Segmental analysis for cocaine and metabolites by HPLC in hair of suspected drug overdose cases

Hair samples of eight postmortem cases were analyzed in segments of 1 to 3 cm for cocaine, benzoylecgonine and cocaethylene. Samples were prepared for analysis by digestion in 0.1 M HCl and subsequent extraction with mixed-mode solid-phase extraction columns. Measurement was made by reversed-phase, narrow-bore HPLC and fluorescence detection using two laboratory-made internal standards. The concentrations were in the region of 0.29-316 ng/mg of hair for cocaine, 0.43-141 ng/mg of hair for benzoylecgonine and 0.93-1.83 ng/mg of hair for cocaethylene. All eight investigated cases had cocaine-positive segments. In six of the cases, all segments were positive, suggesting regular cocaine use and two showed in-between negative segments indicating an interruption or a change of the abuse intensity. The results showed a second, remarkable observation, i.e. enormous concentration differences (factor >150) for both cocaine and benzoylecgonine between the different subjects. Furthermore, interindividual cocaine/benzoylecgonine ratios ranged from 0.02 to 8.43. We believe these observations could in part be attributed to both some of the still existing limitations in the analytical approach(es), especially the mandatory hair washing steps, and in our still too limited knowledge of the hair incorporation processes. Nevertheless, in some cases, segmental analysis proved to be an important tool to distinguish, together with postmortem examination, deadly chronic abuse from single acute drug overdosage.     

Simultaneous quantification of opiates, cocaine and cannabinoids in hair

The present paper describes a sensitive method developed in our laboratory for the simultaneous analysis of opiates (morphine, codeine and monoacetylmorphine), cocainics (cocaine and benzoylecgonine) and cannabinoids (Δ⁹-tetrahydrocannabinol and 11-nor-Δ⁹-tetrahydrocannabinol-9-carboxylic acid) in hair samples. After decontaminating the sample with dichloromethane, two consecutive hydrolyses were performed in order to achieve the best conditions for extracting the three kinds of drugs from the protein matrix. First the opiate and cocainic compounds were extracted by means of a soft acidic hydrolysis with 0.1 N HCl at 50 °C overnight and organic solvent extraction at pH 9.2. The cannabinoids need a stronger basic hydrolysis with 11.8 N KOH for 10 min at laboratory temperature. After adding maleic acid, the cannabinoids were extracted with an organic solvent. The derivatization was carried out with heptafluorobutyric anhydride and hexafluoropropanol. Calibration curves were linear between 0.5–100 ng/mg of hair. Recovery and reproducibility were assured. The quantification limits ranged between 0.04–0.26 ng/mg of hair. Seventy hair samples from known drug abusers were cut into 1-cm segments and analyzed by this method. The ranges of measured concentrations (ng/mg) were 0.31–89 for cocaine, 0.1–5.76 for benzoylecgonine, 0.34–45.79 for morphine, 0.45–39.59 for codeine, 0.09–48.18 for monoacetylmorphine, 0.06–7.63 for THC and 0.06–3.87 for THC---COOH. The results of sectional analyses agreed with the self reported drug histories. The usefulness of this method is in assessing earlier drug consumption, and also at the same time obtaining a chronological profile of the consumption of these three types of drugs.     

Levels of cocaine and its metabolites in washed hair of demonstrated cocaine users and workplace subjects

In a study of subjects in drug rehabilitation programs, cocaine and cocaine metabolite levels were determined in the hair of 75 subjects who had produced cocaine-positive urine results. The hair was analyzed after being washed with the 3.75 h wash procedure developed by this laboratory. In addition, results of testing 73 non-users are presented, as well as levels of cocaine, benzoylecgonine (BE), cocaethylene, and norcocaine from workplace population samples. The data support a recommendation of reporting as positive a sample with cocaine of 500 pg/mg hair and either a 5% ratio of benzoylecgonine (BE) to cocaine in samples, or the presence of cocaethylene at 50 pg/mg hair, or norcocaine at 50 pg/mg hair for samples < or =2000 pg cocaine/mg hair. For samples with cocaine present at >2000 pg/mg hair, the data indicate that a ratio of 5% BE may be an overly conservative approach. In appropriately washed hair samples, cocaine users can produce hair levels of <5% BE and thus a minimum BE cutoff in lieu of a ratio could be considered.     

Simultaneous determination of opiates,cocaine and major metabolites of cocaine in human hair by gas chromotography/mass spectrometry (GC/MS)

A procedure is presented for the simultaneous identification and quantification of morphine (MOR), codeine (COD), ethylmorphine (EM), 6-monoacetylmorphine (6-MAM), cocaine (COC), benzoylecgonine (BZE), ecgonine methylester (EME) and cocaethylene (CE), contained in the hair of opiates and cocaine addicts. The method involves decontamination in dichloromethane, pulverization in a ball mill, heat-acid hydrolysis, addition of deuterated internal standards, liquid-liquid extraction and gas chromatography/mass spectrometry (GC/MS) after silylation. The limit of detection (LOD) was ~0.1–0.8 ng/mg for each drug, using a 30-mg hair sample. The method is reproductible, with a coefficient of variation (CV) of ~8–17%. Cocaine and 6-monoacetylmorphine were the major compounds detected in cases of cocaine (14 cases) and heroin (68 cases) intake. Concentrations were in the range 0.4–78.4 ng/mg (COC), 0.0–36.3 ng/mg (BZE), 0.0–1.6 ng/mg (EME), 0.0–2.1 ng/mg (CE), 0.0–84.3 ng/mg (6-MAM), 0.2–27.1 ng/mg (MOR) and 0.1–19.6 ng/mg (COD). An application in forensic sciences, involving multi-sectional analysis, is given.     

Gas chromatographic detection of cocaine and cocaethylene in hair of mice chronically injected with cocaine or cocaethylene and fed ethanol.

GC and GC/MS analysis was used to detect cocaine and cocaethylene in hair extracts of mice injected with 20 mg/kg cocaine hydrochloride or an equivalent dose of cocaethylene fumarate twice daily for 3 weeks. Some mice were fed liquid Lieber-DeCarli diets containing ethanol (26% of total calories) and injected twice daily with the same doses of cocaine or cocaethylene or combination of cocaine and morphine (5 mg/kg). The average concentrations of cocaine in different experimental groups were in the range of 0.9-2.4 ng/mg of hair and for cocaethylene, 2.4-2.8 ng/mg of hair. There were no significant differences in hair concentrations of cocaine among groups receiving cocaine treatment, nor were there significant difference in cocaethylene concentration in hair in the two groups administered cocaethylene. In hair extracts of mice treated with cocaine and ethanol, levels of cocaethylene were below the limit of detection.     

Optimized conditions for simultaneous determination of opiates, cocaine and benzoylecgonine in hair samples by GC--MS

The present paper describes a qualitative and quantitative method for the simultaneous detection of opiates, cocaine and benzoylecgonine from human hair samples. Every step of the analytical procedure was studied to find the optimized conditions. Nine different incubation systems were examined. The influence of different pH values of samples on the isolation of analytes from the incubation media by Bond Elut cartridges and the stability of the compounds of interest in the different incubation media and conditions were investigated. The extracting power of different incubation media was studied as well. The phosphate buffer 0.1 N at pH 5 was chosen as the extraction medium in an optimized procedure for simultaneous determination of opiates, cocaine and benzoylecgonine in hair samples. The method developed was validated. Recoveries were 90% for morphine (M), 81% for 6-monoacetylmorphine (6-AM), 90% for codeine (CD), 86% for cocaine (C) and 90% for benzoylecgonine (BE). Relative standard deviation for inter-day precision was better than 12%. The limits of detection resulted as 0.05 ng/mg for M and C, as 0.08 for 6-AM and as 0.2 ng/mg for BE. Forty hair samples collected from drug abusers admitted to centers for detoxification treatment were analyzed obtaining 23 positive results for opiates and/or cocaine. Twelve hair specimens longer than 10 cm were analyzed following a sectional approach. In the six positive cases, it was interesting to find that the 6-AM/M ratio generally decreased for each sample from the proximal segment to the distal segments. Moreover, the 6-AM/M ratio was generally lower than 1 in the intermediate and distal segments.     

Testing human hair for drugs of abuse. IV. Environmental cocaine contamination and washing effects

Active cocaine use results in sequestration of parent drug in hair. In addition, hair has unique physicochemical properties that permit absorption of cocaine from the environment. When hair is tested for evidence of cocaine, it is important to consider whether the positive test resulted from active drug use or environmental contamination. In a series of laboratory experiments, it was found that exposure of ‘cut’ hair to cocaine vapor (‘crack’ smoke) and to aqueous solutions of cocaine hydrochloride resulted in significant contamination of hair samples. Similar results were obtained with two subjects who were exposed to cocaine vapor in an unventilated room. The amount of contamination adsorbed by hair depended upon both time and extent of exposure. Washing the hair samples with methanol removed >70% of the cocaine contaminant after cocaine vapor exposure, but was less effective (<50%) following contamination with aqueous cocaine. Shampoo treatment cycles (overnight soaking) progressively removed increasing amounts of cocaine from the contaminated hair, but residual cocaine remained after 10 cycles. Studies were also performed to determine the usefulness of benzoylecgonine as a marker of active cocaine administration. Small amounts of benzoylecgonine (ca. 1 ng/mg) were formed in hair as a result of environmental contamination with cocaine. Also, it was found that benzoylecgonine could be adsorbed from illicit cocaine contaminated with benzoylecgonine. It was concluded that positive hair test results should be interpreted cautiously due to the possibility of environmental contamination from cocaine and related constituents.     

Evaluation of the IDS One-Step™ ELISA kits for the detection of illicit drugs in hair

This work presents the validation of a new immunological assay, the One-Step™ enzyme-linked immunosorbent assay (ELISA) tests from International Diagnostic Systems Corp. for the screening of drugs of abuse (cannabis, amphetamines, opiates, and cocaine) in human hair, with subsequent GC–MS confirmation. After decontamination and segmentation into small pieces, 50 mg of hair sample were incubated in 1 ml of methanol during 16 h at 40 °C. A 100 μL aliquot was collected and evaporated to dryness in presence of 100 μL of methanol/hydrochloric acid (99:1, v/v) to avoid amphetamines loss. The dried extract was dissolved in 100 μL of the “sample and standard diluent” solution included in the kit. This solution was submitted to analysis according to the recommended instructions of the manufacturer. During the validation phase, GC–MS confirmations were conducted according to our fully validated and published methods for opiates, cocaine, cannabis, and amphetamines determinations in hair. In a last development step, these procedures were slightly modified to directly confirm ELISA results by GC–MS using the methanolic extract. Ninety-three specimens were simultaneously screened by the ELISA tests (103 for tetrahydrocannabinol (THC)) and confirmed by GC–MS. Twenty were found positive for cannabis (THC: 0.10–6.50 ng/mg), 21 for cocaine (0.50–55.20 ng/mg), 24 for opiates (6-acetylmorphine (6-AM): 0.20–11.60 ng/mg, MOR: 0.20–8.90 ng/mg, codeine (COD): 0.20–5.90 ng/mg), and 13 for amphetamines (AP: 0.20 and 0.27 ng/mg, methamphetamine (MAP): 0.30 and 1.10 ng/mg, methylenedioxymethamphetamine (MDMA): 0.22–17.80 ng/mg). No false negative results were observed according to the Society of Hair Testing's (SoHT) cutoffs (0.5 ng/mg for cocaine, 0.2 ng/mg for opiates and amphetamines, and 0.1 ng/mg for THC). The One-Step™ ELISA kits appear suitable due to their sensitivity and specificity for drug of abuse screening in hair. This technology should find interest in workplace drug testing or driving license regranting, especially when many samples have to be tested with a high rate of negative samples, as ELISA is an easy and high-throughput method.     

Correlation of the incidence of cocaine and cocaethylene in hair and postmortem biologic samples

Hair samples are useful as a matrix for drug testing because drugs can be detected in hair for longer periods than in blood or urine. The authors report a prospective comparison of the detection of cocaine and cocaethylene in routine postmortem biologic specimens to the detection of cocaine and cocaethylene in hair. The authors collected hair samples from various areas of the head in 53 autopsy cases, prepared them, and analyzed them by gas chromatography/mass spectrometry (GC/MS) for cocaine and cocaethylene. The authors compared the results of hair analysis with the results of toxicologic analysis performed on routine postmortem samples by enzyme multiplied immunoassay technique and GC/MS. Cocaine was found in either biologic fluids or in hair in 16 of 53 samples tested. Nine samples were positive for cocaine in both biologic fluids and hair. Five samples contained cocaine only in biologic fluids, and two contained cocaine only in hair. Cocaethylene was present in two cases. Drug screening of hair provides additional information in some autopsy cases, but the authors have not made hair analysis a routine practice. It may prove useful to save hair samples in all cases for later analysis if warranted by additional history or autopsy findings.     

Determination of opiates and cocaine in hair using automated enzyme immunoassay screening methodologies followed by gas chromatographic-mass spectrometric (GC-MS) confirmation

The objective of this study was to develop a two-step strategy for analysis of opiates and cocaine in hair samples involving an immunological screening procedure followed by confirmation of results using gas chromatography-mass spectrometry (GC-MS). A semi-quantitative automated competitive enzyme-linked immunosorbent assay (ELISA) methodology using Oral Fluid Micro-Plate Enzyme Immunoassays (Orasure Technologies, Inc.) was developed and validated. Applicability was proven by analysis of authentic head hair samples from drug users (n=103) and from opiate associated fatalities (n=21). The optimum cutoff values for the ELISA tests were 0.1 ng cocaine-equivalents/mg hair and 0.05 ng morphine-equivalents/mg hair using a 50 mg hair sample. Both ELISA tests had a sensitivity of 100%, the specificity was 66% for cocaine-equivalents and 42% for morphine-equivalents. The intraassay precision was 11% for the cocaine and 3% for the opiates ELISA, while interassay precision was 12% for the cocaine and 4% for the opiates ELISA test. The actual analyte concentrations in the hair samples were determined using GC-MS and were between 0.04 and 5.20 ng/mg for heroin (HER), between 0.04 and 30.01 ng/mg for 6-monoacetylmorphine (MAM), between 0.03 and 11.87 ng/mg for morphine (MOR), between 0.02 and 1.84 ng/mg for codeine (COD), between 0.02 and 2.48 ng/mg for acetylcodeine (AC), between 0.01 and 21.37 ng/mg for cocaine (COC), between 0.03 and 10.51 ng/mg for benzoylecgonine (BE) and between 0.05 and 1.26 ng/mg for cocaethylene (CE). The automated ELISA tests were proven to be valid screening procedures for the detection of cocaine and opiates in hair as confirmed by GC-MS. Screening methods provide rapid and inexpensive automated pre-test procedures to detect drugs in hair or other matrices. For forensic purposes screening therefore represents an ideal complement to routinely applied GC-MS procedures.     

Solid-phase microextraction for the determination of cocaine and cocaethylene in human hair by gas chromatography-mass spectrometry

A method for the simultaneous determination of cocaine (COC) and cocaethylene (CE) in human hair was developed, using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) as analytical technique to identify and quantify the drugs. Selected ion monitoring (SIM) mode was used to obtain higher sensitivity. The deuterated-labeled analogues were used as internal standards. The detector response was linear for the drugs studied over the range 0.4-15 ng/mg, with correlation coefficients higher than 0.995. The coefficients of variation oscillated between 0.65% and 14.18% and the accuracy was in the range from 0.73% to 11.20%. The limits of quantitation and detection were found to be acceptable. Finally, this method was applied to 15 hair samples from cocaine users, obtaining positive results in all cases. The mean concentrations were 5.39 ng/mg (range: 0.43-8.98 ng/mg) for cocaine and 1.11 ng/mg (range: 0.42-2.23 ng/mg) for cocaethylene.     

Simultaneous hair testing for opiates, cocaine, and metabolites by GC-MS: a survey of applicants for driving licenses with a history of drug use

A sensitive GC-MS method for the simultaneous determination of opiates, cocaine, and metabolites in hair at a cut-off level of 0.1 ng/mg was adopted to assess past exposure to these drugs in applicants for driving licenses with a history of drug use. The sampling protocol consisted of collection of one hair (sample A, 5-cm length) and one urine sample. When hair and urine (EMIT Syva, cut-off levels: 0.3 mg/l for opiates, 0.15 mg/l for cocaine, GC-MS confirmation of positives) were both positive or negative the protocol was concluded. In the other cases, the assessment of 'current exposure' to drugs was carried out, in order to avoid seriated random urinalysis, by collecting a second hair sample (sample B) 6 weeks later and analysing the proximal 1-cm segment. Out of the 214 'A' hair samples analyzed, 14 (6.5%) tested positive for morphine and/or 6-acetylmorphine (6AM), and 26 (12%) for cocaine and/or benzoylecgonine (BE), whereas none of the samples tested positive for both drugs. Levels between 0.1 and 1 ng/mg of the single analytes were found in eight out of the 14 morphine-6AM positives (57%) and in 18 out of the 26 cocaine-BE positives (69%). The time course of positive cases showed a progressive decrease of morphine-6AM positives and a corresponding increase of cocaine-BE positives within the study period September 1995-February 1999. No cases with positive urine and negative hair were observed. Among the 40 positive cases, seven (four and three for opiates and cocaine, respectively) were found to be 'currently exposed to drug', four by urinalysis (three and one) and three by analysis of the hair sample B (1 and 2).     

A fatal case of cocaine poisoning in a body packer

A 27-year-old man was carrying in his digestive tract 99 packages each containing about 10 g of a 86% cocaine powder. The courier died by acute cocaine intoxication due to inflation and rupture of four packages during a flight from Bogotá to Rome. At the autopsy, the external examination was unremarkable. The internal examination showed edema and generalized congestion of the organs. Toxicological analyses were performed by gas chromatography-mass spectrometry after solid phase extraction using Bond Elut Certify columns and derivatization with BSTFA/TMCS. High levels of cocaine and benzoylecgonine were found in blood (4.0 microg/mL and 17.0 microg/mL), urine (152.0 microg/mL and 512.0 microg/mL), bile (99.8 microg/mL and 54.0 microg/mL), vitreous humor (7.1 microg/mL and 5.8 microg/mL), brain (7.5 microg/mL and 3.5 microg/mL), and hair (55.5 ng/mg and 27.7 ng/mg). The presence of the cocaine and its metabolite in the hair suggested that the man was a cocaine user.     

Distribution of methamphetamine and amphetamine in drug abusers’ head hair

In order to aid the interpretation of hair results from methamphetamine (MA) abusers the MA and amphetamine (AP) concentrations in 2070 hair samples were statistically evaluated. The MA and AP concentrations in hair were put into three groups arbitrarily representing low, medium and high ranges and the metabolite-to-parent drug ratios of each group were examined. The concentration ranges proposed here were also applied to the interpretation of five authentic cases. The low, medium and high ranges of MA were 0.5–4.2, 4.2–24.5 and 24.5–608.9 ng/mg and those of AP were 0.1–0.4, 0.4–1.7 and 1.7–41.4 ng/mg. The AP-to-MA ratios showed large variation but a tendency that it decreased as the MA ranges increased. This evaluation was very useful to presume the severity of individuals’ MA abuse and to provide law enforcement agencies more understandable information. It could also facilitate the court's decision regarding specific circumstances surrounding the drug-related crimes.     

Hair and urine analysis: relative distribution of drugs and their metabolites

This work studies the distribution of cocaine and heroin metabolites in hair and urine of living polidrug abusers. Cocaine, benzoylecgonine (BEG), ecgonine methyl ester (EME), morphine, codeine and 6-monoacetylmorphine (6-MAM) were simultaneously extracted and analyzed by GC/MS in SIM mode. The results obtained show a different distribution of heroin and cocaine metabolites in urine and hair. In urine, we generally find BEG and EME for cocaine abuse, and morphine for heroin abuse. In hair, we detect cocaine and MAM as major metabolites for cocaine and heroin abuse, respectively.     

Determination of cocaine and its metabolites in brain tissue using high-flow solid-phase extraction columns and high-performance liquid chromatography.

A new solid-phase extraction procedure for the determination of cocaine and some of its metabolites in brain tissue, using high-flow co-polymeric sorbents is reported as a substantial improvement on our recently reported procedure. The recovery of cocaine, norcocaine and cocaethylene was excellent as was the reproducibility of the extraction. The use of high-flow sorbents allowed the easy extraction of tissue without the need for a time-consuming lipase digestion, regardless of sample viscosity or physical nature. The use of these solid-phase columns provided many advantages over the more commonly used solvent extraction, including an increase in extraction speed and efficiency, reduced operator time, reduced solvent use and disposal volumes and exceptional extract quality. The procedure was successfully applied to rabbit brains spiked with cocaine, benzoylecgonine, norcocaine and cocaethylene.     

Confirmation by LC–MS of drugs in oral fluid obtained from roadside testing

The aim of this study was to assess the effectiveness of two current on-site oral fluid (OF) drug detection devices (OraLab and Dräger), as part of the Spanish participation in the Roadside Testing Assessment Project (ROSITA Project). The study was done in collaboration with the Spanish Traffic Police, in Galicia (NW Spain), during 2004 and 2005. A total of 468 drivers selected at the police controls agreed to participate through informed consent. In addition, saliva samples were collected and sent to the laboratory to confirm the on-site results. For this purpose, two different analytical liquid chromatography–mass spectrometry (LC–MS) methods were used to detect 11 drugs or metabolites in a 300 μL sample. Simultaneous analysis of morphine, 6-acetylmorphine, amphetamine, methamphetamine, MDA, MDMA, MDEA, MBDB, cocaine and benzoylecgonine was carried out using 100 μL of oral fluid, after an automated solid phase extraction. A different LC–MS method was performed to detect Δ⁹-THC in 200 μL of oral fluid using liquid–liquid extraction with hexane at pH 6. Both methods were fully validated, including linearity (1–250 ng/mL, 2–250 ng/mL) recovery (>50%), within-day and between-day precision (CV < 15%), accuracy (mean relative error < 15%), limit of detection (0.5 and 1 ng/mL), quantitation (1 and 2 ng/mL) and matrix effect. All of the positive cases and a random selection of 30% of the negatives were analyzed for confirmation analysis. Good results (sensitivity, specificity, accuracy, positive predictive value and negative predictive value > 90%) were obtained for cocaine and opiates by OraLab, and for cocaine by Dräger. However, the results for the other compounds could be improved for both detection devices. Differences in the ease of use and in the interpretation mode (visual or instrumental) were observed.     

Distribution of drugs of abuse within specific regions of the human brain

Since concentration of drugs of abuse found in the brain better reflect drug concentration at their site of action, brain specimens are useful in the determination of the role of drugs of abuse in the cause of death. In order to allow for the routine use of brain specimens in this field, a comprehensive database with reliable reference values is needed and should include both post-mortem data for cases where drugs have been taken in therapeutic doses as well as for cases of overdose. In this study, a semi-automated extraction procedure, in combination with gas chromatography/mass spectrometry (GC–MS) using stable isotope internal standards was applied to yield reproducible, quantitative results which could be used to investigate the distribution patterns of drugs of abuse within specific regions of the brain, by analyzing several segments of both medulla oblongata and cerebellum. A homogenous distribution of unconjugated morphine, dihydrocodeine, and benzoylecgonine within the investigated segments of medulla oblongata or cerebellum could be found. However, when these two brain regions from the same case were compared to each other, significantly higher concentrations of unconjugated morphine, dihydrocodeine, and benzoylecgonine were found in the cerebellum than in the medulla oblongata.     

Tandem mass spectrometry: a helpful tool in hair analysis for the forensic expert

The Bavarian State Bureau of Investigation in Munich has the exclusive responsibility for investigation of criminal acts. One considerable expertise is that of hair analysis. According to the legal system in Germany, there is a special interest when some clients' hair tested positive for illicit drugs. An accused with a lot of drugs in his hair will be treated as a supposed addict and will be guaranteed extenuating circumstances. The instrumentation used for hair analysis is a powerful analytical tool: a Varian 3400 gas chromatograph linked to a Finnigan Tandem-MS (TSQ 700). The methanol extraction method is used for the detection of illegal drugs and metabolites: amphetamine, methamphetamine, MDA, MDMA (ecstasy), MDE, MBDB, methadone, THC, EDDP (metabolite of methadone), cocaine, benzoylecgonine, cocaethylene, opiates (dihydrocodeine, codeine, heroin, 6-monoacetylmorphine, morphine, acetylcodeine). For the detection of 9-carboxy-THC by negative chemical ionization the hair sample is hydrolyzed under alkaline conditions. Solid-phase extraction is used for clean-up. The LOQ for the determination of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic-acid is 0.16 pg/mg hair. An unsurpassed combination for rendering an expert opinion based on hair analysis may be: a forensic expert using diligence and experience, coupled with the performance of a sophisticated analytical instrument.     

Brain concentrations of cocaine and benzoylecgonine in fatal cases

Since cocaine in blood rapidly hydrolyzes to benzoylecgonine, cocaine concentrations determined in postmortem blood may not reflect the presence or concentration of cocaine in the body at the time of death. The interpretative value of the determination of cocaine and benzoylecgonine in brain tissue was investigated. Cocaine and benzoylecgonine were quantitated by coextraction and formation of the propyl derivative of benzoylecgonine followed by selected ion monitoring gas chromatography/mass spectrometry (GC/MS) using electron ion impact ionization. Cocaine and benzoylecgonine were found to be evenly distributed throughout the brain. Cocaine and benzoylecgonine concentrations were stable in frozen brain tissue (-4 degrees C) on reanalysis after 1 to 3 months of storage, and in refrigerated tissue (10 degrees C) after 30 days of storage. Blood, brain, and liver concentrations of cocaine and benzoylecgonine in 37 cocaine overdose cases and 46 cases in which cocaine was incidental to the cause of death were reviewed. The ratios of cocaine/benzoylecgonine in the toxic cases (brain mean 14.7 and blood mean 0.64) were clearly different from those found in the incidental cases (brain mean 0.87 and blood mean 0.27). The brain/blood ratios of cocaine and benzoylecgonine concentrations generally were characteristic of the time elapsed since cocaine dosing. In cocaine overdose cases, the mean ratio was 9.6 for cocaine and 0.36 for benzoylecgonine. These are within the range found in animal studies for brain/blood ratios of cocaine and benzoylecgonine 0.5 to 2 h after cocaine administration. In incidental cases, the brain/blood ratios were mean 2.5 for cocaine and 1.4 for benzoylecgonine.(ABSTRACT TRUNCATED AT 250 WORDS)