Determination of 1,4-benzodiazepines and their metabolites by capillary electrophoresis and high-performance liquid chromatography using ultraviolet and electrospray ionisation mass spectrometry

Investigation of midazolam electro-oxidation on boron doped diamond electrode by voltammetric techniques and density functional theory calculations: Application in beverage samples

Midazolam (MID) is a sedative drug which can be added in beverage samples as drug-facilitated-sexual assault (date rape drug). This type of drug has short half-life in biological fluids (not detectable) which often prevents the correlation between drug abuse and crime. In this work, we described a simple and low-cost method for fast screening and selective determination of MID in beverage samples (vodka, whiskey and red wine). For the first time, the electrochemical oxidation of MID was used for this purpose. The oxidation mechanism was studied using electrochemical techniques (cyclic and square-wave voltammetry) and computational simulations (density functional theory calculations). Differential-pulse voltammetry, boron-doped diamond electrode (BDDE), and Britton-Robinson (BR) buffer (pH = 2) were selected as electrochemical analysis technique, working electrode and supporting electrolyte, respectively. Different linear response ranges (4-25 μmol L^-1 with r = 0.9972; 1-10 μmol L^-1 with r = 0.9951; 1-15 μmol L^-1 with r = 0.9982) and limits of detection (0.46, 0.43 and 0.33 μmol L^-1) were obtained for the analysis of vodka, whisky, and red wine solutions, respectively. The precision and accuracy were satisfactory considering the low relative standard deviation values (RSD < 6.3%, n = 15) and minimal sample matrix effects (recovery values between 87 and 103%).

A Molecular Imprinted Polymer as a Flow-Through Optical Sensor for Oxazepam

A flow-through optosensing system for oxazepam recognition with fluorescence detection was performed by means of a molecular imprinted polymer based on its acid hydrolysis product, 2-amino-5-chlorobenzophenone. The synthesis was conducted via a noncovalent imprinting methodology, using methacrylic acid as a functional monomer and ethylene glycol dimethacrylate as a cross-linking agent. Hydrolysis (types and concentration of acids), polymer retention capacity, binding properties, and elution (selectivity and reversibility) conditions were optimized. The selected molecular imprinted polymer had a molar ratio composition of 1 : 6 : 45 (template : functional monomer : cross-linker). The proposed method was applied to the determination of oxazepam in a pharmaceutical formulation. External standard calibration, standard additions calibration, and Youden's calibration were carried out in order to evaluate constant and proportional errors due to the matrix. The developed metabolite-based recognition system for benzodiazepines is an innovative procedure that could be followed in routine and quality control assays.

Hair as a Biological Indicator of Drug Use, Drug Abuse or Chronic Exposure to Environmental Toxicants

In recent years hair has become a fundamental biological specimen, alternative to the usual samples blood and urine, for drug testing in the fields of forensic toxicology, clinical toxicology and clinical chemistry. Moreover, hair-testing is now extensively used in workplace testing, as well as, on legal cases, historical research etc. This article reviews methodological and practical issues related to the application of hair as a biological indicator of drug use/abuse or of chronic exposure to environmental toxicants. Hair structure and the mechanisms of drug incorporation into it are commented. The usual preparation and extraction methods as well as the analytical techniques of hair samples are presented and commented on. The outcomes of hair analysis have been reviewed for the following categories: drugs of abuse (opiates, cocaine and related, amphetamines, cannabinoids), benzodiazepines, prescribed drugs, pesticides and organic pollutants, doping agents and other drugs or substances. Finally, the specific purpose of the hair testing is discussed along with the interpretation of hair analysis results regarding the limitations of the applied procedures.

A new chemiluminescence method for determination of clonazepam and diazepam based on 1-Ethyl-3-Methylimidazolium Ethylsulfate/copper as catalyst

A novel chemiluminescence (CL) reaction, Benzodiazepines-H2O2-1-Ethyl-3-Methylimidazolium Ethylsulfate/copper, for determination of clonazepam and diazepam at nanogram per milliliter level in batch-type system have been described. The method relies on the catalytic effect of 1-Ethyl-3-Methylimidazolium Ethylsulfate/copper on the chemiluminescence reaction of Benzodiazepines, the oxidation of Benzodiazepines with hydrogen peroxide in natural medium. The influences of various experimental parameters such as solution pH, the ratio of 1-Ethyl-3 Methylimidazolium ethylsulfate concentration to copper ion, the type of buffer and the concentration of CL reagents were investigated. Under the optimum condition, the proposed method was satisfactorily applied for the determination of these drugs in tablets and urine without the interference of their potential impurities.

Benzodiazepines: sample preparation and HPLC methods for their determination in biological samples

Benzodiazepines (BDZs) belong to a group of substances known for their sedative, antidepressive, muscle relaxant, tranquilizer, hypnotic and anticonvulsant properties. Their determination in biological fluids is essential in clinical assays as well as in forensics and toxicological studies. Researchers focus on the development of rapid, accurate, precise and sensitive methods for the determination of BDZs and their metabolites. A large number of analytical methods using different techniques have been reported, but none can be considered as the method of choice. BDZs are usually present at trace levels (microgram or nanogram per milliliter) in a complex biological matrix and the potentially interfering compounds must be isolated by various extraction techniques before analysis. An extended and comprehensive review is presented herein, focusing on sample preparation (pretreatment and extraction) and HPLC conditions applied by different authors. These methods enable bioanalysts to achieve detection limits down to 1-2 ng/ml using UV/diode array detection, readily available in most laboratories, and better than 1 ng/ml using electron capture detection, which is lower than that obtained using a nitrogen phosphorus detector. MS interfaced with electrospray ionization offered a similar sensitivity, while negative chemical ionization MS or sonic spray ionization MS provided sensitivity down to 0.1 ng/ml.

A comparative study of UV-spectrophotometry and first-order derivative UV-spectrophotometry methods for the estimation of diazepam in presence of Tween-20 and propylene glycol

Nonionic surfactants like polysorbates (Tweens) and co-surfactant like propylene glycol are used in pharmaceutical dosage forms, like microemulsion of diazepam. These additives interfere significantly with the estimation of diazepam by UV spectrophotomery method. The aim of this work was to develop a first-order derivative UV-spectrophotometry method that can estimate diazepam in presence of Tween-20 and propylene glycol. The experimental results clearly suggested that, in comparison with the UV-spectrophotometry method, the first-order derivative UV-spectrophotometry is a simple method to estimate diazepam with sufficient accuracy, specificity, and precision even in the presence of 282-times Tween-20 and 2,072-times propylene glycol.

Comparison of molecularly imprinted solid-phase extraction (MISPE) with classical solid-phase extraction (SPE) for the detection of benzodiazepines in post-mortem hair samples

This preliminary study compares the benzodiazepine results for 10 post-mortem scalp hair samples using a classical solid-phase extraction (SPE) and a molecularly imprinted solid-phase extraction (MISPE) system. The hair samples selected for testing were from drug-related deaths where a positive benzodiazepine blood result was obtained. Samples were decontaminated with 0.1% sodium dodecyl sulfate, distilled water and dichloromethane, incubated overnight in methanol/25% aqueous ammonium hydroxide (20:1), extracted by SPE or MISPE and subsequently analysed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Both extraction methods detected diazepam, nordiazepam, oxazepam, temazepam and nitrazepam in the samples. Diazepam was detected in a greater number of samples using MISPE due to both its lower limit of detection (LOD) and higher extraction recovery as a result of excellent molecular recognition of the template (diazepam) imparted by the imprinting process. The selective recognition of two diazepam analogues, nordiazepam and oxazepam, was demonstrated using MISPE since they were also detected in a greater number of samples. In contrast, another diazepam analogue, temazepam, was detected in a greater number of samples using SPE since the LOD using this extraction was lower than with MISPE. Nitrazepam was detected in one sample using both extraction methods. Overall the MISPE and SPE hair results were in good qualitative agreement. For the samples, where both extraction methods detected nordiazepam, temazepam and oxazepam, the concentrations were always higher for SPE. This is probably due to the MIP procedure producing extracts with fewer matrix interferences than the extracts produced using the classical SPE method. MISPE could be used as a complementary method to classical SPE for the analysis of benzodiazepine positive hair samples collected from chronic users.

A rapid CZE method for the analysis of benzodiazepines in spiked beverages

A rapid CZE method was developed for the simultaneous determination of nine benzodiazepines in spiked beverages (nitrazepam oxazepam, alprazolam, flunitrazepam, temazepam, diazepam, 7-aminoflunitrazepam, 7-aminonitrazepam and 7-aminoclonazepam). The method employed a double-coated capillary coated with poly(diallyldimethylammonium chloride) and then dextran sulphate. The BGE conditions were 100 mM ammonium phosphate buffer, pH 2.5, which gave baseline resolution between consecutive peaks and a run time of less than 6.5 min. This method offers improvements in both resolution and run time, compared to those attained under analogous conditions with an uncoated capillary. The validated method was successfully applied to beverages that had been spiked with benzodiazepines at concentrations simulating prescription tablets. No sample pretreatment was required to quantify five benzodiazepines in Coca-Cola, orange juice, beer, bourbon and Bacardi. The exception was white wine, where the complex sample matrix did not enable the accurate quantification of nitrazepam.

Development of a validated HPLC method for the determination of four 1,4-benzodiazepines in human biological fluids

A simple and sensitive HPLC method was developed and validated for the determination of four frequently prescribed 1,4-benzodiazepines: alprazolam (ALP), bromazepam (BRZ), diazepam (DZP), and flunitrazepam (FNZ). Separation was achieved on an Inertsil C8 analytical (250 mm x 4 mm, 5 microm) column, after selective extraction of benzodiazepine drugs from biological matrices by means of SPE. Isocratic elution was performed with a mobile phase consisting of CH3COONH4, 0.05 M CH3OH, and CH3CN (33:57:10 by volume). Quantification was performed at 240 nm with mefenamic acid (6 ng/microL) as the internal standard. DSC-18 Supelco cartridges provided high absolute recoveries (81-115%). The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 8) and between-day precision (n = 8) revealed RSD <12%. Recoveries from biological samples ranged from 81.2 to 115%. The detection limit of the method was calculated as 3.3-10.2 ng in blood plasma and 2.6-12.6 ng in urine for 20 microL injection volume. The method was applied to spiked biological matrices. Moreover, the method was applied to real samples of urine after an oral administration.

Separation of 1,4-benzodiazepines by micellar elektrokinetic capillary chromatography

In this work the applicability of micellar elektrokinetic capillary chromatography (MECC) for the determination of benzodiazepines (BZD) has been studied. The applied method was used for the simultaneous separation of 8 BZDs (alprazolam, bromazepam, chlordiazepoxide, diazepam, flunitrazepam, medazepam, oxazepam, nitrazepam), and also for the study of stability in acidic medium. A fast and reliable method has been developed; using a separation buffer composed of sodium tetraborate 25 mM (pH 9.5), SDS (50 mM) and methanol (at least 12%) as an organic modifier.

Molecularly Imprinted Solid-Phase Extraction of Diazepam and Its Metabolites from Hair Samples

An anti-diazepam, molecularly imprinted polymer (MIP) has been synthesized and used to extract diazepam and other benzodiazepines from hair samples via a molecularly imprinted solid-phase extraction (MISPE) protocol. Optimum retention of diazepam on the MIP columns was achieved using an apolar solvent, and the binding capacity of the polymer toward diazepam was found to be 110 ng of diazepam/mg of polymer. The recovery of a 50 ng diazepam standard spiked into blank hair was 93%, with good precision (RSD = 1.5%). The LOD and LOQ of diazepam in spiked hair samples were 0.09 and 0.14 ng/mg, respectively. The MISPE method was demonstrated to be applicable to the analysis of diazepam metabolites and other benzodiazepine drugs, in addition to diazepam itself. The application of the extraction method to postmortem hair samples yielded results that were in good agreement with the corresponding ELISA data (from blood samples) and data arising from the analysis of the same blood samples using a validated in-house SPE-LC-MS-MS method.

CE as orthogonal technique to HPLC for alprazolam degradation product identification

The control of degradation products is currently a critical issue to the pharmaceutical industry. A degradation product that appeared in alprazolam tablets during their stability assay, 7-chloro-1-methyl-5-phenyl-[1,2,4]triazolo[4,3-a]quinolin-4-amine, also named triazolaminoquinoline, was tested as possible candidate in the HPLC method employed for the study. The impurity showed the same retention time and spectra as the degradation product; but as all these compounds are very closely related, a confirmation with an independent technique was necessary, and CE was chosen for that purpose. Problems related to the adsorption of the analytes to the negatively charged silica surface were solved by employing a new polymeric capillary coating consisting of poly(3-aminopropylmethylsiloxane). The polymer provided EOF towards the anode, and the two compounds were separated in less than 8 min in a 60 cm total-length capillary, 75 microm id capillary with a BGE containing 50 mM phosphate buffer at pH 2.0 with 20% ACN. When the sample containing the degradation product was injected, the presence of triazolaminoquinoline was confirmed.

Liquid Chromatography–Tandem Mass Spectrometry for Detection of Low Concentrations of 21 Benzodiazepines, Metabolites, and Analogs in Urine: Method with Forensic Applications

Background: Commonly used methods for detecting benzodiazepines (BZPs) and BZP-like substances, such as zolpidem and zopiclone, may not detect low concentrations of these drugs. We developed a liquid chromatographic–tandem mass spectrometric method for identifying these drugs and their relevant metabolites.

Methods: We extracted BZPs from urine by solid-phase extraction with a mixed-mode phase (OASIS® HLB cartridges). Chromatographic separation was performed with a Waters XTerra MS C18 [150 × 2.1 mm (i.d.); bead size, 5 μm] reversed-phase column with deuterated analogs of the analytes as internal standards (IS). Detection was performed with a triple-quadruple mass spectrometer that monitored 2 specific transitions per compound in the electrospray, positive-ion selected-reaction monitoring mode. We tested this technique on urine samples from 12 healthy volunteers and 1 forensic sample obtained in a case of alleged drug-facilitated sexual assault.

Results: Chromatographic separation was achieved within 18 min. The linear dynamic ranges extended from 0.02 or 0.1 μg/L (depending on the drug or metabolite) to 50 μg/L. Extraction recovery (range) was 77%–110%. Limits of detection were ≤0.05 μg/L. No ion suppression was seen except for alprazolam, for which baseline decreased by almost 20%. In the forensic urine sample, the method detected alprazolam (3.5 μg/L) and its characteristic metabolite, α-hydroxyalprazolam (0.17 μg/L).

Conclusion: This method measured low concentrations of BZPs and BZP-like substances and might be useful for analyses of urine in suspected drug-facilitated sexual assault cases.

LC–UV and LC–MS evaluation of stress degradation behaviour of avizafone

It has been known for many years that benzodiazepine compounds effectively antagonize seizures induced by organophosphorous nerve agents. In the event of poisoning, a combination of three drugs is commonly used: an anticholinergic drug (e.g. atropine), an oxime used as cholinesterase reactivator (e.g. pralidoxime or HI-6) and an anticonvulsant (i.e. benzodiazepine). Most of anticholinergics and oximes are freely soluble in water, whereas many benzodiazepines are not. However, a water-soluble prodrug form of diazepam, avizafone, has been adopted by French armed forces for the immediate treatment of nerve agent seizure. The degradation behaviour of this new drug was investigated under different stress degradation conditions (hydrolytic, oxidative, photolytic and thermal) as recommended by International Conference on Harmonization. Successful separation of the active pharmaceutical ingredient from decomposition products formed under stress conditions was achieved using liquid chromatography. The method was validated with respect to specificity, linearity, precision and accuracy.

Progress in capillary electrophoresis of biomarkers and metabolites between 2002 and 2005

Biomarker discovery and metabolite research is a fast-growing and extremely important domain not only for the early detection of certain diseases but also for controlling its progress as well as in pharmaceutical investigations. For the analytical separation and identification, CE plays an indisputable role. Capillary systems enhancing different selectivity are applied and connected to different kind of detection systems. As the choice of buffer and its composition is responsible for a successful separation, special emphasis is put on solvent effects in this review. Altogether the most important capillary electrophoretic techniques applied for biomarker and metabolites analysis published between 2002 and 2005 are summarized and discussed.

On-Line Solid-Phase Extraction Coupled With High-Performance Liquid Chromatography and Tandem Mass Spectrometry (SPE-HPLC-MS-MS) for Quantification of Bromazepam in Human Plasma

A validated method for on-line solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (SPE-HPLC-MS-MS) is described for the quantification of bromazepam in human plasma. The method involves a dilution of 300 muL of plasma with 100 muL of carbamazepine (2.5 ng/mL), used as internal standard, vortex-mixing, centrifugation, and injection of 100 muL of the supernate. The analytes were ionized using positive electrospray mass spectrometry then detected by multiple reaction monitoring (MRM). The m/z transitions 316-->182 (bromazepam) and 237-->194 (carbamazepine) were used for quantification. The calibration curve was linear from 1 ng/mL (limit of quantification) to 200 ng/mL. The retention times of bromazepam and carbamazepine were 2.6 and 3.2 minutes, respectively. The intraday and interday precisions were 3.43%-15.45% and 5.2%-17%, respectively. The intraday and interday accuracy was 94.00%-103.94%. This new automated method has been successfully applied in a bioequivalence study of 2 tablet formulations of 6 mg bromazepam: Lexotan(R) from Produtos Roche Químicos e Farmacêuticos SA, Rio de Janeiro, Brazil (reference) and test formulation from Laboratórios Biosintética Ltda, São Paulo, Brazil. Because the 90% CI of geometric mean ratios between reference and test were completely included in the 80%-125% interval, the 2 formulations were considered bioequivalent. The comparison of different experimental conditions for establishing a dissolution profile in vitro along with our bioavailability data further allowed us to propose rationally based experimental conditions for a dissolution test of bromazepam tablets, actually lacking a pharmacopeial monograph.

Comparison of CZE, MEKC, MEEKC and non-aqueous capillary electrophoresis for the determination of impurities in bromazepam

The purpose of the present investigation was to develop a test for related substances in the benzodiazepine drug substance bromazepam based on capillary electrophoresis (CE). A final method for the determination of impurities in bromazepam is based on non-aqueous capillary electrophoresis (NACE). Five modes of capillary electrophoresis were investigated and compared for the said purpose. All the CE systems investigated make use of running buffers at low pH in order to protonate the analytes. A low pH of the running buffers was needed as the pK(a) values of benzodiazepines in general are in the range from 1.3 to 4.6. Dynamically coated capillaries were used to overcome the low electro-osmotic flow at low pH in the aqueous buffers investigated. CZE with and without dynamical coating of the internal surface of the fused capillaries was compared and also micellar electrokinetic chromatography (MEKC) as well as microemulsion electrokinetic chromatography (MEEKC) performed in dynamically coated capillaries were investigated. The NACE was chosen as the best technique as the low solubility of the benzodiazepines in water is easily overcome. The NACE system showed good selectivity and detectability for the substances investigated and the limit of quantitation for the impurities corresponded to 0.05% of the drug substance. Linearity was good.

Comparison of capillary electrophoresis and reversed-phase liquid chromatography methodologies for determination of diazepam in pharmaceutical tablets

Two novel analytical methodologies using capillary electrophoresis (CE) and reversed-phase high-performance liquid chromatography (RP-HPLC) for the determination of diazepam in commercial and simulated tablet formulations were developed and compared. The CE analysis was carried out in a bare fused-silica capillary with 75 microm i.d. and total length of 50 cm (28 cm to the detector) with a buffer solution containing 20 mmol L(-1) sodium tetraborate and 20 mmolL(-1) sodium dodecylsulfate (SDS), pH 9.23. The applied voltage was 20 kV and bromazepam was used as internal standard (IS). The RP-HPLC analysis was carried out in a LiChrospher((R)) 100 RP-18 (5 microm) column with a mobile phase constituted of methanol, acetonitrile and water (45:25:30) with a flow rate of 0.8 mL/min, using acetaminophen as IS. In both cases, detection was carried out by ultraviolet (UV) absorption at 242 nm. Under the optimized conditions, the CE retention times for the standard diazepam and bromazepam (IS) were 4.08 and 3.43 min, respectively, and the retention times of the RP-HPLC analysis for the standard diazepam and acetaminophen (IS) were 4.86 and 1.58 min, respectively. The resolution and efficiency for CE were 7.4 and 1.18 x 10(5)plates/m and for RP-HPLC, 7.5 and 1.76 x 10(4) plates/m. Analytical curves of peak area versus concentration presented correlation coefficients of 0.9996 for CE and 0.9994 for RP-HPLC. The limits of detection (LOD) and quantitation (LOQ) were 4.24 and 12.85 microg/mL for CE and 1.44 and 4.36 microg/mL for RP-HPLC. Relative standard deviations (R.S.D.) were 1.62 and 0.98% for CE and RP-HPLC, respectively. The percentage recovery determined with CE was 100.27+/-1.25 and with RP-HPLC was 101.12+/-2.48. Although both methodologies were shown to be suitable for the determination of diazepam in tablets, performing in a similar manner with regards to several aspects (linearity, recovery and specificity), CE provided a faster analysis and column efficiency whereas RP-HPLC presented a superior repeatability and sensitivity.

Analysis of Benzodiazepines in Dynamically Coated Capillaries by CE-DAD, CE-MS and CE-MS2

The applicability of a low pH volatile electrolyte for fast analysis of benzodiazepines with CE-MS was investigated. The electrolyte is based on a commercially available CEofix buffer system that produces a substantial and highly reproducible electroosmotic flow through a dynamic double coating principle. The system was first evaluated with a mixture of benzodiazepine standards in CE-DAD and the electrolyte composition was further optimized for CE-MS. The LOD for the six selected benzodiazepines with CE-MS was ca. 100 ppb, except for diazepam, for which the LOD was lower than 50 ppb. RSDs varied from 0.51 to 1.02% (n = 7) for migration times and from 4.75 to 11.80% (n = 7) for peak areas. The method was successfully applied to the analysis of a spiked urine sample after solid-phase extraction (SPE). CE-MS2 was performed on a standard mixture.

Analysis of glyphosate and glufosinate by capillary electrophoresis-mass spectrometry utilising a sheathless microelectrospray interface

The potential of capillary electrophoresis combined with mass spectrometry for the simultaneous determination of two herbicides (glyphosate and glufosinate) and their metabolites (aminomethylphosphonic acid and methylphosphinicopropionic acid) as the native species is demonstrated utilising a simple microelectrospray interface. The interface uses the voltage applied to the CE capillary to drive separation and generate the electrospray, avoiding sample dilution associated with the use of a sheath liquid interface. The chemistry of the internal walls of the capillary has a marked influence on peak shape, and appropriate choice is essential to successful operation of the interface. A linear polyacrylamide coated capillary, which has no electroosmotic flow, gave best reproducibility, with precision of migration time and peak area in the range 1-2 and 7-12% RSD, respectively, for the four analytes. Limits of detection, low-pg on-column, are substantially better than for previous methods and calibration curves over the range 1-100 microM have R2 values greater than 0.97. The observed concentration limit of detection for glyphosate in water is 1 microM and for a water-acetone extract of wheat is 2.5 microM, allowing the underivatised herbicide to be detected at 10% of the maximum residue limit in wheat.

Automated solid-phase extraction and liquid chromatography-electrospray ionization-mass spectrometry for the determination of flunitrazepam and its metabolites in human urine and plasma samples

A sensitive and specific method using reversed-phase liquid chromatography coupled with electrospray ionization-mass spectrometry (LC-ESI-MS) has been developed for the quantitative determination of flunitrazepam (F) and its metabolites 7-aminoflunitrazepam (7-AF), N-desmethylflunitrazepam (N-DMF) and 3-hydroxyflunitrazepam (3-OHF) in biological fluids. After the addition of deuterium labelled standards of F,7-AF and N-DMF, the drugs were isolated from urine or plasma by automated solid-phase extraction, then chromatographed in an isocratic elution mode with a salt-free eluent. The quantification was performed using selected ion monitoring of protonated molecular ions (M+H(+)). Experiments were carried out to improve the extraction recovery (81-100%) and the sensitivity (limit of detection 0.025 ng/ml for F and 7-AF, 0.040 ng/ml for N-DMF and 0.200 ng/ml for 3-OHF). The method was applied to the determination of F and metabolites in drug addicts including withdrawal urine samples and in one date-rape plasma and urine sample.

Capillary electrophoresis and its application in the clinical laboratory

Over the past 10 years, capillary electrophoresis (CE) is an analytical tool that has shown great promise in replacing many conventional clinical laboratory methods, especially electrophoresis and high performance liquid chromatography (HPLC). The main attraction of CE was that it was fast, used small amounts of sample and reagents, and was extremely versatile, being able to separate large and small analytes, both neutral and charged. Because of this versatility, numerous methods for clinically relevant analytes have been developed. However, with the exception of the molecular diagnostic and forensic laboratories CE has not had a major impact. A possible reason is that CE is still perceived as requiring above-average technical expertise, precluding its use in a laboratory workforce that is less technically adept. With the introduction of multicapillary instruments that are more automated, less technique-dependent, in addition to the availability of commercial and cost effective test kit methods, CE may yet be accepted as a instrument routinely used in the clinical laboratories. Thus, this review will focus on the areas where CE shows the most potential to have the greatest impact on the clinical laboratory. These include analysis of proteins found in serum, urine, CSF and body fluids, immunosubstraction electrophoresis, hemoglobin variants, lipoproteins, carbohydrate-deficient transferrin (CDT), forensic and therapeutic drug screening, and molecular diagnostics.

Analysis of certain tranquilizers in biological fluids

A review with 282 references is presented that deals with the reported methods of analysis of phenothiazines, thioxanthenes, and benzodiazepine derivatives of pharmaceutical interest. The review includes the methods adapted in biological fluids.

The simultaneous determination of diazepam and its three metabolites in dog plasma by high-performance liquid chromatography with mass spectroscopy detection

A fast, sensitive and specific LC/MS/MS method for the simultaneous determination of diazepam and its three metabolites, oxazepam, temazepam and desmethyldiazepam, in dog plasma is described. The method consists of an automated 96-well solid phase extraction procedure and electrospray LC/MS/MS analysis. D(5)-Diazepam is used as the internal standard for all the compounds. Intra-day and inter-day assay coefficients of variations are less than 12.7%. The lower limit of quantitation (LLOQ) is 1 nM for each analyte, based on 0.1 ml aliquots of dog plasma. The analytical run time was 5 min. Linearity is observed over the range of 1--500 nM. This method has been used to support the discovery of pharmacokinetic studies.

Pressure-assisted capillary electrophoresis–electrospray ion trap mass spectrometry for the analysis of heparin depolymerised disaccharides

A pressure-assisted capillary electrophoresis-ion trap mass spectrometry method was developed for the analysis of eight heparin-derived disaccharides. A 30 mM formic acid buffer at pH 3.20 was selected as running electrolyte, and the separation was performed by the simultaneous application of a CE voltage of -30 kV and an overimposed pressure of 0.5 p.s.i. (3.45 kPa). The application of pressure assistance was needed to provide stable electrospray conditions for successful coupling. The linearity of the CE-MS and CE-MS-MS methods was checked under these conditions. Quality parameters such as run-to-run precision and limits of detection were established in both CE-MS and CE-MS-MS modes. Finally, enzymatically depolymerised bovine and porcine mucosal heparins were analysed in this CE-MS system and the characteristic relative molar percentages of major and minor disaccharides were calculated.

Liquid chromatography-mass spectrometry as a routine method in forensic sciences: a proof of maturity

The applications of LC-API-MS in routine forensic toxicological casework were presented. This technique has been used for routine determination of several groups of drugs: opiate agonists (like morphine, codeine, dihydrocodeine and their glucuronides, methadone, buprenorphine) cocaine and its metabolites (benzoylecgonine and ecgonine methyl ester), amphetamine and other psychoactive phenethylamines, like MDMA, MDE or MDA, benzodiazepine derivatives (flunitrazepam and metabolites, triazolam, bromazepam), hallucinogens (LSD, psilocybin, psilocin) and olanzapine, A common solid-phase extraction procedure for all drugs (with exception of LSD) has been developed. Among two ionization sources, atmospheric pressure chemical ionization appeared more universal and assured generally higher sensitivity. Only in the case of very polar drugs (e.g. psilocin or psilocybin) electrospray ionization was more sensitive. LC-API-MS became a very powerful and flexible method for dedicated analyses of substances of forensic interest. The use of this technique for general, broad applicable screening depends on the establishing of interlaboratory database of standardized mass spectra.

Liquid chromatography-mass spectrometry in the study of the metabolism of drugs and other xenobiotics

The application of liquid chromatography-mass spectrometry (LC/MS) to the study of metabolism of drugs and other xenobiotics is reviewed. Original research papers covering the period from 1998 to early 2000 and concerning the use of LC/MS in the study of xenobiotic metabolism in humans and other mammalian species are reviewed. LC/MS interfaces, sample preparation steps, column types, mobile phases and additives, and the type of metabolites detected are summarized and discussed in an attempt to identify the current and future trends in the use of LC/MS for metabolism studies. Applications are listed according to the parent xenobiotic type and include substances used in therapeutics, drug candidates, compounds being evaluated in clinical trials, environmental pollutants, adulterants and naturally occurring substances.

Determination of ebrotidine and its metabolites by capillary electrophoresis with UV and mass spectrometry detection

This study describes the application of capillary electrophoresis (CE) to the analysis of ebrotidine and its metabolites as an alternative analytical technique to liquid chromatography. Comparison between UV-diode array spectroscopy and mass spectrometry (MS) using an ion-trap system with electrospray ionization as detection systems has been performed. The quality parameters of the UV detection method were established, obtaining linear calibration curves over the range studied (8-200 mg ml(-1)), limits of detection between 3.4 and 4.3 microg ml(-1), and run-to-run and day-to-day precision lower than 14%. For these compounds the protonated species [M+H]+ and, in some cases, sodium adducts were observed in the MS spectra. Using MS coupled to CE, limits of detection were between 0.5 and 2.6 microg ml(-1).

Qualitative determination of urinary morphine by capillary zone electrophoresis and ion trap mass spectrometry

A rapid, sensitive method for the determination of morphine and amphetamine was developed using capillary zone electrophoresis coupled with electrospray interface (ESI), ion-trap tandem mass spectrometry (CE-ESI-MS2). Morphine and amphetamine were separated in 20 mM ammonium acetate buffer (pH 6.6) and detected by ion-trap mass detector in different analytical time segments (0-6.25 min for amphetamine and 6.25-12.0 min for morphine) in which the tune file for each compound was used separately. Molecular ions of morphine (m/z 286) and amphetamine (m/z 136) were detected at 5.77 and 6.83 min, respectively, while product ions of MS2 for each compound (m/z 229, 201 for morphine and m/z 119 for amphetamine) were detected almost exactly at the same time with their parent compounds. The limits of detection (LOD) for MS2 determination were 30 and 50 ng/mL for amphetamine and morphine, respectively, with an S/N ratio of 3. For more sensitive detection of morphine, the sample was injected for a longer time (i.e., 80 s) and hydrodynamically transported into a CE capillary for MS detection. Morphine and its product ion appear at 0.36 and 0.39 min on the ion chromatogram, respectively, with a five-fold increase of detection sensitivity (LOD, 10 ng/mL). The CE-MS system thus established was further applied for forensic urine samples screened as morphine-positive by fluorescence polarization immunoassay (FPIA). These results indicated the feasibility of CE-ESI-MS2 for confirmative testing of morphine in urine sample.

Electrospray ionisation-mass spectrometric characterisation of selected anti-psychotic drugs and their detection and determination in human hair samples by liquid chromatography-tandem mass spectrometry

Electrospray ionisation quadrupole ion-trap mass spectrometric (ESI-MS) characterisation of the anti-psychotic drugs chlorpromazine, trifluoperazine, flupenthixol, risperidone and the antidepressant/internal standard trimipramine is presented and possible mechanisms for the observed MSn fragmentation patterns proposed. A validated liquid chromatography (LC)-MS-MS method is then applied to the detection and determination of these drugs in the hair of a patient under clinical treatment for schizophrenia. Chlorpromazine, trifluoperazine and flupenthixol are identified and determined in this hair sample following alkaline degradation of the matrix, solvent extraction and LC-MS-MS using trimipramine as internal standard.

The identification and determination of selected 1,4-benzodiazepines by an optimised capillary electrophoresis-electrospray mass spectrometric method

An optimised capillary electrophoresis-electrospray mass spectrometric method is presented for the identification and determination of diazepam and its metabolites N'-desmethyldiazepam, oxazepam and temazepam. By investigating constituent parts of the capillary electrophoresis-electrospray mass spectrometric interface and optimising their function, a relatively fast and reproducible method is described for the identification and determination of selected 1,4-benzodiazepines. Optimisation of sheath and auxiliary gas flows, capillary tip tapering, capillary tip positioning, sheath liquid composition and flow rate and pressure application during the separation step have led to acceptable relative standard deviation (RSD) values for migration time and peak area, correlation coefficients and limits of detection. This has been achieved as a result of stabilising the electrospray current prior to analysis, a procedure that takes a matter of minutes when using the method described. Sequential product ion fragmentation (MS(n)) characterisation of 15 1,4-benzodiazepines is also presented and mechanisms for the observed fragmentation patterns proposed.

A study of the electrospray ionisation of pharmacologically significant 1,4-benzodiazepines and their subsequent fragmentation using an ion-trap mass spectrometer

The electrospray ionisation (ESI) of sixteen pharmacologically significant 1,4-benzodiazepines and their subsequent fragmentation using an ion-trap mass spectrometer have been investigated. Sequential product ion fragmentation experiments (MSn) were performed in order to elucidate the degradation pathways for these compounds. Comparisons were also made between these ESI spectra and those obtained under electron impact (EI) conditions. The data presented in this paper provide useful information on the effect of different substituents on the ionisation/fragmentation processes and can be used in the characterisation of this important class of drugs and their metabolites.