Temporal indication of marijuana use can be estimated from plasma and urine concentrations of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol, and 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid

Current technology establishes marijuana use based upon detection of the pharmacologically inactive cannabinoid metabolite (11-nor-delta9-carboxy-tetrahydrocannabinol-9-carboxylic acid, THC-COOH) in urine. No accurate prediction of time of use is possible because THC-COOH has a half-life of 6 days. To determine if a temporal relationship between marijuana use and metabolite excretion patterns could be established, eight healthy user-volunteers (18-35 years old) smoked marijuana cigarettes containing 0% (placebo), 1.77%, and 3.58% delta9-tetrahydrocannabinol (THC). Plasma and urine were collected prior to smoking, 5 min after smoking, and hourly thereafter for 8 h for measurement of cannabinoid concentrations by gas chromatography-mass spectrometry. Mathematical models proposed for determination of recent marijuana use were applied to data from this study and verified the temporal use of marijuana. One subject, who later admitted chronic marijuana use (urine baseline THCCOOH, 529.2 ng/mL; plasma, 75.5 ng/mL), excreted 8beta-dihydroxy-THC, peaking 2 h postsmoking (92.3 ng/mL). Urinary THC, the psychoactive component of marijuana, concentrations peaked 2 h after smoking and declined to assay limit of detection (LOD) (1.5 ng/mL) by 6 h. 11-Hydroxy-delta9-tetrahydrocannabinol (11-OH-THC) and THCCOOH were detectable for the entire 8-h testing period but continued to decrease. Urinary concentrations of THC greater than 1.5 ng/mL suggests marijuana use during the previous 8-h time period.     

Cannabinoid concentrations in plasma after passive inhalation of marijuana smoke

delta-9-tetrahydrocannabinol (THC) and its metabolite, 9-carboxy-THC, were detected in the plasma of a subject during a one-hour passive exposure to the smoke from four marijuana cigarettes containing a total of 104.8 mg of THC. Plasma concentrations of THC were determined by RIA and reached an apparent steady-state concentration of 2.2 ng/mL after 20 minutes of exposure. The presence of THC was confirmed by GC/MS analysis. Results from the two analyses exhibited excellent correlation (r = 0.990), although the concentrations determined by GC/MS were higher than those determined by RIA. Concentrations of 9-carboxy-THC were also determined by GC/MS, and remained consistently below the GC/MS determined concentrations of THC. By administering an infusion of THC, the dose that was inhaled and absorbed during the passive exposure was estimated to be 3.2 micrograms/min.     

Confirmation of cannabis use. II. Determination of tetrahydrocannabinol metabolites in urine and plasma by HPLC with ECD

Simultaneous determination of delta 9-tetrahydrocannabinol (THC) and its major metabolites--11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and 11-hydroxy-delta 9-tetrahydrocannabinol (11-OH THC)--in urine and plasma by HPLC with electrochemical detection (LC/EC) was studied. After biological fluids were hydrolyzed, samples were extracted with an automatic extractor and analyzed by LC/EC. HPLC was carried out with a reversed-phase silica C8 column and a mobile phase of acetonitrile/methanol/0.02N H2SO4 (35:15:50) at 1.8 mL/min. Coefficients of variation at 10-500 ng/mL of THC metabolites were 2.19-5.91%. The detection limit was under 0.5 ng/mL (S/N greater than 3). Time course of excretion of THC and THC-COOH in rabbit urine was studied. THC-COOH could be detected until 216 h after administration. By this method, urine samples of suspects arrested in Japan were tested.     

Review of biologic matrices (urine, blood, hair) as indicators of recent or ongoing cannabis use

Especially for cannabinoids, analytical procedures for the verification of recent use and generally for the assessment of the extent of drug abuse are of interest in clinical and forensic toxicology. For confirmation of abstinence, urine analysis seems to be a useful tool. Serial monitoring of THC-COOH to creatinine ratios can differentiate between recent drug use and residual THC-COOH excretion (THC-COOH/creatinine ratio > or = 0.5 compared with previous specimen ratio). For an assessment of the extent of cannabis use, the determination of free and bound THC-COOH and especially of THC and 11-OH-THC glucuronides are suggested as useful but need further confirmation. Blood analysis is preferred for the interpretation of acute effects after cannabis abuse. The cannabis influence factor (CIF) was demonstrated as a better tool to interpret the concentrations of THC and its metabolites in blood in forensic cases and therefore it was proposed to assume absolute driving inability because of cannabis intoxication from a CIF > or = 10. Additionally, a higher CIF is indicative of a recent cannabis abuse. Also discrimination between occasional use of cannabis and regular drug consumption is possible by analysis of THC-COOH in blood samples because of the long plasma half-life of THC-COOH and its accumulation in the blood of frequent cannabis consumers. In routine tests, blood samples have to be taken within a prescribed 8-day-period, and a THC-COOH concentration >75 ng/mL is assumed to be associated with regular consumption of cannabis products, whereas plasma THC-COOH concentrations <5 ng/mL are associated with occasional consumption. In contrast to other illicit drugs, hair analysis lacks the sensitivity to act as a detector for cannabinoids. THC and especially the main metabolite THC-COOH have a very low incorporation rate into hair and THC is not highly bound to melanin, resulting in much lower concentrations in hair compared with other drugs. Additionally, THC is present in cannabis smoke and also can be incorporated into the hair only by contamination. For the determination of the main metabolite THC-COOH in the picogram or femtogram per milligram range, which indicates an active consumption, special analytical procedures, such as GC/MS/MS techniques, are required.     

Detection of the marijuana metabolite 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in oral fluid specimens and its contribution to positive results in screening assays

The detection of the marijuana metabolite 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in oral fluid specimens is described, and its contribution to an immunoassay for the detection of cannabinoids is investigated. Oral fluid specimens, screened using an enzyme-linked immunosorbent immunoassay (ELISA), were carried forward to confirmation for both tetrahydrocannabinol (THC) and THC-COOH using gas chromatography-mass spectrometry (GC-MS). One hundred and fifty-three specimens were analyzed, of which 143 screened positive for cannabinoids. Ninety-five (66.4%) of these specimens were positive for both THC and THC-COOH; 14 (9.7%) were positive for THC-COOH only, and 27 (18.8%) were positive for THC only. The GC-MS assay for the detection of THC-COOH in oral fluid was linear to 160 pg/mL with a limit of quantitation of 2 pg/mL. The detection of the marijuana metabolite, THC-COOH, in 76.2% of oral fluid specimens screening positive for cannabinoids is reported. As a potential defense against passive exposure claims, proposed SAMHSA regulations may require the simultaneous collection of a urine sample when oral fluid samples are used. The detection of the metabolite, THC-COOH, is a significant alternative to this approach because its presence in oral fluid minimizes the argument for passive exposure to marijuana in drug testing cases.     

Simultaneous quantification of major cannabinoids and metabolites in human urine and plasma by HPLC‐MS/MS and enzyme‐alkaline hydrolysis

A high performance liquid chromatography coupled to tandem mass spectrometry (HPLC‐MS/MS) method for simultaneous quantification of Δ9‐tetrahydrocannabinol (THC), its two metabolites 11‐hydroxy‐Δ9‐tetrahydrocannabinol (11‐OH‐THC) and 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (THC‐COOH), and four additional cannabinoids (cannabidiol (CBD), cannabigerol (CBG), tetrahydrocannabivarin (THCV), and cannabinol (CBN)) in 1 mL of human urine and plasma was developed and validated. The hydrolysis process was studied to ensure complete hydrolysis of glucuronide conjugates and the extraction of a total amount of analytes. Initially, urine and plasma blank samples were spiked with THC‐COOH‐glucuronide and THC‐glucuronide, and four different pretreatment methods were compared: hydrolysis‐free method, enzymatic hydrolysis with Escherichia Coli β‐glucuronidase, alkaline hydrolysis with 10 M NaOH, and enzyme‐alkaline tandem hydrolysis. The last approach assured the maximum efficiencies (close to 100%) for both urine and plasma matrices. Regarding the figures of merit, the limits of detection were below 1 ng/mL for all analytes, the accuracy ranged from 84% to 115%, and both within‐day and between‐day precision were lower than 12%. Finally, the method was successfully applied to real urine and plasma samples from cannabis users. Copyright © 2016 John Wiley & Sons, Ltd.     

Correlation of creatinine‐ and specific gravity‐normalized free and glucuronidated urine cannabinoid concentrations following smoked,vaporized, and oral cannabis in frequent and occasional cannabis users

Variability in urine dilution complicates urine cannabinoid test interpretation. Normalizing urine cannabinoid concentrations to specific gravity (SG) or creatinine was proposed to account for donors' hydration states. In this study, all urine voids were individually collected from eight frequent and eight occasional cannabis users for up to 85 hours after each received on separate occasions 50.6 mg Δ9‐tetrahydrocannabinol (THC) by smoking, vaporization, and oral ingestion in a randomized, within‐subject, double‐blind, double‐dummy, placebo‐controlled protocol. Each urine void was analyzed for 11 cannabinoids and phase I and II metabolites by liquid chromatography?tandem mass spectrometry (LC–MS/MS), SG, and creatinine. Normalized urine concentrations were log₁₀ transformed to create normal distributions, and Pearson correlation coefficients determined the degree of association between the two normalization methods. Repeated‐measures linear regression determined if the degree of association differed by frequent or occasional cannabis use, or route of administration after adjusting for gender and time since dosing. Of 1880 urine samples examined, only 11‐nor‐9‐carboxy‐THC (THCCOOH), THCCOOH‐glucuronide, THC‐glucuronide, and 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabivarin (THCVCOOH) were greater than the method's limits of quantification (LOQs). Associations between SG‐ and creatinine‐normalized concentrations exceeded 0.90. Repeated‐measures regression analysis found small but statistically significant differences in the degree of association between normalization methods for THCCOOH and THCCOOH‐glucuronide in frequent vs occasional smokers, and in THCVCOOH and THC‐glucuronide by route of administration. For the first time, SG‐ and creatinine‐normalized urine cannabinoid concentrations were evaluated in frequent and occasional cannabis users and following oral, smoked, and inhaled cannabis. Both normalization methods reduced variability, improving the interpretation of urine cannabinoid concentrations and methods were strongly correlated.     

False negative GC/MS assay for carboxy THC due to ibuprofen interference

A case of a false negative THC metabolite confirmation by GC/MS is presented. A urine specimen testing positive by the EMIT d.a.u. Cannabinoid 100-ng assay was subjected to confirmation by a GC/MS procedure designed to detect the methyl derivative of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH). No methylated THC-COOH was found. Analysis of the specimen by the TOXI-LAB Cannabinoids TLC procedure yielded a positive confirmation. Subsequent work-up of the specimen revealed a high concentration of ibuprofen, which is shown to interfere with the methylation of THC-COOH. Reanalysis of the specimen by GC/MS with an increased amount of methylating reagent yielded a positive result.     

Detection of past and recurrent marijuana use by a modified GC/MS procedure

A published gas chromatography/mass spectrometry method for detecting 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH) in urine was modified. In the new procedure, five GC/MS ion peaks of a pentafluoropropylpentafluoropropionyl derivative of THC-COOH are monitored in the multiple-ion mode for improved reliability; two ion peaks of the trideuterated internal standard are used for greater quantitative precision; and methanolic KOH is employed instead of NaOH in the hydrolysis and extraction steps to produce a cleaner extract. Finally, the new procedure is designed to keep THC-COOH either in basic solution or in an organic solvent at all times to prevent adsorption onto glass or plastic, so that disposable, non-silanized glassware may be used. Patient urines were analyzed by both the new procedure and the EMIT method. For 32 specimens, the average and range of EMIT/GC/MS concentration ratios were 2.8 and 0.9-7.2, respectively. Concentrations of THC-COOH measured by the GC/MS procedure may be more indicative of recent marijuana use than the EMIT semi-quantitative concentration values.     

Forensic aspects of the metabolism and excretion of cannabinoids following oral ingestion of cannabis resin

Following oral ingestion of cannabis resin, delta 9-THC-11-oic acid and its O-ester glucuronide were detected using RIA and combined hplc/RIA and shown to be major plasma metabolites of delta 9-THC. delta 9-THC-11-oic acid was not excreted in the urine in significant concentrations, the glucuronide conjugate being the major urinary metabolite detected. delta 9-THC metabolites were detected in blood for up to 5 days and in urine for up to 12 days following a single oral dose of delta 9-THC (20 mg). Estimates for the half life of delta 9-THC-11-oic acid and its glucuronide in plasma, and total metabolites in urine have been obtained. Interpretation of blood or urine total cannabinoid levels is most difficult, however, drug/metabolite ratios and metabolite/metabolite ratios may have potential for indicating recent cannabis use.     

Delta9-tetrahydrocannabivarin as a marker for the ingestion of marijuana versus Marinol: results of a clinical study

Delta9-tetrahydrocannabinol (THC), the main psychologically active ingredient of the cannabis plant (marijuana), has been prepared synthetically and used as the bulk active ingredient of Marinol, which was approved by the FDA for the control of nausea and vomiting in cancer patients receiving chemotherapy and as an appetite stimulant for AIDS patients. Because the natural and the synthetic THC are identical in all respects, it is impossible to determine the source of the urinary metabolite of THC, 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), in a urine specimen provided in a drug-testing program. Over the last few years there has been a need to determine whether a marijuana positive drug test is the result of the ingestion of marijuana (or a related product) or whether it results from the sole use of Marinol. We have previously proposed the use of delta9-tetrahydrocannabivarin (THCV, the C3 homologue of THC) as a marker for the ingestion of marijuana (or a related product) because THCV is a natural component of most cannabis products along with THC and does not exist in Marinol. We have also reported that THCV is metabolized by human hepatocytes to 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid (THCV-COOH); therefore, the presence of the latter in a urine specimen would indicate that the donor must have used marijuana or a related product (with or without Marinol). In this study, we provide clinical data showing that THCV-COOH is detected in urine specimens collected from human subjects only after the ingestion of marijuana and not after the ingestion of Marinol (whether the latter is ingested orally or by smoking). Four subjects (male and female) participated in the study in a three-session, within-subject, crossover design. The sessions were conducted at one-week intervals. Each subject received, in separate sessions and in randomized order, an oral dose of Marinol (15 mg), a smoked dose of THC (16.88 mg) in a placebo marijuana cigarette, or a smoked dose of marijuana (2.11% THC and 0.12% THCV). Urine samples were collected and vital signs were monitored every 2 h for a 6-h period following drug administration. Subjects were then transported home, were given sample collection containers and logbooks, and were instructed to record at home the volume and time of every urine collection for 24 h, and once a day for the remainder of a week (6 days). Subjects were also instructed to freeze the urine samples until the next session. All urine samples were analyzed by GC-MS for THC-COOH and THCV-COOH using solid-phase extraction and derivatization procedure on RapidTrace and TBDMS as the derivative. The method had a limit of detection of 1.0 ng/mL and 1.0 ng/mL for THCV-COOH and THC-COOH, respectively.     

Δ-Tetrahydrocannabivarin testing may not have the sensitivity to detect marijuana use among individuals ingesting dronabinol

The purpose of this study was to determine whether Δ⁹-tetrahydrocannabivarin (THCV), a plant cannabinoid, is a sensitive measure to detect recent marijuana use in cannabis dependent patients. It has been purported that smoking an illicit plant cannabis product will result in a positive THCV urinalysis, whereas the oral ingestion of therapeutic THC such as dronabinol will result in a negative THCV urinalysis, allowing for discrimination between pharmaceutical THC products and illicit marijuana products. In a double-blind placebo-controlled trial to determine the efficacy of dronabinol in cannabis dependence, all 117 patients produced a positive urine for the marijuana metabolite 11-nor-Δ⁹-THC-9-carboxylic acid; THC-COOH, but 50% had an undetectable (<1 ng/ml) THCV-COOH test. This suggests that THCV may not be a sensitive enough measure to detect recent marijuana use in all heavy marijuana users or that its absence may not discriminate between illicit marijuana use and oral ingestion of THC products such as dronabinol. We propose that the lack of THCV detection may be due to the variability of available cannabis strains smoked by marijuana users in community settings.     

Quantitative determination of five cannabinoids in blood and urine by gas chromatography tandem mass spectrometry applying automated on-line solid phase extraction

Cannabis is the most frequently consumed illegal substance worldwide. More recently, an increasing number of legal cannabis products low in psychoactive Δ⁹-tetrahydrocannabinol (THC) but high in non-intoxicating cannabidiol (CBD) are being more widely consumed. While the detection and quantification of THC and its metabolites in biological matrices is an important forensic-toxicological task, additional detection of CBD is also important, for example, when examining the plausibility of consumer's statements. This report describes the method validation for the quantitative determination of THC and its two major metabolites, 11-hydroxy-THC (OH-THC) and 11-nor-9-carboxy-THC (THC-COOH), as well as CBD and cannabinol (CBN) in whole blood and urine. The method employs automated on-line solid phase extraction coupled to gas chromatography tandem mass spectrometry (GC–MS/MS). The method was fully validated according to guidelines of the Swiss Society of Legal Medicine (SGRM) and the Society of Toxicological and Forensic Chemistry (GTFCh). The method fulfilled the validation criteria regarding analytical limits, accuracy and precision, extraction efficacy, and sample stability. The limits of detection (LODs) in whole blood and urine were 0.15 ng/mL for THC, OH-THC and CBD, 0.1 ng/mL for CBN, and 1.0 ng/mL for THC-COOH. The limits of quantification (LOQ) in whole blood and urine were 0.3 ng/mL for THC, OH-THC and CBD, 0.2 ng/mL for CBN, and 3.0 ng/mL for THC-COOH. The fully validated and automated method allows sensitive and robust measurement of cannabinoids in whole blood and urine. Detection of CBD provides additional information regarding consumed products.     

Evaluating the impact of hemp food consumption on workplace drug tests.

Foods containing seeds or oil of the hemp plant (Cannabis sativa L.) are increasingly found in retail stores in the U.S. The presence of delta9-tetrahydrocannabinol (THC) in these foods has raised concern over their impact on the results of workplace drug tests for marijuana. Previous studies have shown that eating hemp foods can cause screening and confirmed positive results in urine specimens. This study evaluated the impact of extended daily ingestion of THC via hemp oil on urine levels of its metabolite 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH) for four distinct daily THC doses. Doses were representative of THC levels now commonly found in hemp seed products and a range of conceivable daily consumption rates. Fifteen THC-na?ve adults ingested, over four successive 10-day periods, single daily THC doses ranging from 0.09 to 0.6 mg. Subjects self-administered THC in 15-mL aliquots (20 mL for the 0.6-mg dose) of four different blends of hemp and canola oils. Urine specimens were collected prior to the first ingestion of oil, on days 9 and 10 of each of the four study periods, and 1 and 3 days after the last ingestion. All specimens were screened for cannabinoids by radioimmunoassay (Immunalysis Direct RIA Kit), confirmed for THC-COOH by gas chromatography-mass spectrometry (GC-MS), and analyzed for creatinine to identify dilute specimens. None of the subjects who ingested daily doses of 0.45 mg of THC screened positive at the 50-ng/mL cutoff. At a daily THC dose of 0.6 mg, one specimen screened positive. The highest THC-COOH level found by GC-MS in any of the specimens was 5.2 ng/mL, well below the 15-ng/mL confirmation cutoff used in federal drug testing programs. A THC intake of 0.6 mg/day is equivalent to the consumption of approximately 125 mL of hemp oil containing 5 microg/g of THC or 300 g of hulled seeds at 2 microg/g. These THC concentrations are now typical in Canadian hemp seed products. Based on our findings, these concentrations appear to be sufficiently low to prevent confirmed positives from the extended and extensive consumption of hemp foods.     

Application of two-dimensional gas chromatography with electron capture chemical ionization mass spectrometry to the detection of 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in hair

The proposed federal regulations for the detection in hair of 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), a metabolite of marijuana, require a confirmatory detection level of 0.05 pg/mg. At present, the only way to achieve this on a routine basis has been with the use gas chromatography with tandem mass spectrometry (GC-MS-MS) technology. Tandem MS is an expensive approach and dissuades laboratories from attempting to enter the hair-testing market. A procedure for the determination of THC-COOH in hair using two-dimensional gas chromatography (GC x GC) coupled to mass spectrometry (GC-GC-MS) is described for the first time. The method makes use of several small improvements in the extraction, GC, and MS procedures to allow the required sensitivity to be achieved. The results of this approach demonstrate detection of THC-COOH in hair at a concentration level of 0.05 pg/mg with both a target quantitation ion and a unique confirming qualifier ion, using a single-quadrupole mass selective detector. These two ions and the enhanced separation of the GC-GC provide a high degree of confidence in the determinations. The method has been successfully applied to the detection of THC-COOH in hair specimens from known marijuana users, and it reaches the levels currently proposed in the Federal Register.     

GC/MS and EMIT analyses for delta 9-tetrahydrocannabinol metabolites in plasma and urine of human subjects

Ten male subjects smoked placebo marijuana cigarettes spiked with delta 9-tetrahydrocannabinol (THC) at 150 micrograms/kg body weight. Plasma and urine samples were collected for 22 hr after smoking. Total cross-reacting cannabinoids were measured by immunoassay (EMIT) and THC and major metabolites were identified and quantitated by gas chromatographic/mass spectrometric (GC/MS) procedures. In plasma, THC concentration provided the best indication of recent (less than 6 hr) smoking. In enzyme-hydrolyzed urine, 8 beta, 11-dihydroxy-THC at high concentration was identified in the earliest voidings, falling rapidly to the limit of detection before 22 hr in most subjects. Levels above 15 to 20 ng/mL were indicative of use within the previous 4 to 6 hr.     

Passive inhalation of marijuana smoke: urinalysis and room air levels of delta-9-tetrahydrocannabinol

In two separate studies, 5 drug-free male volunteers with a history of marijuana use were passively exposed to the sidestream smoke of 4 and 16 marijuana cigarettes (2.8% delta-9-tetrahydrocannabinol [THC]) for 1 h each day for 6 consecutive days. A third study was similarly performed with 2 marijuana-naive subjects passively exposed to the smoke of 16 marijuana cigarettes. Passive smoke exposure was conducted in a small, unventilated room. Room air levels of THC and CO were monitored frequently. All urine specimens were collected and analyzed by EMIT d.a.u. assay, Abuscreen radioimmunoassay and GC/MS. The studies show that significant amounts of THC were absorbed by all subjects at the higher level of passive smoke exposure (eg., smoke from 16 marijuana cigarettes), resulting in urinary excretion of significant amounts of cannabinoid metabolites. However, it seems improbable that subjects would unknowingly tolerate the noxious smoke conditions produced by this exposure. At the lower level of passive marijuana-smoke exposure, specimens tested positive only infrequently or were negative. Room air levels of THC during passive smoke exposure appeared to be the most critical factor in determining whether a subject produced cannabinoid-positive urine specimens.     

Simultaneous and sensitive analysis of THC, 11-OH-THC, THC-COOH, CBD, and CBN by GC-MS in plasma after oral application of small doses of THC and cannabis extract

Besides the psychoactive Delta(9)-tetrahydrocannabinol (THC), hashish and marijuana as well as cannabis-based medicine extracts contain varying amounts of cannabidiol (CBD) and of the degradation product cannabinol (CBN). The additional determination of these compounds is interesting from forensic and medical points of view because it can be used for further proof of cannabis exposure and because CBD is known to modify the effects of THC. Therefore, a method for the simultaneous quantitative determination of THC, its metabolites 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THC-COOH), CBD and CBN from plasma was developed. The method was based on automatic solid-phase extraction with C(18) ec columns, derivatization with N,O-bistrimethylsilyltrifluoroacetamide (BSTFA), and gas chromatography-electron impact ionization-mass spectrometry (GC-EI-MS) with deuterated standards. The limits of detection were between 0.15 and 0.29 ng/mL for THC, 11-OH-THC, THC-COOH, and CBD and 1.1 ng/mL for CBN. The method was applied in a prospective pharmacokinetic study after single oral administration of 10 mg THC alone or together with 5.4 mg CBD in cannabis extract. The maximum plasma concentrations after cannabis extract administration ranged between 1.2 and 10.3 ng/mL (mean 4.05 ng/mL) for THC, 1.8 and 12.3 ng/mL (mean 4.9 ng/mL) for 11-OH-THC, 19 and 71 ng/mL (mean 35 ng/mL) for THC-COOH, and 0.2 and 2.6 ng/mL (mean 0.95 ng/mg) for CBD. The peak concentrations (mean values) of THC, 11-OH-THC, THC-COOH, and CBD were observed at 56, 82, 115, and 60 min, respectively, after intake. CBN was not detected. Caused by the strong first-pass metabolism, the concentrations of the metabolites were increased during the first hours after drug administration when compared to literature data for smoking. Therefore, the concentration ratio 11-OH-THC/THC was discussed as a criterion for distinguishing oral from inhalative cannabis consumption.     

Passive consumption of marijuana through milk: a low level chronic exposure to delta-9-tetrahydrocannabinol(THC)

Cannabis sativa grows abundantly among other natural vegetation in the northern part of Pakistan. Buffalo, the common dairy animals of the region, are allowed to graze upon this vegetation. These animals ingest significant amounts of marijuana, which after absorption is metabolized into a number of psychoactive agents which are ultimately excreted through the urine and milk. This potentially contaminated milk is used by the people of the region. Depending upon the amount of milk ingested and the degree of contamination, the milk could result in a low to moderate level of chronic exposure to Delta-9-Tetrahydrocannabinol (THC) and other metabolites especially among the children raised on this milk. This research was conducted to investigate the extent of passive consumption of marijuana by the consumers of potentially contaminated milk. Urine and milk specimens were obtained from buffalo and were analyzed for 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) which is a major metabolite for THC. The analysis was done by using gas chromatography/mass spectrometry. It was observed that during the months of June and July, 60 percent of the buffalo contained detectable levels of THC-COOH in their urine and 50 percent of these animals produced milk which was contaminated with THC or other metabolites. Analysis of the urine obtained from children with ages ranging from six months to 3 years, who were being raised on the milk from these animals, indicated that 29 percent of them had low levels of THC-COOH in their urine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Delta-9-tetrahydrocannabinol pharmacokinetics

Delta-9-tetrahydrocannabinol (Delta-9-THC) is the main psychoactive ingredient of cannabis. Smoking is currently most common use of cannabis. The present review focuses on the pharmacokinetics of THC. The variability of THC in plant material which has significantly increased in recent years leads to variability in tissue THC levels from smoking, which is, in itself, a highly individual process. This variability of THC content has an important impact on drug pharmacokinetics and pharmacology. After smoking THC bioavailability averages 30%. With a 3.55% THC cigarette, a peak plasma level near 160 ng/mL occurs approximately 10 min after inhalation. THC is eliminated quickly from plasma in a multiphasic manner and is widely distributed to tissues, which is responsible for its pharmacologic effects. Body fat then serves as a long-term storage site. This particular pharmacokinetics explains the noncorrelation between THC blood level and clinical effects as is observed for ethanol. A major active 11-hydroxy metabolite is formed after both inhalation and oral dosing (20 and 100% of parent, respectively). The elimination of THC and its many metabolites, mainly THC-COOH, occurs via the feces and urine for several weeks. Thus, to confirm abstinence, urine THC-COOH analysis would be a useful tool. A positive result could be checked by gas chromatography-mass spectrometry THC blood analysis, indicative of a recent cannabis exposure.