Simultaneous Determination of Amphetamine-Related New Psychoactive Substances in Urine by Gas Chromatography-Mass Spectrometry.

Despite the efforts to prevent the spread of new psychoactive substances (NPS) such as synthetic amphetamine derivatives, it is apparent that newer types of NPS are still emerging on the market in recent years. Due to high potential for their abuse, reliable analytical methods are required to determine these substances in biological samples. The objective of this study was to develop and validate the gas chromatography-mass spectrometric (GC-MS) method for the simultaneous determination of 13 amphetamine-related NPS (amphetamine; AP, 4-fluoroamphetamine; 4FA, methamphamine; MA, 4-fluoromethamphetamine; 4FMA, 4-chloroamphetamine; 4CA, para-methoxyamphetamine; PMA, 4-chloromethamphetamine; 4CMA, 6-(2-aminopropyl)benzofuran; 6APB, 4-methylenedioxyamphetamine; MDA, para-methoxymethamphetamine; PMMA, 6-(2-methylaminopropyl)benzofuran; 6MAPB, 3,4-methylenedioxymethamphetamine; MDMA, 5,6-methylenedioxy-2-aminoindane; MDAI) in urine. The analytes were extracted at pH 7.4 by liquid-liquid extraction prior to their trifluoroacetyl derivatives and then analyzed by GC-MS. The validation parameters included selectivity, linearity, lower limits of quantification (LLOQ), intra and interday precision and accuracy, recovery and stability. The linear ranges were 2-100 ng/mL for AP, 4FA, 4FMA, 4CA, PMA, 6APB, MDA, and MDAI, 2-250 ng/mL for 4CMA, PMMA, and 6MAPB and 25-1,000 ng/mL for MA and MDMA, with acceptable coefficients of determination (r2 > 0.9963). The intra and interday precision were within 11.9 and 12.5%, while the intra and interday accuracies ranged from -10.6% to 13.0% and -11.0% to 6.8% for the nominal concentration at all studied levels, respectively. The LLOQs for each analyte were 2.0-25 ng/mL. The recoveries ranged from 69.3% to 96.4%. The short- and long-term variations of the analytes in urine were lower than 8.5 and 12.7%, indicating that the analytes are stable at least for 16 h at room temperature and for 7 days at 4°C, respectively. The applicability of the method was examined by analyzing urine samples from drug abusers and was determined to be effective for detecting multiple drug use.

The impact of violence on sex risk and drug use behaviors among women engaged in sex work in Phnom Penh, Cambodia.

BACKGROUND: Violence, substance use, and HIV disproportionately impact female entertainment and sex workers (FESW), but causal pathways remain unclear. METHODS: We examined data from an observational cohort of FESW age 15-29 in Phnom Penh, Cambodia for associations between violence exposure and sexual risk and drug use. Validated measures of physical and sexual violence were assessed at baseline. Self-reported outcomes measured quarterly over the next 12-months included past month sexual partners, consistent condom use by partner type, sex while high, and amphetamine type stimulant (ATS) use. Biomarkers measured quarterly included prostate specific antigen (PSA) and urine toxicology. Generalized estimating equations were fit adjusting for age, education, marital status and sex work venue. RESULTS: Of 220 women, 48% reported physical or sexual violence in the preceding 12-months. Physical violence was associated with increased number of sex partners (adjusted incidence rate ratio [aIRR] 1.33; 95% CI: 1.04-1.71), greater odds of sex while high (adjusted odds ratio [aOR] 2.42; 95% CI: 1.10-5.33), increased days of ATS use (aIRR 2.74; 95% CI: 1.29-5.84) and increased odds of an ATS+ urine screen (aOR 2.80, 95%CI: 1.38-5.66). Sexual violence predicted decreased odds of consistent condom use with non-paying partners (aOR 0.24; 95% CI: 0.10-0.59) and greater odds of a PSA+ vaginal swab (aOR 1.83; 95% CI: 1.13-2.93). CONCLUSIONS: Physical and sexual violence are prevalent among Cambodian FESW and associated with subsequent sexual risk and drug use behaviors. Clinical research examining interventions targeting structural and interpersonal factors impacting violence is needed to optimize HIV/AIDS prevention among FESW.

Transfer of Methamphetamine (MA) into Breast Milk and Urine of Postpartum Women who Smoked MA Tablets during Pregnancy: Implications for Initiation of Breastfeeding.

BACKGROUND: Methamphetamine (MA) use by pregnant women remains a growing problem in South East Asia. After delivery, a negative maternal urine MA assay is assumed to reflect the absence of MA in breast milk and marks breastfeeding initiation. To date, no data exist that describe the relationship between the peripartum and postpartum transfer of MA into breast milk and its urinary excretion in women, following recreational use by smoking. OBJECTIVE: This study aimed to determine the pharmacokinetic of smoked MA in breast milk and its relationship to urinary MA excretion in postpartum women who tested positive for MA before delivery. METHODS: Timed urine and breast milk samples of 33 women who had positive urine drug screens for MA prior to delivery were analyzed for MA using Acquity Ultra Performance Liquid Chromatography (Waters, Milford, Massachusetts, USA) with the ACQUITY UPLC Photodiode Array Detector (Waters). Those participants with 4 or more timed breast milk samples were included for pharmacokinetic calculation using log-linear trapezoidal rule. RESULTS: Pharmacokinetic data from 2 women were analyzed. The half-life values for MA in the breast milk were 11.3 and 40.3 hours. The absolute infant doses were 21.3 and 51.7 µg/kg/day. Methamphetamine disappears from breast milk approximately 1 day before the maternal urine MA becomes negative. CONCLUSION: Smoked MA shows a similar breast milk pharmacokinetic pattern to previously reported intravenous MA. Breastfeeding can be safely initiated in mothers whose urine MA screen has turned negative for ≥ 24 hours. However, concurrent maternal substance use treatment and screening is necessary for continued promotion of lactation.

Illicit Heroin and Methamphetamine Use among Methadone Maintenance Treatment Patients in Dehong Prefecture of Yunnan Province, China.

OBJECTIVE: Methadone maintenance treatment (MMT) was introduced to China in 2004 to reduce the harm of injecting drug users (IDUs). However, little is known about continued drug use, especially methamphetamine (MAMP), among MMT patients. METHODS: A survey was conducted among patients attending five major MMT clinics in Dehong Prefecture in 2014 to investigate the heroin and MAMP use and their associated risk factors. Participants were administered with face-to-face interviews, and urine tests for morphine and MAMP. RESULTS: A total of 2,121 were eligible and participated in the study. Among them, 220 (10.4%) were only positive for morphine, 12.9% were only positive for MAMP, and 196 (9.2%) were positive for both morphine and MAMP. Compared with neither use of heroin nor MAMP during MMT, heroin use (not using MAMP) was associated with ethnicity, shorter duration of MMT, lower dose of methadone, and having had no more than two sex partners in the past year; MAMP use (not using heroin) was associated with ethnicity, longer duration of MMT, higher dose of methadone and being aged <30 years (vs. ≥50 years); use of both heroin and MAMP was associated with being Dai minority (vs. Han), a marital status of divorced or widowed, having used drugs for ≥10 years and shorter duration of MMT. CONCLUSION: These findings indicate the complexity in the treatment of heroin users and underscore the importance in prescribing appropriate methadone dosages in order to reduce both heroin and MAMP use.

Toxicology screening in oral and maxillofacial trauma patients.

The role of alcohol in facial trauma is recognised but we know of no research on the possible contribution made by the use of illicit drugs in patients with facial injuries, or the interactions that may occur during anaesthesia. We aimed to find out whether illegal drugs were identified in the urine of patients with maxillofacial injuries, what substances were present, and whether patients were willing to disclose use of drugs at the time of injury. Over a 12-month period we prospectively studied consecutive patients with facial injuries who were referred by accident and emergency (A&E) to the department of oral and maxillofacial surgery (OMFS) for inpatient assessment and treatment within 24 h of injury. Anonymised data on patients were obtained from questionnaires that were linked to a urine sample provided on admission. Results were obtained using immunoassay and gas chromatography with mass spectrometry. A total of 105 patients with facial injuries were eligible and 95 (90%) provided a urine sample and completed the questionnaire; 2 samples were of insufficient volume and were discarded before analysis. Twelve patients (13%) admitted using drugs at the time of injury but 44 (47%) samples tested positive for illegal drugs; fewer showed the presence of alcohol (n=37; 40%). Use of drugs, although often denied, is widespread among patients with facial injuries. It is important to consider the role that drugs have in patients who present with traumatic injuries, the interactions misused drugs may have with anaesthesia, and any possible benefits that targeted prevention strategies would have in this group.

A continuidade do uso de anfetaminas por motoristas de caminhão no Estado de São Paulo, Brasil, a despeito da proibição de sua produção, prescrição e uso / Persistent amphetamine consumption by truck drivers in São Paulo State, Brazil, despite the ban on production, prescription, and use / El uso continuado de anfetaminas por parte de los conductores de camión en el estado de São Paulo, Brasil, a pesar de la prohibición de su producción, prescripción y uso

O uso de anfetaminas por motoristas de caminhão com fins ocupacionais é amplamente reconhecido, entretanto, no mês de outubro de 2011, sua produção e uso foram proibidos através de uma resolução da Agência Nacional de Vigilância Sanitária (ANVISA). O objetivo deste estudo foi identificar o uso de anfetaminas entre motoristas de caminhão após a implementação da referida resolução. Uma amostra de conveniência de 427 motoristas de caminhão foi abordada em rodovias do Estado de São Paulo, Brasil, durante o ano de 2012. Os participantes foram solicitados a responder um instrumento de pesquisa estruturado, assim como fornecer uma amostra de urina para avaliar o uso recente de anfetaminas através de análise toxicológica. Entre os motoristas avaliados, 7% fizeram uso recente de alguma substância ilícita, dos quais 2,7% usaram anfetaminas. Aparte a periculosidade associada ao uso de anfetaminas, assim como a despeito da resolução que o regulamenta, esse uso continua entre os motoristas de caminhão. Assim, sugere-se que as autoridades competentes fiscalizem a posse, assim como o uso de anfetaminas no contexto do trânsito.

Amphetamine use by truck drivers for occupational purposes is widely known. The production and consumption of amphetamines was banned by the Brazilian National Health Surveillance Agency (ANVISA) in October 2011. This study analyzes persistent amphetamine use by truck drivers since the ban was implemented. A convenience sample of 427 truck drivers was taken along highways in São Paulo State in 2012. Participants were asked to answer a structured questionnaire and provide a urine sample to screen for recent amphetamine consumption through toxicological analysis. Among the interviewed drivers, 7% had used some illicit drug recently and 2.7% had used amphetamines. Amphetamines are still consumed by truck drivers despite the risks and the recent ban. The authorities should thus monitor the possession and use of amphetamines by drivers in order to effectively enforce the ban.

El uso de anfetaminas con fines profesionales entre los conductores de camiones es ampliamente reconocido, sin embargo, en octubre de 2011, su producción y uso fueron prohibidos por una resolución de la Agencia Nacional de Vigilancia Sanitaria (ANVISA). El objetivo de este estudio fue identificar el uso de anfetaminas entre conductores de camión después de la implementación de esa resolución. Una muestra de conveniencia compuesta por 427 conductores de camiones fue abordada en las carreteras del estado de São Paulo, Brasil, en el año 2012. A los participantes se les pidió rellenar una encuesta estructurada, así como dar una muestra de orina para determinar el consumo reciente de anfetaminas, a través de análisis toxicológico. Entre los conductores evaluados, el 7% consumió recientemente algún estupefaciente, de los cuales un 2,7% había consumido anfetaminas. Aparte de los peligros asociados al uso de anfetaminas, y de la resolución que lo regula, ese uso sigue vigente entre los conductores de camión. Por lo tanto, se sugiere que las autoridades competentes supervisen la posesión, así como el consumo de anfetaminas, en el tráfico rodado.

Dextromethorphan attenuated inflammation and combined opioid use in humans undergoing methadone maintenance treatment.

Recent studies show that proinflammatory cytokines might be related to the development of opioid dependence (physiological, psychological, or both). In a double-blind, randomly stratified clinical trial investigating whether add-on dextromethorphan (60-120 mg/day) attenuated inflammation and the combined use of opioids in heroin-dependent patients undergoing methadone maintenance treatment, we evaluated whether inflammation is related to the progression of opioid dependence. All participants (107 heroin-dependent patients and 84 nondependent healthy controls) were recruited from National Cheng Kung University Hospital. Their plasma cytokine levels were measured to evaluate the effect of add-on dextromethorphan. Plasma TNF-α and IL-8 levels were significantly higher in long-term heroin-dependent patients than in healthy controls (p < 0.001). Chronic heroin-use-induced TNF-α and IL-8 levels were significantly (p < 0.05) attenuated in patients treated for 12 weeks with add-on dextromethorphan. Moreover, both tolerance to methadone and the combined use of opioids were significantly (p < 0.05) attenuated in patients taking dextromethorphan. We conclude that dextromethorphan might be a feasible adjuvant therapeutic for attenuating inflammation and inhibiting methadone tolerance and combined opioid use in heroin-dependent patients.

Be wary of a mature adult, who presents with a parent.

The importance of interviewing a patient alone cannot be overemphasised, especially when a mature adult patient presents with a parent. We present the case of a 47-year-old man who was seen in the outpatient clinic with his mother, as his general practitioner (GP) was concerned whether he had a pheochromocytoma. The GP had arranged a CT scan of the abdomen, to investigate for an abdominal cause for oedematous legs. This had picked a benign growth in the right adrenal gland. A 24-hour urinary normetanephrine level checked was raised. Further tests and regular monitoring showed persistently raised levels of catecholamines to the point that adrenalectomy was being considered. He was always accompanied by his mother except on the clinic visit, when he admitted to taking amphetamine. Urinary catecholamine levels normalised, after he stopped taking it.

[Comparative analysis of amphetamine identification by immunoenzyme assay and gas chromatography with mass spectrometric detection].

The objective of this study was to simultaneously identify amphetamine in biological materials by enzyme-linked immunosorbent assay (ELISA) and gas chromatography with mass spectrometric detection (GH/MS) for the verification of diagnostic value of the proposed ELISA technique. Urine samples from suspected amphetamine and related drug users were available for analysis. It is concluded that the new modification of ELISA can be recommended for application in narcological practice and for the purpose of forensic medical examination.

Multiple-drug toxicity caused by the coadministration of 4-methylmethcathinone (mephedrone) and heroin.

An accidental death caused by the combined use of a new designer drug, 4-methylmethcathinone (mephedrone), and heroin is reported. A 22-year-old Caucasian male was found unresponsive in his living quarters and was transported to the hospital where he died. During autopsy, needle marks were found along the decedent's lower legs and ankles. Investigators discovered the decedent and his roommate had been using "Black Tar" heroin and mephedrone. Routine toxicological analysis detected morphine in the decedent's blood at 0.06 mg/L. Additionally, 6-acetylmorphine, morphine, codeine, and doxylamine were detected in his urine. A designer drug screen, employing a basic liquid-liquid extraction followed by pentafluropropionic anhydride derivatization, was used to isolate mephedrone from both blood and urine specimens. The derivatized extracts were analyzed by gas chromatography- mass spectrometry (GC-MS) operating in full-scan mode. Quantitative analysis of mephedrone was performed by GC-MS operating in selective ion monitoring mode using methamphetamine-d(14) as an internal standard. Mephedrone was confirmed in the decedent's blood and urine at 0.50 and 198 mg/L, respectively. The physiological and pharmacological effects of mephedrone and any associated toxicity have not been reported. However, because of its structural similarities with methcathinone and the high concentration in the decedent's blood, the overall contribution of mephedrone to the death could not be minimized. Therefore, the medical examiner reported the cause of death as multiple-drug toxicity and the manner of death as accidental.

The reliability and validity of drug users' self reports of amphetamine use among primarily heroin and cocaine users.

Relatively few studies have addressed the psychometric properties of self-report measures of amphetamine use. This study examines the reliability and validity of the Risk Behavior Assessment's (RBA) lifetime and recent amphetamine-use questions. To evaluate validity, 4027 out-of-treatment primarily cocaine and heroin users provided urine samples that were compared to self-report data; to evaluate reliability, 218 completed the RBA at two time points, 48h apart. In the overall sample, self-reports demonstrated moderately high validity, with a 95% accuracy rate (kappa=.54). When analysis was restricted to recent amphetamine users validity was slightly lower (71.5% accuracy; kappa=.41). Test-retest data indicated good reliability for self-reports of ever having used amphetamine (kappa=.79), and amphetamine use in the past 30 days (.75

Trace evidence of trans-phenylpropene as a marker of smoked methamphetamine.

This case study investigates trans-phenylpropene as a potential marker for smoked methamphetamine. The decedent, a 31-year-old male, was found with paraphernalia that indicated that he may have been smoking abused drugs prior to death. Methamphetamine and cocaine were detected in the residue remaining in the paraphernalia. Markers of thermal degradation of methamphetamine and cocaine were also detected in the paraphernalia. Gas chromatography-mass spectrometry (GC-MS) analysis detected trans-phenylpropene as a marker of smoked methamphetamine and anhydroecgonine methyl ester as a marker of smoked cocaine. Both trans-phenylpropene and anydroecgonine methyl ester were detected in the urine of the decedent, connecting the link between the paraphernalia for smoking and the ingestion of the pyrolysis products of methamphetamine and cocaine. Several other drugs of abuse were identified either in blood and urine or in hexane extracts of the paraphernalia, including phenylacetone, fentanyl, norfentanyl, amphetamine, ecgonine methyl ester, oxycodone, acetaminophen, chlorpheniramine, and caffeine. Using a pyrolysis GC-MS, the characteristic pyrolytic products of cocaine HCl, methamphetamine HCl, and combinations of the two were evaluated and the results showed that combining the drugs in a single run did not alter the pyrolysis pattern. The detection of trans-phenylpropene in both biological specimens and in paraphernalia is the first example of this analyte being applied as evidence of smoked methamphetamine.

Solvent-enhanced microwave-assisted derivatization following solid-phase extraction combined with gas chromatography-mass spectrometry for determination of amphetamines in urine.

An approach using microwave-assisted derivatization (MAD) following solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS) was developed to determine amphetamines in urine samples. The parameters affecting the derivatization efficiency - including microwave power and irradiation time - were investigated. Besides, solvent is thought critically important to MAD. Derivatization performance was studied using various solvents and compared with the performance obtained without solvent. Derivatization efficiency was clearly found to be enhanced by the presence of solvent. The highest derivatization efficiencies were obtained in ethyl acetate (EA) under microwave power of 250W for 1min. Calibration curves for all amphetamines were linear over a range from 1 to 1000ng/mL, with correlation coefficients above 0.9992. The intra-day and inter-day precision were less than 15%. The applicability of the method was tested by analyzing amphetamine-abusing subjects urine samples. Accordingly, the solvent-enhanced MAD-GC-MS method appears to be adequate for determining amphetamines in urine.

Bupropion for the treatment of methamphetamine dependence.

Bupropion was tested for efficacy in increasing weeks of abstinence in methamphetamine-dependent patients, compared to placebo. This was a double-blind placebo-controlled study, with 12 weeks of treatment and a 30-day follow-up. Five outpatient substance abuse treatment clinics located west of the Mississippi participated in the study. One hundred and fifty-one treatment-seekers with DSM-IV diagnosis of methamphetamine dependence were consented and enrolled. Seventy-two participants were randomized to placebo and 79 to sustained-release bupropion 150 mg twice daily. Patients were asked to come to the clinic three times per week for assessments, urine drug screens, and 90-min group psychotherapy. The primary outcome was the change in proportion of participants having a methamphetamine-free week. Secondary outcomes included: urine for quantitative methamphetamine, self-report of methamphetamine use, subgroup analyses of balancing factors and comorbid conditions, addiction severity, craving, risk behaviors for HIV, and use of other substances. The generalized estimating equation regression analysis showed that, overall, the difference between bupropion and placebo groups in the probability of a non-use week over the 12-week treatment period was not statistically significant (p=0.09). Mixed model regression was used to allow adjustment for baseline factors in addition to those measured (site, gender, level of baseline use, and level of symptoms of depression). This subgroup analysis showed that bupropion had a significant effect compared to placebo, among male patients who had a lower level of methamphetamine use at baseline (p<0.0001). Comorbid depression and attention-deficit/hyperactivity disorder did not change the outcome. These data suggest that bupropion, in combination with behavioral group therapy, was effective for increasing the number of weeks of abstinence in participants with low-to-moderate methamphetamine dependence, mainly male patients, regardless of their comorbid condition.

Determination of amphetamine, methamphetamine, and hydroxyamphetamine derivatives in urine by gas chromatography-mass spectrometry and its relation to CYP2D6 phenotype of drug users.

Amphetamine, a CYP2D6 substrate, is widely used by truck drivers, and the extent to which different people metabolize the drug has only been determined in an isolated or reduced number of samples. A gas chromatography-mass spectrometry method is implemented to simultaneously determine amphetamine, methamphetamine, and hydroxyamphetamine in the urine of drug users. This method is a useful contribution to a well-established field. The main improvements are the use of liquid-liquid extraction, the trapping of the amphetamines as their hydrochloride salt, as a solution to the volatility of these analytes, and its application to assess the CYP2D6 metabolic phenotype of amphetamine users, which is innovative. Calibration curves ranged from 125 to 1000 ng/mL and had an r(2) greater than 0.99. The validation data (precision, accuracy, and recovery) shows the reproducibility and selectiveness of the method. The method is applied to determine the metabolic ratio (MR) in 121 urine specimens of federal highway drivers who underwent random mandatory roadside testing for drugs. The statistical analysis of the MR shows the presence of three different groups, which according to the established groups for CYP2D6 and the amount of the drug metabolized, are classified into extensive metabolizers (EM), intermediate metabolizers (IM), and poor metabolizers (PM). The biological consequences of these differences in amphetamine metabolism, such as impaired driving, a risk to develop Parkinson's disease, or an addiction, need to be further studied.

Rapid simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyethylamphetamine in urine by fast gas chromatography-mass spectrometry.

The use of fast gas chromatography-mass spectrometry (FGC-MS) was investigated to improve the efficiency of analysis of urine specimens that previously screened presumptively positive for amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and/or 3,4 methylenedioxyethylamphetamine (MDEA) by immunoassay testing. Specimens were pretreated with basic sodium periodate, extracted using a positive-pressure manifold/cation-exchange solid-phase cartridge methodology, and derivatized using 4-carbethoxyhexafluorobutyryl chloride (4-CB). The analytical method was compared to traditional GC-MS analysis and evaluated with respect to assay chromatography, linearity, sensitivity, precision, accuracy, and reproducibility. The limits of detection were 62.5 ng/mL for MDA and 31.25 ng/mL for AMP, MAMP, MDMA, and MDEA. All of the target analytes were linear to 12,000 ng/mL with the exception of MAMP which was linear to 10,000 ng/mL. The intra-assay precision of a 500 ng/mL multiconstituent control (n=15) ranged from 522.6 to 575.9 ng/mL with a coefficient of variation of less than 3.8%. Authentic human urine specimens (n=187) previously determined to contain the target analytes were re-extracted and analyzed by both FGC-MS and the currently utilized GC-MS method. No significant differences in specimen concentration were observed between these analytical methods. No interferences were seen when the performance of the FGC-MS method was challenged with ephedrine, pseudoephedrine, phenylpropanolamine, and phentermine. When compared to traditional GC-MS analysis, FGC-MS analysis provided a dramatic reduction in retention time for amphetamine (1.8 min vs. 4.12 min). For example, the FGC-MS method reduced overall run time for a batch of 56 specimens from 12.0 h to 7.25 h. This reduction in analysis time makes FGC-MS an attractive alternative to traditional GC-MS by allowing a laboratory greater flexibility in the purchase and use of capital equipment and in the assignment of laboratory personnel, all resulting in greater overall efficiency by decreasing reporting times for AMP, MAMP, and designer amphetamine positive specimens.

Urinary excretion of amphetamine after termination of drug abuse.

Important issues in urinary drug testing are the variability between consecutive urine specimens, the duration of positive specimens after last intake, and the usefulness of creatinine concentration to correct for variability in urine concentration. These issues were addressed in the present study with amphetamine as the drug of abuse. Drug users who were starting their sentences in prison participated in the study. Urine specimens were collected 1 to 5 times per day. Screening was performed by EMIT d.a.u. (cutoff, 0.30 microgram/mL) and EMIT II (cutoff, 1.00 microgram/mL), and confirmation was performed with gas chromatography-mass spectrometry. Creatinine and pH were recorded. Amphetamine was demonstrated in seven subjects. The highest concentration was 135 micrograms/mL. The last positive-screened specimen was observed by EMIT d.a.u. after almost 9 days of imprisonment and by EMIT II after 3 days. Large concentration differences could be found between consecutive specimens, accompanied by considerable differences in creatinine and pH. The individual curves were generally smoother after creatinine correction of concentrations. As expected, urinary pH was observed to influence the excretion.