Simultaneous quantification of Delta9-tetrahydrocannabinol, 11-hydroxy-Delta9-tetrahydrocannabinol, and 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in human plasma using two-dimensional gas chromatography, cryofocusing, and electron impact-mass spectrometry

Determination of Δ9-tetrahydrocannabinol, 11-nor-carboxy-Δ9-tetrahydrocannabinol and cannabidiol in human plasma and urine after a commercial cannabidiol oil product intake

PURPOSE

Cannabidiol (CBD) products are widely used for pain relief, sleep improvement, management of seizures etc. Although the concentrations of Δ9-tetrahydrocannabinol (Δ9-THC) in these products are low (≤0.3% w/w), it is important to investigate if its presence and/or that of its metabolite 11-nor-carboxy-Δ9-THC, is traceable in plasma and urine samples of individuals who take CBD oil products.

METHODS

A sensitive GC/MS method for the determination of Δ9-THC, 11-nor-carboxy-Δ9-THC and CBD in plasma and urine samples was developed and validated. The sample preparation procedure included protein precipitation for plasma samples and hydrolysis for urine samples, solid-phase extraction and finally derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide) with 1% trimethylchlorosilane.

RESULTS

For all analytes, the LOD and LOQ were 0.06 and 0.20 ng/mL, respectively. The calibration curves were linear (R2 ≥ 0.992), and absolute recoveries were ≥91.7%. Accuracy and precision were within the accepted range. From the analysis of biologic samples of 10 human participants who were taking CBD oil, it was realized that Δ9-THC was not detected in urine, while 11-nor-carboxy-Δ9-THC (0.69-23.06 ng/mL) and CBD (0.29-96.78 ng/mL) were found in all urine samples. Regarding plasma samples, Δ9-THC (0.21-0.62 ng/mL) was detected in 10, 11-nor-carboxy-Δ9-THC (0.20-2.44 ng/mL) in 35, while CBD (0.20-1.58 ng/mL) in 25 out of 38 samples, respectively.

CONCLUSION

The results showed that Δ9-THC is likely to be found in plasma although at low concentrations. In addition, the detection of 11-nor-carboxy-Δ9-THC in both urine and plasma samples raises questions and concerns for the proper interpretation of toxicological results, especially considering Greece's zero tolerance law applied in DUID and workplace cases.

Simple Method for the Determination of THC and THC-COOH in Human Postmortem Blood Samples by Gas Chromatography-Mass Spectrometry

A simple and sensitive analytical method was developed for qualitative and quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) and its metabolite 11-nor-Δ9-tetrahydrocannabinol-carboxylic acid (Δ9-THC-COOH) in human postmortem blood using gas chromatography/mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The method involved a liquid-liquid extraction in two steps, one for Δ9-THC and a second one for Δ9-THC-COOH. The first extract was analyzed using Δ9-THC-D3 as internal standard. The second extract was derivatized and analyzed using Δ9-THC-COOH-D3 as internal standard. The method was shown to be very simple, rapid, and sensitive. The method was validated for the two compounds, including linearity (range 0.05-1.5 µg/mL for Δ9-THC and 0.08-1.5 µg/mL for Δ9-THC-COOH), and the main precision parameters. It was linear for both analytes, with quadratic regression of calibration curves always higher than 0.99. The coefficients of variation were less than 15%. Extraction recoveries were superior to 80% for both compounds. The developed method was used to analyze 41 real plasma samples obtained from the Forensic Toxicology Service of the Institute of Forensic Sciences of Santiago de Compostela (Spain) from cases in which the use of cannabis was involved, demonstrating the usefulness of the proposed method.

Simple and simultaneous quantification of cyanide, ethanol, and 1-propanol in blood by headspace GC–MS/NPD with Deans switch dual detector system

Cyanide is a powerful and rapidly acting poison. In Japan, cyanide poisoning is rare, and regular cyanide testing can be costly and time consuming. In contrast, alcohol analysis is routinely performed in most forensic laboratories. In this study, we attempted to develop a method for the simultaneous quantification of cyanide and alcohols in blood using headspace gas chromatography (HS-GC). As nitrogen-phosphorus detection (NPD) is more sensitive to hydrogen cyanide than mass spectrometry (MS), a Deans switch was used to switch the detectors during a single run. The separation provided by three analytical columns, PoraBOND Q, CP-Sil 5 CB, and HP-INNOWax, was investigated, and PoraBOND Q was selected. The use of HS-GC-MS/NPD with a Deans switch enabled the simple and simultaneous quantification of cyanide, ethanol, and 1-propanol. Eighteen other volatile compounds were detected in the SIM/scan mode of the MS.

Developing a novel packed in-tube solid-phase extraction method for determination ∆ 9-tetrahydrocannabinol in biological samples and cannabis leaves

A novel plate-like nano-sorbent based on copper/cobalt/chromium layered double hydroxide was synthesized by a simple coprecipitation method. The synthesized nanoparticels were introduced into a stainless steel cartridge using a dry packing method. Then, the packed cartridge was introduced as a novel on-line "packed in-tube" configuration and followed by high performance liquid chromatography for the determination of trace amounts of ^∆ 9-tetrahydrocannabinol from biological samples and cannabis leaves. The as-prepared sorbent exhibited long lifetime, good chemical stability, and high anion-exchange capacity. Several important factors affecting the extraction efficiency, such as extraction and desorption times, pH of the sample solution and flow rates of the sample and eluent solutions, were investigated and optimized. Under optimized conditions, this method showed good linearity for ^∆ 9-tetrahydrocannabinol in the ranges of 0.09-500, 0.3-500, and 0.4-500 µg/L with coefficients of determination of 0.9999, 0.9991, and 0.9994 in water, serum and plasma samples, respectively. The inter- and intra-assay precisions (n = 3) were respectively in the ranges of 1.8-4.6% and 1.9-4.0% at three concentration levels of 10, 50, and 100 µg/L. The limits of detection were also in the range of 0.02-0.1 µg/L.

Alkylsilyl speciation and direct sample preparation of plant cannabinoids prior to their analysis by GC-MS

A literature criticism is given on methods currently using gas chromatography mass spectrometry (GC-MS) to determine plant cannabinoids (p-CBDs). In this study, trialkylsilylation of seven p-CBDs (including their transformation products formed in the drug user's body) was compared applying various alkylsilyl reagents¹ and the mass fragmentation properties of the corresponding derivatives were characterized. Derivatization, mass fragmentation and quantitation related model investigations were optimized as a function of the reaction times and conditions. Special emphasis was put (i) on the maximum responses of species, (ii) on the proportions of formed stable products, suitable for selective quantitation of all seven p-CBDs simultaneously. Results, as novel to the field confirmed that HMDS + TFA, for p-CBDs never applied reagent before, serves as their derivatization reagent of choice. These species were characterized by their retention, mass fragmentation and analytical performance characteristics. In model solutions with injected amounts in the range of 20 pg-2000 pg, repeatability (average 4.98% RSD, varying between 2.98 and 6.2% RSD), linearity (R², 0.9956-0.9995), LOQ (20-80 pg/μL injected species) and recovery (95.2-104%) values were defined. The practical utility of this proposal, along with method development validation, was shown in a particularly unique manner and supported by the novel, extraction free, direct sample preparation working strategy. For this purpose, two Cannabis-type ruderalis (C-trd) plant tissues (C-trd1, C-trd2) were directly derivatized in the presence of the matrix. This process, which approaches green chemistry, performed without the use of organic solvents, was associated with the quantitation of self p-CBD contents of C-trd plant tissues. Applying 0.5-2.0 mg dried tissues, adding standards, the following self p-CBDs contents were confirmed: in C-trd1 6.6 μg/mg CBD, 4.4 μg/mg CBN and 1.3 μg/mg CBC, while in C-trd2 0.46 μg/mg CBD, 0.27 μg/mg CBC and 0.19 μg/mg CBG were found. The latter results were characterized by repeatability (2.52-4.99% RSD), linearity (R², 0.9640-0.9997) and recovery (87.9-109%) data.

Nabiximols combined with motivational enhancement/cognitive behavioral therapy for the treatment of cannabis dependence: A pilot randomized clinical trial

BACKGROUND

The current lack of pharmacological treatments for cannabis use disorder (CUD) warrants novel approaches and further investigation of promising pharmacotherapy. We previously showed that nabiximols (27 mg/ml Δ9-tetrahydrocannabinol (THC)/ 25 mg/ml cannabidiol (CBD), Sativex®) can decrease cannabis withdrawal symptoms. Here, we assessed in a pilot study the tolerability and safety of self-titrated nabiximols vs. placebo among 40 treatment-seeking cannabis-dependent participants.

METHODS

Subjects participated in a double blind randomized clinical trial, with as-needed nabiximols up to 113.4 mg THC/105 mg CBD or placebo daily for 12 weeks, concurrently with Motivational Enhancement Therapy and Cognitive Behavioral Therapy (MET/CBT). Primary outcome measures were tolerability and abstinence, secondary outcome measures were days and amount of cannabis use, withdrawal, and craving scores. Participants received up to CDN$ 855 in compensation for their time.

RESULTS

Medication was well tolerated and no serious adverse events (SAEs) were observed. Rates of adverse events did not differ between treatment arms (F1,39 = 0.205, NS). There was no significant change in abstinence rates at trial end. Participants were not able to differentiate between subjective effects associated with nabiximols or placebo treatments (F1,40 = 0.585, NS). Cannabis use was reduced in the nabiximols (70.5%) and placebo groups (42.6%). Nabiximols reduced cannabis craving but no significant differences between the nabiximols and placebo groups were observed on withdrawal scores.

CONCLUSIONS

Nabiximols in combination with MET/CBT was well tolerated and allowed for reduction of cannabis use. Future clinical trials should explore the potential of high doses of nabiximols for cannabis dependence.

Addictions Neuroclinical Assessment: A reverse translational approach

Incentive salience, negative emotionality, and executive function are functional domains that are etiologic in the initiation and progression of addictive disorders, having been implicated in humans with addictive disorders and in animal models of addictions. Measures of these three neuroscience-based functional domains can capture much of the effects of inheritance and early exposures that lead to trait vulnerability shared across different addictive disorders. For specific addictive disorders, these measures can be supplemented by agent specific measures such as those that access pharmacodynamic and pharmacokinetic variation attributable to agent-specific gatekeeper molecules including receptors and drug-metabolizing enzymes. Herein, we focus on the translation and reverse translation of knowledge derived from animal models of addiction to the human condition via measures of neurobiological processes that are orthologous in animals and humans, and that are shared in addictions to different agents. Based on preclinical data and human studies, measures of these domains in a general framework of an Addictions Neuroclinical Assessment (ANA) can transform the assessment and nosology of addictive disorders, and can be informative for staging disease progression. We consider next steps and challenges for implementation of ANA in clinical care and research. This article is part of the Special Issue entitled "Alcoholism".

Determination of ∆-9-Tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC and Cannabidiol in Human Plasma using Gas Chromatography-Tandem Mass Spectrometry

Two marijuana compounds of particular medical interest are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). A gas chromatography-tandem mass spectrometry (GC-MS-MS) method was developed to test for CBD, THC, hydroxy-THC (OH-THC) and carboxy-THC (COOH-THC) in human plasma. Calibrators (THC and OH-THC, 0.1 to 100; CBD, 0.25 to 100; COOH-THC, 0.5-500 ng/mL) and controls (0.3, 5 and 80 ng/mL, except COOH-THC at 1.5, 25 and 400 ng/mL) were prepared in blank matrix. Deuterated (d3) internal standards were added to 1-mL samples. Preparation involved acetonitrile precipitation, liquid-liquid extraction (hexane:ethyl acetate, 9:1), and MSTFA derivatization. An Agilent 7890 A GC was interfaced with an Agilent 7000 MS Triple Quadrupole. Selected reaction monitoring was employed. Blood samples were provided from a marijuana smoking study (two participants) and a CBD ingestion study (eight participants). Three analytes with the same transitions (THC, OH-THC and COOH-THC) were chromatographically separated. Matrix selectivity studies showed endogenous chromatographic peak area ratios (PAR) at the analyte retention times were <20% of the analyte limit of quantitation PAR. The intra-assay accuracy ranged from 83.5% to 118% of target and the intra-run imprecision ranged from 2.0% to 19.1%. The inter-assay accuracy ranged from 90.3% to 104% of target and the inter-run imprecision ranged from 6.5% to 12.0%. Stability was established for 25 hours at room temperature, 207 days at -20°C, after three freeze-thaw cycles and for 26 days for rederivatized processed samples. After smoking marijuana predictable concentrations of THC, OH-THC and COOH-THC were seen; low concentrations of CBD were detected at early time points. In moderate users who had not smoked for at least 9 hours before ingesting an 800 mg oral dose of CBD, the method was sensitive enough to follow residual concentrations of THC and OH-THC; sustained COOH-THC concentrations over 50 ng/mL validated its higher analytical range.

Sativex Associated With Behavioral-Relapse Prevention Strategy as Treatment for Cannabis Dependence: A Case Series

OBJECTIVES

Cannabis is the most commonly used illicit drug; a substantial minority of users develop dependence. The current lack of pharmacological treatments for cannabis dependence warrants the use of novel approaches and further investigation of promising pharmacotherapy. In this case series, we assessed the use of self-titrated dosages of Sativex (1:1, Δ-tetrahydrocannabinol [THC]/cannabidiol [CBD] combination) and motivational enhancement therapy and cognitive behavioral therapy (MET/CBT) for the treatment of cannabis dependence among 5 treatment-seeking community-recruited cannabis-dependent subjects.

METHODS

Participants underwent a 3-month open-label self-titration phase with Sativex (up to 113.4 of THC/105 mg of CBD) and weekly MET/CBT, with a 3-month follow-up.

RESULTS

Sativex was well-tolerated by all participants (average dosage 77.5 THC/71.7 mg CBD). The combination of Sativex and MET/CBT reduced the amount of cannabis use and progressively reduced craving and withdrawal scores. THC/CBD metabolite concentration indicated reduced cannabis use and compliance with medication.

CONCLUSIONS

In summary, this pilot study found that with Sativex in combination with MET/CBT reduced cannabis use while preventing increases in craving and withdrawal in the 4 participants completing the study. Further systematic exploration of Sativex as a pharmacological treatment option for cannabis dependence should be performed.

Plasma Cannabinoid Pharmacokinetics After Controlled Smoking and Ad libitum Cannabis Smoking in Chronic Frequent Users

More Americans are dependent on cannabis than any other illicit drug. The main analytes for cannabis testing include the primary psychoactive constituent, Δ(9)-tetrahydrocannabinol (THC), equipotent 11-hydroxy-THC (11-OH-THC) and inactive 11-nor-9-carboxy-THC (THCCOOH). Eleven adult chronic frequent cannabis smokers resided on a closed research unit with unlimited access to 5.9% THC cannabis cigarettes from 12:00 to 23:00 during two ad libitum smoking phases, followed by a 5-day abstinence period in seven participants. A single cigarette was smoked under controlled topography on the last day of the smoking and abstinence phases. Plasma cannabinoids were quantified by two-dimensional gas chromatography-mass spectrometry. Median plasma maximum concentrations (Cmax) were 28.3 (THC), 3.9 (11-OH-THC) and 47.0 μg/L (THCCOOH) 0.5 h after controlled single cannabis smoking. Median Cmax 0.2-0.5 h after ad libitum smoking was higher for all analytes: 83.5 (THC), 14.2 (11-OH-THC) and 155 μg/L (THCCOOH). All 11 participants' plasma samples were THC and THCCOOH-positive, 58.3% had THC ≥5 μg/L and 79.2% were 11-OH-THC-positive 8.1-14 h after last cannabis smoking. Cannabinoid detection rates in seven participants 106-112 h (4-5 days) after last smoking were 92.9 (THC), 35.7 (11-OH-THC) and 100% (THCCOOH), with limits of quantification of 0.5 μg/L for THC and THCCOOH, and 1.0 μg/L for 11-OH-THC. These data greatly expand prior research findings on cannabinoid excretion profiles in chronic frequent cannabis smokers during ad libitum smoking. Smoking multiple cannabis cigarettes led to higher Cmax and AUC compared with smoking a single cigarette. The chronic frequent cannabis smokers exhibited extended detection windows for plasma cannabinoids, reflecting a large cannabinoid body burden.

Development and validation of an automated liquid-liquid extraction GC/MS method for the determination of THC, 11-OH-THC, and free THC-carboxylic acid (THC-COOH) from blood serum

The analysis of Δ⁹-tetrahydrocannabinol (THC) and its metabolites 11-hydroxy-Δ⁹-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH) from blood serum is a routine task in forensic toxicology laboratories. For examination of consumption habits, the concentration of the phase I metabolite THC-COOH is used. Recommendations for interpretation of analysis values in medical-psychological assessments (regranting of driver’s licenses, Germany) include threshold values for the free, unconjugated THC-COOH. Using a fully automated two-step liquid-liquid extraction, THC, 11-OH-THC, and free, unconjugated THC-COOH were extracted from blood serum, silylated with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and analyzed by GC/MS. The automation was carried out by an x-y-z sample robot equipped with modules for shaking, centrifugation, and solvent evaporation. This method was based on a previously developed manual sample preparation method. Validation guidelines of the Society of Toxicological and Forensic Chemistry (GTFCh) were fulfilled for both methods, at which the focus of this article is the automated one. Limits of detection and quantification for THC were 0.3 and 0.6 μg/L, for 11-OH-THC were 0.1 and 0.8 μg/L, and for THC-COOH were 0.3 and 1.1 μg/L, when extracting only 0.5 mL of blood serum. Therefore, the required limit of quantification for THC of 1 μg/L in driving under the influence of cannabis cases in Germany (and other countries) can be reached and the method can be employed in that context. Real and external control samples were analyzed, and a round robin test was passed successfully. To date, the method is employed in the Institute of Legal Medicine in Giessen, Germany, in daily routine. Automation helps in avoiding errors during sample preparation and reduces the workload of the laboratory personnel. Due to its flexibility, the analysis system can be employed for other liquid-liquid extractions as well. To the best of our knowledge, this is the first publication on a comprehensively automated classical liquid-liquid extraction workflow in the field of forensic toxicological analysis.

Graphical abstract

Effects of fixed or self-titrated dosages of Sativex on cannabis withdrawal and cravings

BACKGROUND

There is currently no pharmacological treatment approved for cannabis dependence. In this proof of concept study, we assessed the feasibility/effects of fixed and self-titrated dosages of Sativex (1:1, Δ(9)-tetrahydrocannabinol (THC)/cannabidiol (CBD)) on craving and withdrawal from cannabis among nine community-recruited cannabis-dependent subjects.

METHODS

Participants underwent an 8-week double-blind placebo-controlled trial (an ABACADAE design), with four smoke as usual conditions (SAU) (A) separated by four cannabis abstinence conditions (B-E), with administration of either self-titrated/fixed doses of placebo or Sativex (up to 108 mg THC/100 mg CBD). The order of medication administration during abstinence conditions was randomized and counterbalanced. Withdrawal symptoms and craving were assessed using the Cannabis Withdrawal Scale (CWS), Marijuana Withdrawal Checklist (MWC) and Marijuana Craving Questionnaire (MCQ). Medication use was assessed during the study by means of self-reports, vial weight control, toxicology and metabolite analysis. Cannabis use was assessed by means of self-reports.

RESULTS

High fixed doses of Sativex were well tolerated and significantly reduced cannabis withdrawal during abstinence, but not craving, as compared to placebo. Self-titrated doses were lower and showed limited efficacy as compared to high fixed doses. Participants reported a significantly lower "high" following Sativex or placebo as compared to SAU conditions. Cannabis/medication use along the study, as per self-reports, suggests compliance with the study conditions.

CONCLUSIONS

The results found in this proof of concept study warrant further systematic exploration of Sativex as a treatment option for cannabis withdrawal and dependence.

Extended plasma cannabinoid excretion in chronic frequent cannabis smokers during sustained abstinence and correlation with psychomotor performance

Cannabis smoking increases motor vehicle accident risk. Empirically defined cannabinoid detection windows are important to drugged driving legislation. Our aims were to establish plasma cannabinoid detection windows in frequent cannabis smokers and to determine if residual cannabinoid concentrations were correlated with psychomotor performance. Twenty-eight male chronic frequent cannabis smokers resided on a secure research unit for up to 33 days with daily blood collection. Plasma specimens were analyzed for Δ(9) -tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) by gas chromatography-mass spectrometry. Critical tracking and divided attention tasks were administered at baseline (after overnight stay to ensure lack of acute intoxication) and after 1, 2, and 3 weeks of cannabis abstinence. Twenty-seven of the twenty-eight participants were THC-positive at admission (median 4.2 µg/L). THC concentrations significantly decreased 24 h after admission, but were still ≥2 µg/L in 16 of the 28 participants 48 h after admission. THC was detected in 3 of 5 specimens on day 30. The last positive 11-OH-THC specimen was 15 days after admission. THCCOOH was measureable in 4 of 5 participants after 30 days of abstinence. Years of prior cannabis use significantly correlated with THC concentrations on admission, and days 7 and 14. Tracking error, evaluated by the Divided Attention Task, was the only evaluated psychomotor assessment significantly correlated with cannabinoid concentrations at baseline and day 8 (11-OH-THC only). Median THC was 0.3 µg/L in 5 chronic frequent cannabis smokers' plasma samples after 30 days of sustained abstinence. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Cannabis withdrawal in chronic, frequent cannabis smokers during sustained abstinence within a closed residential environment

OBJECTIVES

Chronic, frequent cannabis smokers may experience residual and offset effects, withdrawal, and craving when abstaining from the drug. We characterized the prevalence, duration, and intensity of these effects in chronic frequent cannabis smokers during abstinence on a closed research unit.

METHODS

Non-treatment-seeking participants (N = 29 on admission, 66% and 34% remaining after 2 and 4 weeks) provided subjective effects data. A battery of five instruments was computer-administered daily to measure psychological, sensory, and physical symptoms associated with cannabinoid intoxication and withdrawal. Plasma and oral fluid specimens were concurrently collected and analyzed for cannabinoids. Outcome variables were evaluated as change from admission (Day 0) with regression models.

RESULTS

Most abstinence effects, including irritability and anxiety were greatest on Days 0-3 and decreased thereafter. Cannabis craving significantly decreased over time, whereas decreased appetite began to normalize on Day 4. Strange dreams and difficulty getting to sleep increased over time, suggesting intrinsic sleep problems in chronic cannabis smokers. Symptoms likely induced by residual drug effects were at maximum intensity on admission and positively correlated with plasma and oral fluid cannabinoid concentrations on admission but not afterward; these symptoms showed overall prevalence higher than cannabis withdrawal symptoms.

CONCLUSIONS

The combined influence of residual/offset drug effects, withdrawal, and craving was observed in chronic cannabis smokers during monitored abstinence. Abstinence symptoms were generally more intense in the initial phase, implying importance of early intervention in cannabis quit attempts. Sleep disturbance persisting for an extended period suggests that hypnotic medications could be beneficial in treating cannabis dependence.

Oral fluid cannabinoids in chronic frequent cannabis smokers during ad libitum cannabis smoking

Oral fluid (OF) offers a simple, non-invasive, directly observable sample collection for clinical and forensic drug testing. Given that chronic cannabis smokers often engage in drug administration multiple times daily, evaluating OF cannabinoid pharmacokinetics during ad libitum smoking is important for practical development of analytical methods and informed interpretation of test results. Eleven cannabis smokers resided in a closed research unit for 51 days, and underwent four, 5-day oral delta-9-tetrahydrocannabinol (THC) treatments. Each medication period was separated by 9 days of ad libitum cannabis smoking from 12:00 to 23:00 h daily. Ten OF samples were collected from 9:00-22:00 h on each of the last ad libitum smoking days (Study Days 4, 18, 32, and 46). As the number of cannabis cigarettes smoked increased over the study days, OF THC, cannabinol (CBN), and 11-nor-9-carboxy-THC (THCCOOH) also increased with a significant effect of time since last smoking (Δtime; range, 0.0-17.4 h) and ≥88% detection rates; concentrations on Day 4 were significantly lower than those on Days 32 and 46 but not Day 18. Within 30 min of smoking, median THC, CBN, and THCCOOH concentrations were 689 µg/L, 116 µg/L, and 147 ng/L, respectively, decreasing to 19.4 µg/L, 2.4 µg/L, and 87.6 ng/L after 10 h. Cannabidiol and 11-hydroxy-THC showed overall lower detection rates of 29 and 8.6%, respectively. Cannabinoid disposition in OF was highly influenced by Δtime and composition of smoked cannabis. Furthermore, cannabinoid OF concentrations increased over ad libitum smoking days, in parallel with increased cannabis self-administration, possibly reflecting development of increased cannabis tolerance.

Impact of oral fluid collection device on cannabinoid stability following smoked cannabis

Evaluation of cannabinoid stability in authentic oral fluid (OF) is critical, as most OF stability studies employed fortified or synthetic OF. Participants (n = 16) smoked a 6.8% delta-9-tetrahydrocannabinol (THC) cigarette, and baseline concentrations of THC, 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) were determined within 24 h in 16 separate pooled samples (collected 1 h before to 10.5 or 13 h after smoking). OF was collected with the StatSure Saliva Sampler™ and Oral-Eze® devices. Oral-Eze samples were re-analyzed after room temperature (RT) storage for 1 week, and for both devices after 4 °C for 1 and 4 weeks, and -20 °C for 4 and 24 weeks. Concentrations ±20% from initial concentrations were considered stable. With the StatSure device, all cannabinoids were within 80-120% median %baseline for all storage conditions. Individual THC, CBD, CBN and THCCOOH pool concentrations were stable in 100%, 100%, 80-94% and >85%, respectively, across storage conditions. With the Oral-Eze device, at RT or refrigerated storage (for 1 and 4 weeks), THC, CBD and THCCOOH were stable in 94-100%, 78-89%, and 93-100% of samples, respectively, while CBN concentrations were 53-79% stable. However, after 24 weeks at -20 °C, stability decreased, especially for CBD, with a median of 56% stability. Overall, the collection devices' elution/stabilizing buffers provided good stability for OF cannabinoids, with the exception of the more labile CBN. To ensure OF cannabinoid concentration accuracy, these data suggest analysis within 4 weeks at 4 °C storage for Oral-Eze collection and within 4 weeks at 4 °C or 24 weeks at -20 °C for StatSure collection. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Around-the-clock oral THC effects on sleep in male chronic daily cannabis smokers

BACKGROUND AND OBJECTIVES

Δ9-tetrahydrocannabinol (THC) promotes sleep in animals; clinical use of THC is associated with somnolence. Human laboratory studies of oral THC have not shown consistent effects on sleep. We prospectively evaluated self-reported sleep parameters during controlled oral THC administration to research volunteers.

METHODS

Thirteen male chronic daily cannabis smokers (mean ± SD age 24.6± 3.7 years, self-reported smoking frequency of 5.5 ± 5.9 (range 1-24) joint-equivalents daily at study entry) were administered oral THC doses (20 mg) around-the-clock for 7 days (40-120 mg daily) starting the afternoon after admission. The St. Mary's Hospital Sleep Questionnaire was completed every morning. Plasma THC and 11-OH-THC (active metabolite) concentrations were measured in venous blood samples collected every evening. Changes in sleep characteristics over time and associations between sleep characteristics and plasma cannabinoid concentrations were evaluated with repeated measures mixed linear regression.

RESULTS

Higher evening THC and 11-OH-THC concentrations were significantly associated with shorter sleep latency, less difficulty falling asleep, and more daytime sleep the following day. In contrast, the duration of calculated and self-reported nighttime sleep decreased slightly (3.54 and 5.34 minutes per night, respectively) but significantly during the study.

CONCLUSIONS

These findings suggest that tolerance to the somnolent effects of THC may have occurred, but results should be considered preliminary due to design limitations.

SCIENTIFIC SIGNIFICANCE

Somnolence from oral THC may dissipate with chronic, high-dose use. This has implications for patients who may take chronic oral THC for medicinal purposes, including cannabis dependence treatment. (Am J Addict 2013;22:510-514).

Plasma cannabinoid concentrations during dronabinol pharmacotherapy for cannabis dependence

BACKGROUND

Recently, high-dose oral synthetic delta-9-tetrahydrocannabinol (THC) was shown to alleviate cannabis withdrawal symptoms. The present data describe cannabinoid pharmacokinetics in chronic, daily cannabis smokers who received high-dose oral THC pharmacotherapy and later a smoked cannabis challenge.

METHODS

Eleven daily cannabis smokers received 0, 30, 60, or 120 mg/d THC for four 5-day medication sessions, each separated by 9 days of ad libitum cannabis smoking. On the fifth day, participants were challenged with smoking one 5.9% THC cigarette. Plasma collected on the first and fifth days was quantified by two-dimensional gas chromatography mass spectrometer for THC, 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH). Linear ranges (ng/mL) were 0.5-100 for THC, 1-50 for 11-OH-THC, and 0.5-200 for THCCOOH.

RESULTS

During placebo dosing, THC, 11-OH-THC, and THCCOOH concentrations consistently decreased, whereas all cannabinoids increased dose dependently during active dronabinol administration. THC increase over time was not significant after any dose, 11-OH-THC increased significantly during the 60- and 120-mg/d doses, and THCCOOH increased significantly only during the 120-mg/d dose. THC, 11-OH-THC, and THCCOOH concentrations peaked within 0.25 hours after cannabis smoking, except after 120 mg/d THC when THCCOOH peaked 0.5 hours before smoking.

CONCLUSIONS

The significant withdrawal effects noted during placebo dronabinol administration were supported by significant plasma THC and 11-OH-THC concentration decreases. During active dronabinol dosing, significant dose-dependent increases in THC and 11-OH-THC concentrations support withdrawal symptom suppression. THC concentrations after cannabis smoking were only distinguishable from oral THC doses for 1 hour, too short a period to feasibly identify cannabis relapse. THCCOOH/THC ratios were higher 14 hours after overnight oral dronabinol abstinence but cannot distinguish oral THC dosing from the smoked cannabis intake.

Oral fluid cannabinoid concentrations following controlled smoked cannabis in chronic frequent and occasional smokers

Oral fluid (OF) is an alternative biological matrix for monitoring cannabis intake in drug testing, and drugged driving (DUID) programs, but OF cannabinoid test interpretation is challenging. Controlled cannabinoid administration studies provide a scientific database for interpreting cannabinoid OF tests. We compared differences in OF cannabinoid concentrations from 19 h before to 30 h after smoking a 6.8% THC cigarette in chronic frequent and occasional cannabis smokers. OF was collected with the Statsure Saliva Sampler™ OF device. 2D-GC-MS was used to quantify cannabinoids in 357 OF specimens; 65 had inadequate OF volume within 3 h after smoking. All OF specimens were THC-positive for up to 13.5 h after smoking, without significant differences between frequent and occasional smokers over 30 h. Cannabidiol (CBD) and cannabinol (CBN) had short median last detection times (2.5-4 h for CBD and 6-8 h for CBN) in both groups. THCCOOH was detected in 25 and 212 occasional and frequent smokers' OF samples, respectively. THCCOOH provided longer detection windows than THC in all frequent smokers. As THCCOOH is not present in cannabis smoke, its presence in OF minimizes the potential for false positive results from passive environmental smoke exposure, and can identify oral THC ingestion, while OF THC cannot. THC ≥ 1 μg/L, in addition to CBD ≥ 1 μg/L or CBN ≥ 1 μg/L suggested recent cannabis intake (≤13.5 h), important for DUID cases, whereas THC ≥ 1 μg/L or THC ≥ 2 μg/L cutoffs had longer detection windows (≥30 h), important for workplace testing. THCCOOH windows of detection for chronic, frequent cannabis smokers extended beyond 30 h, while they were shorter (0-24 h) for occasional cannabis smokers.

Oral fluid cannabinoids in chronic cannabis smokers during oral δ9-tetrahydrocannabinol therapy and smoked cannabis challenge

BACKGROUND

Oral Δ(9)-tetrahydrocannabinol (THC) is effective for attenuating cannabis withdrawal and may benefit treatment of cannabis use disorders. Oral fluid (OF) cannabinoid testing, increasing in forensic and workplace settings, could be valuable for monitoring during cannabis treatment.

METHODS

Eleven cannabis smokers resided on a closed research unit for 51 days and received daily 0, 30, 60, and 120 mg of oral THC in divided doses for 5 days. There was a 5-puff smoked cannabis challenge on the fifth day. Each medication session was separated by 9 days of ad libitum cannabis smoking. OF was collected the evening before and throughout oral THC sessions and analyzed by 2-dimensional GC-MS for THC, cannabidiol (CBD), cannabinol (CBN), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH).

RESULTS

During all oral THC administrations, THC OF concentrations decreased to ≤ 78.2, 33.2, and 1.4 μg/L by 24, 48, and 72 h, respectively. CBN also decreased over time, with concentrations 10-fold lower than THC, with none detected beyond 69 h. CBD and 11-OH-THC were rarely detected, only within 19 and 1.6 h after smoking, respectively. THCCOOH OF concentrations were dose dependent and increased over time during 120-mg THC dosing. After cannabis smoking, THC, CBN, and THCCOOH concentrations showed a significant dose effect and decreased significantly over time.

CONCLUSIONS

Oral THC dosing significantly affected OF THCCOOH but minimally contributed to THC OF concentrations; prior ad libitum smoking was the primary source of THC, CBD, and CBN. Higher cannabinoid concentrations following active oral THC administrations vs placebo suggest a compensatory effect of THC tolerance on smoking topography.

Oral fluid/plasma cannabinoid ratios following controlled oral THC and smoked cannabis administration

Oral fluid (OF) is a valuable biological alternative for clinical and forensic drug testing. Evaluating OF to plasma (OF/P) cannabinoid ratios provides important pharmacokinetic data on the disposition of drug and factors influencing partition between matrices. Eleven chronic cannabis smokers resided on a closed research unit for 51 days. There were four 5-day sessions of 0, 30, 60, and 120 mg oral ∆(9)-tetrahydrocannabinol (THC)/day followed by a five-puff smoked cannabis challenge on Day 5. Each session was separated by 9 days ad libitum cannabis smoking. OF and plasma specimens were analyzed for THC and metabolites. During ad libitum smoking, OF/P THC ratios were high (median, 6.1; range, 0.2-348.5) within 1 h after last smoking, decreasing to 0.1-20.7 (median, 2.1) by 13.0-17.1 h. OF/P THC ratios also decreased during 5-days oral THC dosing, and after the smoked cannabis challenge, median OF/P THC ratios decreased from 1.4 to 5.5 (0.04-245.6) at 0.25 h to 0.12 to 0.17 (0.04-5.1) at 10.5 h post-smoking. In other studies, longer exposure to more potent cannabis smoke and oromucosal cannabis spray was associated with increased OF/P THC peak ratios. Median OF/P 11-nor-9-carboxy-THC (THCCOOH) ratios were 0.3-2.5 (range, 0.1-14.7) ng/μg, much more consistent in various dosing conditions over time. OF/P THC, but not THCCOOH, ratios were significantly influenced by oral cavity contamination after smoking or oromucosal spray of cannabinoid products, followed by time-dependent decreases. Establishing relationships between OF and plasma cannabinoid concentrations is essential for making inferences of impairment or other clinical outcomes from OF concentrations.

Impact of prolonged cannabinoid excretion in chronic daily cannabis smokers' blood on per se drugged driving laws

BACKGROUND

Cannabis is the illicit drug most frequently reported with impaired driving and motor vehicle accidents. Some "per se" laws make it illegal to drive with any amount of drug in the body, while others establish blood, saliva, or urine concentrations above which it is illegal to drive. The persistence of Δ(9)-tetrahydrocannabinol (THC) in chronic daily cannabis smokers' blood is unknown.

METHODS

Thirty male chronic daily cannabis smokers resided on a secure research unit for up to 33 days, with daily blood collection. Samples were processed in an ice bath during sample preparation to minimize cannabinoid adsorption onto precipitant material. We quantified THC by 2-dimensional GC-MS.

RESULTS

Of the 30 participants, 27 were THC-positive on admission, with a median (range) concentration of 1.4 μg/L (0.3-6.3). THC decreased gradually; only 1 of 11 participants was negative at 26 days, 2 of 5 remained THC-positive (0.3 μg/L) for 30 days, and 5.0% of participants had THC ≥ 1.0 μg/L for 12 days. Median 11-hydroxy-THC concentrations were 1.1 μg/L on admission, with no results ≥ 1.0 μg/L 24 h later. 11-Nor-9-carboxy-THC (THCCOOH) detection rates were 96.7% on admission, decreasing slowly to 95.7% and 85.7% on days 8 and 22, respectively; 4 of 5 participants remained THCCOOH positive (0.6-2.7 μg/L) after 30 days, and 1 remained positive on discharge at 33 days.

CONCLUSIONS

Cannabinoids can be detected in blood of chronic daily cannabis smokers during a month of sustained abstinence. This is consistent with the time course of persisting neurocognitive impairment reported in recent studies.

The dose effects of short-term dronabinol (oral THC) maintenance in daily cannabis users

BACKGROUND

Prior studies have separately examined the effects of dronabinol (oral THC) on cannabis withdrawal, cognitive performance, and the acute effects of smoked cannabis. A single study examining these clinically relevant domains would benefit the continued evaluation of dronabinol as a potential medication for the treatment of cannabis use disorders.

METHODS

Thirteen daily cannabis smokers completed a within-subject crossover study and received 0, 30, 60 and 120mg dronabinol per day for 5 consecutive days. Vital signs and subjective ratings of cannabis withdrawal, craving and sleep were obtained daily; outcomes under active dose conditions were compared to those obtained under placebo dosing. On the 5th day of medication maintenance, participants completed a comprehensive cognitive performance battery and then smoked five puffs of cannabis for subjective effects evaluation. Each dronabinol maintenance period occurred in a counterbalanced order and was separated by 9 days of ad libitum cannabis use.

RESULTS

Dronabinol dose-dependently attenuated cannabis withdrawal and resulted in few adverse side effects or decrements in cognitive performance. Surprisingly, dronabinol did not alter the subjective effects of smoked cannabis, but cannabis-induced increases in heart rate were attenuated by the 60 and 120mg doses.

CONCLUSIONS

Dronabinol's ability to dose-dependently suppress cannabis withdrawal may be therapeutically beneficial to individuals trying to stop cannabis use. The absence of gross cognitive impairment or side effects in this study supports safety of doses up to 120mg/day. Continued evaluation of dronabinol in targeted clinical studies of cannabis treatment, using an expanded range of doses, is warranted.

Psychomotor function in chronic daily Cannabis smokers during sustained abstinence

Background

The present study assessed psychomotor function in chronic, daily cannabis smokers during 3 weeks continuously monitored abstinence on a secure research unit. We hypothesized that psychomotor performance would improve during abstinence of chronic, daily cannabis smokers.

Methodology/Principal Findings

Performance on the critical tracking (CTT) and divided attention (DAT) tasks was assessed in 19 male chronic, daily cannabis smokers at baseline and after 8, 14–16 and 21–23 days of continuously monitored abstinence. Psychomotor performance was compared to a control group of non-intoxicated occasional drug users. Critical frequency (λ_c) of the CTT and tracking error and control losses of the DAT were the primary outcome measures. Results showed that chronic cannabis smokers’ performance on the CTT (p<0.001) and the DAT (p<0.001) was impaired during baseline relative to the comparison group. Psychomotor performance in the chronic cannabis smokers improved over 3 weeks of abstinence, but did not recover to equivalent control group performance.

Conclusions/Significance

Sustained cannabis abstinence moderately improved critical tracking and divided attention performance in chronic, daily cannabis smokers, but impairment was still observable compared to controls after 3 weeks of abstinence. Between group differences, however, need to be interpreted with caution as chronic smokers and controls were not matched for education, social economic status, life style and race.

Tolerance to effects of high-dose oral δ9-tetrahydrocannabinol and plasma cannabinoid concentrations in male daily cannabis smokers

Oral cannabinoids are taken for medicinal or recreational purposes, yet little is known about tolerance to their effects after high-dose extended exposure. The development of tolerance to effects of around-the-clock oral synthetic Δ9-tetrahydrocannabinol (THC) (20 mg every 3.5-6 h) was evaluated in 13 healthy male daily cannabis smokers residing on a secure research unit: 40 mg on Day 1; 100 mg on Days 2-4; 120 mg on Days 5-6. Systolic and diastolic blood pressure (BP), heart rate, and symptoms of subjective intoxication (100 mm visual-analogue scales, VAS) were assessed the morning of Day 1 (before any oral THC), and on Days 2, 4 and 6, every 30 min for 3 h after the first morning THC dose. Morning subjective intoxication ratings increased from Days 1 to 2, and then declined on Days 4 and 6. The morning THC dose increased intoxication ratings on Day 2, but had less effect on Days 4 and 6, a pattern consistent with tolerance. THC lowered BP and increased heart rate over the six days. Plasma THC and 11-OH-THC concentrations increased significantly over the first five days of dosing. Six days of around-the-clock, oral THC produced tolerance to subjective intoxication, but not to cardiovascular effects.

Predictive model accuracy in estimating last Δ9-tetrahydrocannabinol (THC) intake from plasma and whole blood cannabinoid concentrations in chronic, daily cannabis smokers administered subchronic oral THC

BACKGROUND

Determining time since last cannabis/Δ9-tetrahydrocannabinol (THC) exposure is important in clinical, workplace, and forensic settings. Mathematical models calculating time of last exposure from whole blood concentrations typically employ a theoretical 0.5 whole blood-to-plasma (WB/P) ratio. No studies previously evaluated predictive models utilizing empirically-derived WB/P ratios, or whole blood cannabinoid pharmacokinetics after subchronic THC dosing.

METHODS

Ten male chronic, daily cannabis smokers received escalating around-the-clock oral THC (40-120 mg daily) for 8 days. Cannabinoids were quantified in whole blood and plasma by two-dimensional gas chromatography-mass spectrometry.

RESULTS

Maximum whole blood THC occurred 3.0 h after the first oral THC dose and 103.5h (4.3 days) during multiple THC dosing. Median WB/P ratios were THC 0.63 (n=196), 11-hydroxy-THC 0.60 (n=189), and 11-nor-9-carboxy-THC (THCCOOH) 0.55 (n=200). Predictive models utilizing these WB/P ratios accurately estimated last cannabis exposure in 96% and 100% of specimens collected within 1-5h after a single oral THC dose and throughout multiple dosing, respectively. Models were only 60% and 12.5% accurate 12.5 and 22.5h after the last THC dose, respectively.

CONCLUSIONS

Predictive models estimating time since last cannabis intake from whole blood and plasma cannabinoid concentrations were inaccurate during abstinence, but highly accurate during active THC dosing. THC redistribution from large cannabinoid body stores and high circulating THCCOOH concentrations create different pharmacokinetic profiles than those in less than daily cannabis smokers that were used to derive the models. Thus, the models do not accurately predict time of last THC intake in individuals consuming THC daily.

Recent advances in flow-controlled multidimensional gas chromatography

The continued development of flow-controlled two-dimensional gas chromatography (2-D GC) is reviewed, with a special emphasis on results published from 2001 through 2011. Heart-cutting 2-D GC continues to be used for isolating selected components in complex mixtures. The programmable and highly precise flows and temperatures produced by modern gas chromatographs have made it easier to selectively transfer analytes to the secondary column and to backflush unwanted components from the primary column. Several new Deans switch interfaces for performing heart-cutting 2-D GC have been introduced, with most attention given to devices that integrate the flow connections into a single unit. Heart-cutting 2-D GC has been used to isolate analytes in a wide variety of complex mixtures including fuels, industrial feedstocks, fragrances, and environmental extracts. Valve-based comprehensive 2-D GC (GC×GC) was also actively developed in the past decade. Valve-based modulation is a simple way to generate GC×GC separations without using cryogenic fluids. More than ten new valve-based modulators were introduced. Diaphragm valves fitted with sample loops are the most common low duty cycle modulators, whereas fluidic modulators that employ differential flow conditions are the most common high duty cycle modulators. Applications of valve-based GC×GC include analysis of hydrocarbon mixtures, essential oils, and environmental samples.

Antagonist-elicited cannabis withdrawal in humans

Cannabinoid CB1 receptor antagonists have potential therapeutic benefits, but antagonist-elicited cannabis withdrawal has not been reported in humans. Ten male daily cannabis smokers received 8 days of increasingly frequent 20-mg oral Δ⁹-tetrahydrocannabinol (THC) dosages (40-120 mg/d) around-the-clock to standardize cannabis dependence while residing on a closed research unit. On the ninth day, double-blind placebo or 20- (suggested therapeutic dose) or 40-mg oral rimonabant, a CB1-cannabinoid receptor antagonist, was administered. Cannabis withdrawal signs and symptoms were assessed before and for 23.5 hours after rimonabant. Rimonabant, THC, and 11-hydroxy-THC plasma concentrations were quantified by mass spectrometry. The first 6 subjects received 20-mg rimonabant (1 placebo); the remaining 4 subjects received 40-mg rimonabant (1 placebo). Fourteen subjects enrolled; 10 completed before premature termination because of withdrawal of rimonabant from clinical development. Three of 5 subjects in the 20-mg group, 1 of 3 in the 40-mg group, and none of 2 in the placebo group met the prespecified withdrawal criterion of 150% increase or higher in at least 3 visual analog scales for cannabis withdrawal symptoms within 3 hours of rimonabant dosing. There were no significant associations between visual analog scale, heart rate, or blood pressure changes and peak rimonabant plasma concentration, area-under-the-rimonabant-concentration-by-time curve (0-8 hours), or peak rimonabant/THC or rimonabant/(THC + 11-hydroxy-THC) plasma concentration ratios. In summary, prespecified criteria for antagonist-elicited cannabis withdrawal were not observed at the 20- or 40-mg rimonabant doses. These data do not preclude antagonist-elicited withdrawal at higher rimonabant doses.

Oral fluid and plasma cannabinoid ratios after around-the-clock controlled oral Δ(9)-tetrahydrocannabinol administration

BACKGROUND

Oral fluid (OF) testing is increasingly important for drug treatment, workplace, and drugged-driving programs. There is interest in predicting plasma or whole-blood concentrations from OF concentrations; however, the relationship between these matrices is incompletely characterized because of few controlled drug-administration studies.

METHODS

Ten male daily cannabis smokers received around-the-clock escalating 20-mg oral Δ(9)-tetrahydrocannabinol (THC, dronabinol) doses (40-120 mg/day) for 8 days. Plasma and OF samples were simultaneously collected before, during, and after dosing. OF THC, 11-hydroxy-THC and 11-nor-9-carboxy-THC (THCCOOH) were quantified by GC-MS at 0.5-μg/L, 0.5-μg/L, and 7.5-ng/L limits of quantification (LOQs), respectively. In plasma, the LOQs were 0.25 μg/L for THC and THCCOOH, and 0.5 μg/L for 11-hydroxy-THC.

RESULTS

Despite multiple oral THC administrations each day and increasing plasma THC concentrations, OF THC concentrations generally decreased over time, reflecting primarily previously self-administered smoked cannabis. The logarithms of the THC concentrations in oral fluid and plasma were not significantly correlated (r = -0.10; P = 0.065). The OF and plasma THCCOOH concentrations, albeit with 1000-fold higher concentrations in plasma, increased throughout dosing. The logarithms of OF and plasma THCCOOH concentrations were significantly correlated (r = 0.63; P < 0.001), although there was high interindividual variation. A high OF/plasma THC ratio and a high OF THC/THCCOOH ratio indicated recent cannabis smoking.

CONCLUSIONS

OF monitoring does not reliably detect oral dronabinol intake. The time courses of THC and THCCOOH concentrations in plasma and OF were different after repeated oral THC doses, and high interindividual variation was observed. For these reasons, OF cannabinoid concentrations cannot predict concurrent plasma concentrations.

CB1 - cannabinoid receptor antagonist effects on cortisol in cannabis-dependent men

BACKGROUND

The endocannabinoid system modulates the hypothalamic-pituitary-adrenal (HPA) axis, but the effect of cannabinoid type 1 (CB1) receptor antagonism following chronic CB1 receptor stimulation in humans is unknown.

OBJECTIVES

To evaluate effects of the CB1 receptor antagonist rimonabant on the HPA axis in cannabis-dependent individuals.

METHODS

Fourteen daily cannabis smokers received increasingly frequent 20 mg oral Δ9-tetrahydrocannabinol (THC) doses (60-120 mg/day) over 8 days to standardize cannabis tolerance. Concurrent with the last THC dose, double-blind placebo or rimonabant (20 or 40 mg) was administered. Cannabinoid, rimonabant, and cortisol plasma concentrations were measured 1.5 hours prior to rimonabant administration and 2.0, 5.5, and 12.5 hours post-dose.

RESULTS

Ten participants completed before premature study termination due to rimonabant's withdrawal from development. Five participants received 20 mg, three received 40 mg, and two placebo. There was a significant positive association between rimonabant concentration and change in cortisol concentration from baseline (r = .53, p < .01). There also was a borderline significant association between rimonabant dose and cortisol concentrations when the dose-by-time interaction was included. Four of eight participants receiving rimonabant (none of two receiving placebo) had greater cortisol concentrations 2 hours after dosing (at 11:30) than at 08:00, while normal diurnal variation should have peak concentrations at 08:00.

CONCLUSION

Rimonabant 20 or 40 mg did not significantly increase plasma cortisol concentrations, consistent with an absence of antagonist-elicited cannabis withdrawal.

SCIENTIFIC SIGNIFICANCE

Rimonabant doses >40 mg might elicit cortisol changes, confirming a role for CB1 receptors in modulating the HPA axis in humans.

Forensic toxicology

Forensic toxicology has developed as a forensic science in recent years and is now widely used to assist in death investigations, in civil and criminal matters involving drug use, in drugs of abuse testing in correctional settings and custodial medicine, in road and workplace safety, in matters involving environmental pollution, as well as in sports doping. Drugs most commonly targeted include amphetamines, benzodiazepines, cannabis, cocaine and the opiates, but can be any other illicit substance or almost any over-the-counter or prescribed drug, as well as poisons available to the community. The discipline requires high level skills in analytical techniques with a solid knowledge of pharmacology and pharmacokinetics. Modern techniques rely heavily on immunoassay screening analyses and mass spectrometry (MS) for confirmatory analyses using either high-performance liquid chromatography or gas chromatography as the separation technique. Tandem MS has become more and more popular compared to single-stage MS. It is essential that analytical systems are fully validated and fit for the purpose and the assay batches are monitored with quality controls. External proficiency programs monitor both the assay and the personnel performing the work. For a laboratory to perform optimally, it is vital that the circumstances and context of the case are known and the laboratory understands the limitations of the analytical systems used, including drug stability. Drugs and poisons can change concentration postmortem due to poor or unequal quality of blood and other specimens, anaerobic metabolism and redistribution. The latter provides the largest handicap in the interpretation of postmortem results.

Conventional and alternative matrices for driving under the influence of cannabis: recent progress and remaining challenges

In the past decade much research concerning the impact of cannabis use on road safety has been conducted. More specifically, studies on effects of cannabis smoking on driving performance, as well as epidemiological studies and cannabis-detection techniques have been published. As a result, several countries have adopted driving under the influence of drugs (DUID) legislations, with varying approaches worldwide. A wide variety of bodily fluids have been utilized to determine the presence of cannabis. Urine and blood are the most widely used matrices for DUID legislations. However, more and more publications focus on the usability of oral fluid testing for this purpose. Each matrix provides different information about time and extent of use and likelihood of impairment. This review will focus on the practical aspects of implying a DUID legislation. The pros and cons of the different biological matrices used for Δ9-tetrahydrocannabinol screening and quantification will be discussed. In addition, a literature overview concerning (roadside) cannabinoid detection, as well as laboratory confirmation techniques is given. Finally, we will discuss important issues influencing interpretation of these data, such as oral fluid collection, choice of cut-offs, stability and proficiency testing.

Validation of a two-dimensional gas chromatography mass spectrometry method for the simultaneous quantification of cannabidiol, Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC, and 11-nor-9-carboxy-THC in plasma

A sensitive analytical method for simultaneous quantification of sub-nanogram concentrations of cannabidiol (CBD), Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) in plasma is presented for monitoring cannabinoid pharmacotherapy and illicit cannabis use. Analytes were extracted from 1 mL plasma by solid-phase extraction, derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide with 1% trimethylchlorosilane, and analyzed by two-dimensional gas chromatography mass spectrometry (2D-GCMS) with cryofocusing. The lower calibration curve was linear from 0.25-25 ng/mL for CBD and THC, 0.125-25 ng/mL for 11-OH-THC and 0.25-50 ng/mL for THCCOOH. A second higher linear range from 5-100 ng/mL, achieved through modification of injection parameters, was validated for THC, 11-OH-THC, and THCCOOH and was only implemented if concentrations exceeded the lower curve upper limit of linearity. This procedure prevented laborious re-extraction by allowing the same specimen to be re-injected for quantification on the high calibration curve. Intra- and inter-assay imprecision, determined at four quality control concentrations, were <or=7.8% CV. Analytical bias was within +/-9.2% of target and extraction efficiencies were >or=72.9% for all analytes. Analytes were stable when stored at 22 degrees C for 16 h, 4 degrees C for 48 h, after three freeze-thaw cycles at -20 degrees C and when stored on the autosampler for 48 h. This sensitive and specific 2D-GCMS assay provides a new means of simultaneously quantifying CBD, THC and metabolite biomarkers in clinical medicine, forensic toxicology, workplace drug testing, and driving under the influence of drugs programs.