Dried blood spots: Liquid chromatography–mass spectrometry analysis of Δ9-tetrahydrocannabinol and its main metabolites

Quantitative determination by UHPLC-MS/MS of 18 common drugs of abuse and metabolites, including THC and OH-THC, in volumetric dried blood spots: a sustainable method with minimally invasive sampling

The increased use of drugs of abuse urges forensic toxicologists to create quick, simple, minimally invasive sampling techniques for biological fluids combined with analytical methods assuring accurate results. To this purpose, a method was developed aimed at quantifying 18 drugs of abuse and metabolites in DBS. Validation of the method was conducted by spiking blank whole blood with the analytes on Capitainer® B cards. The extracts were analyzed by a targeted UHPLC-MS/MS method. Linear calibration was achieved in the range of 1-100 ng/mL for: amphetamine, MDA, MDMA, methamphetamine, cocaine, codeine, benzoylecgonine, cocaethylene, morphine, 6-MAM, buprenorphine, methadone, EDDP, ketamine, norbuprenorphine norketamine, THC, and OH-THC. Experimental LOD was found at 0.5 ng/mL for all analytes except for norbuprenorphine, THC and THC-OH which yielded a LOD of 1 ng/mL. Intra- and inter-day accuracy was satisfactory with bias% resulting within 5%. Evaluation of intra- and inter-day precision yielded CV% values within 20%, for all compounds except EDDP. Average extraction recovery calculated at low (2 ng/mL) and high (75 ng/mL) concentration levels was 63% while average matrix effect determined at the same levels was found to be within 85% - 115% for all analytes except from codeine (70%) and MDMA (131%). The method was applied to authentic blood samples spotted onto the DBS card and the minimum value detected was 1.3 ng/mL. HPLC-MS/MS proved capable to identify all the targeted analytes at low concentrations in the small blood volumes obtainable from DBS cards, which in turn confirmed to be effective and sustainable micro-sampling devices.

New Trend in Toxicological Screening Using Volumetric Absorptive Microsampling (VAMS) and High-Resolution Mass Spectrometry (HR/MS) Combination

In toxicology, screenings are routinely performed using chromatographic methods coupled to detection systems such as high-resolution mass spectrometry (HR/MS). The increase in specificity and sensitivity of HRMS is responsible for the development of methods for alternative samples such as Volumetric Adsorptive Micro-Sampling. Whole blood overloaded with 90 drugs was sampled with 20 µL Mitra^TM to optimize the pre-analytical step as well as to determine the identification limits of drugs. Elution of chemicals was carried out in a solvent mixture through agitation and sonication. After dissolution, 10 μL was injected into the chromatographic system coupled to the Orbitrap^TM HR/MS. Compounds were confirmed against the laboratory library. The clinical feasibility was assessed in fifteen poisoned patients using the simultaneous sampling of plasma, whole blood and Mitra^TM. The optimized extraction procedure allowed us to confirm 87 compounds out of the 90 present in the spiked whole blood. Cannabis derivatives were not detected. For 82.2% of the investigated drugs, the identification limits were below 12.5 ng·mL^-1, with the extraction yields ranging from 80.6 to 108.7%. Regarding the patients' analysis, 98% of the compounds in plasma were detected in Mitra^TM compared to whole blood, with a satisfying concordance (R² = 0.827). Our novel screening approach opens new insights into different toxicologic fields appropriate for pediatrics, forensics or to perform mass screening.

Development and validation of an LC-MS/MS assay for the quantitative analysis of alprazolam, α-hydroxyalprazolam and hydrocodone in dried blood spots

Dried blood spot (DBS) has been used as an alternative matrix in drug testing. In forensic testing it offers enhanced stability of analytes and ease of storage that requires minimal space. This is compatible with long term archiving of large numbers of samples for future investigation. We employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify alprazolam, α-hydroxyalprazolam, and hydrocodone in a DBS sample that has been stored for 17 years. We achieved linear dynamic ranges (0.1-50 ng/mL) that capture wide ranges of concentration of the analytes below and above their reported reference ranges, and limits of detection (0.05 ng/mL) of 40-100X lower than the lower limit of the analyte's reference ranges. The method was validated according to FDA and CLSI guidelines and successfully confirmed and quantified alprazolam and α-hydroxyalprazolam in a forensic DBS sample.

Effects of the Storage Conditions on the Stability of Natural and Synthetic Cannabis in Biological Matrices for Forensic Toxicology Analysis: An Update from the Literature

The use and abuse of cannabis, be it for medicinal or recreational purposes, is widely spread among the population. Consequently, a market for more potent and consequently more toxic synthetic cannabinoids has flourished, and with it, the need for accurate testing of these substances in intoxicated people. In this regard, one of the critical factors in forensic toxicology is the stability of these drugs in different biological matrices due to different storage conditions. This review aims to present the most updated and relevant literature of studies performed on the effects of different storage conditions on the stability of cannabis compounds present in various biological matrices, such as blood and plasma, urine, and oral fluids, as well as in alternative matrices, such as breath, bile fluid, hair, sweat, cerumen, and dried blood spots.

Dried matrix spots: an evolving trend in the toxicological field

Dried matrix spot (DMS) is a sampling technique, primarily used to analyze blood to diagnose metabolic diseases in newborns. As this technique has several advantages, DMS has started to be employed for other purposes using other biological matrices and increasingly in toxicology over the last decade. The aim of this work was to review the analytical methods using DMS which can be applied to drugs of abuse and which have been published since 2010. Three different databases were searched, using dried, spots, and drugs of abuse as the descriptors and using a snowball search. After applying the exclusion criteria, 39 papers remained. The most common publications were related to the use of blood, which corresponded to 77% of the papers, followed by urine and oral fluid, which corresponded to 13 and 10% of the papers, respectively. The selected studies covered different illicit drugs, sample sizes of 5 to 250 µL and spot sizes ranging from 3 to 18 mm in diameter. This review also examined the extraction techniques and the methods employed to analyze various biological matrices and drugs of abuse, mostly by liquid-extraction and liquid chromatography-tandem mass spectrometry. The benefits of DMS include: a simple sample pretreatment, better stability than liquid matrices, a simple extraction procedure, lower costs, and environmental benefits. DMS appears to be a promising technique in the field of toxicology and provides new perspectives for use in forensic laboratories.

Dispersive liquid-liquid microextraction of 11-nor-Δ9-tetrahydrocannabinol-carboxylic acid applied to urine testing

Aim: THC-COOH is the major metabolite of Δ⁹-tetrahydrocannabinol commonly tested in urine to determine cannabis intake. In this study, a method based on dispersive liquid-liquid microextraction was developed for testing THC-COOH in urine. Materials & methods: Hydrolyzed urine specimens were extracted via dispersive liquid-liquid microextraction with acetonitrile (disperser solvent) and chloroform (extraction solvent). Derivatization was performed with N,O-Bis(trimethylsilyl)trifluoroacetamide with 1% trichloro(chloromethyl)silane. Analysis was performed by GC-MS/MS. Results: The method showed acceptable linearity (5-500 ng/ml), imprecision (<10.5%) and bias (<4.9%). Limits of detection and quantitation were 1 and 5 ng/ml, respectively. Twenty-four authentic samples were analyzed, with 22 samples being positive for THC-COOH. Conclusion: The proposed method is more environmentally friendly and provided good sensitivity, selectivity and reproducibility.

Dried matrix spots in forensic toxicology

Dried matrix spots (DMS) has gained the attention of different professionals in different fields, including toxicology. Investigations have been carried out in order to assess the potential of using DMS for the analysis of illicit substances, the main interest of forensic toxicologists. This technique uses minimal volumes of samples and solvents, resulting in simple and rapid extraction procedures. Furthermore, it has proved to increase analyte stability, improving storage and transportation. However, DMS presents some limitations: the hematocrit influencing accuracy and inconsistencies regarding the means of spotting samples and adding internal standard on paper. Thus, we provide an overview of analytical methodologies with forensic applications focusing on drugs of abuse and discussing the main particularities, limitations and achievements.

Study of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) extraction FROM dried oral fluid spots (DOFS) and LC-MS/MS detection

Background

Oral fluid is a widely studied matrix able to isolate the primary Cannabis constituent THC, facilitating its detection via mass spectrometry, and in most cases link these findings to recent drug use. As an alternative to liquid oral fluid, dried oral fluid spots (DOFS) is a simple and a low-cost sampling technique. It has shown improved stability compared to liquid samples, allowing for the possibility to preserve the specimens under various temperature and humidity conditions. The sampling strategy is straightforward and involves the application of a small quantity of oral fluid aliquot to a paper substrate that is set to air dry allowing for on-site collection at a large-scale demand. The goal of this study is to study THC and CBD extraction from DOFS, applying a previous established protocol for a LC–MS/MS qualitative method validation. Although other drugs of abuse have been included in DOFS methods, this is the first method validation including cannabinoids. An alternative oral fluid extraction method (WAX-S tips) is demonstrated to improve the recovery of the analytes.

Methods

A pool of blank oral fluid was used to prepare THC and CBD spiked DOFS samples for method validation and application. Spiked oral fluid was used to demonstrate WAX-S tips THC and CBD extraction. All samples were analyzed on a LC–MS/MS instrument.

Results

The qualitative method validation for THC and CBD confirmation in DOFS included method selectivity, matrix effects (< 20%), recovery (average of 25%), process efficiency (average of 21%), LOD (2 ng/mL for THC and 4 ng/mL for CBD), absence of carryover, and DOFS stability (70% in 35 days) as figures of merit. The method application in blindly prepared samples demonstrated the method capability to identify THC and CBD. WAX-S tips extraction showed an average of 91% recovery of THC and CBD from liquid oral fluid.

Conclusions

THC and CBD extraction from DOFS showed low recoveries. However, the LC–MS/MS qualitative confirmation of THC and CBD in DOFS could improve cannabinoids screening in oral fluid, as it shows adequate LOD and stability over time. This method has potential for assisting the screening of drivers under possible drug influence by facilitating sample transportation and temporary storage in dried spot form. Additional research is suggested for WAX-S tips extraction and quantitative method validation.

Development of an electrochemical sensor based on carbon black for the detection of cannabidiol in vegetable extracts

A glassy carbon electrode chemically modified with a carbon black coating is proposed here for the rapid and portable determination of cannabidiol (CBD) in a commercial Cannabis seed oil and in fibre-type Cannabis sativa L. leaves.

Quantitative microsampling for bioanalytical applications related to the SARS-CoV-2 pandemic: Usefulness, benefits and pitfalls

The multiple pathological effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and its total novelty, mean that currently a lot of diagnostic and therapeutic tools, established and tentative alike, are needed to treat patients in a timely, effective way. In order to make these tools more reliable, faster and more feasible, biological fluid microsampling techniques could provide many advantages. In this review, the most important microsampling techniques are considered (dried matrix spots, volumetric absorptive microsampling, microfluidics and capillary microsampling, solid phase microextraction) and their respective advantages and disadvantages laid out. Moreover, currently available microsampling applications of interest for SARS-CoV-2 therapy are described, in order to make them as much widely known as possible, hopefully providing useful information to researchers and clinicians alike.

Dried blood spots for anti-doping: Why just going volumetric may not be sufficient

The perspective discusses quantitative DBS analysis for anti-doping testing in an athletic population and why only using volumetric sampling for this subgroup might not be enough. It presents examples to highlight where HCT variations occur, followed by a whole blood to plasma ratio and an HCT extraction bias discussion. Finally, options to correct for the HCT bias are presented.

Emerging challenges in the extraction, analysis and bioanalysis of cannabidiol and related compounds

Cannabidiol (CBD) is a bioactive terpenophenolic compound isolated from Cannabis sativa L. It is known to possess several properties of pharmaceutical interest, such as antioxidant, anti-inflammatory, anti-microbial, neuroprotective and anti-convulsant, being it active as a multi-target compound. From a therapeutic point of view, CBD is most commonly used for seizure disorder in children. CBD is present in both medical and fiber-type C. sativa plants, but, unlike Δ⁹-tetrahydrocannabinol (THC), it is a non-psychoactive compound. Non-psychoactive or fiber-type C. sativa (also known as hemp) differs from the medical one, since it contains only low levels of THC and high levels of CBD and related non-psychoactive cannabinoids. In addition to medical Cannabis, which is used for many different therapeutic purposes, a great expansion of the market of hemp plant material and related products has been observed in recent years, due to its usage in many fields, including food, cosmetics and electronic cigarettes liquids (commonly known as e-liquids). In this view, this work is focused on recent advances on sample preparation strategies and analytical methods for the chemical analysis of CBD and related compounds in both C. sativa plant material, its derived products and biological samples. Since sample preparation is considered to be a crucial step in the development of reliable analytical methods for the determination of natural compounds in complex matrices, different extraction methods are discussed. As regards the analysis of CBD and related compounds, the application of both separation and non-separation methods is discussed in detail. The advantages, disadvantages and applicability of the different methodologies currently available are evaluated. The scientific interest in the development of portable devices for the reliable analysis of CBD in vegetable and biological samples is also highlighted.

A review on the recent advances in HPLC, UHPLC and UPLC analyses of naturally occurring cannabinoids (2010-2019)

INTRODUCTION

Organic molecules that bind to cannabinoid receptors are called cannabinoids, and they have similar pharmacological properties like the plant, Cannabis sativa L. Hyphenated liquid chromatography (LC), incorporating high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC, also known as ultrahigh-performance liquid chromatography, UHPLC), usually coupled to an ultraviolet (UV), UV-photodiode array (PDA) or mass spectrometry (MS) detector, has become a popular analytical tool for the analysis of naturally occurring cannabinoids in various matrices.

OBJECTIVE

To review literature on the use of various LC-based analytical methods for the analysis of naturally occurring cannabinoids published since 2010.

METHODOLOGY

A comprehensive literature search was performed utilising several databases, like Web of Knowledge, PubMed and Google Scholar, and other relevant published materials including published books. The keywords used, in various combinations, with cannabinoids being present in all combinations, in the search were Cannabis, hemp, cannabinoids, Cannabis sativa, marijuana, analysis, HPLC, UHPLC, UPLC, quantitative, qualitative and quality control.

RESULTS

Since 2010, several LC methods for the analysis of naturally occurring cannabinoids have been reported. While simple HPLC-UV or HPLC-UV-PDA-based methods were common in cannabinoids analysis, HPLC-MS, HPLC-MS/MS, UPLC (or UHPLC)-UV-PDA, UPLC (or UHPLC)-MS and UPLC (or UHPLC)-MS/MS, were also used frequently. Applications of mathematical and computational models for optimisation of different protocols were observed, and pre-analyses included various environmentally friendly extraction protocols.

CONCLUSIONS

LC-based analysis of naturally occurring cannabinoids has dominated the cannabinoids analysis during the last 10 years, and UPLC and UHPLC methods have been shown to be superior to conventional HPLC methods.

Improved Dried Blood Spot-Based Metabolomics: A Targeted, Broad-Spectrum, Single-Injection Method

Dried blood spots (DBS) have proven to be a powerful sampling and storage method for newborn screening and many other applications. However, DBS methods have not yet been optimized for broad-spectrum targeted metabolomic analysis. In this study, we developed a robust, DBS-based, broad-spectrum, targeted metabolomic method that was able to measure over 400 metabolites from a 6.3 mm punch from standard Whatman 903^TM filter paper cards. The effects of blood spot volumes, hematocrit, vacutainer chemistry, extraction methods, carryover, and comparability with plasma and fingerstick capillary blood samples were analyzed. The stability of over 400 metabolites stored under varying conditions over one year was also tested. No significant impacts of blood volume and hematocrit variations were observed when the spotted blood volume was over 60 µL and the hematocrit was between 31% and 50%. The median area under the curve (AUC) of metabolites in the DBS metabolome declined by 40% in the first 3 months and then did not decline further for at least 1 year. All originally detectable metabolites remained within detectable limits. The optimal storage conditions for metabolomic analysis were -80 °C with desiccants and without an O₂ scavenger. The method was clinically validated for its potential utility in the diagnosis of the mitochondrial disease mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). Our method provides a convenient alternative to freezing, storing, and shipping liquid blood samples for comparative metabolomic studies.

Blood and Plasma Volumetric Absorptive Microsampling (VAMS) Coupled to LC-MS/MS for the Forensic Assessment of Cocaine Consumption

Reliable, feasible analytical methods are needed for forensic and anti-doping testing of cocaine and its most important metabolites, benzoylecgonine, ecgonine methyl ester, and cocaethylene (the active metabolite formed in the presence of ethanol). An innovative workflow is presented here, using minute amounts of dried blood or plasma obtained by volumetric absorptive microsampling (VAMS), followed by miniaturized pretreatment by dispersive pipette extraction (DPX) and LC-MS/MS analysis. After sampling 20 µL of blood or plasma with a VAMS device, the sample was dried, extracted, and loaded onto a DPX tip. The DPX pretreatment lasted less than one minute and after elution with methanol the sample was directly injected into the LC-MS/MS system. The chromatographic analysis was carried out on a C8 column, using a mobile phase containing aqueous formic acid and acetonitrile. Good extraction yield (> 85%), precision (relative standard deviation, RSD < 6.0%) and matrix effect (< 12%) values were obtained. Analyte stability was outstanding (recovery > 85% after 2 months at room temperature). The method was successfully applied to real blood and plasma VAMS, with results in very good agreement with those of fluid samples. The method seems suitable for the monitoring of concomitant cocaine and ethanol use by means of plasma or blood VAMS testing.

Cannabinoids from Cannabis sativa L.: A New Tool Based on HPLC-DAD-MS/MS for a Rational Use in Medicinal Chemistry

Cannabis sativa L. represents one of the most widely used source of drugs and drugs of abuse worldwide. Its biologically active compounds are mainly cannabinoids, including Δ⁹-tetrahydrocannabinol (THC), which is responsible for the psychoactive effects, tetrahydrocannabinolic acid (THCA), cannabinol (CBN), cannabidiol (CBD), and cannabidiolic acid (CBDA). Together with recreational and drug-type (or medicinal) Cannabis, some new products have been recently released into the market as fiber-type Cannabis variants (also known as hemp or industrial hemp) with low THC content and high content of nonpsychoactive CBD. In this research work, the aim was to characterize Cannabis recreational and drug-type samples by quantifying their active principles, after the development and validation of a suitable analytical method. In addition to the Cannabis samples described above, fiber-type plant varieties were also analyzed to monitor their content of nonpsychoactive compounds for both pharmaceutical and nutraceutical purposes. To do this, a highly efficient HPLC-DAD-MS/MS method, with an electrospray ionization (ESI) source and a triple-quadrupole mass analyzer acquiring in the multiple reaction monitoring (MRM) mode also coupled to a diode array detector (DAD), was developed and applied. Satisfactory validation results were obtained in terms of precision (RSD < 6.0% for all the analytes) and accuracy (>92.1% for all the compounds). The proposed methodology represents a versatile and reliable tool to assess both psychoactive and nonpsychoactive cannabinoid levels in Cannabis samples for a more rational use in both medicinal chemistry and nutraceutics.

Tutorial: Volumetric absorptive microsampling (VAMS)

Volumetric absorptive microsampling (VAMS) is a recent microsampling technique used to obtain dried specimens of blood and other biological matrices for application to a plethora of bioanalytical purposes. As such, it can be likened to dried blood spot (DBS) technique that has been in wide use for the last 40 years. However, VAMS promises to bring some significant advantages over DBS, related to sampling volume accuracy, haematocrit (HCT) dependence, pre-treatment and automation. Although some aspects still need to be investigated in depth, VAMS is increasingly recognised as a viable alternative to DBS and other dried microsampling techniques. In this tutorial, different aspects of VAMS approach are described and discussed, presenting the procedures adopted and the results obtained by those authors who have developed this kind of analytical workflow in the last few years. Hopefully, this will help other scientists to find new solutions to old and recent problems related to microsampling and to produce new, sound and interesting science in this field.

Multi-mycotoxin analysis using dried blood spots and dried serum spots

In this study, a rapid multi-mycotoxin approach was developed for biomonitoring and quantification of 27 important mycotoxins and mycotoxin metabolites in human blood samples. HPLC-MS/MS detection was used for the analysis of dried serum spots (DSS) and dried blood spots (DBS). Detection of aflatoxins (AFB₁, AFB₂, AFG₁, AFG₂, AFM₁), trichothecenes (deoxynivalenol, DON; DON-3-glucoronic acid, DON-3-GlcA; T-2; HT-2; and HT-2-4-GlcA), fumonisin B₁ (FB₁), ochratoxins (OTA and its thermal degradation product 2'R-OTA; OTα; 10-hydroxychratoxin A, 10-OH-OTA), citrinin (CIT and its urinary metabolite dihydrocitrinone, DH-CIT), zearalenone and zearalanone (ZEN, ZAN), altenuene (ALT), alternariols (AOH; alternariol monomethyl ether, AME), enniatins (EnA, EnA₁, EnB, EnB₁) and beauvericin (Bea) was validated for two matrices, serum (DSS), and whole blood (DBS). HPLC-MS/MS analysis showed signal suppression as well as signal enhancement due to matrix effects. However, for most analytes LOQs in the lower pg/mL range and excellent recovery rate were achieved using matrix-matched calibration. Besides validation of the method, the analyte stability in DBS and DSS was also investigated. Stability is a main issue for some analytes when the dried samples are stored under common conditions at room temperature. Nevertheless, the developed method was applied to DBS samples of a German cohort (n = 50). Besides positive findings of OTA and 2'R-OTA, all samples were positive for EnB. This methodical study establishes a validated multi-mycotoxin approach for the detection of 27 mycotoxins and metabolites in dried blood/serum spots based on a fast sample preparation followed by sensitive HPLC-MS/MS analysis. Graphical Abstract ᅟ.

Cocaine and metabolite concentrations in DBS and venous blood after controlled intravenous cocaine administration

BACKGROUND

DBS are an increasingly common clinical matrix.

METHODS & RESULTS

Sensitive and specific methods for DBS and venous blood cocaine and metabolite detection by LC-HRMS and 2D GC-MS, respectively, were validated to examine correlation between concentrations following controlled intravenous cocaine administration. Linear ranges from 1 to 200 µg/l were achieved, with acceptable bias and imprecision. Authentic matched specimens' (392 DBS, 97 venous blood) cocaine and benzoylecgonine concentrations were qualitatively similar, but DBS had much greater variability (21.4-105.9 %CV) and were lower than in blood.

CONCLUSION

DBS offer advantages for monitoring cocaine intake; however, differences between capillary and venous blood and DBS concentration variability must be addressed.

Identification and quantification of psychoactive drugs in whole blood using dried blood spot (DBS) by ultra-performance liquid chromatography tandem mass spectrometry

A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of twenty three psychoactive drugs and metabolites in whole blood using dried blood spot (DBS). Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.1% formic acid in acetonitrile and 5mM ammonium formate at pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electro-spray ionization. The method was linear from the limit of quantification (5ng/ml for all the analytes apart from 15ng/ml for Δ-9-tetrahydrocannabinol and metabolites) to 500ng/ml, and showed good correlation coefficients (r(2)=0.990) for all substances. Analytical recovery of analytes under investigation was always higher than 75% and intra-assay and inter-assay precision and accuracy always better than 15%. Using the validated method, ten DBS samples, collected at the hospital emergency department in cases of acute drug intoxication, were found positive to one or more psychoactive drugs. Our data support the potential of DBS sampling for non invasive monitoring of exposure/intoxication to psychoactive drugs.

Analysis of ochratoxin A in dried blood spots - Correlation between venous and finger-prick blood, the influence of hematocrit and spotted volume

We report the improvement of a method for the detection of ochratoxin A (OTA) and its thermal degradation product 2'R-ochratoxin A in dried blood spots (DBS) by high performance liquid chromatographic (HPLC) tandem mass spectrometry (MS/MS). The DBS technique was advanced for the analysis of these two compounds in DBS with unknown amounts of blood as well as varying hematocrit values. Furthermore the comparability of venous vs. capillary blood was investigated. Human whole blood samples were spotted, dried, and extracted with a solvent consisting of acetone, acetonitrile and water for analysis by HPLC-MS/MS. Quantification was carried out by stable isotope labelled internal standards. Blood samples of volunteers (n=50) were used to further optimize and simplify the procedure. Ochratoxin A and 2'R-ochratoxin A concentrations found in the entire spots (approx. 100 μL blood) were compared with punched DBS discs of 8.8mm size containing approximately 20 μL blood. As a result the amounts of both toxins in a punched 8.8mm disc correlate well with the entire DBS. Also the use of capillary blood from finger-pricks versus venous blood was evaluated. The analyte levels correlate as well indicating that the less invasive finger-prick sampling gives also reliable results. The influence of hematocrit was investigated in a range of 25-55% according to the hematocrit in the used real blood samples (34-46% hematocrit). However no significant hematocrit effect was observed for the utilized real blood samples. Moreover different blood volumes were spotted and punched as a minimal spot size is usually recommended for accurate analysis. In this experiment finger-prick samples typically consist of about 90 μL blood. Therefore spots of 75, 100 and 125 μL blood were prepared and analyzed. Similar to the hematocrit effect, no considerable influence was observed.

Biomonitoring using dried blood spots: detection of ochratoxin A and its degradation product 2'R-ochratoxin A in blood from coffee drinkers

SCOPE

In this study, human exposure to the mycotoxin ochratoxin A (OTA) and its thermal degradation product 2'R-ochratoxin A (2'R-OTA, previously named as 14R-Ochratoxin A [22]) through coffee consumption was assessed. LC-MS/MS and the dried blood spot (DBS) technique were used for the analysis of blood samples from coffee and noncoffee drinkers (n = 50), and food frequency questionnaires were used to document coffee consumption.

METHODS AND RESULTS

For the detection of OTA and 2'R-OTA in blood, a new sensitive and efficient sample preparation method based on DBS was established and validated. Using this technique 2'R-OTA was for the first time detected in biological samples. Comparison between coffee drinkers and noncoffee drinkers showed for the first time that 2'R-OTA was only present in blood from the first group while OTA could be found in both groups in a mean concentration of 0.21 μg/L. 2'R-OTA mean concentration was 0.11 μg/L with a maximum concentration of 0.414 μg/L. Thus, in average 2'R-OTA was approx. half the concentration of OTA but in some cases even exceeded OTA levels. No correlation between the amounts of coffee consumption and OTA or 2'R-OTA levels was observed.

CONCLUSION

The results of this study revealed for the first time a high exposure of coffee consumers to 2'R-OTA, a compound formed from OTA during coffee roasting. Since little information is available regarding toxicity and possible carcinogenicity of this compound, further OTA monitoring in blood including 2'R-OTA is advisable.

Procedures and practices for the validation of bioanalytical methods using dried blood spots: a review

Dried blood spot (DBS) sampling, the collection of whole blood samples on paper, is an emerging technique used for bioanalytical methods. Several analytical challenges, such as possible effects of spotting volume, hematocrit and spot inhomogeneity are identified for these methods, however, no regulatory-based guidelines for the specific validation of DBS-based assays are available hitherto. To date, 68 validation reports concerning methods for the quantitative determination of drugs in human DBS could be traced in the literature, with large differences in the extensiveness of the reported validations. This review aims to present an overview of these published validations. Additionally, the different challenges of DBS-based assays are discussed and recommendations on how to perform validation tests addressing these challenges are provided.

Spot them in the spot: analysis of abused substances using dried blood spots

Dried blood spot (DBS) sampling and DBS analysis have increasingly received attention during recent years. Furthermore, a substantial number of DBS methods has recently become available in clinical, forensic and occupational toxicology. In this review, we provide an overview of the different DBS-based methods that have been developed for detecting (markers of) abused substances. These include both legal and illegal drugs belonging to different categories, including cannabinoids, cocaine and metabolites, opioids, benzodiazepines and Z-drugs, amphetamines and analogs, gamma-hydroxybutyric acid, ketamine and novel psychoactive substances such as cathinones. Markers of ethanol consumption and tobacco use are also covered in this review. Since the majority of published methods has shown promising results overall, an interesting role for DBS analysis in diverse toxicological applications can be envisaged. For the distinct applications, we discuss the specific potential and benefits of DBS, the associated limitations and challenges, as well as recent developments and future perspectives.

Dried blood spot testing: a novel approach for the therapeutic drug monitoring of ziprasidone-treated patients

Background: A novel analytical approach, based on dried blood spot (DBS) testing, has been developed, validated and applied for the first time to the analysis of ziprasidone (ZPR) for the therapeutic drug monitoring (TDM) of schizophrenic patients. DBS represent a more feasible but reliable matrix, alternative to blood and plasma. Methods: The assays were carried out using an HPLC method with native fluorescence. Blood drops were applied to DBS cards and dried by microwaves, an internal standard solution was added to the DBS and 5-mm punches were cut out for analysis. ZPR was extracted from DBS with methanol, giving good extraction yields, precision and selectivity results. Results: The method was applied with satisfactory results to DBS samples from psychiatric patients to determine ZPR levels for therapy optimization. Conclusion: This innovative methodology provides reliable and significant TDM information, with important advantages over classical blood sampling in terms of collection, storage and processing.

Δ⁹-Tetrahydrocannabinol-induced anti-inflammatory responses in adolescent mice switch to proinflammatory in adulthood

Marijuana abuse is prominent among adolescents. Although Δ(9)-THC, one of its main components, has been demonstrated to modulate immunity in adults, little is known about its impact during adolescence on the immune system and the long-lasting effects in adulthood. We demonstrate that 10 days of Δ(9)-THC treatment induced a similar alteration of macrophage and splenocyte cytokines in adolescent and adult mice. Immediately at the end of chronic Δ(9)-THC, a decrease of proinflammatory cytokines IL- 1β and TNF-α and an increase of anti-inflammatory cytokine IL-10 production by macrophages were present as protein and mRNA in adolescent and adult mice. In splenocytes, Δ(9)-THC modulated Th1/Th2 cytokines skewing toward Th2: IFN-γ was reduced, and IL-4 and IL-10 increased. These effects were lost in adult animals, 47 days after the last administration. In contrast, in adult animals treated as adolescents, a perturbation of immune responses, although in an opposite direction, was present. In adults treated as adolescents, a proinflammatory macrophage phenotype was observed (IL-1β and TNF-α were elevated; IL-10 decreased), and the production of Th cytokines was blunted. IgM titers were also reduced. Corticosterone concentrations indicate a long-lasting dysregulation of HPA in adolescent mice. We measured blood concentrations of Δ(9)-THC and its metabolites, showing that Δ(9)-THC plasma levels in our mice are in the order of those achieved in human heavy smokers. Our data demonstrate that Δ(9)-THC in adolescent mice triggers immune dysfunctions that last long after the end of abuse, switching the murine immune system to proinflammatory status in adulthood.

Marijuana: current concepts(†)

Marijuana (cannabis) remains a controversial drug in the twenty-first century. This paper considers current research on use of Cannabis sativa and its constituents such as the cannabinoids. Topics reviewed include prevalence of cannabis (pot) use, other drugs consumed with pot, the endocannabinoid system, use of medicinal marijuana, medical adverse effects of cannabis, and psychiatric adverse effects of cannabis use. Treatment of cannabis withdrawal and dependence is difficult and remains mainly based on psychological therapy; current research on pharmacologic management of problems related to cannabis consumption is also considered. The potential role of specific cannabinoids for medical benefit will be revealed as the twenty-first century matures. However, potential dangerous adverse effects from smoking marijuana are well known and should be clearly taught to a public that is often confused by a media-driven, though false message and promise of benign pot consumption.

State-of-the-art dried blood spot analysis: an overview of recent advances and future trends

Dried blood spots have become a popular method in a variety of micro blood-sampling techniques in the life sciences sector, consequently competing with the field of conventional, invasive blood sampling by venepuncture. Dried blood spots are widely applied in numerous bioanalytical assays and have gained a significant role in the screening of inherited metabolic diseases, in PK and PD modeling; in the treatment and diagnosis of infectious diseases; and in therapeutic drug monitoring. Recent technological developments such as automation, online extraction, mass spectrometric direct analysis and also conventional dried blood spot bioanalysis, as well as future developments in dried blood spot bioanalysis are highlighted and presented in this article.