Simultaneous determination of ofloxacin, norfloxacin and ciprofloxacin in human hair by high-performance liquid chromatography and fluorescence detection

Evaluation of physicochemical properties as supporting information on quality control of raw materials and veterinary pharmaceutical formulations

This study aimed to show that the physicochemical proprieties obtained by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and scanning electronic microscopy (SEM) can be useful tools for evaluating the quality of active pharmaceutical ingredients (APIs) and pharmaceutical products. In addition, a simple, sensitive, and efficient method employing HPLC-DAD was developed for simultaneous determination of lidocaine (LID), ciprofloxacin (CFX) and enrofloxacin (EFX) in raw materials and in veterinary pharmaceutical formulations. Compounds were separated using a Gemini C₁₈ (250 mm × 4.6 mm, 5 µm) Phenomenex^® column, at a temperature of 25 °C, with a mobile phase containing 10 mM of phosphoric acid (pH 3.29): acetonitrile (85.7:14.3, v/v) and a flow rate of 1.5 mL/min. Physicochemical characterization by TG, FTIR, and SEM of raw materials of LID, CFX, and EFX provided information useful for the evaluation, differentiation, and qualification of raw materials. Finally, the HPLC method was proved to be useful for evaluation of raw material and finished products, besides satisfying the need for an analytical method that allows simultaneous determination of EFX, CFX, and LID, which can also be extended to other matrices and applications.

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FTIR, TGA, and SEM are useful tools for the evaluation of the quality of APIs.

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A RP-HPLC method was developed and validated for the determination of LID, CFX, EFX.

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The proposed RP-HPLC method showed precise and accurate results in quality control.

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This method can be applied to the analysis of veterinary pharmaceutical products.

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.

Determination of ciprofloxacin in human plasma using high-performance liquid chromatography coupled with fluorescence detection: application to a population pharmacokinetics study in children with severe malnutrition

Clinical pharmacokinetic studies of ciprofloxacin require accurate and precise measurement of plasma drug concentrations. We describe a rapid, selective and sensitive HPLC method coupled with fluorescence detection for determination of ciprofloxacin in human plasma. Internal standard (IS; sarafloxacin) was added to plasma aliquots (200 μL) prior to protein precipitation with acetonitrile. Ciprofloxacin and IS were eluted on a Synergi Max-RP analytical column (150 mm×4.6 mm i.d., 5 μm particle size) maintained at 40°C. The mobile phase comprised a mixture of aqueous orthophosphoric acid (0.025 M)/methanol/acetonitrile (75/13/12%, v/v/v); the pH was adjusted to 3.0 with triethylamine. A fluorescence detector (excitation/emission wavelength of 278/450 nm) was used. Retention times for ciprofloxacin and IS were approximately 3.6 and 7.0 min, respectively. Calibration curves of ciprofloxacin were linear over the concentration range of 0.02-4 μg/mL, with correlation coefficients (r(2))≥0.998. Intra- and inter-assay relative standard deviations (SD) were <8.0% and accuracy values ranged from 93% to 105% for quality control samples (0.2, 1.8 and 3.6 μg/mL). The mean (SD) extraction recoveries for ciprofloxacin from spiked plasma at 0.08, 1.8 and 3.6 μg/mL were 72.8±12.5% (n=5), 83.5±5.2% and 77.7±2.0%, respectively (n=8 in both cases). The recovery for IS was 94.5±7.9% (n=15). The limits of detection and quantification were 10 ng/mL and 20 ng/mL, respectively. Ciprofloxacin was stable in plasma for at least one month when stored at -15°C to -25°C and -70°C to -90°C. This method was successfully applied to measure plasma ciprofloxacin concentrations in a population pharmacokinetics study of ciprofloxacin in malnourished children.

Spectrofluorimetric determination of fluoroquinolones in pharmaceutical preparations

Simple, rapid and highly sensitive spectrofluorimetric method is presented for the determination of four fluoroquinolone (FQ) drugs, ciprofloxacin, enoxacin, norfloxacin and moxifloxacin in pharmaceutical preparations. Proposed method is based on the derivatization of FQ with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 9.0 to yield a yellow product. The optimum experimental conditions have been studied carefully. Beer's law is obeyed over the concentration range of 23.5-500 ng mL(-1) for ciprofloxacin, 28.5-700 ng mL(-1) for enoxacin, 29.5-800 ng mL(-1) for norfloxacin and 33.5-1000 ng mL(-1) for moxifloxacin using NBD-Cl reagent, respectively. The detection limits were found to be 7.0 ng mL(-1) for ciprofloxacin, 8.5 ng mL(-1) for enoxacin, 9.2 ng mL(-1) for norfloxacin and 9.98 ng mL(-1) for moxifloxacin, respectively. Intra-day and inter-day relative standard deviation and relative mean error values at three different concentrations were determined. The low relative standard deviation values indicate good precision and high recovery values indicate accuracy of the proposed methods. The method is highly sensitive and specific. The results obtained are in good agreement with those obtained by the official and reference method. The results presented in this report show that the applied spectrofluorimetric method is acceptable for the determination of the four FQ in the pharmaceutical preparations. Common excipients used as additives in pharmaceutical preparations do not interfere with the proposed method.

Deposition of cannabinoids in hair after long-term use of cannabis

Hair analysis has shown great potential in the detection and control of drug use. Whether an assay is of quantitative value roughly corresponding to the amount of drug consumed, is still a matter of debate. The present investigation was aimed at a possible relationship between the cannabinoid concentration in hair and the cumulative dose in regular users of cannabis. Hair samples from the vertex region of the scalp were obtained from 12 male regular users of cannabis, and 10 male subjects with no experience of cannabis served as controls. None of the subjects had his hair permed, bleached or colored. Cannabis users provided information on drug use such as the current cannabis dose per day, the cumulative cannabis dose of the last 3 months, as well as the frequency of cannabis use during the last year. The concentration of delta-9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in hair was determined using gas chromatography-mass spectrometry. Cannabinoids were present in any hair sample of cannabis users, but were not detectable in control specimens. An increase in the amount of cannabinoids in hair with increasing dose was evident. The concentration of major cannabinoids (sum of THC, CBD and CBN) was significantly correlated to either the reported cumulative cannabis dose during the last 3 months or to the cannabis use during the last 3 months estimated from the daily dose and the frequency per year (r=0.68 or 0.71, p=0.023 or 0.014). A significant relationship between THC and the amount of cannabis used could not be established. As a conclusion, the sum of major cannabinoids in hair of regular users may provide a better measure of drug use than THC.

Analytical pitfalls in hair testing

This review focuses on possible pitfalls in hair testing procedures. Knowledge of such pitfalls is useful when developing and validating methods, since it can be used to avoid wrong results as well as wrong interpretations of correct results. In recent years, remarkable advances in sensitive and specific analytical techniques have enabled the analysis of drugs in alternative biological specimens such as hair. Modern analytical procedures for the determination of drugs in hair specimens - mainly by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) - are reviewed and critically discussed. Many tables containing information related to this topic are provided.

Assessment of enrofloxacin and ciprofloxacin accumulation in pig and calf hair by HPLC and fluorimetric detection

Enrofloxacin is a synthetic bacteriostatic administered in veterinary therapy. It can also be used illegally as a growth promoter to enhance feed efficiency and weight gain. This practice is banned in several countries due to its potential negative effects on the environment and human health. A suitable method for extracting and quantifying enrofloxacin (ENR) and its main metabolite ciprofloxacin (CPR) in cattle and pig hair by high-performance liquid chromatography-fluorimetric detection (HPLC-FLD) had been proposed. ENR and CPR were extracted from hair samples with methanol acidified with trifluoroacetic acid for 24 h at 70 degrees C. The extracts were evaporated and redissolved in the mobile phase before injection. This simplified procedure enabled the detection of both CPR and ENR at ng g-1 levels (limit of detection 4-5 ng g-1) without further purification. Detectable residues of ENR were found in calf and pig hairs after the pharmacological treatment was started. Mean concentrations of quinolone (ENR, CPR) in contaminated hairs ranged from 20 to 2,518 ng g-1 in calves and from 152 to 1,140 ng g-1 in pigs. Hair pigmentation enhanced quinolone accumulation significantly. Hair analysis seems to increase the time window available for the retrospective detection of illegal ENR administration compared to edible tissue analysis.

State of the art in hair analysis for detection of drug and alcohol abuse

Hair differs from other materials used for toxicological analysis because of its unique ability to serve as a long-term storage of foreign substances with respect to the temporal appearance in blood. Over the last 20 years, hair testing has gained increasing attention and recognition for the retrospective investigation of chronic drug abuse as well as intentional or unintentional poisoning. In this paper, we review the physiological basics of hair growth, mechanisms of substance incorporation, analytical methods, result interpretation and practical applications of hair analysis for drugs and other organic substances. Improved chromatographic-mass spectrometric techniques with increased selectivity and sensitivity and new methods of sample preparation have improved detection limits from the ng/mg range to below pg/mg. These technical advances have substantially enhanced the ability to detect numerous drugs and other poisons in hair. For example, it was possible to detect previous administration of a single very low dose in drug-facilitated crimes. In addition to its potential application in large scale workplace drug testing and driving ability examination, hair analysis is also used for detection of gestational drug exposure, cases of criminal liability of drug addicts, diagnosis of chronic intoxication and in postmortem toxicology. Hair has only limited relevance in therapy compliance control. Fatty acid ethyl esters and ethyl glucuronide in hair have proven to be suitable markers for alcohol abuse. Hair analysis for drugs is, however, not a simple routine procedure and needs substantial guidelines throughout the testing process, i.e., from sample collection to results interpretation.

Analysis of antibiotics in urine and wipe samples from environmental and biological monitoring—Comparison of HPLC with UV-, single MS- and tandem MS-detection

Results of the simultaneous determination of the structurally different antibiotics cefazoline, cefotiame, cefuroxime, chloramphenicol, ciprofloxacin, ofloxacin, sulfamethoxazole and trimethoprim from environmental and biological monitoring using high-performance liquid chromatography with UV, single mass and tandem mass spectrometry were compared. For sample enrichment and clean-up a SPE method using bakerbond C18 cartridges was developed. Mean recovery rates were above 70%. Because of the complex urine matrix, only the wipe samples could be analyzed by UV-detection. However, UV-detection and single MS-detection are useful for control measurements after spillage, e.g. (LOD=1-2 ng/cm(2)). Samples from biological monitoring of occupational uptake should be analyzed by LC-MS/MS. The limits of detection (LOD) in urine ranged from 0.4 to 70 microg/L for LC-MS and 0.01 to 0.9 microg/L for LC-MS/MS detection. The limits of detection in wipe samples ranged from 0.003 to 0.13 ng/cm(2).

Spectrofluorimetric study of the charge-transfer complexation of certain fluoroquinolones with 7,7,8,8-tetracyanoquinodimethane

Simple, rapid and sensitive spectrofluorimetric methods are described, for the first time, for the determination of ciprofloxacin (CIP), norfloxacin (NOR), pefloxacin (PEF) and fleroxacin (FLE). The methods are based on the charge-transfer (CT) reaction of these drugs as n-electron donors with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as pi-electron acceptor. TCNQ was found to react with these drugs to produce intensely transfer reaction complexes and the fluorescence intensity of the complexes was enhanced in 21-35 fold higher than that of the studied fluoroquinolones itself. The formation of such complexes was also confirmed by both infrared and ultraviolet-visible measurements. The different experimental parameters that affect the fluorescence intensity were carefully studied. At the optimum reaction conditions, the drug-TCNQ complexes showed excitation maxima ranging from 277 to 284 nm and emission maxima ranging from 451 to 458 nm. Rectilinear calibration graphs were obtained in the concentration range of 0.03-0.9, 0.04-1.2, 0.04-1.3 and 0.08-2.4 microg ml(-1) for CIP, NOR, PEF and FLE, respectively. The developed methods were applied successfully for the determination of the studied drugs in their pharmaceutical dosage forms with a good precision and accuracy compared to official and reported methods as revealed by t- and F-tests.

High-performance liquid chromatographic analysis of beta-carbolines in human scalp hair

A chromatographic method was studied for the quantitation of beta-carbolines in hair as potent biomarkers. Under optimal conditions, human scalp hair was enzymatically digested to release analytes effectively. The hair digests were treated with fluorescamine before serial extractions to inhibit the artifactual production of beta-carbolines during analysis and purify them selectively, followed by reversed-phase high-performance liquid chromatography with fluorometric detection. Hair samples were found to contain beta-carboline and 1-methyl-beta-carboline, which were identified by tandem mass spectrometry, but not their reduced form 1,2,3,4-tetrahydro-beta-carboline and 1-methyl-1,2,3,4-tetrahydro-beta-carboline. Both beta-carboline and 1-methyl-beta-carboline were quantified in the concentration range of 0.1-10.0 ng/ml. Their mean recoveries from hair digests were 70-72%, and the intra- and inter-assay RSD ranged between 6.0 and 10.3% in spiking experiments with standards (1.0 ng/ml). When quantitatively analyzing scalp hair collected from alcoholics, smokers, non-smokers and autistics, beta-carboline and 1-methyl-beta-carboline showed the concentrations of ng/mg levels or less which characterized different hair samples. The proposed method will be useful for detecting the in vivo concentration changes of beta-carbolines associated with alcohol abuse, smoking behavior and neuropsychiatric disorder.

Detection of enrofloxacin and its metabolite ciprofloxacin in equine hair

Hair analysis to detect drug administration has not been studied extensively in horses. This study aimed to (a) develop an analytical method for enrofloxacin and its metabolite ciprofloxacin in mane and tail hair, (b) relate measured values to doses, routes of administration, hair colour, and (c) demonstrate long-term detectability. Samples were extracted in trifluoroacetic acid at 70 degrees C. Extracts were cleaned-up by solid-phase extraction and analysed by high-performance liquid chromatography with UV-diode array detection. Analyte recoveries were > 87%. Horses were sampled after therapeutic enrofloxacin administration either orally at 7.5 mg/kg daily for 3-13 days or twice daily for 10-14 days (Group 1, n=7) or intravenously at 5.0 mg/kg daily for 12 and 15 days (Group 2, n=2). Enrofloxacin and ciprofloxacin were detected at concentrations up to 452 and 19 ng/mg, respectively, up to 10 months post-treatment. In vitro, enrofloxacin and ciprofloxacin were extensively bound to melanin (> 96%) and in vivo, their uptake was 40-fold greater in black than white hair. Enrofloxacin and ciprofloxacin concentrations correlated to enrofloxacin dose (r2=0.777 and r2=0.769). Enrofloxacin:ciprofloxacin ratios were 21:1 and 13:1 following intravenous and oral administration, respectively. Longitudinal analyte distributions correlated to treatment-sampling interval.

Fluorescence spectroscopy determination of fluoroquinolones by charge-transfer reaction

The charge-transfer (CT) reaction between chloranilic acid (CL) as a pi-electron acceptor and lomefloxacin (LOM), fleroxacin (FLX), ciprofloxacin (CPFX), norfloxacin (NOR) as electron donor have been studied by fluorimetry. The CT complexes have stable purple color in acetone solution and the fluorescence intensity of the CT complexes was enhanced in 4-14 fold higher than that of the four fluoroquinolones (FQS) itself, therefore a new spectrofluorimetric method with simple, rapid, accurate, high sensitivity and good selectivity for determination of the four FQS has been developed. The method was applied for determination of drugs (LOM, FLX, CPFX and NOR) in tablets with mean percentage accuracies 99.80+/-1.12, 99.93+/-0.92, 99.23+/-1.36 and 99.87+/-0.81, respectively.

Simple high-performance liquid chromatographic assay for the determination of ciprofloxacin in human plasma with ultraviolet detection

A simple high-performance liquid chromatographic method is described for the quantitative analysis of ciprofloxacin in human plasma. Following protein precipitation from plasma by means of 6% perchloric acid, the upper layer which contains the analyte and the internal standard lomefloxacin, was analysed on a reverse phase column LiChrospher 60 RP-select B (5 microm) (EcoCART 125-3) with ultraviolet detection at 280 nm. The mobile phase was acetic acid 5%-methanol-acetonitrile (90:5:5, v/v/v). The assay was linear for ciprofloxacin over the concentration range of 0.050 to 6.00 microg ml(-1). The limit of quantification (LOQ) was 0.050 microg ml(-1). The method was successfully applied to a bioavailability study with five different ciprofloxacin formulations.

The concentration of three anti-seizure medications in hair: the effects of hair color, controlling for dose and age

BACKGROUND

This paper assess the relationship between the quantity of three anti-seizure medications in hair and the color of the analyzed hair, while controlling for the effects of dose, dose duration, and patient age for 140 clinical patients undergoing anti-seizure therapy. Three drugs are assessed: carbamazepine (40 patients), valproic acid (40 patients), and phenytoin (60 patients). The relationship between hair assay results, hair color, dose, dose duration, and age is modeled using an analysis of covariance. The covariance model posits the hair assay results as the dependent variable, the hair color as the qualitative categorical independent variable, and dose, dose duration, and age as covariates. The null hypothesis assessed is that there is a no relationship between hair color and the quantity of analyte determined by hair assay such that darker colored hair will demonstrate higher concentrations of analyte than lighter colored hair.

RESULTS

The analysis reveals that there is a significant relationship between dose and concentration for all hair color categories independent of the other covariates or the categorical independent variable.

CONCLUSION

There does not appear to be any relationship between carbamazepine concentration and hair color. There is a weak relationship between hair color and valproic acid concentration, which the data suggest may be mediated by age. There is a significant, moderate relationship between phenytoin concentration and hair color such that darker colored hair has greater concentration values than lighter colored hair.

Hair analysis for abused and therapeutic drugs

This review focuses on basic aspects and recent studies of hair analysis for abused and therapeutic drugs and is discussed with 164 references. Firstly, biology of hair and sampling of hair specimens have been commented for the sake of correct interpretation of the results from hair analysis. Then the usual washing methods of hair samples and the extraction methods for drugs in hair have been shown and commented on. Analytical methods for each drug have been discussed by the grouping of three analytical methods, namely immunoassay, HPLC-CE and GC-MS. The outcomes of hair analysis studies have been reviewed by dividing into six groups; morphine and related, cocaine and related, amphetamines, cannabinoids, the other abused drugs and therapeutic drugs. In addition, reports on stability of drugs in the living hair and studies on drug incorporation into hair and dose-hair concentration relationships have been reviewed. Applications of hair analysis to the estimation of drug history, discrimination between OTC drug use and illegal drug use, drug testing for acute poisoning, gestational drug exposure and drug compliance have also been reviewed. Finally, the promising prospects of hair analysis have been described.

Testing hair for pharmaceuticals

More than hundred pharmaceuticals, drugs of abuse or doping agents have been reported to be detectable in human hair. This article reviews the analysis of 90 drugs and drug metabolites by chromatographic procedures, including the pretreatment steps, the extraction methods, the reported limits of detection and the measured concentrations in real human hair samples. Some progress is observed in the detection of low dose drugs, like fentanyl or flunitrazepam. The general tendency in the last years, to highly sophisticated techniques (GC-MS-NCI, HPLC-MS, GC-MS-MS) illustrates well this constant fight for sensitivity. Some new findings, based on the recent experience of the authors, are also added.

A reproducible, simple, and sensitive high-performance capillary electrophoresis method for simultaneous determination of capreomycin, ofloxacin and pasiniazide in urine

Separation and determination of capreomycin (Cp), ofloxacin (Oflx) and pasiniazide (Ipa) in urine by high-performance capillary electrophoresis (HPCE) with 280 nm detection have been studied systematically. The calibration lines were linear in the range of 0.5 approximately 50 mg 1(-1), and the detection limits (S/N = 3) were 0.15, 0.20 and 0.10 mg 1(-1) for Cp, Oflx and Ipa, respectively. The recoveries for these materials from urine were higher than 93.5%. The accuracy and intra- and inter- day reproducibility of Cp, Oflx and Ipa were determined with satisfactory results. This method was successfully used for determining Cp. Oflx and Ipa in human urine.

Analysis of fluoroquinolones in biological fluids by high-performance liquid chromatography

High-performance liquid chromatographic methods for the analysis of fluoroquinolones in biological fluids are reviewed. In particular, sample preparation and handling procedures, chromatographic conditions, and detection methods are discussed. A summary of published high-performance liquid chromatographic assays for individual fluoroquinolones is included.

Comparative dispositions of ofloxacin in human head, axillary, and pubic hairs

The distribution of ofloxacin (OFLX) along the shaft of each of three hair types, i.e., head, axillary and pubic, was investigated and compared among five healthy male volunteers 1 to 4 months after ingestion of OFLX for 1 or 2 days (total dose, 200 or 600 mg). Five strands of each hair type were sectioned together into successive 0.5-cm lengths starting from the dermal end, over a length of < or = 6 cm, and the OFLX concentration in each hair section was measured by high-pressure liquid chromatography with fluorescence detection. The distribution of OFLX along the head hair shaft was narrow, having a single peak even 3 to 4 months after administration, suggesting a rather uniform growth rate among hair strands. On the other hand, the OFLX distribution along axillary or pubic hair shafts tended to be broad, even having two apparent peaks, and the growth rate did not seem uniform. Since axillary hair seemed to stop growing after having gained a length of < or = 4 to 5 cm, it was suggested to enter a resting stage after the growth of < or = 3 cm over the 2 to 4 months after OFLX incorporation. These findings indicate that head hair is the most suitable for analysis of individual drug use and the larger growth rate and cycle stage variabilities of strands of the other types of hair should be taken into account.

Determination of BAY 12-8039, a new 8-methoxyquinolone, in human body fluids by high-performance liquid chromatography with fluorescence detection using on-column focusing

A reversed-phase (RP) high-performance liquid chromatographic (HPLC) method with fluorescence detection allowing the sensitive and specific quantification of BAY 12-8039, a new antimicrobially active 8-methoxyquinolone, in biological fluids is described. The method is compared to a microbiological assay (bioassay) based on B. subtilis test strain with a limit of quantification of approximately 60 microg/l. Following dilution and centrifugation, plasma, saliva or urine supernatant is directly injected onto the HPLC system. Concentrations down to a limit of quantification of 2.5 microg/l can be quantified in plasma, saliva and urine. Data on recovery, accuracy and precision of the method throughout the whole working range as well as results on stability of the analyte are presented. The concentration data are correlated with results from the bioassay. BAY 12-8039 is stable in plasma after repeated freeze-thaw cycles and following storage at -20 degrees C for at least 12 months. The results of HPLC measurements excellently agree with bioassay data indicating the relevance of the method as a tool in clinical development to answer pharmacokinetic questions related to antimicrobial activity. The method was applied to human plasma, saliva and urine from subjects after a single oral dose of 400 mg of BAY 12-8039.

Simultaneous quantification of cefotaxime, desacetylcefotaxime, ofloxacine and ciprofloxacine in ocular aqueous humor and in plasma by high-performance liquid chromatography

Cefotaxime, given intravenously, is currently used as a broad-spectrum antibiotic for prophylaxis of intra- and postoperative infections in ocular lens surgery. A proposed therapeutic and economic alternative is the use of orally active fluoroquinolone ofloxacine as prophylactic agent. A HPLC method was developed for determination of both antibiotics in ocular aqueous humor and plasma in order to optimize dosage for safe surpassing minimal inhibitory concentration in the humor compartment. For plasma determinations a solid-phase extraction procedure was used with ciprofloxacine as internal standard. Detection limits for direct HPLC-analysis of ocular aqueous humor was 0.08 microg/ml for all compounds, whereas in plasma 0.31 microg/ml could be determined after solid-phase extraction.

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

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