An automated preconcentration-derivatization system for the determination of cocaine and its metabolites in urine and illicit cocaine samples by gas chromatography/mass spectrometry

Microwave assisted extraction of drugs of abuse from human urine

Microwave assisted extraction (MAE) was used to extract drugs of abuse from urine samples for the simultaneous determination of morphine, codeine, 6-acetylmorphine (6AM), cocaine, cocaethylene, benzoylecgonine (BEG), methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) by high performance liquid chromatography with diode array detector (HPLC-DAD). The working wavelengths used were 285 nm for morphine, codeine and 6AM; 233 nm for cocaine, cocaethylene and BEG; and 292 nm for methadone and EDDP. The mobile phase was a gradient of acetonitrile and phosphate buffer at pH 6.5. A full factorial design was used to identify the most suitable extraction conditions as regards pH, solvent and time of extraction. The optimum conditions thus established provided analyte recoveries from 61% to 109%. The detector response was linear over the drug concentration range 0.1-4.0 microg ml(-1) in urine. The within- and between-day precision and accuracy were less than 8% and 6.5%, respectively. The method was applied successfully to samples obtained from Galician hospitals and courts.

Analysis of opiates, cocaine and metabolites in urine by high-performance liquid chromatography with diode array detection (HPLC-DAD)

An analytical method is proposed for the simultaneous determination of morphine, codeine, 6-acetyl-morphine (MAM), cocaine, benzoylecgonine (BEG), cocaethylene, methadone and 2-ethylen-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in urine using high performance liquid chromatography coupled to a diode array detector (HPLC-DAD). The selection of working wavelengths is based on the highest chromatographic response for each component: 233 nm for cocaine, BEG and cocaethylene; 285 nm for morphine, codeine and MAM; and 292 nm for methadone and EDDP. The mobile phase, which is a mixture of acetonitrile and 0.02 M phosphate buffer at pH 6.53, was eluted in gradient mode through an XTerra RP-8 column (250 mm x 4.6 mm i.d., 5 microm particle size). After applying a solid-phase extraction procedure with Bond Elut Certify cartridges, the recoveries obtained were between 60% (EDDP) and 97% (cocaethylene). A good linearity of the method in the 0.1-10 microg mL(-1) range of urinary concentrations was obtained because the coefficient of correlation exceeded 0.99 for each drug. The precision and accuracy were quite good, with values of <7% and within the range +/- 6%, respectively. Finally, the proposed method was applied to 23 urine samples from fatal intoxications related to methadone, heroin and[sol ]or cocaine.

Automatic screening in postmortem toxicology

The systematic analysis of postmortem samples is one of the most challenging tasks in forensic toxicology. For determining cause of death, analysis of different tissues can be indispensable. Automation of these analyses would increase reproducibility and therefore lead to more reliable and comparable results. Recent developments in analytical toxicology and the availability of automation devices for various analytical stages, such as sampling, preliminary testing, sample extraction, chromatographic separation, identification, and data processing are examined and discussed. At present only parts of the analytical procedure have been automated-however, the goal should be the integration of these parts into a single, continuous process. Currently, only one "fully-automated" procedure for the comprehensive screening of blood and urine (excluding sample pretreatment, which remains separate) has been published. But it can be expected that automation of analytical procedures in forensic toxicology will indeed progress, even with regard to the very complex screening of postmortem samples.

Immunosuppression and oxidative stress induced by acute and chronic exposure to cocaine in rat

The objective of the present study was to verify if immunosuppression caused by cocaine (CO) can be mediated, at least in part, by increased formation of oxidative metabolites and reactive oxygen species (ROS) in rat. Pharmacokinetics of cocaine and its metabolites, cell-mediated immune function and cytokines production, biomarkers of cell redox state maintenance and lipidic peroxidation, and variations of activity in the enzymatic systems involved in cell antioxidant defence were measured in spleen of Wistar rats acutely and chronically treated with cocaine.C(max), AUC, and t(1/2) of norcocaine (NC) significantly increased after chronic exposure to cocaine while kinetic parameters of benzoylecgonine (BE) significantly decreased. A decrease in cultured T-lymphocytes proliferation and natural killer (NK) cell activity, a high increase of immunosuppressive cytokines and a switch from Th1-type cytokines to Th2-type cytokines together with an unbalance toward anti-inflammatory cytokines recovered within 4 h after acute treatment while subsisted for 14 days after chronic treatment. A significant increase in ascorbic acid (AA), reduced glutathione and glutathione reductase (GR) with a simultaneous decrease in oxidized glutathione were observed in the first hours after acute administration. Conversely, the increase in oxidized glutathione and malondialdehyde (MDA) production and the simultaneous depletion of reduced glutathione and ascorbic acid persisted at least 24 h after chronic cocaine treatment as well as the increase in the activities of glutathione reductase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). The results suggest that chronic cocaine administration affects cellular enzyme and non-enzyme-mediated antioxidant defence systems and promotes immunotoxicity in rat. Cocaine N-oxidative metabolism may be an indirect contributor, via oxidative stress.

Automated amplified flow immunoassay for cocaine

An amplified flow immunoassay (AFIA) was developed for cocaine, which combines a noncompetitive immunoenzymometric assay (IEMA) with an on-line detection of the enzyme label alkaline phosphatase (ALP) by a substrate-recycling biosensor. In the IEMA, the analyte cocaine first binds to a labeled polyclonal anti-cocaine antibody. Then, the excess labeled antibody is separated on an affinity column that contains a perfusion chromatography carrier modified by immobilized cocaine. The unbound complexes of the analyte cocaine with the ALP-labeled antibody are detected postcolumn. The detector senses phenol produced by ALP from phenyl phosphate. As detector, an amperometric substrate-recycling biosensor was used, which consists of a Clark-type oxygen electrode covered by tyrosinase and pyrroloquinoline quinone-dependent glucose dehydrogenase. The lower limit of detection is 380 pM (38 fmol) for cocaine. The sampling rate is 26/h. Cocaine could be detected from "real samples" with an imprecision of +/- 10% (n = 3) and with a recovery of 49 +/- 3% for various concentrations. AFIA is generally important as a new approach for the fast detection of picomolar concentrations of haptens.