPME) for the determination of methadone and its main metabolite, EDDP, in plasma by gas chromatography-mass spectrometry.

A simple, rapid method for the determination of methadone and its metabolite 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in plasma using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry is proposed. A 100-microm polydimethylsiloxane film fiber was exposed by immersion for 30 min in a diluted plasma solution (1:4 with buffer pH 9) containing both compounds and an internal standard (proadifen). Calibration curves were linear over the concentration range 50-2000 ng/mL. The analysis time was 45 min per sample. The determination of methadone and EDDP was subject to no interference. The performance of SPME was compared with that of liquid-liquid extraction, obtaining lower limits of detection for EDDP. The method using the two extraction procedures was applied to 10 plasma samples from methadone-treated patients.

Application of hygrine and cuscohygrine as possible markers to distinguish coca chewing from cocaine abuse on WDT and forensic cases.

The objectives of present work are twofold. First, we want to verify that hygrine and cuscohygrine are good markers to distinguish between chewing coca leaves and cocaine abuse. Secondly, we try to develop a quick and easy qualitative method to determine the two mentioned markers. We analyzed two kinds of urine samples: the first group consisted of twenty-four (24) subjects: urine samples were obtained from various types of workers (e.g. doctors, chemists, nurses, technicians, painters, contractors, employees and some retired persons) who admitted chewing coca leaves. Frequency of the habit of chewing coca leaves was variable. They practiced "coqueo" between two (2) and forty-four (44) years. Sixteen (16) of them used alkaline substances to enhance the extraction of cocaine from the leaves The second group of urine samples consisted on thirty-eight (38) cocaine abusers, from forensic cases from Spain and Argentina. A GC/MS qualitative method, performed after liquid-liquid extraction, was developed and validated (the parameters studied were selectivity/specificity, LOD and stability), and then applied to the urine samples. Hygrine and cuscohygrine are good markers to distinguish between chewing coca leaves and cocaine abuse, and the qualitative method presented can be used successfully in workplace drug testing and forensic cases.

Prenatal alcohol exposure and its repercussion on newborns.

BACKGROUND: Alcohol consumption during pregnancy, even when moderate, implies a risk of impaired neurodevelopment, physical impairments and malformations. Its early identification is essential for establishing preventive measures to diminish disabilities among newborns. METHODS: To determine the frequency of consumption of substance use in pregnant women, we have used the techniques of gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry to detect drugs and markers of chronic consumption of alcohol in meconium. We performed a prospective study during a period of 10 months among 110 infants in our hospital, assessing anthropometry, neuromuscular development and determination of toxic substances in urine and meconium. Furthermore, meconium analysis identified fatty acid ethyl esters (FAEEs) and ethyl glucuronide (Etg). We also conducted a survey regarding the obstetric history, toxic habits, and employment status of the mothers. RESULTS: According to early detection markers analyzed in meconium (FAEE >1000 ng/g and/or Etg >50 ng/g meconium), 34.65% of pregnant women consumed alcohol during pregnancy, and 17% were positive for both markers. Within the positive cases, 50% of those exceeding a FAEE's value of 5000 ng/g in meconium had low birth-weight children. Only 5/110 mothers (4.5%) admitted to occasional alcohol consumption during pregnancy. Nobody admitted to frequent intake. The cocaine test was positive in three cases; two of them were positive for alcohol as well. CONCLUSION: As expected, many screening devices do not accurately capture use during pregnancy and supplemental methods such as meconium analysis of biomarkers of chronic alcohol consumption may be warranted.

Hygrine and cuscohygrine as possible markers to distinguish coca chewing from cocaine abuse in workplace drug testing.

Cocaine abuse is widespread all over the world, and is performed generally by sniffing, injecting or smoking cocaine or crack. The distinction between the recreational use of cocaine from the practice of the so called "coqueo" is still an issue in those countries where this habit is diffused and where it is not considered an addiction, by this reason is necessary to develop a method for to distinguish the coca chewers and cocaine abusers. The use of an unique marker to distinguish between cocaine abuse and chewing of coca leaves is of fundamental importance in those countries where this habit is diffused. Certain alkaloids of the leaves of Erythroxylum coca are lost during the process of extraction/purification of cocaine and it is not possible to find them neither in seizures of chlorhidrate of cocaine nor urine samples of cocaine abusers. These markers are the hygrine and cuscohygrine that are present in the leaves of E. coca. A fast GC/MS method involving a liquid:liquid extraction procedure with tertbutylmethylether (TBME) is proposed for the determination of some alkaloids in cocaine leaves, cocaine seizures and biological samples. All specimens were alkalinized to pH 9 with a carbonate/bicarbonate buffer and then extracted with TBME. The analysis was carry out by GC/MS with electron impact at 70 eV and in full scan mode. The results demonstrate that hygrine and cuscohygrine are not found neither in the urine of cocaine abusers nor in cocaine seizures. For this reason this compounds could be considered as markers of coca chewing. This developed method permits to distinguish coca chewing from cocaine abuse in workplace drug testing through the analysis of urine samples.

Analysis of six benzodiazepines in vitreous humor by high-performance liquid chromatography-photodiode-array detection.

The purpose of this study was to validate a high-performance liquid chromatography-photodiode-array detetion method for the determination of six benzodiazepines in vitreous humor. The sample preparation was carried out using solid-phase extraction with Oasis HLB cartridges and 10% acetic acid/MeOH as elution solvent. The vitreous humor is less affected by postmortem changes and is a very useful sample when blood or urine specimens are not available. Linear curves for bromazepam, alprazolam, lorazepam, lormetazepam, diazepam, and tetrazepam were obtained within the range 0.03-3 µg/mL, with coefficients of correlation lower than 0.999. The limit of detection was 3 ng/mL, and the lower limit of quantification was 30 ng/mL for each benzodiazepine. Intra- and interassay for precision and accuracy provided results less than 16.81% and 16.78%, respectively. Recoveries were higher than 68.51% in all cases. Finally, the method was applied to determine benzodiazepines in vitreous humor from intoxicated patients.

Optimization of a rapid microwave-assisted extraction method for the simultaneous determination of opiates, cocaine and their metabolites in human hair.

A rapid and cleanup-free microwave-assisted extraction (MAE) method is proposed for the simultaneous extraction of six illegal drugs of abuse - cocaine, benzoylecgonine (BZE), cocaethylene (CCE), morphine, 6-monoacethylmorphine (6AM) and codeine - from human hair samples. The analytes were determined using high performance liquid chromatography (HPLC) with photodiode array UV detection. The influence of several variables on the efficiency of the MAE procedure was investigated in detail by a multi-objective optimization approach based on a hybrid experimental design (17 experiments) and desirability functions. Six drugs were successfully extracted from human hair with recoveries close to 100% and good reproducibility (<3.6% RSD) under the optimal MAE conditions: 11 mL dichloromethane (DCM) extraction solvent, 60 degrees C extraction temperature, 9 min extraction time and 0.5 mL of methanol (MeOH) added to 50mg of the hair sample in the extraction vessels. Limits of quantification of 0.2 ng mg(-1) were found for the studied compounds. A comparison of sample preparation procedures, including MAE, enzymatic digestion and digestion by aqueous acids, was also conducted. The results indicated that the global behaviour of sample procedures provided similar satisfactory recoveries ranging from 86 to 100%. Indeed, the MAE procedure resulted in a reduction of extraction time by 100-fold and the elimination of cleanup steps. Slightly higher recoveries of morphine, 6AM, BZE and CCE, at 1 ng mg(-1) concentration level and cocaine at 40 ng mg(-1) concentration level, were achieved using MAE. Lastly, the proposed MAE method was applied to several human hair samples from multidrug abusers.

Determination of cocaine and heroin with their respective metabolites in meconium by gas chromatography-mass spectrometry.

The analysis of meconium specimens is a relatively accurate method for the detection of fetal exposure to drugs. The purpose of this study was to develop and validate a method for meconium sample preparation for a gas chromatography-mass spectrometry (GC-MS) confirmation of meconium extracts for cocaine, benzoylecgonine, codeine, morphine and 6-monoacetylmorphine. The analytes were initially extracted from the matrix by methanol. Subsequently a solid-phase extraction with Waters Oasis HLB cartridges was applied. Analytes were determined in GC-MS single monitoring mode. The method was validated in the range 40-2000 ng g(-1) using 0.5 g of meconium per assay. The detector response was linear over the studied range, and limits of quantitation and detection were found to be acceptable. Intra- and inter-batch coefficients of variation oscillated between 2.54% and 20.5%, and mean relative errors were in the range 0.79%-19.9%. The recoveries were higher than 42.1% in all cases. Finally the method was applied to analysis of meconium in newborns to assess fetal exposure to cocaine and opiates.

GC-FID determination of cocaine and its metabolites in human bile and vitreous humor.

Gas chromatography was used in combination with flame ionization detection (GC-FID) to develop a method for determining cocaine and its two metabolites, benzoylecgonine (BEG) and ecgonine methyl ester (EME), in bile and vitreous humor. The method used a 12 m x 0.2 mm i.d. column of 0.33 microm film thickness packed with 5% phenylmethylsiloxane, and proadifen as a reference compound. Drug-free bile and vitreous humor samples were used to prepare solutions of the target compounds at concentrations over the range 0.1-4 microg ml(-1) that were subjected to solid-phase extraction through Bond Elut Certify columns and derivatized with 99:1 (v/v) N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS). Calibration graphs were highly linear, with correlation coefficients above 0.99 in all instances. Also, the precision of the method was found to be quite acceptable, with coefficients of variation less than 5% for bile and less than 7% for vitreous humor. The average extraction yields ranged from 73.6% to 91.2% for bile and from 71.5% to 92.2% for vitreous humor. The proposed method was used to analyse 26 samples of bile and as many of vitreous humor from individuals fatally poisoned by cocaine, whether alone or in combination with other drugs. The mean drug levels found were 0.75 and 1.54 microg ml(-1) for cocaine in bile and vitreous humor, respectively, 6.35 and 0.94 microg ml(-1) for BEG, and 2.18 and 0.61 microg ml(-1) for EME.