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

Variability associated with interpreting drugs within forensic hair analysis: A three-stage interpretation

Hair analysis is capable of determining both an individual's long-term drug history and a single exposure to a drug, which can be particularly important for corroborating incidents of drug-facilitated crimes. As a source of forensic evidence that may be used in a court of law, it must be credible, impartial and reliable, yet the pathways of drug and metabolite entry into hair are still uncertain. Many variables may influence drug analysis results, most of which are outside of the control of an analyst. An individual's pharmacokinetic and metabolic responses, hair growth rates, drug incorporation routes, axial migration, ethnicity, age and gender, for example, all display interpersonal variability. At present there is little standardization of the analytical processes involved with hair analysis. Both false positives and negative results for drugs are frequently encountered, regardless of whether a person has consumed a drug or not. In this regard, we have categorized these variables and proposed a three-stage analytical approach to facilitate forensic toxicologists, hair analysis experts, judiciaries and service users in the analytical and interpretation process.

Comparative Evaluation of Drug Deposition in Hair Samples Collected from Different Anatomical Body Sites

In this study, we focused on the validation of a method for the simultaneous detection and quantification of cannabinoids, cocaine and opiates in hair as well as on the distribution of the drugs deposition in hair collected from different anatomical body sites. The proposed analytical procedure was validated for various parameters such as selectivity, linearity, limit of quantification, precision, accuracy, matrix effect and recovery. Four hundred and eighty-one samples were collected during 2010-2015 from 231 drug abusers. A 6-h ultrasonic-assisted methanolic extraction was applied for the isolation of the drugs. The analysis was performed in an liquid chromatography-mass spectrometry system for the opiates and cocaine and in a gas chromatography-mass spectrometry system for the cannabinoids. Cocaine was the most frequent detected drug (68.8-80.5%) followed by cannabinoids (47.6-63.3%) and opiates (34.7-46.7%) depending on the body site that the samples were collected. The mean concentrations of Δ9-tetrahydrocannabinol (THC) were 0.63 ± 2.11 for head, 0.54 ± 1.03 for pubic, 0.34 ± 0.51 for axillary and 0.18 ± 0.18 ng/mg for chest hair samples. The values of cocaine were 6.52 ± 15.98, 4.64 ± 10.77, 6.96 ± 38.21 and 3.94 ± 6.35 ng/mg, while the values of 6-monoacetylmorphine (MAM) were 3.33 ± 5.89, 3.06 ± 9.33, 1.37 ± 1.37 and 16.4 ± 1.77 ng/mg for head, pubic, axillary and chest samples, respectively. Differences between the detected concentrations of cocaine and opiates between the hair samples of different anatomical sites, as well as the ratio of drug metabolites to the parent compounds were observed in some cases. Statistically significant differences in the mean detected levels were noticed for morphine and heroin between head and pubic hair and also for cocaine and benzoylecgonine, between head and axillary hair samples. Moreover, the ratio of MAM to morphine and THC to cannabinol seems to correlate statistically with the total opiate or cannabinoid detected concentrations. The above differences could be attributed to several parameters associated with the structure, morphology, growth rate and other characteristics of the collected hair.

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

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

Determination of drugs of abuse in hair: evaluation of external heroin contamination and risk of false positives

One of the most controversial point regarding the validity of hair testing is the risk of false positive due to external contamination. The aim of our experience is to verify if a 5 consecutive days contamination with a small amount of a powdered mixture of heroin hydrochloride and acetylcodeine hydrochloride (10:1 w/w) will last sufficiently long to make a contaminated subject indistinguishable from active users, and if normal washing practices together with the decontamination procedure are sufficient to completely remove the external contamination. Our results suggest that decontamination procedures are not sufficient to remove drugs penetrated into hair from external source. In fact, all contaminated subjects were positive for opiates (heroin, 6-MAM, morphine, acetylcodeine and codeine) for at least 3 months. Significant 6-MAM concentrations (>0.5 ng/mg) were found in each subject until 6th week. Further, 6-MAM/morphine ratio were always above 1.3.

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

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

Verification of the drug history given by potential blood donors: results of drug screening that combines hair and urine analysis

BACKGROUND

Besides modern virus-screening methods, the avoidance of transfusion transmission of viral diseases is based on the best possible selection of healthy donors. Unfortunately, most of the relevant behavior-related risk factors are not accessible to objective verification. Drug screening can be used to validate a defined section of donor statements. It may be assumed that donors who conceal drug consumption may also conceal other relevant risk factors.

STUDY DESIGN AND METHODS

Hair and urine samples from 186 young potential donors who denied having consumed drugs were investigated by gas chromatography with mass selective detection and a urine fluorescence polarization immunoassay for cannabinoids, amphetamine and amphetamine derivatives, cocaine, and opiates.

RESULTS

Ten potential donors with 14 positive results on hair and urine analyses (6x cannabinoids, 4x cocaine, 1x opiates, 3x dihydrocodeine) could be identified in the population investigated.

CONCLUSIONS

The donor history is not adequate for identifying potential donors with risk factors. Deliberately false statements concerning risk factors are a clear breach of trust between the blood bank and potential donors. These unreliable donors represent an incalculable risk for the transfusion recipient. Therefore, it is appropriate to validate donor statements about drug consumption by random hair and urine analyses and to exclude from the donor pool all persons revealed as drug users.

Derivatization procedures for gas chromatographic-mass spectrometric determination of xenobiotics in biological samples, with special attention to drugs of abuse and doping agents

The development of low cost MS detectors in recent years has promoted an important increase in the applicability of GC-MS system to analyze for the presence of foreign substances in the human body. Drugs and toxic agents are in vivo metabolized in such a way that more polar compounds are usually formed. Derivatization of these metabolites is often an unavoidable requirement for gas chromatographic analysis. Application of derivatization methods in recent years has been relevant, especially for silylation, acylation, alkylation and the formation of cyclic or diastereomeric derivatives. Given the relevance of drug of abuse testing in modern toxicology, main derivatization procedures for opiates, cocaine, cannabis, amphetamines, benzodiazepines and LSD have been reviewed. Papers describing the analyses of drugs of abuse in matrixes other than blood, such as hair or sweat, have received special attention. Advances in derivatization for sports drug testing have been particularly relevant for anabolic steroids, diuretics and corticosteroids. Among the several methodologies applied, the formation of trimethylsilyl, perfluoroacyl or methylated derivatives have proved to be both versatile and extensively used. Further advances in derivatization for GC-MS applications in clinical and forensic toxicology will depend on the one hand on the degree of further use of GC-MS for routine applications and, on the other hand, on the alternative progress made for developments in LC-MS or CE-MS. Last but not least, the appearance of comprehensive libraries in which reference spectra for different derivatives of many drugs and their metabolites are collected will have an important impact on the expansion of derivatization in GC-MS for toxicological applications.