A study on the concentrations of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in hair root and whole hair

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.

THC and THC-COOH hair concentrations: Influence of age, gender, consumption habits, cosmetics treatment, and hair features

Evaluation of Cannabis consumption is required for many purposes (i.e., workplace drug testing and driving license renewal). Hair analysis represents the most adopted and reliable approach for the investigation of repeated or chronic exposure to Cannabis. The main markers are the Δ9-tetrahydrocannabinol (THC) and its main metabolite, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), as stated by the Society of Hair Testing (SoHT) and the European Workplace Drug Testing Society (EWDTS). In this paper we presented an observational study on the hair concentrations of THC and THC-COOH and influences due to age, gender, consumption habits, and hair features. Data were collected from analysis of scalp hair samples (3-cm proximal segment) provided by subjects tested for THC consumption for personal purposes (i.e., workplace drug testing, personal use proving). The subjects provided an informed consent and a short questionnaire. A new analytical method was previously developed and then adopted. It consisted in a hydrolysis (1 mL of 1 M NaOH at 65 °C, 20 min) and a liquid-liquid extraction (with hexane/ethyl acetate,90/10, v/v in presence of 1.5 mL of H₂SO₄ 1 M) of 25 mg of hair. A liquid chromatograph - tandem mass spectrometer (LC-MS/MS) equipped with a C18 column was used. The acquisition was in multiple reaction monitoring for the following transitions: 315→259, 193 m/z, for THC; 318→196, 123 m/z, for THC-d3; 345→299, 193 m/z for THC-COOH; 348→196, 302 m/z for THC-COOH-d3. Correlation between THC and THC-COOH hair concentrations was analyzed by Spearman's rank correlation coefficient. In order to study the influences of several variables, a new value, Sqrt(THC*THCCOOH), was adopted. Its effectiveness and reliability were proved by the Principal Component Analysis. Relationships between the Sqrt(THC*THCCOOH) and the variables were studied through the Stepwise regression (p = 0.05). The normality of data distribution was tested by the Shapiro-Wilk test. The Lower limits of quantification were 10.0 (THC) and 0.2 (THC-COOH) pg/mg. Accuracy and precision always met the acceptable criteria. Recoveries were > 78% and ion suppression was observed for both the compounds. Data from 126 hair samples were included in this study: 54 subjects(42.9%) were positive both for THC and THC-COOH; none of the samples was positive for a single substance. Concentrations ranged from 0.18 to 1.75 ng/mg (median: 0.78 ng/mg) for THC and from 0.04 to 0.85 ng/mg (median: 0.31 ng/mg) for THC-COOH. Cannabinoids levels seemed to decrease with the age, with lower amounts in the subjects aged > 40 years (p < 0.05). Also years of consumption seemed to have a significant impact on hair concentrations, as higher levels were observed in consumers from > 10 years (p = 0.013). Moreover, this study further provided evidences of a significant reduction of THC and THC-COOH in bleached hair (p = 0.042).

Quantification of cannabinoids in human hair using a modified derivatization procedure and liquid chromatography-tandem mass spectrometry

The aim of this work was to develop and validate a liquid chromatography-tandem mass spectrometry method for detecting of the main cannabinoids, cannabinol (CBN) and tetrahydrocannabinol (THC) and the primary metabolite 11-nor-9-carboxy-Δ⁹ -tetrahydrocannabinol (THC-COOH) in hair samples. Extraction of the cannabinoids was carried out by a polymeric strong anion mixed-mode solid-phase extraction cartridge and then employing methanolic HCl followed by 2-fluoro-1-methylpyridinium-p-toluenesulfonate (FMP-TS) as a derivatization procedure of carboxyl and phenolic groups, respectively, offering enhanced sensitivity for the detection of THC-COOH in hair matrices. Formation of a methyl ester increased its lipophilicity and removed the negative charge on the carboxyl group. Calibration curves were prepared over the range of 0.02-4 pg/mg of hair for THC and CBN and 0.2-12 pg/mg of hair for THC-COOH. The extraction recovery was between 81% and 105% for all compounds. The limit of detection (LOD) and limit of quantification (LOQ) were 2 and 20 pg/mg, respectively, for both CBN and THC and 0.1 and 0.2 pg/mg, respectively, for THC-COOH, which met the society of hair testing recommendation. Intra-assay and interassay precision were always lower than 4% and 11%, respectively for these cannabinoids, whereas intra-assay and interassay bias were between +14% and -18% and +15% and -12%, respectively. Twenty-seven hair specimens from cannabis users were investigated. The concentrations of CBN, THC and THC-COOH gave ranges of (0.022-2.562 ng/mg), (0.049-0.431 ng/mg) and (0.222-4.867 pg/mg), respectively. This new method of derivatization improves the LOD to ensure detection of the metabolite.

Simultaneous Quantitative Determination of Amphetamines, Opiates, Ketamine, Cocaine and Metabolites in Human Hair: Application to Forensic Cases of Drug Abuse

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously quantify amphetamines, opiates, ketamine, cocaine, and metabolites in human hair is described. Hair samples (50 mg) were extracted with methanol utilizing cryogenic grinding. Calibration curves for all the analytes were established in the concentration range 0.05-10 ng/mg. The recoveries were above 72%, except for AMP at the limit of quantification (LOQ), which was 48%. The accuracies were within ±20% at the LOQ (0.05 ng/mg) and between -11% and 13.3% at 0.3 and 9.5 ng/mg, respectively. The intraday and interday precisions were within 19.6% and 19.8%, respectively. A proficiency test was applied to the validated method with z-scores within ±2, demonstrating the accuracy of the method for the determination of drugs of abuse in the hair of individuals suspected of abusing drugs. The hair concentration ranges, means, and medians are summarized for abused drugs in 158 authentic cases.

A review of bioanalytical techniques for evaluation of cannabis (Marijuana, weed, Hashish) in human hair

Cannabis products (marijuana, weed, hashish) are among the most widely abused psychoactive drugs in the world, due to their euphorigenic and anxiolytic properties. Recently, hair analysis is of great interest in analytical, clinical, and forensic sciences due to its non-invasiveness, negligible risk of infection and tampering, facile storage, and a wider window of detection. Hair analysis is now widely accepted as evidence in courts around the world. Hair analysis is very feasible to complement saliva, blood tests, and urinalysis. In this review, we have focused on state of the art in hair analysis of cannabis with particular attention to hair sample preparation for cannabis analysis involving pulverization, extraction and screening techniques followed by confirmatory tests (e.g., GC–MS and LC–MS/MS). We have reviewed the literature for the past 10 years’ period with special emphasis on cannabis quantification using mass spectrometry. The pros and cons of all the published methods have also been discussed along with the prospective future of cannabis analysis.

Hair analysis for Δ(9) -tetrahydrocannabinolic acid A (THCA-A) and Δ(9) -tetrahydrocannabinol (THC) after handling cannabis plant material

A previous study has shown that Δ(9) -tetrahydrocannabinolic acid A (THCA-A), the non-psychoactive precursor of Δ(9) -tetrahydrocannabinol (THC) in the cannabis plant does not get incorporated in relevant amounts into the hair through the bloodstream after repeated oral intake. However, THCA-A can be measured in forensic hair samples in concentrations often exceeding the detected THC concentrations. To investigate whether the handling of cannabis plant material prior to consumption is a contributing factor for THC-positive hair results and also the source for THCA-A findings in hair, a study comprising ten participants was conducted. In this study, the participants rolled a marijuana joint on five consecutive days and hair samples of each participant were obtained. Urine samples were taken to exclude cannabis consumption prior to and during the study. THCA-A and THC could be detected in the hair samples from all participants taken at the end of the exposure period (concentration range: 15-1800 pg/mg for THCA-A and < 10-93 pg/mg for THC). Four weeks after the first exposure, THCA-A could still be detected in the hair samples of nine participants (concentration range: 4-57 pg/mg). Furthermore, THC could be detected in the hair samples of five participants (concentration range: < 10-17 pg/mg). Based on these results, it can be concluded that at least parts of the THC as well as the major part of THCA-A found in routine hair analysis derives from external contamination caused by direct transfer through contaminated fingers. This finding is of particular interest in interpreting THC-positive hair results of children or partners of cannabis users, where such a transfer can occur due to close body contact. Analytical findings may be wrongly interpreted as a proof of consumption or at least passive exposure to cannabis smoke. Such misinterpretation could lead to severe consequences for the people concerned.

THCCOOH concentrations in whole blood: are they useful in discriminating occasional from heavy smokers?

Some forensic and clinical circumstances require knowledge of the frequency of drug use. Care of the patient, administrative, and legal consequences will be different if the subject is a regular or an occasional cannabis smoker. To this end, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) has been proposed as a criterion to help to distinguish between these two groups of users. However, to date this indicator has not been adequately assessed under experimental conditions. We carried out a controlled administration study of smoked cannabis with a placebo. Cannabinoid levels were determined in whole blood using tandem mass spectrometry. Significantly high differences in THCCOOH concentrations were found between the two groups when measured during the screening visit, prior to the smoking session, and throughout the day of the experiment. Receiver operating characteristic (ROC) curves were determined and two threshold criteria were proposed in order to distinguish between these groups: a free THCCOOH concentration below 3 µg/L suggested an occasional consumption (≤ 1 joint/week) while a concentration higher than 40 µg/L corresponded to a heavy use (≥ 10 joints/month). These thresholds were tested and found to be consistent with previously published experimental data. The decision threshold of 40 µg/L could be a cut-off for possible disqualification for driving while under the influence of cannabis. A further medical assessment and follow-up would be necessary for the reissuing of a driving license once abstinence from cannabis has been demonstrated. A THCCOOH level below 3 µg/L would indicate that no medical assessment is required.

Rapid and robust confirmation and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine by column switching LC-MS-MS analysis

A method for the rapid and robust confirmation of 11-nor-∆9-tetrahydrocannabinol-9-carboxylic acid (THCA) in urine involving basic hydrolysis with NaOH and direct injection of the hydrolysate in a column-switching LC-MS-MS system was developed and validated. THCA-d3 was used as internal standard. Detection was performed in negative-ion mode by monitoring the transitions from the [M-CO(2) ]- ion m/z 299.2→245.2 and and m/z 299.2→191.1 that were found to provide a better signal-to-noise ratio than the transition from the pseudomolecular ion at m/z 343. The high sensitivity of detection enabled the injection of a small volume (10 µl) of the NaOH hydrolysate which, together with the applied column switching system, proved to confer ruggedness to the method and to avoid the deterioration of the instrumental apparatus despite the large amount of inorganic ions in the hydrolysate. The LLOQ was established at 5 ng/ml, and the LLOD was calculated as 0.2 ng/ml (S/N =3). The method was submitted to thorough validation including evaluation of the calibration range (5-500 ng/ml), accuracy and precision, matrix effects, overall process efficiency, autosampler stability, carryover and cross-talk, and 10-times reduction of sample volume (0.1 ml). Proof of applicability was obtained by direct comparison with the reference GC-MS method in use in the lab (the R(2) between the two methods was 0.9951).