Windows of detection of zolpidem in urine and hair: application to two drug facilitated sexual assaults

Developing, validating, and comparing an analytical method to simultaneously detect z-drugs in urine samples using the QuEChERS approach with both liquid chromatography and gas chromatography-tandem mass spectrometry

Detecting z-drugs, a sedative-hypnotic medication, is also misused for criminal activities. Therefore, the analysis of urine samples is crucial for clinical and forensic purposes. We conducted a study where we developed, validated, and compared an analytical method for simultaneously detecting z-drugs in urine samples. Our approach uses the QuEChERS method for sample preparation, combined with liquid chromatography (LC) and gas chromatography (GC) coupled with tandem mass spectrometry (MS/MS). We optimized the QuEChERS method to effectively extract z-drugs from urine samples while minimizing matrix effects and achieving high recovery rates. After extraction, we split the samples into two parts for analysis using LC-MS/MS and GC-MS/MS. We validated our methods, and the results showed good linearity over a broad concentration range (1-200 ng/mL) for each z-drug. The limits of detection and quantification were within clinically relevant ranges, ensuring sensitivity for detecting z-drugs in urine samples. We compared the two chromatographic techniques by analyzing a set of urine samples spiked with known concentrations of z-drugs using both LC-MS/MS and GC-MS/MS methods and then applied to the real samples. The results were statistically analyzed to assess any significant differences in accuracy and precision above 95 %, and both methods offered reliable and consistent results with the samples as well. In conclusion, our analytical method coupled with both LC-MS/MS and GC-MS/MS using the QuEChERS approach provides a comprehensive and robust solution for the simultaneous detection of z-drugs in urine samples. The choice between the two chromatographic techniques can be based on the specific z-drugs of interest and the required analytical performance. This method holds promise for applications in clinical toxicology, forensic analysis, and monitoring z-drug usage.

Evaluation of applicability of micro-segmental analysis to hair treated with heat and haircare products

PURPOSE

Micro-segmental analysis (MSA), which enables the measurement of detailed drug distributions in hair by segmenting a single hair strand at 0.4 mm intervals, is indispensable for estimating the day of drug ingestion. However, haircare with dryers and various products can influence drug concentrations in hair. Therefore, the applicability of MSA to hair that was treated with heat or various haircare products was evaluated.

METHODS

Reference hair strands containing drugs consistently along the hair shafts were collected from patients who ingested four hay-fever medicines (fexofenadine, epinastine, cetirizine, and loratadine) daily for 4 months. The hair strands were divided into eight 4 mm regions from the proximal end, and each region was placed on an electric hot plate at 100-200 °C or soaked in haircare products, such as shampoo and bleaching agent. The hair regions were subjected to MSA. Moreover, after a patient was administered midazolam at a single dose and the hair was bleached, the day of midazolam administration was estimated using MSA.

RESULTS

Repetitive heating for 1 min and daily haircare products, such as shampoo, hardly affected the drugs in hair, whereas bleaching products containing H2O2 decreased the amounts of hay-fever medicines in the hair up to 58%. However, the amount of midazolam did not decrease in bleached hair and the day of midazolam administration was successfully estimated.

CONCLUSIONS

The analytes used in this study were minimally affected by ordinary haircare and could be detected even in bleached hair. Therefore, MSA can be applicable regardless of haircare history.

Speedy Gonzales analysis method in one drop of beverage, for crimes committed with drugs from three different groups

Sertraline, zolpidem and fentanyl, are drugs with potential to be used in cases of rape, property theft and organ theft. In this study, a 15 min dilute-and-shoot analysis method was developed for the simultaneous confirmation and quantification of these drugs, using liquid chromatography tandem mass spectrometry (LC-MS/MS), in the residues of fruit juice types (mixed fruit juice, cherry juice and apricot juice), frequently consumed soft drinks. A C₁₈ phenomenex column (3 µm × 100 mm × 3 mm) was used in LC-MS/MS analysis. Validation parameters were determined by means of linearity, linear range, LOD, LOQ, repeatability and intermediate precision studies. The linearity of the method was shown up to 2.0 μgmL^-1 concentration and r² was ≥ 0.99, for each analyte. LOD and LOQ values were found in the ranges of 4.9-10.2 and 13.0-57.5 ngmL^-1 for all the analytes. Accuracies were between 74 and 126%. HorRat values calculated (between 0.57 and 0.97), revealed that the inter-day precisions (RSD% ≤ 15.5%) are acceptable. The simultaneous extraction and determination of these analytes in beverage residues in very low amounts as 100 µL is challenging because of the difficulty arising from the different chemical properties, the complexity of mixed fruit juice matrix. The method is important for hospitals (especially in emergency-toxicology cases), criminal and special laboratories from the point of determining the combined or single use of these drugs in drug facilitated crimes (DFC) and finding out the reasons of deaths related to these drugs.

Simultaneous Analysis of Zolpidem, Four Hydroxyzolpidems and Two Zolpidem Carboxylic Acids in Postmortem Urine Using Liquid Chromatography--Tandem Mass Spectrometry

Zolpidem (ZOL) is a short-acting hypnotic that is sometimes used in drug-facilitated crimes such as sexual assaults, robbery and homicides. Therefore, it is important to understand the metabolism of ZOL. This study quantified ZOL and its metabolites, including two carboxylic acids (zolpidem phenyl-4-carboxylic acid [M1] and 6-carboxylic acid [M2]) and four hydroxyzolpidems (4-(hydroxymethyl)phenyl zolpidem [M3], 6-hydroxymethyl zolpidem [M4], 7-hydroxyzolpidem [7OH] and 8-hydroxyzolpidem [8OH]) in postmortem urine using liquid chromatography--triple quadrupole mass spectrometry. The concentration of M1 was highest in all cases, followed by total 7OH in five of six samples. The concentrations of M2 and total M4 were relatively high. Most of M4 and 8OH were excreted as conjugates, whereas up to 55% of 7OH was excreted in its free form. Peaks corresponding to zolpidem dihydrodiol (ZHDH), dihydro(hydroxy)zolpidem cysteine adduct (DHZCys) and zolpidem cysteine adduct (ZCys) were also detected in all the urine samples. ZDHD was excreted as conjugates, whereas almost all DHZCys and ZCys were in their free form.

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.

Analysis of conventional and nonconventional forensic specimens in drug-facilitated sexual assault by liquid chromatography and tandem mass spectrometry

The incidence of drug-facilitated sexual assault (DFSA) has dramatically increased in the last decades. Forensic analytical scientists continuously seek new methods and specimens to prove the incidence of intoxication for the judiciary system. Factors influencing sample selection include the ease of obtaining the samples and the window of detection of the drugs, among others. Both conventional (blood, urine) and non-conventional specimens (hair, nails, fluids) have been proposed as suitable in DFSA cases. Reported sample treatments include a variety of liquid-liquid and solid-phase extraction as well as dilute-and-shoot procedures and microextraction techniques. Regarding analysis, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has emerged as the preferred confirmatory technique, due to its sensitivity, selectivity, and wide-scope applicability. In this review, we critically discuss the most common specimens and sample treatments/analysis procedures (related to LC-MS/MS) that have been reported during the last ten years. As a final goal, we intend to provide a critical overview and suggest analytical recommendations for the establishment of suitable analytical strategies in DFSA cases.

Levels of GHB in hair after regular application

Gamma hydroxybutyrate (GHB) is a central nervous system depressant that is an approved drug for the treatment of narcolepsy with cataplexy and other syndromes. Due to its dose dependent stimulating, relaxing or sedative effects, illicit abuses include recreational use by young people and cases of drug-facilitated crime (DFC). Since GHB is also produced endogenously, for forensic questions, it is important to be able to differentiate between endogenous GHB and elevated levels due to additional intake. In this study, we measured GHB concentrations in hair of patients with narcolepsy receiving daily GHB treatment. The results were compared to endogenous concentrations and concentrations after chronic intake presented in several former studies. The aim of this study was to investigate whether a regular intake of a known dosage of GHB leads to elevated levels of GHB concentration in hair. We collected hair samples of 19 patients (14 female, 5 male) with narcolepsy under regular GHB treatment and examined the hair samples segmentally by digestion of the hair followed by liquid-liquid extraction and analysis using a Shimadzu LC20 UFLC system coupled with an AB Sciex API 4000 Qtrap tandem mass spectrometer. All volunteers received daily treatment with different doses of sodium oxybate (sodium salt of GHB) ranging between 3 and 9g per night. The observed mean value of GHB concentration in hair was 2.69ng GHB per mg hair for the 5 male participants, 1.56ng/mg for the 14 female participants giving an overall mean value of 1.86ng/mg for all participants. Our results showed no correlation between the daily dose or the duration intake of GHB and the measured concentration of GHB in hair. Although we did find a significant (p<0.01) difference between published endogenous levels of GHB in hair and GHB levels in hair of patients with regular daily GHB intake, the forensic relevance however is disputable. We hypothesise this narrow margin or even overlap to be the reason why analytical results from hair analysis in some cases fail to provide a reliable prove of a single exposition.

Incorporation of five common hypnotics into hair after a single dose and application to a forensic case of drug facilitated crimes

In order to obtain fundamental information on the disposition of hypnotics into hair after a single oral dose the quantitative hair analysis of triazolam (TZ), etizolam (EZ), flunitrazepam (FNZ), nitrazepam (NZ) and zolpidem (ZP) have been performed using a validated LC-MS/MS procedure. Hair specimens (straight, black) were collected from three subjects about one month and three months after a single 0.25 mg dose of TZ, 1 mg of EZ, 2 mg of FNZ, 5 mg of NZ and 10 mg of ZP tartrate. The subjects ingested just one out of five different hypnotics on each day, each of five days in turn. All ingested hypnotics have been detected in hair from each subject both one month and three months after intake, and their concentrations were in the range of 0.023-0.043 pg/hair strand (0.077-0.36 pg/mg) for TZ, 0.11-0.63 pg/hair strand (0.44-5.2 pg/mg) for EZ, 0.14-2.6 pg/hair strand (0.56-22 pg/mg) for FNZ, 0.33-1.7 pg/hair strand (1.3-17 pg/mg) for NZ and 20-40 pg/hair strand (120-270 pg/mg) for ZP. For FNZ and NZ, not only the parent drugs but also their metabolites, 7-amino-FNZ and 7-amino-NZ, were detected in the range of 2.3-9.2 pg/hair strand (9.2-82 pg/mg) and 2.4-9.1 pg/hair strand (8.0-55 pg/mg), respectively. The calculated incorporation ratios into hair against the dose were found to exhibit similarity between the four benzodiazepines. This finding suggests the ability to apply these quantitative data to approximately estimating the amounts of other benzodiazepines, which have similar chemical structures, in hair although it should be noted that the amounts of drugs in hair varies considerably depending on the hair color. On the other hand, the incorporation ratio of ZP showed 15-29 times higher than that of TZ, indicating that lipophilic ZP was more likely to incorporate into hair than benzodiazepines. In addition, the application of the present data to a drug-facilitated sexual assault was shown.

LC-MS/MS method for determining picogram-level of zolpidem and its main metabolites in hair using a zirconia-based sorbent

Although urine and blood samples have been conventionally used for testing zolpidem (ZPD), a sedative-hypnotic, these matrices have limited application because they have a relatively short detection period and can be used only in case of recent drug exposure. Therefore, it is necessary to use an alternative biological sample to obtain the evidence of ZPD misuse. Herein, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of ZPD and its metabolites, zolpidem phenyl-4-carboxylic acid (ZPCA) and zolpidem 6-carboxylic acid (ZCA), in hair to resolve the above-mentioned problems. Mechanical pulverization of hair, methanol extraction with sonication, and the zirconia-based hybrid solid-phase extraction technique were used for obtaining improved extraction efficiency and effective sample purification. The treated hair sample was analyzed using the LC-MS/MS method with the electrospray ionization source in positive and multiple-reaction monitoring modes. The target analytes were separated and detected within 8 min using an Xselect HSS T3 column. Gradient elution was performed using 5 mM ammonium formate and acetonitrile. The lower limit of quantification of ZPD, ZPCA, and ZCA were 1.0, 0.5, and 1.0 pg mg^-1, respectively. The calibration ranges were 1.0-1000.0 pg mg^-1 for ZPD, 0.5-200.0 pg mg^-1 for ZPCA, and 1.0-200.0 pg mg^-1 for ZCA, with the determination coefficients (r² ≥ 0.9986). The intraday accuracy and precision ranged from -7.1 to 9.0% and within 6.5%, respectively, and the interday accuracy and precision ranged from -6.1 to 7.9% and within 5.4%, respectively. The recovery, matrix effect, and process efficiency were 65.2-96.6%, 64.6-106.5%, and 44.3-100.5%, respectively, with the relative standard deviation of 4.0-5.0%. The developed method was successfully applied to analyze 13 forensic hair samples of ZPD abusers, and the concentration ratios of ZPD and its two main metabolites (ZPCA and ZCA) in the ZPD-positive samples were also presented. These results revealed that ZPCA and ZCA were not easily incorporated into hair, and demonstrated that their analysis in hair samples requires the employed method to have picogram-level sensitivity. Therefore, the developed method was suitable for simultaneous analysis of ZPD, ZPCA, and ZCA in hair samples, and it could provide clear evidence for illegal ZPD administration, including ZPD-facilitated sexual assault.

Determination of zolpidem phenyl-4-carboxylic acid and zolpidem 6-carboxylic acid in hair using gas chromatography-electron ionization-tandem mass spectrometry

A gas chromatography-electron ionization-tandem mass spectrometric (GC-EI-MS/MS) method was developed and validated for determination of the major metabolites of zolpidem, zolpidem phenyl-4-carboxylic acid (ZPCA) and zolpidem 6-carboxylic acid (ZCA) in human hair. The sample preparation procedure involves decontamination, mechanical pulverization, incubation, extraction and purification prior to instrumental analysis. The extracts were derivatized using hexafluoroisopropanol and heptafluorobutyric anhydride and analyzed by GC-EI-MS/MS. The linear ranges were 8-100 pg/mg for ZPCA and 16-200 pg/mg for ZCA, with the correlation coefficients >0.997. The limits of detection were 1.8 pg/mg for ZPCA and 1.7 pg/mg for ZCA. The recoveries ranged from 77.6 to 111.7%. The intra- and inter-day precisions were within 16.9 and 11.7%, while intra- and inter-day accuracies were -7.0-8.7 and -2.8-7.8%, respectively. The developed method was applied for the analysis of forensic hair samples obtained from suspected zolpidem abusers and the following concentration ranges were monitored: ZPCA 11.9-35.9 pg/mg and ZCA 16.6-21.8 pg/mg. The method proved to be suitable for picogram-level determination of ZPCA and ZCA in human hair.

Long-Term Detection In Hair Of Zolpidem, Oxazepam And Flunitrazepam In A Case Of Drug-Facilitated Sexual Assault

Drug-facilitated sexual assault (DFSA) cases are pretty common in forensic toxicology. In this case report, a 56-year-old female tourist claimed to have been sexually assaulted by five men after having had a drug-spiked alcoholic drink. Urine samples were collected at 38, 44, and 45 hours after the alleged rape. After 7 months, hair strands (28 cm in length) were also sampled to perform the segmental hair testing. Urine and decontaminated hair segments were tested for different groups of basic, acid, and neutral substances (GHB, Z-drugs, barbiturates, benzodiazepines, hypnotics, antipsychotics, drugs of abuse). GC/MS and LC-MS/MS methods were applied for the qualitative and quantitative analyses. Toxicological analyses performed on urine samples gave inconclusive findings. Zolpidem, flunitrazepam, and oxazepam were detected in the hair segments corresponding to the time frame of the alleged assault. Endogenous levels of GHB were detected along the hair shaft. No drugs were detected in the proximal and distal hair segments or in washing solutions. This DFSA case demonstrated that the segmental toxicological analysis of hair, even when performed 7 months after the sexual assault, can provide evidence consistent in a single exposure to psychoactive drugs, at the time of the offence.

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

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

[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.

Quantitation of zolpidem in biological fluids by electro-driven microextraction combined with HPLC-UV analysis

In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R² >0.9991) with repeatability ( %RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.

Hair analysis in toxicological investigation of drug-facilitated crimes in Denmark over a 8-year period

Hair can serve as a specimen for identifying past drug exposure. Segmental hair analysis may differentiate a single exposure from chronic use. Consequently, segmental hair analysis is useful for disclosing a single drug ingestion, as well as for determining repeated exposures in drug-facilitated crimes (DFCs). This paper presents an overview of toxicological investigations that have used hair analysis in DFC cases from 2009 to 2016 in Denmark. Hair concentrations were determined for 24 DFC-related drugs and metabolites, including benzodiazepines and other hypnotics, antihistamines, opioid analgesics, antipsychotics, barbiturates, and illicit drugs from DFC cases. Drug detection in hair in DFC cases following a single or few intakes of chlorprothixene, codeine, diphenhydramine, oxazepam, oxycodone, promethazine, and phenobarbital is reported for the first time in forensic toxicology. A literature review on concentrations in the published DFC-related hair cases and on concentrations in hair of these substances after single and multiple doses is included. These cases demonstrate the value of segmental hair analysis in DFCs and facilitate future interpretations of results.

The Appearance, Taste, and Concentrations of Zolpidem Dissolved in Still Water and Carbonated Beverages

Zolpidem is a sedative that could be used to drug victims, but its suitability to dissolve in drinks is unknown. In this small study, we added either crushed or whole tablets of zolpidem hemitartrate to carbonated beverages or still water to observe how this affected the taste and appearance. Also, concentrations were measured by ultra-high performance liquid chromatography tandem mass spectrometry at different time intervals. Two crushed tablets (20 mg) in cider (250 mL) lead to a maximum concentration of 84 mg/L zolpidem base after 30 min, while the corresponding concentration after adding fifteen tablets (150 mg) was 467 mg/L. There was little change in taste, but froth and turbidity were observed when adding high doses to carbonated beverages. Carbonated beverages spiked with 20 mg of crushed zolpidem hemitartrate tablets reached concentrations that could cause impairment. Spiking with 150 mg could possibly be lethal if several mouthfuls were ingested.

A comprehensive and sensitive method for hair analysis in drug-facilitated crimes and incorporation of zolazepam and tiletamine into hair after a single exposure

Hair is a highly relevant specimen that is used to verify drug exposure in victims of drug-facilitated crime (DFC) cases. In the present study, a new analytical method involving ultrahigh-performance liquid chromatography-tandem mass spectrometry was developed for determining the presence of model drugs, including zolazepam and tiletamine and their metabolites in hair specimens from DFCs. The incorporation of zolazepam and tiletamine into hair after a single exposure was investigated in Long-Evans rats with the ratio of the hair concentration to the area under the curve. For rapid and simple sample preparation, methanol extraction and protein precipitation were performed for hair and plasma, respectively. No interference was observed in drug-free hair or plasma, except for hair-derived diphenhydramine in blank hair. The coefficients of variance of the matrix effects were below 12%, and the recoveries of the analytes exceeded 70% in all of the matrices. The precision and accuracy results were satisfactory. The limits of quantification ranged from 20 to 50 pg in 10 mg of hair. The drug incorporation rates were 0.03 ± 0.01% for zolazepam and 2.09 ± 0.51% for tiletamine in pigmented hair. We applied the present method to real hair samples in order to determine the drug that was used in seven cases. These results suggest that this comprehensive and sensitive hair analysis method can successfully verify a drug after a single exposure in crimes and can be applied in forensic and clinical toxicology laboratories.

Review: Drug concentrations in hair and their relevance in drug facilitated crimes

Segmental hair analysis can provide valuable retrospective information on the history of drug exposure in victims of drug facilitated crimes (DFC). This is now possible with availability of sensitive tandem MS techniques such as GC-MS/MS and LC-MS/MS allowing drugs to be detected at pg/mg concentrations after a single dose. In this review hair concentrations of 35 psychoactive drugs given in 20 controlled dose studies are reviewed and compared to the 25 different drugs detected in reported case work. The most common drugs were the benzodiazepines and related hypnotics, gamma-hydroxybutyrate (GHB), ketamine and methamphetamine. Those concentrations reported in DFC were mostly similar or higher than that seen in controlled dose studies. The factors that affecting interpretation of segmental hair results including hair color, growth rates, sample preparation and surface contamination are discussed.

Segmental analysis of amphetamines in hair using a sensitive UHPLC-MS/MS method

A sensitive and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy methamphetamine in hair samples. Segmented hair (10 mg) was incubated in 2M sodium hydroxide (80°C, 10 min) before liquid-liquid extraction with isooctane followed by centrifugation and evaporation of the organic phase to dryness. The residue was reconstituted in methanol:formate buffer pH 3 (20:80). The total run time was 4 min and after optimization of UHPLC-MS/MS-parameters validation included selectivity, matrix effects, recovery, process efficiency, calibration model and range, lower limit of quantification, precision and bias. The calibration curve ranged from 0.02 to 12.5 ng/mg, and the recovery was between 62 and 83%. During validation the bias was less than ±7% and the imprecision was less than 5% for all analytes. In routine analysis, fortified control samples demonstrated an imprecision <13% and control samples made from authentic hair demonstrated an imprecision <26%. The method was applied to samples from a controlled study of amphetamine intake as well as forensic hair samples previously analyzed with an ultra high performance liquid chromatography time of flight mass spectrometry (UHPLC-TOF-MS) screening method. The proposed method was suitable for quantification of these drugs in forensic cases including violent crimes, autopsy cases, drug testing and re-granting of driving licences. This study also demonstrated that if hair samples are divided into several short segments, the time point for intake of a small dose of amphetamine can be estimated, which might be useful when drug facilitated crimes are investigated.

Simultaneous analysis of zolpidem and its metabolite in whole blood and oral fluid samples by SPE-LC/MS for clinical and forensic purposes

PURPOSE

The new analytical method of qualitative and quantitative determination of zolpidem and qualitative analysis of its main metabolite in blood and oral fluid samples was developed.

MATERIALS AND METHODS

Sample preparation was carried out using a polymeric ion-exchange sorbent in solid phase extraction (SPE). Analysis was realized using liquid chromatography with mass spectrometry detection (LC/MS). The method was validated in terms of few parameters. LOD, LOQ, linearity, precision, selectivity, ion suppression and stability were estimated.

RESULTS

Obtained method showed good linearity with determination coefficient (R(2)) of 0.9989 and 0.9998 for blood and oral fluid samples, respectively. LOD and LOQ of zolpidem were 0.2ng/mL and 1.0ng/mL, respectively, for both blood and oral fluid samples. SPE method recovery varies from 79.9±12.6 to 104.1±1.77 for blood sample and 80.2±0.48 to 103.8±1.51 for oral fluid sample. Samples collected from patients taking zolpidem with a prescription were analyzed. Detection of zolpidem was possible after 15h from ingestion of 10mg zolpidem tartrate in both types of samples.

CONCLUSION

The developed method allows quantitation of zolpidem in therapeutic and subtherapeutic range as well as qualitative analysis of its main metabolite in blood and oral fluid samples. This method meets criteria required for bioanalytical applications and can be used for clinical and forensic purposes.

A screening method for 30 drugs in hair using ultrahigh-performance liquid chromatography time-of-flight mass spectrometry

OBJECTIVES

The objectives of this study were to develop and to validate a qualitative screening method that met the new Society of Hair Testing (SoHT) guideline criteria for thresholds.

METHODS

Extraction of 20 mg hair was performed by a previously validated procedure using overnight incubation in a mixture of methanol:acetonitrile:formiate buffer pH 3 (10:10:80). Analysis was performed on an Agilent 6540 quadrupole time-of-flight mass spectrometer in combination with an Agilent 1290 Infinity ultrahigh-performance liquid chromatography system. Separation was achieved with a 12-minute linear gradient chromatography on a high-strength silica T3 column at acidic conditions. An in-house database containing 30 compounds from the groups amphetamines, opiates, opioids, cocaine, benzodiazepines, and other sedatives including 6 deuterated internal standards was built by analyzing solutions from certified standards. Data were extracted using mass accuracy of ± 10 ppm, retention time deviation of ± 0.15 minutes, and area of ≥ 30,000 counts. Identification was based on scoring of retention time, accurate mass measurement, and isotopic pattern. Validation included selectivity, repeatability of analyte area, and the scoring parameters at the proposed thresholds and a method comparison with the present liquid chromatography-mass spectrometry-mass spectrometry method using 50 authentic hair samples. A daily cutoff calibrator was used to identify positive samples.

RESULTS

All cutoffs could be met with imprecisions of less than 5% for most parameters and analytes. Hair from drug-free subjects did not produce any positive results and the method comparison agreed in more than 90% of the cases.

CONCLUSIONS

We conclude that the developed method meets the criteria of the new SoHT guidelines for screening cutoffs. Even though no thresholds have been suggested for benzodiazepines, we conclude that thresholds between 0.05 and 0.1 ng/mg should be sufficient to determine regular use of these substances.

Application of mass spectrometry to hair analysis for forensic toxicological investigations

The increasing role of hair analysis in forensic toxicological investigations principally owes to recent improvements of mass spectrometric instrumentation. Research achievements during the last 6 years in this distinctive application area of analytical toxicology are reviewed. The earlier state of the art of hair analysis was comprehensively covered by a dedicated book (Kintz, 2007a. Analytical and practical aspects of drug testing in hair. Boca Raton: CRC Press and Taylor & Francis, 382 p) that represents key reference of the present overview. Whereas the traditional organization of analytical methods in forensic toxicology divided target substances into quite homogeneous groups of drugs, with similar structures and chemical properties, the current approach often takes advantage of the rapid expansion of multiclass and multiresidue analytical procedures; the latter is made possible by the fast operation and extreme sensitivity of modern mass spectrometers. This change in the strategy of toxicological analysis is reflected in the presentation of the recent literature material, which is mostly based on a fit-for-purpose logic. Thus, general screening of unknown substances is applied in diverse forensic contexts than drugs of abuse testing, and different instrumentation (triple quadrupoles, time-of-flight analyzers, linear and orbital traps) is utilized to optimally cope with the scope. Other key issues of modern toxicology, such as cost reduction and high sample throughput, are discussed with reference to procedural and instrumental alternatives.

CYP3A4 and CYP2C19 genetic polymorphisms and zolpidem metabolism in the Chinese Han population: a pilot study

Zolpidem (ZPD) is an imidazopyridine hypnotic and little is known about the pharmacogenetics of ZPD. Our objective was to evaluate inter-individual genetic variation in conjunction with metabolic ratios of ZPD found in a toxicological analysis. Healthy individuals (n=300) were genotyped for CYP2D6, CYP2C19, CYP2C9, CYP3A4 and CYP1A2 by allele-specific primer extension followed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Twenty-four Chinese volunteers were chosen and divided into the following four groups (n=6/group): group 1: CYP3A4*18 (wild-type, W), CYP2C19*2 (W); group 2: CYP3A4*18 (mutant, M), CYP2C19*2 (W); group 3: CYP3A4*18 (W), CYP2C19*2 (M); and group 4: CYP3A4*18 (M), CYP2C19*2 (M). ZPD and its major metabolites zolpidem 6-carboxylic acid (ZCA) and zolpidem phenyl-4-carboxylic acid (ZPCA) were determined after oral administration of ZPD (10mg), using an UPLC-MS/MS method. Positive correlations between CYP3A4 and CYP2C19 alleles and ZPD metabolism were found. The results of this study show that CYP3A4*18 increases CYP3A4 activity while CYP2C19*2 reduces CYP2C19 activity; the latter mutation is associated with the poor metabolism of ZPD in the Chinese Han population. The results also suggest that genetic factors play a major role in the metabolism of individual drugs with implications for both forensic science and clinical pharmacogenetics.

Methods for the analysis of nonbenzodiazepine hypnotic drugs in biological matrices

Zopiclone, zolpidem and zaleplon (Z-drugs) are nonbenzodiazepine hypnotic drugs that are used for the treatment of insomnia. These drugs were developed with the intent to overcome some disadvantages of benzodiazepines, such as dependence and next day sedation. In general, the nonbenzodiazepine hypnotic drugs are administered in oral doses daily and are widely biotransformed in the body. A large number of analytical methods based on chromatographic and electrophoretic techniques for the quantification of Z-drugs and their metabolites in biological matrices have been reported. In this review, the bioanalytical methods for Z-drugs were reviewed with the focus placed on sample preparation procedures and the separation techniques used. Furthermore, as these drugs are also reported as drugs of abuse or in drug-facilitated crime, screening methods that simultaneously cover these drugs and also other drugs of abuse were included in this review.

Value of the concept of minimal detectable dosage in human hair

The influence on drug incorporation of melanin affinity, lipophilicity, and membrane permeability is of paramount importance. Despite their high lipophilicity, some drugs have quite low incorporation rate into hair, suggesting that the higher incorporation rates of basic drugs (cocaine, amphetamines.) than neutral (steroids, benzodiazepines, cannabinoids…) or acidic ones are strongly related to the penetrating ability of the drug to break through the membrane based on the pH gradient between blood and the acidic hair matrix. When using hair analysis as a matrix during investigative analysis, e.g. workplace drug testing, doping, driving under the influence, drug-facilitated crime, the question of importance is to know whether the analytical procedure was sensitive enough to identify traces of drugs; this is particularly important when the urine sample(s) of the subject was positive and the hair sample(s) was negative. It has been accepted in the forensic community that a negative hair result cannot exclude the administration of a particular drug, or one of its precursors and the negative findings should not overrule a positive urine result. Nevertheless, the negative hair findings can, on occasion, cast doubt on the positive urine analysis, resulting in substantial legal debate and various consequences for the subject. The concept of minimal detectable dosage in hair is of interest to document the negative findings, but limited data is currently available in the scientific literature. Such data includes cocaine, codeine, ketamine, some benzodiazepines and some unusual compounds. Until laboratories will have sensitive enough methodologies to detect a single use of drug, care should be taken to compare urine and hair findings.