Development and validation of a highly sensitive gas chromatographic–mass spectrometric screening method for the simultaneous determination of nanogram levels of fentanyl, sufentanil and alfentanil in air and surface contamination wipes

Assessing fentanyl and methamphetamine in air and on surfaces of transit vehicles

Recently, the misuse of fentanyl and methamphetamine has increased in the United States. These drugs can be consumed via smoking a powder, which can subsequently contaminate air and surfaces with drug residue. With limited access to safe consumption sites, this misuse often occurs in public spaces such as public transit, leading to potential secondhand exposures among transit operators and riders. In the Pacific Northwest, transit operators have reported acute health symptoms and safety concerns regarding these drug exposures. Researchers conducted an exposure assessment, sampling air and surfaces for fentanyl and methamphetamine. A total of 78 air samples and 89 surface samples were collected on 11 buses and 19 train cars from four transit agencies in the Pacific Northwest. Fentanyl was detected above the limit of quantification (LOQ) in 25% of air samples (range of concentrations > LOQ: 0.002 to 0.14 µg/m3) and 38% of surface samples (range of concentrations > LOQ: 0.011 to 0.47 ng/cm2), while methamphetamine was detected in 100% of air samples (range: 0.003 to 2.32 µg/m3) and 98% of surface samples (range of concentrations > LOQ: 0.016 to 6.86 ng/cm2) The highest fentanyl air sample (0.14 µg/m3) was collected in the passenger area of a train for 4 hr, and would exceed the ACGIH® 8-hr TWA TLV® of 0.1 µg/m3 if conditions remained the same for the unsampled period. No surface samples exceed the ACGIH fentanyl surface level TLV (10 ng/cm2). The prevalence of fentanyl and methamphetamine on public transit highlights the need to protect transit operators from secondhand exposure and from the stress of witnessing and responding to smoking events. Future work is needed to evaluate the utility of engineering and administrative controls such as ventilation and cleaning upgrades in reducing exposures on transit, as well as the utility of training and increased workplace support for operators in addressing their health and well-being after observing or responding to drug use events.

Simultaneous measurement of fentanyl, fentanyl analogues and other drugs of abuse by multiplex bead assay

Quantification of illicit drugs and controlled substances, in urine or as surface contamination, is often performed using expensive analytical techniques such as liquid chromatography with tandem mass spectrometry (LC-MS/MS). A time and cost-effective semi-quantitative surface-wipe and urine screening multiplex immunoassay for fentanyl and its analogues was developed in this investigation. We previously created a surface wipe multiplex immunoassay for methamphetamine, caffeine, cocaine, tetrahy-drocannabinol (THC) and oxycodone. This fluorescent covalent microsphere immunosorbent assay (FCMIA) is a competitive assay where drugs compete with protein-drug conjugates attached to microspheres for antibodies. It was assembled using a commercially available fentanyl antibody and protein-conjugate. Surface recovery from ceramic tiles was assessed by FCMIA, with results ranging from 26% for fentanyl to 60% for methamphetamine. Only fentanyl and its structurally similar analogues showed significant response to the fentanyl assay whereas, analogues structurally similar to carfentanil gave no response. Non-fentanyl drug assays did not appreciably detect fentanyl or its analogues. Overall, this method is a useful tool for assessing surface contamination and the effectiveness of decontamination by multiple drugs of abuse, potentially lowering workplace exposures. To broaden applicability, different antibodies or aptamers must be developed to detect structural differences found in classes of analogues such as carfentanil.

Validation of a sampling method and liquid chromatography mass spectrometry analysis method for measurement of fentanyl and five other illicit drugs

With the increased provision of services by health authorities and community organizations allowing supervised inhalation of illicit substances comes concerns about the potential for secondhand exposure to the substances being used, whether in the adjacent community or to workers at the sites. In order to address community concerns surrounding secondhand illicit substance exposure and better protect harm reduction workers, a validated sampling and LC-MS/MS analysis method was developed for 6 illicit drugs: fentanyl, heroin, methamphetamine, cocaine, etizolam, and bromazolam. It was found that the filter used needed to be silanized to be made more inert and avoid loss of analyte due to degradation. Using the silanized filters, recoveries were good (>90%) and the collected samples were found to be stable at room temperature for 2 wk. The sampling volume validated was up to 960 L. The sensitivity and range of the method make it appropriate for short-term (15 min), full shift (8 h), or environmental sampling.

A promising and highly sensitive electrochemical platform for the detection of fentanyl and alfentanil in human serum

A novel electrochemical method has been developed, based on a covalent organic framework (COF) and reduced graphene oxide (rGO), to detect fentanyl and alfentanil. COF nanomaterials with chrysanthemum morphology obtained by solvothermal reaction contain rich active sites for electrochemical catalytic reaction, thus improving the detection performance of the designed sensor. Reduced graphene oxide improves the sensor's sensitivity due to enhanced electron transfer. Under optimized experimental conditions, the fabricated electrode presents a linear range of 0.02 to 7.26 μM for alfentanil and 0.1 to 6.54 μM for fentanyl, with detection limits of 6.7 nM and 33 nM, respectively. In addition, the sensor possesses excellent selectivity, outstanding reproducibility, and acceptable stability. The proposed sensor is feasible for the reliable monitoring of fentanyl and alfentanil in human serum samples, with acceptable reliability and high potential in real-world applications. Finally, the electrochemical characteristic fingerprint of fentanyl is investigated by studying the electrochemical behavior of alfentanil and fentanyl on the electrode surface.

Characterization of fentanyl HCl powder prior to and after systematic degradation

Fentanyl HCl is of particular interest in forensic cases but there is a notable gap in literature regarding its analysis. This study utilized a multi-method approach to characterize fentanyl HCl powder, both fresh and following a forced degradation process. Using sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) and direct injection gas chromatography-mass spectrometry (GC-MS), five compounds were identified in fresh fentanyl HCl powder. The identified compounds were: N-phenylpropanamide, 1-phenethyl-4-propionyloxypiperidine (1-P-4-POP), 4-anilino-N-phenethylpiperidine (4-ANPP), acetylfentanyl, and fentanyl; all identified compounds but acetylfentanyl and fentanyl decreased in quantity as the sample was degraded. Fresh headspace samples analyzed with solid phase microextraction (SPME)-GC-MS identified four compounds in common with the powder analyses: N-phenylpropanamide,1-P-4-POP, 4-ANPP, and fentanyl. Acetylfentanyl was not present in the headspace samples, although two additional compounds were: N-phenylacetamide and N-phenethyl-4-piperidinone (NPP). Where direct analysis of degraded fentanyl HCl showed decreased quantities of the identified compounds, headspace samples of the degraded fentanyl HCl resulted in higher quantities, implying that the degradation process drove those compounds to volatilize. Notably, fentanyl was identified in the headspace, implying that this could be an appropriate target for standoff detection. Finally, thermogravimetric analysis (TGA) and differential scanning calorimetry (DCS) confirmed that the forced degradation process had little permanent effect on the powder.

Gas Chromatography-Mass Spectrometry Analysis of Synthetic Opioids Belonging to the Fentanyl Class: A Review

The rising number of deaths caused by fentanyl overdosing in the US due to the overwhelming illicit use of this synthetic opioid has started a global campaign to develop efficient ways to control its production and distribution as well as discovering efficient antidotes to mitigate its lethal effects. Another important vein of focused research established by various agencies lies in the development of efficient and practical protocols for the detection of this opioid and analogs thereof in various matrices, whether environmental or biological in nature, particularly in the field of gas chromatography-mass spectrometry (GC-MS). The following review will cover the literature dealing with the detection and identification of synthetic opioids belonging to the fentanyl class by GC-MS means and hyphenated versions of the technique. Detailed descriptions will be given for the GC-MS methods employed for the analysis of the opioid, starting with the nature of the extraction protocol employed prior to analysis to the actual findings presented by the cited reports. Great effort has gone into describing the methods involved in each paper in a detailed manner and these have been compiled by year in tables at the end of each section for the reader's convenience. Lastly, the review will end with concluding remarks about the state of GC-MS analysis with regards to these powerful opioids and what lies ahead for this analytical field.

Central Nervous System-acting chemicals and the Chemical Weapons Convention: A former Scientific Adviser’s perspective

The term Incapacitating Chemical Agents (or Incapacitants) was chosen to describe different classes of chemical warfare agents that were being developed in the 1950s. This article considers some of the types of chemicals and their properties that have been discussed more recently under the terminology of Incapacitating Chemical Agents, including opioids of the fentanyl class, and how these psychochemicals are relevant to the Chemical Weapons Convention. This article argues that the term Incapacitating Chemical Agents is inaccurate and misleading and will be a potential cause of confusion when Member States of the Chemical Weapons Convention are discussing the types of toxic chemicals which are permitted for use for various law enforcement purposes including domestic riot control. This article then argues that the term Central Nervous System-acting chemicals is a more accurate and appropriate description of psychochemicals such as the fentanyls, and use of this term will hopefully facilitate a more constructive discussion within the Organisation for the Prohibition of Chemical Weapons (OPCW). In other words, it is important to ‘get the science clearly understood first’, to enable a more constructive discussion by policy-makers, lawyers and military experts.

Comparison of two automated solid phase extractions for the detection of ten fentanyl analogs and metabolites in human urine using liquid chromatography tandem mass spectrometry

Two types of automated solid phase extraction (SPE) were assessed for the determination of human exposure to fentanyls in urine. High sensitivity is required to detect these compounds following exposure because of the low dose required for therapeutic effect and the rapid clearance from the body for these compounds. To achieve this sensitivity, two acceptable methods for the detection of human exposure to seven fentanyl analogs and three metabolites were developed using either off-line 96-well plate SPE or on-line SPE. Each system offers different advantages: off-line 96-well plate SPE allows for high throughput analysis of many samples, which is needed for large sample numbers, while on-line SPE removes almost all analyst manipulation of the samples, minimizing the analyst time needed for sample preparation. Both sample preparations were coupled with reversed phase liquid chromatography and isotope dilution tandem mass spectrometry (LC-MS/MS) for analyte detection. For both methods, the resulting precision was within 15%, the accuracy within 25%, and the sensitivity was comparable with the limits of detection ranging from 0.002ng/mL to 0.041ng/mL. Additionally, matrix effects were substantially decreased from previous reports for both extraction protocols. The results of this comparison showed that both methods were acceptable for the detection of exposures to fentanyl analogs and metabolites in urine.

Pharmacokinetics of fentanyl administered transdermally and intravenously in sheep

OBJECTIVE

To investigate the pharmacokinetics of fentanyl administered transdermally and IV in sheep.

ANIMALS

21 adult female sheep.

PROCEDURES

Fentanyl was administered IV to 6 healthy sheep. Transdermal fentanyl patches (TFPs) were applied to 15 sheep 12 hours prior to general anesthesia and surgery. Seria blood samples were collected for 18 hours after IV injection and 84 hours after TFP application. Fentanyl concentrations were quantified via liquid chromatography-mass spectrometry, and pharmacokinetic values were estimated.

RESULTS

All sheep completed the study without complications. Following a dose of 2.5 g/kg administered IV, the half-life was 3.08 hours (range, 2.20 to 3.36 hours), volume of distribution at steady state was 8.86 L/kg (range, 5.55 to 15.04 L/kg), and systemic clearance was 3.62 L/kg/h (range, 2.51 to 5.39 L/kg/h). The TFPs were applied at a mean dose of 2.05 g/kg/h. Time to maximum plasma concentration and maximal concentration were 12 hours (range, 4 to 24 hours) and 1.30 ng/mL (range, 0.62 to 2.73 ng/mL), respectively. Fentanyl concentrations were maintained at >0.5 ng/mL for 40 hours after TFP application.

CONCLUSIONS AND CLINICAL RELEVANCE

IV administration of fentanyl resulted in a short half-life. Application of a TFP resulted in stable blood fentanyl concentrations in sheep.

A facile method for preparation of [(2)h(3)]-sufentanil and its metabolites

An improved process for the synthesis of sufentanil with an overall yield of 26% is described. The reactive and high yielding N-debenzylation of the piperidine intermediate 7 using a mixture of Pd/C and Pd(OH)(2) was applied to other drug intermediates affording free amines in short reaction times. The deuterium-labeled sufentanil and the metabolite desmethylsufentanil were synthesized applying the optimized process.

Intravenous fentanyl is exhaled and the concentration fluctuates with time

Previous studies have reported that fentanyl is eliminated predominantly by hepatic biotransformation, and that some is eliminated unchanged in urine and stools. No reports have described the elimination of fentanyl via the lungs. In this study, exhaled gas samples from eight anaesthetized patients undergoing cardiac surgery were analysed using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Results confirmed that fentanyl was exhaled by patients after intravenous administration, that the concentration of exhaled fentanyl fluctuated with time and peak concentrations were reached approximately 15 - 20 min after intravenous fentanyl administration. Thus, in addition to hepatic biotrans formation and elimination via urine and faeces, fentanyl is also eliminated unchanged by the lungs. The potential risk to operating theatre personnel from long-term exposure to low levels of exhaled anaesthetic agents following intravenous administration to patients during surgery warrants further research.

Determination of fentanyl in biological and water samples using single-drop liquid-liquid-liquid microextraction coupled with high-performance liquid chromatography

A single-drop liquid-liquid-liquid microextraction (LLLME) method coupled with high-performance liquid chromatography (HPLC) was developed for the determination of fentanyl in biological (plasma and urine) and wastewater samples. Fentanyl is a potent synthetic narcotic analgesic administered in the form of a transdermal patch for the management of chronic pain. Fentanyl was extracted from 0.01 M NaOH solution (donor phase) into a thin layer of organic phase (100 muL), then back-extracted into 5 muL of the acidic acceptor microdrop (1 x 10(-3)M HClO(4)) immersed in the organic membrane from the tip of a 25-muL HPLC syringe. After the extraction, the microdrop was withdrawn into the syringe and injected directly into a HPLC system for analysis. The parameters influencing the extraction efficiency including the organic solvent and its volume, acceptor microdrop volume, composition of the donor and acceptor phases, stirring rate, temperature, salt addition and pre- and back-extraction times were investigated and optimized. At the most appropriate conditions (100 muL of n-octane, 3.6 mL of the donor phase maintained at 0.01 M NaOH, 5 muL of 1 x 10(-3)M HClO(4) as the acceptor microdrop, stirring rate of 1000 rpm for pre-extraction and 700 rpm for back-extraction, 30 degrees C, no salt addition, 30 min for pre-extraction and 20 min for back-extraction), an enrichment factor (EF) of 355 was obtained. The limit of detection (LOD) was 0.1 ngmL(-1) (based on S/N=3) and intra- and inter-day relative standard deviations less than 9% were obtained. The calibration graph was linear within the range of 0.5-1000 ngmL(-1) with the correlation coefficient (r) of 0.9999. Finally, the feasibility of the proposed method was evaluated by extraction and determination of fentanyl in plasma, urine and wastewater samples and satisfactory results were obtained.

Use of single-drop microextraction for determination of fentanyl in water samples

Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized. The method was found to be linear in the concentration range 0.10-10 ng mL(-1). The limits of quantitation and detection of the method were 100 pg mL(-1) and <75 pg mL(-1), respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up, short analysis time, high sensitivity, and minimum use of organic solvent.

Determination of fentanyl in human plasma by head-space solid-phase microextraction and gas chromatography-mass spectrometry

A head-space solid-phase microextraction (HS-SPME) method coupled to GC-MS was developed to extract fentanyl from human plasma. The protein binding was reduced by acidification and, eventually, the sample was deproteinized with trichloroacetic acid. The parameters influencing adsorption (extraction time, temperature, pH and salt addition) and desorption (desorption time and temperature) of the analyte on the fibre were investigated and validated for method development. The developed method proved to be rapid, simple, easy and inexpensive and offers high sensitivity and reproducibility. Linear range was obtained from 0.1 ng/ml to 2 microg/ml. The limit of detection was 0.03 ng/ml while an inter-day precision of less than 5% (n=15) could be achieved. The method has been applied for the determination of fentanyl in plasma samples after application of 50 microg/h Duragesic fentanyl patch.

Identification of exposure pathways for opioid narcotic analgesics in pharmaceutical production workers

The protection of workers from the potential harmful effects of active pharmaceutical ingredients (APIs) poses a significant challenge for the drug manufacturing industry. The actual pathways through which pharmaceutical production workers are exposed to potent drugs and the processes resulting in actual uptake are up till now virtually unknown. In this study, a detailed exposure assessment survey was conducted in a pharmaceutical 'primary manufacturing' production facility during which environmental and biological exposure monitoring for potent opioid narcotic drugs was performed. On the occasion of multiple consecutive production days, personal half-shift air samples were collected and hand wipes were taken at the end of each half-shift and analysed for fentanyl. All environmental samples showed detectable amounts of fentanyl (>0.1 ng per sample), indicating a potential for both inhalation and dermal exposure. Spatial distribution of fentanyl dermal contamination was further investigated by means of patch samplers placed on five anatomical regions of the body. Body locations showing the highest level of fentanyl contamination were identified as the hands, the neck and lower arms. The effective uptake of fentanyl was demonstrated by the detection of this opioid in urine samples of the workers involved. Individual and group-level analysis of combined external and internal fentanyl exposure measures revealed a positive and significant correlation between fentanyl hand exposure and urinary excretion, while it seemed that the effect of inhalation exposure was largely due to its correlation with dermal exposure. The results of the established individual linear and mixed effects models strongly suggest that in most workers the dermal pathway is actually the primary route of fentanyl exposure.

High sensitive determination of sufentanil in human plasma of parturients and neonates following patient-controlled epidural analgesia (PCEA)

A validated method for the determination of sufentanil in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is described. Sufentanil was extracted from human plasma with solid-phase-extraction using deuterated sufentanil, [(2)H(5)]-sufentanil, as internal standard. Sufentanil and the internal standard were determined with an API 4000 tandem mass spectrometer equipped with a Turbo-V-Source operating in positive ESI mode on an Alltima HP HILIC straight phase column. The method showed a lower limit of quantification of 0.25 pg/ml (12.5 fg on column). The applicability of the method is shown in a clinical study, in which levels of sufentanil in plasma of parturients and arterial umbilical plasma of their neonates following patient-controlled epidural analgesia (PCEA) under several regimen treatments was analyzed.