Position of chromatographic techniques in screening for detection of drugs or poisons in clinical and forensic toxicology and/or doping control

Analytical aspects in doping control: challenges and perspectives

Since the first anti-doping tests in the 1960s, the analytical aspects of the testing remain challenging. The evolution of the analytical process in doping control is discussed in this paper with a particular emphasis on separation techniques, such as gas chromatography and liquid chromatography. These approaches are improving in parallel with the requirements of increasing sensitivity and selectivity for detecting prohibited substances in biological samples from athletes. Moreover, fast analyses are mandatory to deal with the growing number of doping control samples and the short response time required during particular sport events. Recent developments in mass spectrometry and the expansion of accurate mass determination has improved anti-doping strategies with the possibility of using elemental composition and isotope patterns for structural identification. These techniques must be able to distinguish equivocally between negative and suspicious samples with no false-negative or false-positive results. Therefore, high degree of reliability must be reached for the identification of major metabolites corresponding to suspected analytes. Along with current trends in pharmaceutical industry the analysis of proteins and peptides remains an important issue in doping control. Sophisticated analytical tools are still mandatory to improve their distinction from endogenous analogs. Finally, indirect approaches will be discussed in the context of anti-doping, in which recent advances are aimed to examine the biological response of a doping agent in a holistic way.

Micellar liquid chromatography in doping control

The issue of doping control in sport involves the development of reliable analytical procedures and efficient strategies to process a large number of samples in a short period of time. Reversed-phase LC techniques with aqueous-organic mobile phases and MS or diode-array detection yield satisfactory results for the identification of prohibited substances in sport. However, time-consuming sample pretreatment steps are required, which reduces sample throughput. Micellar LC (MLC) that uses hybrid mobile phases of surfactant above its critical micellar concentration and organic solvent has been revealed as an interesting alternative. The surfactant sodium dodecyl sulfate solubilizes the protein components of urine, serum and plasma, which permits their direct injection into the chromatographic system. Only dilution and filtering of the samples may be required. Most MLC analyses are performed in isocratic mode, with short retention times and good selectivity. The sensitivity of MLC allows the detection of a variety of doping substances at least 24-48 h after being administered.

Absorption, distribution, metabolism and excretion pharmacogenomics of drugs of abuse

Pharmacologic and toxic effects of xenobiotics, such as drugs of abuse, depend on the genotype and phenotype of an individual, and conversely on the isoenzymes involved in their metabolism and transport. The current knowledge of such isoenzymes of frequently abused therapeutics such as opioids (oxycodone, hydrocodone, methadone, fentanyl, buprenorphine, tramadol, heroin, morphine and codeine), anesthetics (γ-hydroxybutyric acid, propofol, ketamine and phencyclidine) and cognitive enhancers (methylphenidate and modafinil), and some important plant-derived hallucinogens (lysergide, salvinorin A, psilocybin and psilocin), as well as of nicotine in humans are summarized in this article. The isoenzymes (e.g., cytochrome P450, glucuronyltransferases, esterases and reductases) involved in the metabolism of drugs and some pharmacokinetic data are discussed. The relevance of such data is discussed for predicting possible interactions with other xenobiotics, understanding pharmacokinetic behavior and pharmacogenomic variations, assessing toxic risks, developing suitable toxicological analysis procedures, and finally for interpretating drug testing results.

Studies on the metabolism of the α-pyrrolidinophenone designer drug methylenedioxy-pyrovalerone (MDPV) in rat and human urine and human liver microsomes using GC-MS and LC-high-resolution MS and its detectability in urine by GC-MS

Since the late 1990s, many derivatives of the α-pyrrolidinophenone (PPP) drug class appeared on the drugs of abuse market. The latest compound was described in 2009 to be a classic PPP carrying a methylenedioxy moiety remembering the classic entactogens (ecstasy). Besides Germany, 3,4-methylene-dioxypyrovalerone (MDPV) has appeared in many countries in Europe and Asia, indicating its worldwide importance for forensic and clinical toxicology. The aim of the presented work was to identify the phase I and II metabolites of MDPV and the human cytochrome-P450 (CYP) isoenzymes responsible for its main metabolic step(s). Finally, the detectability of MDPV in urine by the authors' systematic toxicological analysis (STA) should be studied. The urine samples were extracted after and without enzymatic cleavage of conjugates. The metabolites were separated and identified after work-up by GC-MS and liquid chromatography (LC)-high-resolution MS (LC-HR-MS). The studies revealed the following phase I main metabolic steps in rat and human: demethylenation followed by methylation, aromatic and side chain hydroxylation and oxidation of the pyrrolidine ring to the corresponding lactam as well as ring opening to the corresponding carboxylic acid. Using LC-HR-MS, most metabolite structures postulated according to GC-MS fragmentation could be confirmed and the phase II metabolites were identified. Finally, the formation of the initial metabolite demethylenyl-MDPV could be confirmed using incubation of human liver microsomes. Using recombinant human CYPs, CYP 2C19, CYP 2D6 and CYP 1A2 were found to catalyze this initial step. Finally, the STA allowed the detection of MDPV metabolites in the human urine samples.

Evaluation of the identification power of RPLC analyses in the screening for drug compounds

The identification of drugs of abuse is an important issue in forensic science. The main goal is to trace and identify as many drugs as possible in the shortest possible time preferably with a simple analysis method. One possibility is to screen samples using a Liquid Chromatography-Diode Array Detection (LC-DAD) system. However, when simultaneously performing another analysis on a chromatographic column exhibiting selectivity differences from the first one, that is, orthogonal or dissimilar columns, a greater number of drugs can be possibly identified without investing a lot of extra time or money. The primary difficulty is then selecting the most appropriate columns. In this paper, it is demonstrated that selecting the most dissimilar columns based on measures such as correlation or Snyder's F(s) value is not optimal, because these measures do not take into account the identification power of the individual systems. This implies that a large number of drugs may not necessarily be identified on the systems selected using these criteria. Therefore, three other measures are tested to evaluate the identification power obtained by parallel screening on two columns or by comprehensive two-dimensional LC (LC x LC). The simplest approach is counting the number of compounds separable with a difference in retention time greater than a predefined critical value. However, this measure does not reflect the coelution pattern of the unidentified drugs nor the separation degree of all compounds. The second tested measure, information, enables differentiation between systems identifying the same number of compounds but resulting in a different coelution pattern. Multivariate selectivity, the third tested parameter, takes into account the degree of separation of all compounds and has the advantage that it reflects the gain in identification power achieved by introducing DAD data. All three proposed measures also enable evaluation of whether the corresponding LC x LC method will result in a greater identification power.

Difficult-to-control arterial hypertension or uncooperative patients? The assessment of serum antihypertensive drug levels to differentiate non-responsiveness from non-adherence to recommended therapy

Difficult-to-control arterial hypertension is a common medical problem that may result from severe hypertensive disease or from poor adherence to the recommended medical treatment. The identification of non-adherent patients is challenging, especially when non-adherence is intentional. The current report describes the use of serum levels of prescribed antihypertensive drugs to evaluate the adherence in individuals with difficult-to-control arterial hypertension. Serum drug levels (SDLs) were evaluated by liquid chromatography with mass spectrometry. The chromatographic separation was performed on a reversed-phase column with a gradient flow of the mobile phase. The detection of analyzed substances was accomplished on a linear ion-trap mass spectrometer. The subjects were labeled as non-adherent when the serum level of at least one of the evaluated drugs was below the limit of quantification. The study used data from 84 patients with arterial hypertension who underwent SDL assessment to verify compliance with the recommended treatment. Patients who presented with uncontrolled blood pressure despite the recommended combination of at least three antihypertensives were enrolled in the analysis. Based on the evaluation of the SDLs, all of the evaluated drugs were found in the sera of 29 (34.5%) of the study patients. In the remaining 55 (65.5%) patients, non-adherence was diagnosed. None of the prescribed antihypertensive drugs was detected in the sera of the 29 (34.5%) patients. Our data suggest that an assessment of SDLs might be helpful before an extensive evaluation is initiated for difficult-to-control hypertension.

Comparison of analytical approaches for liquid chromatography/mass spectrometry determination of the alcohol biomarker ethyl glucuronide in urine

Official guidelines originating from a European Union directive regulate requirements for analytical methods used to identify chemical compounds in biological matrices. This study compared different liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) and tandem mass spectrometry (LC/ESI-MS/MS) procedures for accurate determination of the conjugated ethanol metabolite and alcohol biomarker ethyl glucuronide (EtG) in urine, and the value of combined EtG and ethyl sulfate (EtS) measurement. Analysis was carried out on 482 urines following solid-phase extraction (SPE) sample cleanup or using direct injection of a diluted sample. SPE combined with LC/MS/MS was demonstrated to be the most selective and sensitive method and was chosen as reference method. The EtG results by different methods showed good correlation (r = 0.96-0.98). When comparing five reporting limits for EtG in the range 0.10-1.00 mg/L, the overall agreement with the reference method (frequency of true positives plus true negatives) was 82-97% for direct-injection LC/MS/MS, 90-97% for SPE-LC/MS, 86-98% for direct-injection LC/MS, and 86-98% for direct-injection LC/MS analysis of EtG and EtS. Most deviations were attributable to uncertainty in quantitation, when the value was close to a cutoff but the respective results were slightly above and below, or vice versa, the critical limit. However, for direct-injection LC/MS/MS, despite earning 4 identification points, equally many negative results were due to a product ion ratio outside the +/-20% deviation accepted by the guidelines. These results indicate that the likelihood of different analytical methods to provide reliable analytical results depends on the reporting limit applied.

Metabolic and toxic causes of canine seizure disorders: A retrospective study of 96 cases

A wide variety of intoxications and abnormal metabolic conditions can lead to reactive seizures in dogs. Patient records of dogs suffering from seizure disorders (n=877) were reviewed, and 96 cases were associated with an underlying metabolic or toxic aetiology. These included intoxications by various agents, hypoglycaemia, electrolyte disorders, hepatic encephalopathy, hypothyroidism, uraemic encephalopathy, hypoxia and hyperglycaemia. The incidence of the underlying diseases was determined. The most common causes of reactive seizures were intoxications (39%, 37 dogs) and hypoglycaemia (32%, 31 dogs). Hypocalcaemia was the most frequent electrolyte disorder causing reactive seizures (5%) and all five of these dogs had ionised calcium concentrations ≤0.69 mmol/L. Eleven per cent of dogs with seizures had metabolic or toxic disorders and this relatively high frequency emphasises the importance of a careful clinical work-up of cases presented with seizures in order to reach a correct diagnosis and select appropriate treatment options.

Use of liquid chromatography coupled to low- and high-resolution linear ion trap mass spectrometry for studying the metabolism of paynantheine, an alkaloid of the herbal drug Kratom in rat and human urine

The Thai medicinal plant Mitragyna speciosa (Kratom in Thai) is misused as a herbal drug of abuse. During studies on the main Kratom alkaloid mitragynine (MG) in rats and humans, several dehydro analogs could be detected in urine of Kratom users, which were not found in rat urine after administration of pure MG. Questions arose as to whether these compounds are formed from MG only by humans or whether they are metabolites formed from the second abundant Kratom alkaloid paynantheine (PAY), the dehydro analog of MG. Therefore, the aim of the presented study was to identify the phase I and II metabolites of PAY in rat urine after administration of the pure alkaloid. This was first isolated from Kratom leaves. Liquid chromatography-linear ion trap mass spectrometry provided detailed structure information of the metabolites in the MS(n) mode particularly with high resolution. Besides PAY, the following phase I metabolites could be identified: 9-O-demethyl PAY, 16-carboxy PAY, 9-O-demethyl-16-carboxy PAY, 17-O-demethyl PAY, 17-O-demethyl-16,17-dihydro PAY, 9,17-O-bisdemethyl PAY, 9,17-O-bisdemethyl-16,17-dihydro PAY, 17-carboxy-16,17-dihydro PAY, and 9-O-demethyl-17-carboxy-16,17-dihydro PAY. These metabolites indicated that PAY was metabolized via the same pathways as MG. Several metabolites were excreted as glucuronides or sulfates. The metabolism studies in rats showed that PAY and its metabolites corresponded to the MG-related dehydro compounds detected in urine of the Kratom users. In conclusion, PAY and its metabolites may be further markers for a Kratom abuse in addition of MG and its metabolites.

Rapid drug detection in oral samples by porous silicon assisted laser desorption/ionization mass spectrometry

The demand for analysis of oral fluid for illicit drugs has arisen with the increased adoption of roadside testing, particularly in countries where changes in legislation allow random roadside testing of drivers for the presence of a palette of illicit drugs such as methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA) and Delta9-tetrahydrocannabinol (THC). Oral samples are currently tested for such drugs at the roadside using an immunoassay-based commercial test kit. Positive roadside tests are sent for confirmatory laboratory analysis, traditionally by means of gas chromatography/mass spectrometry (GC/MS). We present here an alternative rapid analysis technique, porous silicon assisted laser desorption/ionization time-of-flight mass spectrometry (pSi LDI-MS), for the high-throughput analysis of oral fluids. This technique alleviates the need for sample derivatization, requires only sub-microliter sample volumes and allows fast analysis (of the order of seconds). In this study, the application of the technique is demonstrated with real samples from actual roadside testing. The analysis of oral samples resulted in detection of MA and MDMA with no extraction and analysis of THC after ethyl acetate extraction. We propose that, subject to miniaturization of a suitable mass spectrometer, this technique is well suited to underpin the deployment of oral fluid testing in the clinic, workplace and on the roadside.

Two-step silylation procedure for the unified analysis of 190 doping control substances in human urine samples by GC–MS

Background: While a number of different derivatization procedures for screening GC–MS analysis of prohibited substances are followed by doping control laboratories, a unified derivatization procedure for the GC–MS analysis of 190 different doping agents was developed. Results: Following preliminary experiments, a two-step derivatization procedure was selected. The evaluation of various silylation parameters, such as reagent composition, reaction time, reaction temperature, catalysts and microwave oven reaction time, for this procedure was carried out. Conclusion: The suitability of the developed procedure was demonstrated through application on urine samples at concentration levels of the minimum required performance limit for all tested substances. This new derivatization procedure, which significantly decreases time and cost, is suitable for a routine basis application.

Barbiturate intoxication in two dogs confirmed by toxicological urinalysis

Two dogs were presented within 24 hours to the Department of Small Animal Medicine and Surgery at the University of Veterinary Medicine Hannover for investigation of the sudden onset of neurological abnormalities following a walk in the same park. One dog was observed ingesting a piece of meat. Analysis of urine by gas chromatography-mass spectrometry from each of the dogs identified the presence of barbiturates. Both dogs recovered with supportive treatment. This is the first report to describe the use of toxicological urinalysis with gas chromatography-mass spectrometry for the diagnosis of barbiturate intoxication in dogs.

New designer drug alpha-pyrrolidinovalerophenone (PVP): studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques

The aim of the present study was to identify the metabolites of the new designer drug alpha-pyrrolidinovalerophenone (PVP) in rat urine using GC/MS techniques. Eleven metabolites of PVP could be identified suggesting the following metabolic steps: hydroxylation of the side chain followed by dehydrogenation to the corresponding ketone; hydroxylation of the 2''-position of the pyrrolidine ring followed by dehydrogenation to the corresponding lactam or followed by ring opening to the respective aliphatic aldehyde and further oxidation to the respective carboxylic acid; degradation of the pyrrolidine ring to the corresponding primary amine; and hydroxylation of the phenyl ring, most probably in the 4'-position. The authors' screening procedure for pyrrolidinophenones allowed the detection of PVP metabolites after application of a dose corresponding to a presumed user's dose. In addition, the involvement of nine different human cytochrome P450 (CYP) isoenzymes in the side chain hydroxylation of PVP was investigated and CYP 2B6, 2C19, 2D6, and 3A4 were found to catalyze this reaction.

Simultaneous liquid chromatographic-electrospray ionization mass spectrometric quantification of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) and its metabolites 3,4-dihydroxymethamphetamine, 4-hydroxy-3-methoxymethamphetamine and 3,4-methylenedioxyamphetamine in squirrel monkey and human plasma after acidic conjugate cleavage

3,4-Methylenedioxymethamphetamine (MDMA, Ecstasy) is a psychoactive drug with abuse liability and neurotoxic potential. Specimen preparation of a recently presented LC-MS assay with electrospray ionization for quantifying MDMA and its main metabolites in squirrel monkey plasma was modified to include acidic hydrolysis to obtain total 3,4-dihydroxymethamphetamine and 4-hydroxy-3-methoxy-methamphetamine. Method re-validation for squirrel monkey plasma and full validation for human plasma showed selectivity for all analytes. Recoveries were > or = 71.0%. Changed specimen preparation or matrix did not affect accuracy or precision. No instability was observed after repeated freezing or in processed samples. Plasma MDMA and metabolites quantification, derived pharmacokinetic and toxicokinetic data and neurotoxicity research will benefit from this validated method.

Comparison of extraction efficiencies and LC-MS-MS matrix effects using LLE and SPE methods for 19 antipsychotics in human blood

Antipsychotic drugs are frequently associated with sudden death investigations. Detection of these drugs is necessary to establish their use and possible contribution to the death. LC-MS(MS) methods are common; however accurate and precise quantification is assured by using validated methods. This study compared extraction efficiency and matrix effects using common liquid-liquid and solid-phase extraction procedures in both ante-mortem and post-mortem specimen using LC-MS-MS. Extraction efficiencies and matrix effects were determined in five different blank blood specimens of each blood type. The samples were extracted using a number of different liquid-liquid extraction methods and compared with a standard mixed-mode solid-phase extraction method. Matrix effects were determined using a post-extraction addition approach-the blank blood specimens were extracted as described above and the extracts were reconstituted in mobile phase containing a known amount of analytes. The extraction comparison of ante-mortem and post-mortem blood showed considerable differences, in particular the extraction efficiency was quite different between ante-mortem and post-mortem blood. Quantitative methods used for determination of antipsychotic drugs in post-mortem blood should establish that there are no differences in extraction efficiency and matrix effects, particularly if using ante-mortem blood as calibrator.

Analytical techniques for drug detection in oral fluid

Analytical techniques for detection of drugs in oral fluid (OF) are reviewed with emphasis on applications used in European Union (EU) roadside testing projects. Oral fluid is readily accessible and collectible. It has become an interesting material because no medical personnel are needed for sampling. This matrix is especially applicable for preliminary drug testing in driving under the influence controls and for monitoring illicit drug use in drug treatment. Oral fluid is also an increasingly used specimen in epidemiologic studies and in workplace drug testing. Drugs are present at lower levels in OF than in urine. The window of detection of drugs in OF reflects the corresponding window in blood, suggesting OF as a specimen of choice for roadside testing. Saliva/blood ratios vary from drug to drug, from person to person, and even intraindividually making therapeutic drug monitoring in OF challenging. Several sensitive methods for drug testing in OF have been developed during the last years.

Metabolism and toxicological detection of the designer drug 4-chloro-2,5-dimethoxyamphetamine in rat urine using gas chromatography-mass spectrometry

Studies are described on the metabolism and the toxicological analysis of the amphetamine-derived designer drug 4-chloro-2,5-dimethoxyamphetamine (DOC) in rat urine using gas chromatographic-mass spectrometric techniques. The metabolites identified indicated that DOC was metabolized by O-demethylation at position 2 or 5 of the phenyl ring partly followed by glucuronidation and/or sulfation. The authors' systematic toxicological analysis procedure using full-scan gas chromatography-mass spectrometry after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of an intake of a dose of DOC in rat urine that corresponds to a common drug user's dose. Assuming similar metabolism, the STA procedure described should be suitable as proof of an intake of DOC in human urine.

New designer drugs N-(1-phenylcyclohexyl)-2-ethoxyethanamine (PCEEA) and N-(1-phenylcyclohexyl)-2-methoxyethanamine (PCMEA): Studies on their metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques

Studies are described on the metabolism and the toxicological detection of the phencyclidine-derived designer drugs N-(1-phenylcyclohexyl)-2-ethoxyethanamine (PCEEA) and N-(1-phenylcyclohexyl)-2-methoxyethanamine (PCMEA) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques. The identified metabolites indicated that PCEEA and PCMEA were transformed to the same metabolites by N-dealkylation and O-dealkylation partially followed by oxidation of the resulting alcohol to the respective carboxylic acid and hydroxylation of the cyclohexyl ring at different positions and combinations of those. Finally, aromatic hydroxylation of the O-dealkylated metabolites was partially followed by hydroxylation of the cyclohexyl ring at different positions. All metabolites were partially excreted in conjugated form. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of an intake of a common drug users' dose both of PCEEA and PCMEA in rat urine. Assuming similar metabolism in humans, the STA should be suitable for proof of an intake of PCEEA and PCMEA in human urine, although their differentiation is not possible due to common metabolites.

Clathrate nanostructures for mass spectrometry

The ability of mass spectrometry to generate intact biomolecular ions efficiently in the gas phase has led to its widespread application in metabolomics, proteomics, biological imaging, biomarker discovery and clinical assays (namely neonatal screens). Matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization have been at the forefront of these developments. However, matrix application complicates the use of MALDI for cellular, tissue, biofluid and microarray analysis and can limit the spatial resolution because of the matrix crystal size (typically more than 10 mum), sensitivity and detection of small compounds (less than 500 Da). Secondary-ion mass spectrometry has extremely high lateral resolution (100 nm) and has found biological applications although the energetic desorption/ionization is a limitation owing to molecular fragmentation. Here we introduce nanostructure-initiator mass spectrometry (NIMS), a tool for spatially defined mass analysis. NIMS uses 'initiator' molecules trapped in nanostructured surfaces or 'clathrates' to release and ionize intact molecules adsorbed on the surface. This surface responds to both ion and laser irradiation. The lateral resolution (ion-NIMS about 150 nm), sensitivity, matrix-free and reduced fragmentation of NIMS allows direct characterization of peptide microarrays, direct mass analysis of single cells, tissue imaging, and direct characterization of blood and urine.

Validated liquid chromatographic-electrospray ionization mass spectrometric assay for simultaneous determination of 3,4-methylenedioxymethamphetamine and its metabolites 3,4-methylenedioxyamphetamine, 3,4-dihydroxymethamphetamine, and 4-hydroxy-3-methoxymethamphetamine in squirrel monkey plasma

3,4-Methylenedioxymethamphetamine (MDMA) is a recreational drug with neurotoxic potential. Pharmacokinetic data of MDMA and its metabolites may shed light on the mechanism of MDMA neurotoxicity. An LC-MS assay with electrospray ionization (ESI) is presented for quantifying MDMA and its metabolites 3,4-methylenedioxyamphetamine (MDA), 3,4-dihydroxymethamphetamine (HHMA), and 4-hydroxy-3-methoxymethamphetamine (HMMA) in squirrel monkey plasma. The method involved enzymatic conjugate cleavage and protein precipitation. Separation was achieved within 14min. The method was validated according to international guidelines with respect to selectivity, linearity, accuracy, precision, recovery, and matrix effect. The present method should prove useful for acquiring pharmacokinetic and toxicokinetic data in squirrel monkeys.

Proof of a 1-(3-chlorophenyl)piperazine (mCPP) intake—Use as adulterant of cocaine resulting in drug–drug interactions?

Since 2005, increasing numbers of seizures of the designer drug of abuse 1-(3-chlorophenyl)piperazine (mCPP) have been reported. This paper describes the unequivocal proof of a mCPP intake. Differentiation from the intake of its precursor drugs trazodone and nefazodone was performed by a systematic toxicological analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation. The found mCPP/hydroxy-mCPP ratio indicated altered metabolism of this cytochrome (CYP) 2D6 catalyzed reaction compared to published studies using the same procedure. Although this might be ascribed to a poor metabolizer (PM) phenotype, genotyping revealed no PM genotype but indications for an intermediate metabolizer genotype. However, a PM phenotype could also be caused by drug-drug interactions with CYP2D6 inhibitors or substrates such as the co-consumed cocaine and diltiazem and/or diltiazem metabolites, respectively. In conclusion, the presented data indicate a possible relevance of CYP2D6 polymorphism and/or drug interactions to mCPP toxicokinetics, which is important for risk assessment of this new designer drug of abuse, in particular if it is used as adulterant of CYP2D6 substrates such as cocaine.

Simultaneous determination of 13 amphetamine related drugs in human whole blood using an enhanced polymer column and gas chromatography–mass spectrometry

Metamphetamine (MA) is one of the most frequently encountered abused drugs in Japan and the Triage immunoassay kit is often used to screen for this drug. However, immunoassay screening also gives positive results with other structurally related compounds, such as 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), p-methoxyamphetamine (PMA), an ephedrine metabolite and beta-phenethylamine (PEA). Therefore, it is important to develop a simple and reliable method which can determine these drugs simultaneously. This paper describes a simple method for simultaneous identification and quantification of 13 amphetamine related drugs in human whole blood. The method consists of a solid phase extraction using a new polar-enhanced Focus column followed by acetylation and gas chromatography-mass spectrometry in the scan mode. Tetradeuterated MA and trideuterated methylephedrine (ME) were used as internal standards. As the Focus column required only simple extraction steps and provided a clean extract, identification of each drug was feasible even at low concentrations. The calibration curves were linear over the concentration range from 50 to 5000 ng/ml for all drugs with correlation coefficients that exceeded 0.99. The lower limits of detection of the drugs were 5-50 ng/ml. The absolute recoveries for the drugs were 65-95% and 64-89% at concentrations of 100 and 1000 ng/ml, respectively. Accuracy and precision data were satisfactory when using 2 internal standards. The applicability of the assay was proven by the analysis of blood samples in forensic cases. This method should be most useful for confirmation of positive immunoassay results for amphetamines and related drugs.

New analytical strategies in studying drug metabolism

Identification and elucidation of the structures of metabolites play major roles in drug discovery and in the development of pharmaceutical compounds. These studies are also important in toxicology or doping control with either pharmaceuticals or illicit drugs. This review focuses on: new analytical strategies used to identify potential metabolites in biological matrices with and without radiolabeled drugs; use of software for metabolite profiling; interpretation of product spectra; profiling of reactive metabolites; development of new approaches for generation of metabolites; and detection of metabolites with increased sensitivity and simplicity. Most of the new strategies involve mass spectrometry (MS) combined with liquid chromatography (LC).

CAPILLARY ELECTROPHORESIS AS A VERIFICATION TOOL FOR IMMUNOCHEMICAL DRUG SCREENING

BACKGROUND

The aim of this work was to develop a simple capillary electrophoretic method as the verification and confirmation tool in the screening analysis for amphetamines, opiates, benzodiazepines and cocaine and their metabolites for toxicological applications.

METHODS

50 mM phosphate Tris pH 2.0 with 30% (v/v) of methanol was used as a background electrolyte that enabled fast separation of drugs and their metabolites in saliva and urine. Verification of the data from the electrophoretic method was done by High Performance Thin Layer Chromatography (HPTLC) and the immunochemical screening test QuikScreen.

RESULTS

The experimental conditions of the Capillary Electrophoresis (CE) were partially optimized (mainly the influence of concentration and types of additives, e.g. cyclodextrines, organic solvents) and validated; the method was used for analysing samples from drug abusers.

CONCLUSIONS

The non-instrumental, immunoassay tests could only confirm qualitative addictions and are mainly employed when the emergency detection of drugs is needed. For quantitative analysis and verification of obtained results the confirmation step is strongly recommended. The simple screening capillary zone electrophoresis method allows recognition of the most abused drugs. The agreement of the results from CE, HPTLC and QuikScreen test was more than 95%.

Bioanalytical procedures for determination of drugs of abuse in blood

Determination of drugs of abuse in blood is of great importance in clinical and forensic toxicology. This review describes procedures for detection of the following drugs of abuse and their metabolites in whole blood, plasma or serum: Delta9-tetrahydrocannabinol, 11-hydroxy-Delta9-tetrahydrocannabinol, 11-nor-9-carboxy-Delta9-tetrahydrocannabinol, 11-nor-9-carboxy-Delta9-tetrahydrocannabinol glucuronide, heroin, 6-monoacetylmorphine, morphine, morphine-6-glucuronide, morphine-3-glucuronide, codeine, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, N-ethyl-3,4-methylenedioxyamphetamine, 3,4-methylenedioxyamphetamine, cocaine, benzoylecgonine, ecgonine methyl ester, cocaethylene, other cocaine metabolites or pyrolysis products (norcocaine, norcocaethylene, norbenzoylecgonine, m-hydroxycocaine, p-hydroxycocaine, m-hydroxybenzoylecgonine, p-hydroxybenzoylecgonine, ethyl ecgonine, ecgonine, anhydroecgonine methyl ester, anhydroecgonine ethyl ester, anhydroecgonine, noranhydroecgonine, N-hydroxynorcocaine, cocaine N-oxide, anhydroecgonine methyl ester N-oxide). Metabolites and degradation products which are recommended to be monitored for assessment in clinical or forensic toxicology are mentioned. Papers written in English between 2002 and the beginning of 2007 are reviewed. Analytical methods are assessed for their suitability in forensic toxicology, where special requirements have to be met. For many of the analytes sensitive immunological methods for screening are available. Screening and confirmation is mostly done by gas chromatography (GC)-mass spectrometry (MS) or liquid chromatography (LC)-MS(/MS) procedures. Basic information about the biosample assayed, internal standard, workup, GC or LC column and mobile phase, detection mode, and validation data for each procedure is summarized in two tables to facilitate the selection of a method suitable for a specific analytic problem.

Requirements for bioanalytical procedures in postmortem toxicology

The application of analytical techniques in postmortem toxicology is often more difficult than in other forms of forensic toxicology owing to the variable and often degraded nature of the specimens and the diverse range of specimens available for analysis. Consequently, analysts must ensure that all methods are fully validated for the particular postmortem specimen(s) used. Collection of specimens must be standardized to minimize site-to-site variability and should if available include a peripheral blood sample and at least one other specimen. Urine and vitreous humor are good specimens to complement blood. In some circumstances solid tissues such as liver are recommended as well as gastric contents. Substance-screening techniques are the most important element since they will determine the range of substances that were targeted in the investigation and provide initial indication of the possible role of substances in the death. While immunoassay techniques are still commonly used for the most common drugs-of-abuse, chromatographic screening methods are required for general unknown testing. These are still predominately gas chromatography (GC) based using nitrogen/phosphorous detection and/or mass spectrometry (MS) detection, although some laboratories are now using time-of-flight MS or liquid chromatography (LC)-MS(MS) to cover a sometimes more limited range of substances. It is recommended that laboratories include a second chromatographic method to provide coverage of acidic and other substances not readily covered by a GC-based screen when extracts do not include all physiochemical types. This may include a gradient high-performance liquid chromatography (HPLC) photodiode array method, or better LC-MS(MS). Substance-specific techniques (e.g., benzodiazepines, opiates) providing a second form of identification (confirmation) are now divided between GC-MS(MS) and LC-MS(MS) procedures. LC-MS(MS) has taken over from many methods for the more polar compounds previously used in HPLC or in GC methods requiring derivatization. Analysts using LC-MS will need to obtain clean extracts to avoid poor and variable sensitivity caused by background suppression of the signal. Isolation techniques in postmortem toxicology tend to favor liquid extraction; however solid-phase extraction and solid-phase microextraction methods are available for many analytes.

Current role of liquid chromatography–mass spectrometry in clinical and forensic toxicology

This paper reviews multi-analyte single-stage and tandem liquid chromatography-mass spectrometry (LC-MS) procedures using different mass analyzers (quadrupole, ion trap, time-of-flight) for screening, identification, and/or quantification of drugs, poisons, and/or their metabolites in blood, plasma, serum, or urine published after 2004. Basic information about the biosample assayed, work-up, LC column, mobile phase, ionization type, mass spectral detection mode, and validation data of each procedure is summarized in tables. The following analytes are covered: drugs of abuse, analgesics, opioids, sedative-hypnotics, benzodiazepines, antidepressants including selective-serotonin reuptake inhibitors (SSRIs), herbal phenalkylamines (ephedrines), oral antidiabetics, antiarrhythmics and other cardiovascular drugs, antiretroviral drugs, toxic alkaloids, quaternary ammonium drugs and herbicides, and dialkylphosphate pesticides. The pros and cons of the reviewed procedures are critically discussed, particularly, the need for studies on matrix effects, selectivity, analyte stability, and the use of stable-isotope labeled internal standards instead of unlabeled therapeutic drugs. In conclusion, LC-MS will probably become a gold standard for detection of very low concentrations particularly in alternative matrices and for quantification in clinical and forensic toxicology. However, some drawbacks still need to be addressed and finally overcome.

High-performance liquid chromatography analysis of anti-inflammatory pharmaceuticals with ultraviolet and electrospray-mass spectrometry detection in suspected counterfeit homeopathic medicinal products

A simple high-performance liquid chromatography (HPLC) method with both ultraviolet (UV) and electrospray ionisation mass spectrometry (ESI-MS) detection has been developed for the determination of seven pharmaceuticals in counterfeit homeopathic preparations. Naproxen, Ketoprofen, Ibuprofen, Diclofenac, Piroxicam, Nimesulide and Paracetamol were separated by reversed phase chromatography with acetonitrile-water (0.1% acetic acid) mobile phase, and detected by UV at 245 nm and by ESI-MS in negative ionisation mode with the exception of Paracetamol which was detected in positive ionisation mode. Benzoic acid was used as internal standard (IS). This method was successfully applied to the analysis of homeopathic preparations like mother tinctures, solutions, tablets, granules, creams, and suppositories. Linearity was studied with UV detection in the 50-400 microg mL(-1) range and with ESI-MS in the 0.1-50 microg mL(-1) range. Good correlation coefficients were found in both UV and ESI-MS. Detection limits ranged from 0.18 to 41.5 ng in UV and from 0.035 to 1.00 ng in ESI-MS.

Studies on the toxicological detection of the designer drug 4-bromo-2,5-dimethoxy-β-phenethylamine (2C-B) in rat urine using gas chromatography–mass spectrometry

The phenethylamine-derived designer drug 4-bromo-2,5-dimethoxy-beta-phenethylamine (2C-B) is known to be extensively metabolized in various species including humans. In rat urine, 2C-B was found to be excreted mainly via its metabolites. In the current study, the toxicological detection of these metabolites in the authors' systematic toxicological analysis (STA) procedure was examined. The STA procedure using full-scan GC-MS allowed proving an intake of a common drug abusers' dose of 2C-B by detection of the O-demethyl deaminohydroxy and two isomers of the O-demethyl metabolites in rat urine. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of 2C-B in human urine.

Comparison of Urinary On-Site Immunoassay Screening and Gas Chromatography-Mass Spectrometry Results of 111 Patients With Suspected Poisoning Presenting at an Emergency Department

On-site tests based on immunoassay techniques are widely used for toxicologic screening analysis in patients with suspected poisoning. However, such assays usually have been validated using urine samples with known concentrations of the investigated substances. In the present investigation, on-site screening results were evaluated in a clinical setting. This was a retrospective study of patients with suspected poisoning from January to December 2003 in the emergency department of a tertiary urban hospital. Urine samples were analyzed using the Triage 8 panel and gas chromatography-mass spectrometry (GC-MS). A total of 111 patients were included (54 female, 57 male; average age 37.8 +/- 19.7 years). A total of 3.8% of the patients showed no symptoms, 45.2% minor, 24.0% moderate, and 26.9% serious symptoms. In 50 patients (45.0%), Triage 8 results corresponded well with GC-MS results. In 17 patients (15.3%), the Triage 8 results were confirmed by GC-MS, but additional substances were determined that could not be detected by the Triage 8 panel. A completely negative Triage 8 screening result was obtained in 23 patients (20.7%) who showed toxicologically relevant findings in GC-MS. In 21 patients (18.9%), Triage 8 results could not be confirmed by GC-MS. The analysis of the results in view of the patients' medical histories revealed that in 20 patients (18.0%), no relevant toxic substance could be detected. Additionally, 8 patients (7.2%) showed intoxication with alcohol, which could not be detected by the presently applied toxicologic screening investigations. On-site screening results in suspected poisoning were not very helpful in the present study because practically every second patient ingested substances that were not detectable by the Triage 8 device. In addition, every fifth result was not in line with GC-MS findings. On-site test findings should be interpreted very carefully, and in critical cases, a GC-MS screening should be performed.

Current role of LC–MS(/MS) in doping control

Liquid chromatography-(tandem) mass spectrometry (LC-MS/MS) has revolutionized the detection assays used in doping control analysis over the last decade. New methods have enabled the determination of drugs that were formerly difficult to detect or undetectable at preceding sample concentrations, and complex and/or time-consuming procedures based on alternative chromatographic-mass spectrometric or immunochemical principles have been replaced by faster, more comprehensive and robust assays. A critical overview of the contributions of LC-MS(/MS) to sports drug testing is provided, including recent developments regarding low and high molecular weight drugs.