Incorporation of D-amphetamine into pigmented guinea-pig hair

Micro-segmental hair analysis: detailed procedures and applications in forensic toxicology

PURPOSE

Since the 1980s, the detection sensitivity of mass spectrometers has increased by improving the analysis of drugs in hair. Accordingly, the number of hair strands required for the analysis has decreased. The length of the hair segment used in the analysis has also shortened. In 2016, micro-segmental hair analysis (MSA), which cuts a single hair strand at a 0.4-mm interval corresponding to a hair growth length of approximately one day, was developed. The advantage of MSA is that the analytical results provide powerful evidence of drug use in the investigation of drug-related crimes and detailed information about the mechanism of drug uptake into hair. This review article focuses on the MSA technique and its applications in forensic toxicology.

METHODS

Multiple databases, such as SciFinder, PubMed, and Google, were utilized to collect relevant reports referring to MSA and drug analysis in hair. The experiences of our research group on the MSA were also included in this review.

RESULTS

The analytical results provide a detailed drug distribution profile in a hair strand, which is useful for examining the mechanism of drug uptake into hair in detail. Additionally, the analytical method has been used for various scenarios in forensic toxicology, such as the estimation of days of drug consumption and death.

CONCLUSIONS

The detailed procedures are summarized so that beginners can use the analytical method in their laboratories. Moreover, some application examples are presented, and the limitations of the current analytical method and future perspectives are described.

Does ADAM Need a Haircut? A Pilot Study of Self-Reported Drug Use and Hair Analysis in an Arrestee Sample

This article evaluates the potential impact that the use of hair analysis may have on the drug prevalence estimations derived from survey research that has relied upon urinalysis as an indicator of the accuracy of self-reported drug use. The paper reviews the history and nature of the DUF and ADAM programs, the relationship between self-report drug use and urinalysis results for arrestee populations, and the outcome of a pilot study employing hair assays in lieu of urinalysis. The author concludes that hair analysis may have a significant impact on the estimations of drug use for cocaine, heroin, and amphetamines and is less likely to have an effect on estimations of marijuana use. The author recommends consideration of periodic use of hair analysis within the ADAM system to more accurately and effectively monitor drug use.

Melanin affinity and its possible role in neurodegeneration

Certain drugs with melanin affinity are known to have caused pigmentary lesions in the eye and skin. This was the basis for the hypothesis that compounds with melanin affinity may cause damage also in other melanin-bearing tissues such as the substantia nigra. The heterogeneity of compounds that binds to melanin is large. Toxins, drugs, and several other compounds have melanin affinity. Compounds showing the highest affinity are mainly organic amines and metal ions. The binding of toxicants to melanin probably protects the cells initially. However, the binding is normally, slowly reversible and melanin may accumulate the toxicant and gradually release it into the cytosol. Several studies indicate that neuromelanin may play a significant role both in the initiation and in the progression of neurodegeneration. MPTP/MPP(+) that has been causally linked with Parkinsonism has high affinity for neuromelanin, and the induced dopaminergic denervation correlates with the neuromelanin content in the cells. This shows that the toxicological implications of the accumulation of toxicants in pigmented neurons and its possible role in neurodegeneration should not be neglected. Extracellular neuromelanin has been reported to activate dendritic cells and microglia. An initial neuronal damage induced by a neurotoxicant that leaks neuromelanin from the cells may therefore lead to a vicious cycle of neuroinflammation and further neurodegeneration. Although there are many clues to the particular vulnerability of dopaminergic neurons of substantia nigra in Parkinson's disease, the critical factors are not known. Further studies to determine the importance of neuromelanin in neurodegeneration and Parkinson's disease are warranted.

Measuring environmental stress in East Greenland polar bears, 1892-1927 and 1988-2009: what does hair cortisol tell us?

Hair sampled from 96 East Greenland polar bears (Ursus maritimus) over the periods 1892-1927 and 1988-2009 was analyzed for cortisol as a proxy to investigate temporal patterns of environmental stress. Cortisol concentration was independent of sex and age, and was found at significantly higher (p<0.001) concentrations in historical hair samples (1892-1927; n=8) relative to recent ones (1988-2009; n=88). In addition, there was a linear time trend in cortisol concentration of the recent samples (p<0.01), with an annual decrease of 2.7%. The recent hair samples were also analyzed for major bioaccumulative, persistent organic pollutants (POPs). There were no obvious POP related time trends or correlations between hair cortisol and hair POP concentrations. Thus, polar bear hair appears to be a relatively poor indicator of the animal's general POP load in adipose tissue. However, further investigations are warranted to explore the reasons for the temporal decrease found in the bears' hair cortisol levels.

Hair analysis as a biomonitor for toxicology, disease and health status

Hair analysis receives a large amount of academic and commercial interest for wide-ranging applications. However, in many instances, especially for elemental or 'mineral' analysis, the degree of success of analytical interpretation has been quite minimal with respect to the extent of such endeavors. In this critical review we address the questions surrounding hair analysis with specific intent of discovering what hair concentrations can actually relate to in a biogenic sense. This is done from a chemistry perspective to explain why and how elements are incorporated into hair and their meaning. This includes an overview of variables attributed to altering hair concentrations, such as age, gender, melanin content, and other less reported factors. Hair elemental concentrations are reviewed with regard to morbidity, with specific examples of disease related effects summarized. The application of hair analysis for epidemiology and etiology studies is enforced. A section is dedicated specifically to the area of population studies with regards to mercury, which highlights how endogenous and exogenous incorporation relies on species dependant metabolism and metabolic products. Many of the considerations are relevant to other areas of interest in hair analysis, such as for drug and isotopic analysis. Inclusion of a table of elemental concentrations in hair should act as a valuable reference (298 references).

Studies on the persistence of estradiol benzoate and nortestosterone decanoate in hair of cattle following treatment with growth promoters, determined by ultra-high-performance liquid chromatography-tandem mass spectrometry

Measurement of steroid esters in bovine hair samples, using sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS), provides a powerful tool for identifying animals treated illicitly with growth promoters. The successful application of such testing requires appropriate sampling of hair from treated animals. This paper describes the results of hair analysis by LC-MS/MS for two animal studies in which animals were treated with estradiol-3-benzoate and nortestosterone decanoate. The results from the first animal study indicate that animals treated with these anabolic steroids may not always be identified from analysis of hair samples; positive test results occur sporadically and only for some of the treated animals. The results from the second animal study identify conditions attaching to positive hair samples, such as, that concentrations of steroid esters in hair are related to distance of sampling from point of injection and to time post-treatment, that concentrations of steroid esters in hair are related to dose given to the animal but that this relationship may vary over time post-treatment, and that steroid esters may be measured in regrowth hair taken some weeks after treatment. Steroid esters are determined along the length of the hair, confirming that accumulation of steroid esters into hair occurs from various sources, including blood, sweat and sebum. The reported research provides some useful insights into the mechanisms governing the persistence of steroid esters in bovine hair following illicit treatment with growth promoters.

Amphetamine adducts of melanin intermediates demonstrated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The use of hair as a matrix for the determination of a history of drug abuse is becoming increasingly widespread. Melanin has been shown to play a key role in the incorporation of drugs in hair. The mechanism of this incorporation and the nature of the interaction remains poorly understood. Cationic drugs, such as amphetamine, are thought to be ionically bound to melanin; however, their inextricability has led to the suggestion that they may be covalently bound to a great degree. Identification of covalent adducts remains elusive due to the insoluble polymeric nature of melanin. We succeeded in identifying several such adducts by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF) analysis of the products of in vitro synthesis of melanin in the presence of amphetamine. Amphetamine was incubated with L-DOPA and mushroom tyrosinase under a stream of oxygen. After 1 h, a signal at m/z 281.1324 (n = 1, R = H) was observed. After 2 h, the major adduct mass visible in the spectrum was at m/z 470.1074. This appeared to be derived from the mono-decarboxylation of a minor adduct at m/z 514.1245 (n = 2, R = CO(2)H). A totally decarboxylated adduct was also observed at m/z 426.1448 (n = 2, R = H). These were identified as amphetamine adducts of indole quinones. Corroboration of their identity was obtained by observing the mass shifts with deuterated L-DOPA and amphetamine analogues. Accurate mass measurements using the reflectron mode of the MS showed that the smaller adduct was within 14 ppm, and the larger adducts were within 70 ppm of their theoretical monoisotopic masses. Postsource decay experiments agreed with our structural assignments.

Relationship of melanin degradation products to actual melanin content: application to human hair

Methods not only for characterizing but also for quantitating melanin subtypes from the two types of melanin found in hair--eumelanin and pheomelanin--have been established. In relation to testing for drugs of abuse in hair, these methods will allow for correction of drug binding to specific melanin subtypes and will serve to improve drug measurement in hair. 5,6-Dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) make up the majority of the eumelanin polymer while benzothiazene units derived from 2-cysteinyl-S-Dopa (2-CysDopa) and 5-cysteinyl-S-Dopa (5-CysDopa) compose the majority of the pheomelanin polymer. Our results show that: (1) pyrrole-2,3-dicarboxylic acid (PDCA) and pyrrole-2,3,5-tricarboxylic acid (PTCA), markers for DHI and DHICA units, respectively, are produced in 0.37 and 4.8% yields, respectively, when melanins are subjected to alkaline hydrogen peroxide degradation, (2) 3-aminotyrosine (3AT) and 4-amino-3-hydroxyphenylalanine (AHP), markers for 2-CysDopa and 5-CysDopa, respectively, are produced in 16 and 23% yield, respectively, when subjected to hydriodic acid hydrolysis, and (3) that black human hair contains approximately 99% eumelanin and 1% pheomelanin, brown and blond hair contain 95% eumelanin and 5% pheomelanin; and red hair contains 67% eumelanin and 33% pheomelanin. These data will allow deeper investigation into the relationship between melanin composition and drug incorporation into hair.

Hair analysis for drugs of abuse. Hair color and race differentials or systematic differences in drug preferences?

There is currently a debate in the literature on chemical drug analysis concerning the contribution of biophysical attributes associated with specimens and specimen donors to assay outcome. In recent years this debate has focused on hair analysis, but has in the past also been raised in urinalysis interpretation. In this article we examine several aspects of that controversy. First, we present data regarding the effects of hair color on the distribution of positive hair testing results for three drug classes. We compare these results to negative hair samples from comparable donors. This data is derived from head hair from preemployment donors that was classified according to seven visual color categories. We determined the distribution of colors for hair samples devoid of any of three assayed drugs (amphetamines, cocaine, and cannabinoids). Subsequently, this distribution was compared with the distributions for hairs that had tested positive for amphetamines, cocaine or cannabinoids. We examined a total of 2000 randomly selected samples; 500 negative hair samples and 500 positive samples for each of three drugs: cannabinoids, cocaine, and amphetamine. We also evaluated ethnic/racial factors in relation to positive urinalyses for various ethnic/racial groups. We examined approximately 4000 urine specimens from two different groups, each constituting around 2000 specimens. In addition to ethnicity/race and urinalysis outcome, we also examined the relationship between the hair color distributions of urine donors and the corresponding urinalysis results for the three drug classes. We also compared them to drug-negative samples. Our summary impression is that the observed outcome patterns were largely consistent with differences in drug preferences among the various societal groups. There was little evidence of a pattern attributable to hair color bias alone or selective binding of drugs to hair of a particular color. Likewise, there was no discernible pattern associated with race or ethnicity that would lend support to a "race effect" in drug analysis.

Incorporation of drugs for the treatment of substance abuse into pigmented and nonpigmented hair

Hair analysis for drugs may be useful for the long-term monitoring of recidivism and treatment compliance. L-alpha-Acetylmethadol, buprenorphine, and methadone are drugs that are used for the treatment of substance abuse. The purpose of this study was to study the relationship between dose, plasma concentration, hair concentration, and hair pigmentation for these compounds and their major metabolites in an animal model. Male Long-Evans rats received either L-alpha-acetylmethadol (1 and 3 mg/kg; n = 6), buprenorphine (1 and 3 mg/kg; n = 5), or methadone (4 and 8 mg/kg; n = 5) by intraperitoneal injection daily for 5 days. Fourteen days after beginning drug administration, newly grown hair was collected and analyzed for either L-alpha-acetylmethadol and two metabolites (L-alpha-acetyl-N-normethadol and L-alpha-acetyl-N,N-dinormethadol), methadone and two metabolites (D,L-2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium and D,L-2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline), or buprenorphine and one metabolite (norbuprenorphine). The plasma time course (AUC) for each compound was also determined after a single administration of each drug at the specified doses. There was an approximate dose-dependent increase in measured hair concentration of each parent drug in pigmented hair. The concentrations of L-alpha-acetylmethadol, methadone, and buprenorphine in nonpigmented hair were significantly less than that measured in pigmented hair at either the high or low dose. The metabolites L-alpha-acetyl-N-normethadol and D,L-2-ethyl-1,5dimethyl-3,3-diphenylpyrrolinium were detected at lower concentrations than their respective parent compounds (L-alpha-acetylmethadol or methadone) in pigmented hair. However, the L-alpha-acetyl-N,N-dinormethadol metabolite concentrations in pigmented hair were significantly greater than those of the parent drug after either the low or the high L-alpha-acetylmethadol dose. These data demonstrate that L-alpha-acetylmethadol, methadone, buprenorphine, and metabolites are distributed into hair in a dose-related manner with a preference for pigmented hair.

Hair analysis, a novel tool in forensic and biomedical sciences: new chromatographic and electrophoretic/electrokinetic analytical strategies

Hair analysis for abused drugs is recognized as a powerful tool to investigate exposure of subjects to these substances. In fact, drugs permeate the hair matrix at the root level and above. Evidence of their presence remains incorporated into the hair stalk for the entire life of this structure. Most abusive drugs (e.g. opiates, cocaine, amphetamines, cannabinoids etc.) and several therapeutic drugs (e.g. antibiotics, theophylline, beta 2-agonists, etc.) have been demonstrated to be detectable in the hair of chronic users. Hence, hair analysis has been proposed to investigate drug abuses for epidemiological, clinical, administrative and forensic purposes, such as in questions of drug-related fatalities and revocation of driving licences, alleged drug addiction or drug abstinence in criminal or civil cases and for the follow-up of detoxication treatments. However, analytical and interpretative problems still remain and these limit the acceptance of this methodology, especially when the results from hair analysis represent a single piece of evidence and can not be supported by concurrent data. The present paper presents an updated review (with 102 references) of the modern techniques for hair analysis, including screening methods (e.g. immunoassays) and more sophisticated methodologies adopted for results confirmation and/or for research purposes, with special emphasis on gas chromatography-mass spectrometry, liquid chromatography and capillary electrophoresis.

Effect of pigmentation on the drug deposition in hair of grey-haired subjects

The hair samples of 15 grizzled patients with a permanent medical treatment by amitriptyline, carbamazepine, chlorprothixene, diclofenac, doxepine, indomethacine, maprotiline or metoclopramide, or with a chronic heroin and cocaine abuse were separated into white and pigmented fibers and both fractions were independently investigated by GC-MS. The drugs were found in pigmented fibers as well as in white fibers, but the concentrations in the white fibers were smaller than in the pigmented ones for the most of the samples investigated. The concentration ratio of the drugs or their metabolites in both hair fractions (white/pigmented) was found to be between 0.09 and 1.57 (mean 0.70, 30 concentration pairs). There are large differences in this ratio between different subjects with the same drug, whereas for different drugs in the same subject in many cases similar ratios were measured. As a reason a different grade of pigmentation of the hair and the influence of the drug structure are discussed. From these results it follows that the natural hair colour is an important parameter in the evaluation of drug concentration in hair.

Evidence for saturable incorporation of methadone into rat hair: relationships among oral dose, plasma concentration, and hair content

Six groups of six male Wistar rats were administered methadone in their drinking water over the concentration range 0-0.25 mg/ml. Hair and trunk blood samples were collected after a 6-week period of drug administration. Immunoreactive methadone was measured by radioimmunoassay and methadone and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene (EDDP), by gas chromatography in plasma and alkali digests of hair. Plasma methadone concentration increased with increasing oral dose. The mean hair concentration of methadone increased to a maximum of 5.1 ng/mg at a drinking water concentration of 0.1 mg/ml corresponding to a plasma level of 14.0 ng/ml. No further significant rise in hair content was seen with higher drinking water concentrations despite a continuing increase in oral drug intake and in plasma methadone concentration. EDDP was not detected in plasma but was present at > 2 ng/mg in 25% of hair samples. The mean EDDP concentration in hair peaked at 3.2 ng/mg at the lowest dose level of methadone administered. The data suggest that methadone is incorporated into rat hair via a capacity-limited process that becomes saturated at plasma levels of some 14 ng/ml. Competition for uptake into hair between methadone and EDDP may occur.

A discourse on human hair fibers and reflections on the conservation of drug molecules

A gross discourse on human hair fibers and their formation is presented stressing the various interdisciplinary aspects, such as the morphological, biological, structural and biochemical data considered to be important in the field of hair analysis. An attempt is made to explain the incorporation of drug molecules during hair fiber formation by using the classical concepts of drug absorption based on lipoid theory and the pH-partition hypothesis as well as a modern biological approach on the permeability of cell membranes. In addition to the physiochemical considerations of the transport properties of a particular drug molecule such as a) the lipophilicity, which determines permeability through the membrane, b) the pKa value, c) the plasma protein binding and d) the molecular size and shape of the drug molecule, drug absorption is thought to be limited by the surface area and the residence time in the hair bulb. The thermodynamic approach according to the Kedem-Katchalsky equations seems even more satisfying. When the principles of biological transport across cell membranes are applied to the cell populations present in the hair root, a hypothesis of extracellular and intracellular drug localizations results. It is speculated that the cell membrane complex (CMC) and the melanin granules present the main sources of incorporated drug molecules within the keratinized hair fibers.

Detection and diagnostic interpretation of amphetamines in hair

A review with 22 references on detection and incorporation of amphetamines in hair is presented. This review deals with the detection, incorporation into hair, behavior in the hair shaft, confirmation of past drug use and diagnosis of dependence mainly regarding amphetamine and methamphetamine, along with methoxyphenamine, methylenedioxymethamphetamine, bromomethamphetamine, deprenyl, benzphetamine, fenproporex and mefenorex. First, pretreatment, extraction and analytical methods for amphetamines in hair using immunoassay, HPLC and GC/MS are discussed. This is followed by sections describing the animal experiments, incorporation rates of amphetamines from blood to hair and relationship between drug history and drug distribution in hair. Finally, the diagnosis of amphetamine dependence and confirmation of methamphetamine baby by hair analysis is discussed. The paper concludes with a brief outlook.

Capillary electrophoretic profiling of rat hair: a tool for alopecia areata diagnosis

Capillary electrophoretic profiling of hair fractions obtained by 0.25 M HCl treatment of the tissue with subsequent extraction of the solubilized fraction with chloroform-isopropanol (9:1, v/v) revealed clear differences between hair obtained from alopecia areata affected laboratory rats (both in hair obtained from non-affected areas and hair growing on once hairless patches) and controls. Differences were observed both in the organic-phase extractable material as well as in the aqueous phase after extraction. The separations were carried out in 25 mM borate buffer pH 9.2 for the chloroform-isopropanol extractable fraction while profiling of the aqueous phase was done in the same buffer at pH 10. Untreated fused-silica capillaries, 40-45 cm to the detector of I.D. 50 and 75 microns were used at a running voltage of 20 kV. Detection was done either by UV absorbance at a fixed wavelength of 200 nm or by using a diode array detector.

Mechanisms of drug incorporation into hair

The model generally proposed to explain the incorporation of drugs into hair is one in which drugs enter hair only by passive diffusion from the blood stream into the growing cells at the base of the hair follicle. However, this model may be over-simplified. More recent experimental findings suggest that drugs may enter hair from multiple sites, via multiple mechanisms, and at various times during the hair growth cycle. A more complex model is proposed in which drugs and metabolites are incorporated into hair during formation of the hair shaft (via diffusion from blood to the actively growing follicle), after formation (via secretions of the apocrine and sebaceous glands), and after hair has emerged from the skin (from the external environment). Further, drugs can be transferred to hair from multiple body compartments or pools located in tissues surrounding the hair follicle. These mechanisms could also be drug-specific. A more precise understanding of the mechanisms involved in the incorporation of drugs into hair is critical for forensic scientists in order to interpret the results of hair analysis properly.

Overview on extraction procedures

The literature reviewed shows that many of the analytical problems related to the toxicological analysis of hair have been resolved, but in some cases, as for the application of the extraction methods, it is worth highlighting that the parameters must be carefully valued owing to the different operative options that are documented in the literature. Besides, the choice of a suitable extractive procedure may be influenced by various factors, including the following: (i) the type of drug which the analysis is targeted at and its characteristics of stability in different hydrolytic systems; (ii) ratio of distribution of the abused substances and their metabolites in the hair; and (iii) method used for the subsequent qualitative and quantitative analysis. Hence the selection of the extraction method requires some considerations, particularly when this kind of analysis is used in the forensic field. In this regard, emphasis is actually placed on pharmacokinetic incorporation and retention of drugs into hair. Furthermore, lacking any source of certified reference material, more studies concerning the recovery, accuracy and, if possible, quality control programs, could be implemented in order to test each procedure and improve the reliability of the extraction steps in the toxicological analysis of hair.

The accumulation and disappearance of cocaine and benzoylecgonine in rat hair following prolonged administration of cocaine

Hair samples were obtained at various time periods from male Sprague-Dawley rats following the injection of cocaine hydrochloride in doses of 5, 10, and 20 mg/kg, ip, for 28 days. Hair samples were also taken continually after the dosing was stopped until the presence of cocaine and benzoylecgonine were no longer detected in hair. Cocaine and benzoylecgonine in hair and plasma were analyzed by gas chromatography/mass spectrometry. Both cocaine and benzoylecgonine were found in hair samples 4 days after the initiation of cocaine administration. When cocaine dosing was stopped after 28 days, approximately 25 to 30 days were required for cocaine and benzoylecgonine to disappear from rat hair in the group of animals that received the highest dose of cocaine. The disappearance of cocaine and benzoylecgonine followed first-order kinetics. The mean rate constant and mean half-life for cocaine disappearance from hair were 0.212 +/- 0.005 day-1 and 3.31 +/- 0.09 days, respectively, and the mean rate constant and mean half-life for benzoylecgonine disappearance from hair were 0.098 +/- 0.006 day-1 and 6.90 +/- 0.28 days, respectively. The mean plasma concentrations of cocaine on Day 25 for the 5, 10, and 20 mg/kg doses of cocaine were 508 +/- 42, 852 +/- 95, and 2027 +/- 75 ng/mL, respectively, and the mean plasma benzoylecgonine levels for the 5, 10, and 20 mg/kg doses of cocaine were 49.9 +/- 7.0, 103.3 +/- 9.3, and 191.0 +/- 16.0 ng/mL, respectively. There was a positive correlation between the doses of cocaine hydrochloride administered and the plasma levels of both cocaine and benzoylecgonine. This study showed that cocaine and benzoylecgonine can be measured in rat hair following the administration of cocaine and that it was possible to correlate the concentrations of cocaine and benzoylecgonine found in hair with the doses of cocaine that were administered.

Opiate levels in hair

By means of radioimmunoassay-technique, hair samples of users, drug related fatalities, carcinoma patients receiving morphine and of experimental guinea pigs receiving codeine were investigated for opiates. The RIA-investigations require a minimum of material; our routine procedures need only 50 mg of hair. No correlation existed between administered doses of opiates and their concentrations in hair of both human and experimental animals. By sectioning the hair, the approximate period of drug use in man could be detected. However, these findings could not be confirmed by the animal experiments. The growth rate of the hair, diffusion and adhesion processes may influence the transport of drugs along the hair. External contaminations and washing procedures were shown to increase or diminish the drug concentration of the samples.

Determination of methamphetamine in hair after single and repeated administration to rat

Methamphetamine in hair after p.o. administration to rat was identified and determined by mass fragmentography (MF). Rat hair was washed with HCl/methnanol, methanol and water. The hair was crushed in 0.6 M HCl, suspension was alkalized with Na2CO3, and extracted with chloroform/isopropanol. The extract obtained was purified by column chromatography on aluminium oxide. Concentrated eluate was trifluoroacetylated, and methamphetamine was identified and determined by MF. More than 20 pg of methamphetamine was detectable and less than 1 ng of that was determined by MF. Methamphetamine in hair collected from rat after p.o. administration of 20 mg/kg of the drug was detected and determined up to 8 days after. From hair of rat after 5-days or 14-days repeated administration of 20 mg/kg/day, methamphetamine was detected 25 or 45 days after the last administration, respectively.