Hair toxicological analysis of infants and their mothers: a 5-year retrospective study focusing on cocaine

Prenatal and infant exposure to drugs of abuse is an emerging social and public health problem affecting children health and which may relate to child abuse and neglect. Exposure to drugs of abuse may occur through different routes, including intrauterine, breastfeeding, accidental intake, passive inhalation, and intentional administration. Currently, cases of suspected exposure can be investigated by hair toxicological analysis, the interpretation of which is, however, often difficult, leading to consequent difficulties in the management of such cases. In order to provide a contribution in terms of interpretation of the analytical results, this study aimed to search for the possible existence of elements, from a toxicological point of view, indicative towards the route of exposure. A retrospective study was performed on cases of suspected exposure to drugs of abuse in children aged 0-1 year, evaluated at a University Hospital between 2018 and 2022. Data of children hair toxicological analysis were analyzed and then compared with those of their mothers, when available; 41.6% children tested positive for cocaine. The study found a significant correlation between cocaine and benzoylecgonine concentrations, and a benzoylecgonine/cocaine ratio that tends to decrease as the age of children increases. From the comparison with mothers, a child/mother cocaine concentration ratio lower than 1 was found in all cases of hair sampled within the first week of life, and a ratio greater than or equal to 1 in all cases in which the sampling was performed later. These results, if confirmed in a larger cohort, could represent a contribution in the interpretation of cases of infant exposure to drugs of abuse and be integrated in the context of their multidisciplinary evaluation.

Influences of hair dyeing on the distribution shapes of zolpidem and methoxyphenamine in hair

In order to investigate the influences of hair dyeing on the distribution shapes of drugs in hair, different hair dyeing processes ("semi-permanent coloring without bleaching" and "permanent coloring with bleaching") were performed in vitro on black hair specimens collected from two subjects (Asians) who took a single dose of zolpidem (ZP, 10 mg of ZP tartrate) or methoxyphenamine (MOP, 50 mg of MOP hydrochloride). Under the following three different dyeing conditions, (1) semi-permanent coloring, (2) permanent coloring (once), (3) permanent coloring (twice), drug distributions in single hair specimens were investigated using a 2-mm segmental analysis by liquid chromatography-tandem mass spectrometry. Distribution shapes of drugs changed significantly only under the permanent coloring (twice) condition, resulting in reduced peak concentration and extended distribution width. There was, however, no significant difference in the amounts of drugs in hair between non-treated and dyed specimens, suggesting the drugs hardly leaked out of hair or were only slightly degraded during dyeing. In addition, while assuming contact with aqueous environment such as daily hair washing after dyeing, dyed hair specimens were individually immersed in ultrapure water for 20 hours, then the outflow of drugs in ultrapure water as well as the distribution shapes of drugs remaining in hair were determined. The drug outflow after permanent coloring (once and twice) was significantly larger than those after semi-permanent coloring, and the outflow ratios, [outflow]/([outflow] + [amount remaining in hair]), ranged over 9.8-24% (n = 3) for ZP and 68-71% (n = 3) for MOP after permanent coloring (once), and 54-72% (n = 3) for ZP and 86-91% (n = 3) for MOP after permanent coloring (twice). The distribution shapes of drugs after 20 h of immersion tended to flatten as outflow ratios increased, resulting in no change in the shapes after semi-permanent coloring, and complete collapse of their shapes after permanent coloring (twice). Thus, the present results indicated that hair dyeing involving bleaching and subsequent contact with aqueous environment after dyeing could significantly influence distribution shapes of drugs in hair.

Willingness to provide a hair sample for drug testing: results from an anonymous multi-city intercept survey

Background: Hair provision for drug testing can provide secondary measurement to complement self-reported drug use data, thereby providing a more accurate representation of an individual's drug use. Understanding factors associated with hair provision offers valuable insights into recruitment methods.Objective: To identify demographic and drug-related correlates of providing hair samples in a multi-site venue-intercept study.Methods: We utilized venue-intercept sampling for our Rapid Street Reporting study across 12 US cities between January and November 2022. Participants reported past 12-month drug use and were asked if they would provide a hair sample. We conducted multivariable (generalized linear model with logit link) analyses on demographics and drug use characteristics correlated to hair provision for drug testing.Results: Among 3,045 participants, 55.8% were male, 13.6% provided hair samples. Compared to males, those identifying as "other gender" had higher odds of hair collection (adjusted odds ratio = 2.24, 95% confidence interval: 1.28-3.80). Participants identifying as Black (aOR = 0.32, CI: 0.23-0.45) or "other race" (aOR = 0.50, 95% CI: 0.29-0.80) had lower odds of providing hair than those identifying as White. All levels of reported drug use - one drug (aOR=1.50, 95% CI: 1.15-1.96), two-three drugs (aOR=1.51, 95% CI: 1.11-2.05), four or more (aOR = 2.13, 95% CI: 1.50-3.01) - had higher odds of providing hair samples than those reporting no drug use. Similar associations applied to reporting cannabis use with or without another drug (aOR = 1.52-1.81, 95% CI: 1.15-2.38).Conclusion: Differential hair provision based on participant sex, race/ethnicity, and drug use may introduce biases in drug testing, limiting generalizability to individuals from minority backgrounds.

Sample Matrices for Mass Spectrometry-Based Adherence Monitoring: A Systematic Critical Review

BACKGROUND

Analytical monitoring of adherence using mass spectrometry (MS) plays an important role in clinical toxicology. Unambiguous detection of drugs (of abuse) and/or their metabolites in body fluids is needed to monitor intake of medication as prescribed or to monitor abstinence as a follow-up to detoxification procedures. This study focused on the advantages and disadvantages of different sample matrices used for MS-based adherence monitoring.

METHODS

Relevant articles were identified through a literature search in the PubMed database. English articles published between January 01, 2017, and December 31, 2022, were selected using the keywords "adherence assess*" or "adherence monit*" or "compliance assess*" or "compliance monit*" in combination with "mass spectrom*" in the title or abstract.

RESULTS

A total of 51 articles were identified, 37 of which were within the scope of this study. MS-based monitoring was shown to improve patient adherence to prescribed drugs. However, MS analysis may not be able to assess whether treatment was rigorously followed beyond the last few days before the sampling event, except when hair is the sample matrix. For medication adherence monitoring, blood-based analyses may be preferred because reference plasma concentrations are usually available, whereas for abstinence control, urine and hair samples have the advantage of extended detection windows compared with blood. Alternative sample matrices, such as dried blood samples, oral fluid, and exhaled breath, are suitable for at-home sampling; however, little information is available regarding the pharmacokinetics and reference ranges of drug (of abuse) concentrations.

CONCLUSIONS

Each sample matrix has strengths and weaknesses, and no single sample matrix can be considered the gold standard for monitoring adherence. It is important to have sufficient information regarding the pharmacokinetics of target substances to select a sample matrix in accordance with the desired purpose.

Metal levels in waste pickers in Brasilia, Brazil: hair and nail as exposure matrices

The aim of this cross-sectional study was to compare workplace conditions and metal exposures in 431 waste pickers who worked nearby at the Estrutural Dump in Brasilia utilizing hair (n = 310) and nail (n = 355) as matrices of exposure. Waste pickers were grouped according to their workplace (open waste dump: G1 and sorting plants: G2). Hair and nail samples were collected and analyzed using ICP-MS. The work duration in the facilities was significantly different between the groups with averages of 16.46 (8.48) yrs and 9.26 (6.28) yrs for hair donors in G1 and G2, and 15.92 (7.72) yrs and 8.55 (5.77) yrs for toenail donors in G1 and G2, respectively. The arithmetic means (μg/g) of cadmium, copper, lead, and manganese in hair were significantly higher in G2 (0.076 ± 0.133; 19.61 ± 18.16; 2.27 ± .56 and 3.87 ± 5.59, respectively) compared to G1 (0.069 ± 0.235; 15.72 ± 15.18; 1.72 ± 4.04 and 3.65 ± 5.5, respectively). Concentrations of arsenic, barium, cadmium, copper, cobalt, lead, manganese, and molybdenum in nail were significantly higher in G2 (0.57 ± 0.39; 22.74 ± 42.06; 0.1 ± 0.08; 22.7 ± 51.60; 0.48 ± 0.45; 4.69 ± 9.43; 19.07 ± 20.75; 1.80 ± 1.76, respectively) compared to G1 (0.40 ± 0.28; 15.32 ± 22.31; 0.08 ± 0.11; 11.91 ± 16.25; 0.37 ± 0.37; 3.94 ± 15.04; 13.01 ± 19.08; 1.16 ± 1.80, respective. Our findings suggest that the studied population was exposed to toxic metals and indicates the need for chemical exposure prevention policies to monitor chemical risk exposures in waste pickers.

The rate and quality of post-mortem hair root changes in relation to melanin content

Hairs is a relatively environmentally resistant biological material that is often found at crime scenes. Human hair is more durable than other biological traces such as blood or urine, and its collection and storage does not require specific preservation procedures. Melanin is the hair pigment, which is the main determinant of hair colour. There are two pigments present in human hair: eumelanin, predominant in dark hair, and pheomelanin, responsible for red colour. Eumelanin is more resistant and has photoprotective properties, while pheomelanin is phototoxic and shows lower resistance to environmental factors. The differences in the properties of eu- and pheomelanin are the basis of the present study, which aimed to examine the rate and quality of taphonomic changes in hair roots in relation to the predominant melanin type, under the influence of selected environmental factors, such as soil pH, degree of exposure to solar radiation, temperature and water from a natural watercourse (river) and chemically pure water. Therefore, changes in blonde, dark, grey, red and dyed hair roots were microscopically documented for six months under the influence of the above factors. The results of the study indicated the strongest degradation potential among acidic soil and a riverine environment, as well as the protective role of eumelanin against environmental taphonomic factors. Degradation occurred most rapidly in the river environment, where microbial activity was additionally observed. Distilled water, exposure to sunlight and low temperature did not lead to decomposition changes. The results of our team's research provide the basis for an extended analysis of the changes occurring in hair under the influence of environmental factors in relation to melanin content.

In the case of extensively putrefied bodies, the analysis of entomological samples may support and complement the toxicological results obtained with other alternative matrices

Entomotoxicological analysis is not part of routine toxicological analysis. This work aims to present two cases to illustrate the potential of entomological samples as complementary matrices to identify substances in cases of advanced putrefaction. (Case#1) A woman wasexhumed after 14 months to ascertain the exact cause of death. She died after six weeks of hospitalization because of intestinal ischemia followed by multiorgan failure. (Case#2) The corpse of a woman, known to have a psychiatric disorder, was discovered in her apartment. The state of decomposition of the body was consistent with a post-mortem period of several weeks (approximately 6 weeks). Toxicological investigations were performed in the biological and entomological samples of case#1 (hair, adipocere, brain, and pupae) and of case#2 (hair, bone, flies, and pupae) using liquid chromatography with high-resolution mass spectrometry and tandem mass spectrometry detection methods. In case#1, several drugs and metabolites were detected. In particular, the pupae analyses allowed the objectification of morphine administration, whereas morphine was only found in adipocere, but not in hair nor in brain. In case#2, the pupae analyses allowed the detection of three metabolites of quetiapine, and the flies analyses allowed the detection of valpromide, which was only detected in hair. In conclusion, the pupae and flies analyses in these two cases complemented the results obtained in the other alternative biological samples, which may guide hypotheses about the possible causes of death. Nevertheless, additional data and case reports would be of benefit to assess the value of entomotoxicology in routine forensic investigations.

Hair analysis for beta-blockers and calcium-channel blockers by using liquid chromatography-tandem mass spectrometry as a tool for monitoring adherence to antihypertensive therapy

Adherence to therapy is the key to a successful therapeutic intervention, especially in cardiovascular diseases in which a lack of adherence may have serious consequences in terms morbidity and/or mortality. In this context, hair analysis can be an excellent tool to monitor adherence to therapy. Indeed, drugs present in blood are incorporated into the hair matrix, where drugs and metabolites can stay unaltered for a long time protected from metabolism and degradation. In the present study, a simple, specific, and sensitive ultra-high performance liquid-chromatography-tandem mass spectrometry (UHPLC-MS/MS) method set up to determine in human hair seven beta-blockers (viz., metoprolol, sotalol, labetalol, atenolol, nebivolol, bisoprolol, and nadolol) and two calcium-channel blockers (lercanidipine and amlodipine), which are widely prescribed to treat medium-to-severe hypertensive conditions. The optimized method was successfully validated in terms of accuracy, repeatability, reproducibility, matrix effect and extraction recovery. Moreover, the applicability of the method was evaluated by analyzing 34 real samples of hair obtained from patients under long-term therapy with calcium channel blockers and beta-blockers.

Detection and Confirmation of Zilpaterol in Equine Hair Using Liquid Chromatography - Mass Spectrometry

Zilpaterol is a β₂ -adrenergic agonist and a repartitioning agent that has a high potential for abuse in equine performance athletes. Analysis of zilpaterol in hair is an alternative sampling matrix that extends detection time periods beyond those found in urine or blood samples. Our laboratory has been screening for zilpaterol in hair for many years and recently detected and confirmed its presence in official samples. Accordingly, a liquid chromatography - mass spectrometry method was developed and validated to detect and confirm zilpaterol in equine hair. Briefly, equine hair was decontaminated, cut, and pulverized prior to disruption and liquid-liquid extraction in basic conditions. Following extraction, the sample was introduced to an Agilent 1260 HPLC and zilpaterol was separated using a reverse phase gradient with a total run time of 12.5 minutes. Following chromatographic separation, zilpaterol and its corresponding stable isotope labeled internal standard were introduced via positive mode electrospray ionization to a Thermo Q-Exactive Plus mass spectrometer and spectra collected using parallel reaction monitoring. The methodology was validated using in-house criteria including characterization of accuracy, precision, recovery, linear range, matrix effects, limit of detection and limit of quantitation and the method was found to be fit-for-purpose to confirm the presence of zilpaterol in equine hair. This methodology has been used to detect and confirm the presence of zilpaterol from out-of-competition hair samples submitted by regional racing authorities.

Exhumation of a Methamphetamine Body-Packer: Pitfalls of Hair Result Interpretation

Carrying out toxicological investigations in biological samples (e.g. hair) collected from extensively decomposed bodies and even more interpretation of subsequently obtained results is challenging, even more in some particular circumstances of death. In order to illustrate these pitfalls, we report the case of the exhumation of a methamphetamine body-packer. Autopsy examination of a 41-year-old man, one year after his burial, revealed the presence of 44 green pellets (7 out of 44 were torn) along all the gastrointestinal tract. A 6-cm long dark hair strand and pellets were sampled for toxicological analyses. Large toxicological screenings were applied to hair and pellets using both LC-MS/MS and LC-HRMS. Intact pellets contained around 10 g of methamphetamine (MA) with a purity ranging from 29 to 35 %. Positive hair results were amiodarone (4.12 ng/mg), desethylamiodarone (5.29 ng/mg) and methamphetamine (7.63 ng/mg). Methamphetamine pellets in gastrointestinal tract were consistent with the autopsy conclusion, i.e. fatal intoxication due to in corpore pellet rupture in a body-packer (the victim was initially deemed to have died from heart failure). In the absence of available data in the literature, amiodarone and metabolite presence in hair could putatively be the consequence of a chronic treatment. Methamphetamine hair concentration was similar to those observed in regular consumers. However, interpreting this hair result is challenging due to (i) the possibility of contamination by sweat at the time of death, and (ii) the probable contamination by putrefaction fluids. This latter hypothesis (artifactual contamination during the post-mortem period) is highly supported by high concentration of methamphetamine in decontamination bath, and even more by the absence of the major methamphetamine metabolite (amphetamine) in hair. As a conclusion, in this particular situation, the hair analysis result (presence of MA and concomitant absence of amphetamine) is in agreement with the previously-established cause of death.

Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.

Determination of 37 fentanyl analogues and novel synthetic opioids in hair by UHPLC-MS/MS and its application to authentic cases

The recent emergence of new fentanyl analogues and synthetic opioids on the drug market poses a global public health threat. However, these compounds cannot typically be identified using existing analytical methods. In this study, we aimed to develop and validate a rapid and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous determination of 37 fentanyl analogues and novel synthetic opioids in hair samples. Hair samples (20 mg) were extracted by cryogenic grinding in an extraction medium of methanol, acetonitrile, and 2 mmol/L ammonium acetate (pH 5.3). Following centrifugation of the samples, the analytes were separated using a WATERS Acquity UPLC HSS T3 column. The limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.5 to 2.5 pg/mg and from 2 to 5 pg/mg, respectively. The intraday and interday precisions were within 13.32% at LOQ, low, medium, and high levels. The accuracies were within the range of 85.63-116.1%. The extraction recoveries were in the range of 89.42-119.68%, and the matrix effects were within the range of 44.81-119.77%. Furthermore, the method was successfully applied to the detection and quantification of fentanyl and sufentanil in hair samples from two authentic cases. Thus, this method has great potential for detecting fentanyl analogues and novel synthetic opioids in forensic work.

Distribution pattern of common drugs of abuse, ethyl glucuronide, and benzodiazepines in hair across the scalp

While hair analysis is important and accepted in forensic applications, fundamental knowledge gaps still exist, exacerbated by a lack of knowledge of the incorporation mechanisms of substances into hair. The influence of the hair sampling location on the head on ethyl glucuronide (EtG) and cocaine concentrations was investigated by measuring the complete scalp hair of 14 (2 EtG, 4 cocaine, 8 both EtG and cocaine) study participants in a grid pattern for EtG, drugs of abuse, and benzodiazepines. Head skin perfusion and sweating rates were investigated to rationalize the concentration differences. For EtG, ratios between maximum and minimum concentrations on the scalp ranged from 2.5 to 7.1 (mean 4.4). For cocaine, the ratios ranged from 2.8 to 105 (mean 17.6). EtG concentrations were often highest at the vertex, but the distribution was strongly participant dependent. Cocaine and its metabolites showed the lowest concentrations at the vertex and the highest on the periphery, especially at the forehead. These differences led to hair from some head parts being clearly above conventional cut-offs and others clearly below. In addition to EtG and cocaine, the distributions of 24 other drugs of abuse and benzodiazepines/z-substances and metabolites are described. No clear pattern was observed for the head skin perfusion. Sweating rate measurements revealed higher sweating rates on the periphery of the haircut. Therefore, sweat could be a main incorporation route for cocaine. Concentration differences can lead to different interpretations depending on the sampling site. Therefore, the results are highly relevant for routine forensic hair analysis.

[Knockout Drugs: Diagnostics in the Emergency Unit and Clinical Practice]

Knockout Drugs: Diagnostics in the Emergency Unit and Clinical Practice Abstract. Every now and then, physicians are challenged with date rape drugs. If there is a suspicion of substance administration, the question of involving forensic medicine is commonly raised. In obscure situations or questionable offences, however, patients may wish for an initial diagnosis in the emergency department or the private practice. The physicians are often greatly challenged by the variety of substances, the limited analytical methods and difficulties with the interpretion of results. The major goal of this article is to present diagnostic options including their limitations. An overview of frequently involved substances is provided. Particular focus will be placed on practical aspects, including questions regarding pre-analytics and health insurance coverage.

Alternate Matrices: Meconium, Cord Tissue, Hair, and Oral Fluid

Drug testing commonly involves serum, blood, or urine. More recently, alternative specimens for drug testing have been increasingly used for clinical and forensic toxicology. Examples include oral fluid (saliva), hair, meconium, and umbilical cord tissue. Each of these matrices has unique properties that provide advantages for certain applications. Oral fluid has easier and less invasive collection requirements than urine, the most common specimen for drug screening. Oral fluid drug testing is common in Europe and steadily gaining popularity in the United States. Hair accumulates drugs and drug metabolites and provides a much longer window of detection than blood or urine. Meconium and umbilical cord tissue each allow for assessment of prenatal drug exposure over the course of months. Limitations of these alternative matrices include need for laboratory-developed tests (exception being some oral fluid immunoassays), challenges with the specimen matrix, and incomplete understanding of drug incorporation and kinetics. This chapter briefly describes each of the above alternative specimens in terms of their utility, advantages, and limitations.

A Study on Photostability of Amphetamines and Ketamine in Hair Irradiated under Artificial Sunlight

Drugs incorporated into hair are exposed to the environment, and cosmetic and chemical treatments, with possible decreases in their content. Knowledge concerning the effect of sunlight on drug content in hair can be helpful to forensic toxicologists, in particular, when investigating drug concentrations above or below pre-determined cut-offs. Twenty authentic positive hair samples were selected which had previously tested positive for amphetamines and/or ketamine. Washed hair were divided into two identical strands, with the former exposed at 765 W/m² (300–800 nm spectrum of irradiance) for 48 h in a solar simulator, and the latter kept in the dark. Hair samples were extracted and analyzed by liquid chromatography high-resolution mass spectrometry detection. The percentage of photodegradation was calculated for each analyte (i.e., amphetamine, methamphetamine, methylendioxyamphetamine, ketamine, and norketamine). In parallel, photodegradation processes of standard molecules dissolved in aqueous and organic solutions were studied. In 20 hair samples positive for the targeted analytes, exposure to artificial sunlight induced an appreciable decrease in drug concentrations. The concentration ranges in the non-irradiated hair samples were 0.01–24 ng/mg, and 65% of samples exhibited a decrease in post-irradiation samples, with reduction from 3% to 100%. When more drugs were present in the same hair sample (i.e., MDMA and ketamine) the degradation yields were compound dependent. A degradation product induced by irradiation of ketamine in aqueous and methanol solutions was identified; it was also found to be present in a true positive hair sample after irradiation. Ketamine, amphetamines, and their metabolites incorporated in the hair of drug users undergo degradation when irradiated by artificial sunlight. Only for ketamine was a photoproduct identified in irradiated standard solutions and in true positive irradiated hair. When decisional cut-offs are applied to hair analysis, photodegradation must be taken into account since sunlight may produce false negative results. Moreover, new markers could be investigated as evidence of illicit drug use.

The analysis of 132 novel psychoactive substances in human hair using a single step extraction by tandem LC/MS

A rapid LC-MS/MS method for the targeted screening of 132 NPS in hair is described. Drugs include cathinones and synthetic cannabinoids, as well as amphetamine-type stimulants, piperazines and other hallucinogenic compounds. This method utilizes hair pulverization in acidified methanol followed by analysis using liquid chromatography coupled with tandem MS. The limit of detection varied from 0.001 to 0.1ng/mg hair among the various analytes. The method was validated in terms of sensitivity, selectivity, repeatability and stability. The limit of reporting was set at 0.1ng/mg of hair. The method was successfully applied to 23 medico-legal cases where NPS were detected in blood or where NPS use was suspected. The identified NPS included acetyl fentanyl, 25C-NBOMe, MDPV, PB-22 and AB-FUBINACA, allowing hair to be used where historical or retrospective information on use of NPS is sought. This technique has proven to be efficient for the one step extraction from hair of different classes of NPS in routine toxicological investigations; from unstable and volatile compounds, such as most of the cathinones, to hydrophobic compounds such as synthetic cannabinoids.

Incorporation of Zolpidem into Hair and Its Distribution after a Single Administration

To obtain fundamental information on the drug incorporation into hair, time-course changes in drug distribution along single-strand hair were observed after a single oral administration of zolpidem (ZP), one of the most frequently used hypnotic agents. Quantitative sectional hair analyses of 1-mm segments were performed for each single-strand hair using a validated LC-MS/MS procedure. ZP was detected in all specimens plucked at 10 and 24 hours after a single dose, and the distribution ranged over the whole hair root (4-5 mm in length). A significantly high concentration of ZP was detected in the hair bulb region, whereas much lower concentrations were widely observed in the upper part of the hair root of those samples; this suggested that the incorporation of ZP occurred in two regions, mainly in the hair bulb and to a lesser extent in the upper dermis zone. The ZP-positive area formed lengths of up to 10-12 mm after a single administration, indicating that its incorporation from the hair bulb would continue for about 2 weeks. Time-course changes in the ZP concentration in the hair root additionally revealed that only a small portion of ZP that initially concentrated in the bulb was successively incorporated into the hair matrix and moved toward the keratinized region as hair grew. These findings should be taken into account upon discussing individual drug-use history based on hair analysis. The matrix-assisted laser desorption/ionization mass spectrometry imaging of ZP in the same kinds of hair specimens was also successfully achieved.

Recent trends in analytical methods and separation techniques for drugs of abuse in hair

Hair analysis of drugs of abuse has been a subject of growing interest from a clinical, social and forensic perspective for years because of the broad time detection window after intake in comparison to urine and blood analysis. Over the last few years, hair analysis has gained increasing attention and recognition for the retrospective investigation of drug abuse in a wide variety of contexts, shown by the large number of applications developed. This review aims to provide an overview of the state of the art and the latest trends used in the literature from 2005 to the present in the analysis of drugs of abuse in hair, with a special focus on separation analytical techniques and their hyphenation with mass spectrometry detection. The most recently introduced sample preparation techniques are also addressed in this paper. The main strengths and weaknesses of all of these approaches are critically discussed by means of relevant applications.

Hair as an alternative matrix in bioanalysis

Alternative matrices are steadily gaining recognition as biological samples for toxicological analyses. Hair presents many advantages over traditional matrices, such as urine and blood, since it provides retrospective information regarding drug exposure, can distinguish between chronic and acute or recent drug use by segmental analysis, is easy to obtain, and has considerable stability for long periods of time. For this reason, it has been employed in a wide variety of contexts, namely to evaluate workplace drug exposure, drug-facilitated sexual assault, pre-natal drug exposure, anti-doping control, pharmacological monitoring and alcohol abuse. In this article, issues concerning hair structure, collection, storage and analysis are reviewed. The mechanisms of drug incorporation into hair are briefly discussed. Analytical techniques for simultaneous drug quantification in hair are addressed. Finally, representative examples of drug quantification using hair are summarized, emphasizing its potentialities and limitations as an alternative biological matrix for toxicological analyses.