Analysis of the major metabolite of delta 9-tetrahydrocannabinol in urine II. A HPLC procedure

Effects of varying marijuana potency on deposition of tar and delta9-THC in the lung during smoking

To determine whether smoking more, compared to less, potent marijuana (MJ) cigarettes to a desired level of intoxication ("high") reduces pulmonary exposure to noxious smoke components, in 10 habitual smokers of MJ, we measured respiratory delivery and deposition of tar and delta9-tetrahydrocannabinol (THC), carboxyhemoglobin (COHb) boost, smoking topography, including cumulative puff volume (CPV) and breathholding time, change in heart rate (deltaHR) and "high" during ad lib smoking of 0, 1.77, and 3.95% MJ cigarettes on 3 separate days. At each session, subjects had access to only a single MJ cigarette. On average, smoking topography and COHb boost did not differ across the different strengths of MJ, while THC delivery, as well as HR, were significantly greater (p < 0.01) and tar deposition significantly less (p < 0.03) for 3.95% than 1.77% MJ. Although individual adaptations in smoking topography for 3.95% compared to 1.77% MJ were highly variable, three subjects with the lowest 3.95% MJ:1.77% MJ ratios for CPV also displayed the lowest 3.95% MJ:1.77% MJ ratios for tar deposition. In vitro studies using a standardized smoking technique revealed a mean 25% lower tar yield from 3.95% than 1.77% MJ (p < 0.05), but no difference between 1.77% and 0% marijuana. Under the conditions of this study, we conclude that tar delivery is reduced relative to THC content in a minority of subjects, and this reduction appears to be due to a reduced intake of smoke (decreased CPV) and/or a reduced tar yield from the stronger MJ preparation.

Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs

Requirements for the provision of an efficient and reliable service for drugs of abuse screening in urine have been summarized in Part I of this review. The requirements included rapid turn-around times, good communications between requesting clinicians and the laboratory, and participation in quality assessment schemes. In addition, the need for checking/confirmation of positive results obtained for preliminary screening methods was stressed. This aspect of the service has assumed even greater importance with widespread use of dip-stick technology and the increasing number of reasons for which drug screening is performed. Many of these additional uses of drug screening have possible serious legal implications, for example, screening school pupils, professional footballers, parents involved in child custody cases, persons applying for renewal of a driving licence after disqualification for a drug-related offence, doctors seeking re-registration after removal for drug abuse, and checking for compliance with terms of probation orders; as well as pre-employment screening and work-place testing. In many cases these requests will be received from a general practitioner or drug clinic with no indication of the reason for which testing has been requested. This also raises the serious problems of a chain of custody, provision of two samples, stability of samples, and secure and lengthy storage of samples in the laboratory-samples may be requested by legal authorities several months after the initial testing. The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Production of substituted phenethylamines was facilitated by the drug makers' cook book, 'PIHKAL' (Phenethylamines I Have Known And Loved) by Dr Alexander Shulgin and Ann Shulgin, and production of substituted tryptamines is promised in their next book, TIHKAL. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles. Toxicological investigations are likely to be challenged more frequently in the future. Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.

Detection and quantification of low concentrations of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid from minimal amounts of urine

A simple liquid-liquid extraction and GC/MS-method for detection and quantification of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) from merely 1 ml urine is described. The derivatisation to the methyl ester was carried out using methyl iodide and mefenamic acid was used as internal standard. Experiments with urine spiked with 15 ng THC-COOH/ml resulted in a recovery of 91%. Excellent linearity was obtained over the range 5-100 ng/ml.

Solid-phase extraction of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid from human urine with gas chromatographic-mass spectrometric confirmation

A selective and sensitive technique has been developed for detecting and identifying 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in human urine. Using a new, "mixed-mode", bonded silica gel, solid-phase extraction column cartridge, THC-COOH was selectively isolated from urine components. Following extraction, the presence of THC-COOH was confirmed and quantitated using gas chromatography-mass spectrometry (GC-MS) or gas chromatography-flame ionization detection. A linear quantitative response curve for THC-COOH was generated over a concentration range of 10 to 300 ng/ml. Overall extraction efficiency averaged greater than 85% and the quantitative response curve exhibited a correlation coefficient of 0.999. The limit of detection and identification using GC-MS for the drug metabolite was found to be six times below the present NIDA guidelines cut-off concentration of 15 ng/ml.

Accuracy of common drug screen tests

Forty consecutive urine specimens, obtained from patients seen in the emergency center, positive for either cocaine and/or marijuana, were analyzed using five methods of analysis. A new latex agglutination inhibition assay, Abuscreen OnTrak, (Roche Diagnostic Systems, Nutley, NJ), was compared with four other drug abuse assays: mass spectrometry, (Hewlett-Packard Co, Richardson, TX); an automated homogeneous enzyme immunoassay technique, ETS System, (Syva Co, Palo Alto, CA); a manual enzyme multiplied immunoassay technique; EMIT-st, (Syva); and a fluorescence polarization immunoassay, TDx, (Abbott Laboratories, Chicago, IL). For statistical purposes, mass spectrometry was the reference point for the presence or absence of a specific substance. All instrument sensitivities, with the exception of mass spectrometry, were set with the same "cut off" point of 100 micrograms/L for marijuana and 300 micrograms/L for cocaine and its metabolites. Efficiency in the detection of cocaine and its metabolites was 95% by all methods. Efficiency for the detection of marijuana and its metabolites ranged from 70% (Roche's OnTrak) to 90% (Syva's ETS). Simple to use, assays of minimal cost are presently available for rapid, accurate drug of abuse screening.

Neonatal body proportionality and body composition after in utero exposure to cocaine and marijuana

The relationship of maternal use of marijuana and cocaine during pregnancy to measures of neonatal body proportionality and body composition was assessed in a multiethnic sample of 1082 newborn infants. Maternal use of marijuana and cocaine during pregnancy was ascertained by self-report and by an enzyme-multiplied immunoassay technique for screening of urine samples obtained prenatally and again post partum. After each substance was analytically controlled for use of the other and for other potentially confounding variables, detection of marijuana metabolites in maternal urine was associated (p less than 0.05) with depressed mean arm muscle circumference and nonfat area of the arm but not with any measure of neonatal fatness. In contrast, detection of cocaine in maternal urine was associated (p less than 0.05) with decrements of subscapular fat folds and of the fat and nonfat areas of the arm. Although both substances were associated with depressed birth weight, there was no decrement of neonatal ponderal index or of the arm circumference/head circumference ratio in association with exposure to either substance. We conclude that both marijuana exposure and cocaine exposure during pregnancy are associated with symmetric intrauterine growth retardation, but that deficits are in differing compartments of intrauterine growth. These findings suggest that marijuana may retard fetal growth through maternal-fetal hypoxia, whereas cocaine may alter nutrient transfer to the fetus and fetal metabolism.

Violence during pregnancy and substance use

Violent incidents were assessed as part of a prospective study of 1,243 pregnant women. Participants were predominantly poor, urban, minority group women. Seven percent (n = 92) of women reported physical or sexual violence during pregnancy. Most of the women (94 percent) knew their assailant. Victims of violence were at greater risk of having a history of depression and attempted suicide, having more current depressive symptoms, reporting less happiness about being pregnant, and receiving less emotional support from others for the current pregnancy. Comparisons of victims and non-victims showed that victims were more likely to be users of alcohol and drugs. In addition, partners of victims were more likely to use marijuana and cocaine. When possible confounders were controlled using multivariable analyses, a woman's alcohol use during pregnancy and her partner's drug use were independently associated with an increased risk of being a victim of violence during pregnancy. Results of this study highlight the importance of assessing exposure to violence during prenatal care, especially among women who are heavy users of alcohol or drugs or whose partners use these substances.

Effects of maternal marijuana and cocaine use on fetal growth

To investigate the effects on infants of the use of marijuana and cocaine during pregnancy and to compare the importance of urine assays with that of interviews in ascertaining drug use, we prospectively studied 1226 mothers, recruited from a general prenatal clinic, and their infants. On the basis of either interviews or urine assays conducted prenatally or post partum, 27 percent of the subjects had used marijuana during pregnancy and 18 percent had used cocaine. When only positive urine assays were considered, the corresponding values were 16 percent and 9 percent, respectively. When potentially confounding variables were controlled for in the analysis, the infants whose mothers had positive urine assays for marijuana, as compared with the infants whose mothers were negative according to both interviews and urine assays, had a 79-g decrease in birth weight (P = 0.04) and a 0.5-cm decrement in length (P = 0.02). Women who had positive assays for cocaine, as compared with nonusers, had infants with a 93-g decrease in birth weight (P = 0.07), a 0.7-cm decrement in length (P = 0.01), and a 0.43-cm-smaller head circumference (P = 0.01). To compare our findings with those of other investigators who did not use urine assays, we repeated the analyses, considering only self-reported use of marijuana (23 percent) and cocaine (13 percent). There were no significant associations between such use as determined by interviews alone and any of the measures of outcome. We conclude that the use of marijuana or cocaine during pregnancy is associated with impaired fetal growth and that measuring a biologic marker of such use is important to demonstrate the association.

Optimization of the quantitative analysis of the major cannabis metabolite (11-nor-9-COOH-delta 9-tetrahydrocannabinol) in urine by gas chromatography/mass spectrometry

A gas chromatographic/mass spectrometric electron impact method is presented for the detection and quantification of 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (THC-COOH) in urine, for use in the confirmation of presumptive results obtained by other techniques. Four extraction procedures, two solid-liquid and two liquid-liquid, have been compared. A comparison of two trimethylsilylating methods demonstrates that the best results are obtained by the use of a mixture containing N-methyl-N-trimethylsilyl-trifluoroacetamide, trimethyliodosilane and dithioerithritol (100:0.2:1) v/v/w. The use of ketoprofen as a new internal standard for the quantification of THC-COOH has proved to be very effective. Both spiked samples and samples from cannabis users have been successfully analysed. It has also been demonstrated that the presence of other drugs of abuse in urine samples do not interfere with cannabis quantification by the method reported here.

Direct injection of urine on a high-performance liquid chromatographic column-switching system for determination of delta 9-tetrahydrocannabinol-11-oic acid with both ultraviolet and electrochemical detection

A method is presented for determination of delta 9-tetrahydrocannabinol-11-oic acid in urine by means of a fully automated liquid chromatographic system. Aliquots (200 microliter) of hydrolysed urine from prison inmates were directly injected onto a pre-column, followed by chromatography on two columns with different selectivity: CN and C8 columns. To obtain both greater selectivity and a low detection limit a twin-detector principle was used, consisting of both ultraviolet and electrochemical detection. Urine samples found to be positive with the EMIT cannabinoid were analysed, and the results were compared with those obtained from a well established gas chromatographic-mass spectrometric method. The precision of the method was 2.8% at a mean concentration of 85 ng/ml and 13.4% for 6 ng/ml of the acid. The detection limit was below 5 ng/ml.

Marijuana testing--how good is it?

Testing for the use of marijuana necessitates one or more levels of assessment, depending on the clinical application of the test results. The EMIT-dau screening test with a sensitivity limit of 20 ng/ml is highly satisfactory for screening for the absence of marijuana in the urine. This test has a virtual 100% true-negative rate as long as an unadulterated urine specimen is analyzed. Positive results by the EMIT-dau procedure are presumptive because the test seems to produce false-positive results when applied to a random population of suspected drug users. In a population in a specific clinical environment such as in drug-treatment programs in which 20 of every 100 specimens will yield positive THC-COOH results by EMIT-dau screening, 3 (15%) of the 20 positive results will likely be false-positive. Our experience with the EMIT-dau suggests that of 100 test results, 3 will be false-positive, an overall 3% false-positive rate. If a positive test result will put the patient in considerable jeopardy and the screening result is the only evidence of drug use, confirmatory testing is imperative. Of the confirmatory tests, GC/MS seems to have the specificity necessary to provide a high level of confidence in the results. A combination of the EMIT procedure with a sensitivity level of 20 ng/ml and GC/MS confirmation yields virtually 100% accuracy in detection of marijuana abuse.

Maternal marijuana use and neonatal outcome: uncertainty posed by self-reports

To assess the validity of self-reported marijuana use during pregnancy, this study randomly allocated pregnant women into a group who were told their urine would be tested for marijuana, alcohol, and other drugs and another group not so tested. Women told they would be tested reported more marijuana use during pregnancy than did untested women. Moreover, urine assays identified more women who used marijuana during pregnancy than were willing to admit it in the interview even after being told their urine would be tested. No differences in reported drinking or cigarette smoking during pregnancy were found between tested and untested women.

Analysis of 5-(4-acetamidophenyl)pyrazin-2(1H)-one (SK&F 94120) in plasma with an Analytichem automated sample processor liquid chromatography module

A selective and specific assay for 5-(4-acetamidophenyl)pyrazin-2(1H)-one (SK&F 94120), a novel inotropic agent, has been developed. The method incorporates a liquid-solid extraction step with a C18 Analytichem automated sample processor (AASP) cassette, which consists of ten miniature extraction columns. The cassette is then loaded into the AASP auto injector, ready for automated liquid chromatography with UV detection. The AASP consists of a high-pressure sealing chamber which encapsulates each column. The high-performance liquid chromatographic mobile phase is directed through the chamber, and the analytes are eluted onto the analytical column for subsequent separation and measurement. The assay is sufficiently accurate and precise to determine SK&F 94120 at concentrations as low as 0.5 mg/l. The mean coefficient of variation for the concentration range 0.5-10.0 mg/l was 2% with a bias of +/- 1%. The assay has been used for pharmacokinetic and bioavailability studies in several species, including rat, dog, and cynomolgus monkey.

Monitoring urine for inhaled cannabinoids

The current position on the "passive smoking" of cannabis is reviewed with particular reference to the analysis of urine. The pharmacokinetics and metabolism of delta-9-tetrahydrocannabinol are first described, followed by a survey of methods used to identify and quantify its metabolites in urine. Published data concerning the appearance of cannabinoids in urine following "passive smoking" of cannabis are compared and the most important factors described. The problems of interpreting the results of the analysis of urine in forensic cases are discussed and a possible means to clarify the position by means of analysing serum is suggested.