Electrochemical Detection of Oxycodone and Its Main Metabolites with Nafion-Coated Single-Walled Carbon Nanotube Electrodes.

Oxycodone is a strong opioid frequently used as an analgesic. Although proven efficacious in the management of moderate to severe acute pain and cancer pain, use of oxycodone imposes a risk of adverse effects such as addiction, overdose, and death. Fast and accurate determination of oxycodone blood concentration would enable personalized dosing and monitoring of the analgesic as well as quick diagnostics of possible overdose in emergency care. However, in addition to the parent drug, several metabolites are always present in the blood after a dose of oxycodone, and to date, there is no electrochemical data available on any of these metabolites. In this paper, a single-walled carbon nanotube (SWCNT) electrode and a Nafion-coated SWCNT electrode were used, for the first time, to study the electrochemical behavior of oxycodone and its two main metabolites, noroxycodone and oxymorphone. Both electrode types could selectively detect oxycodone in the presence of noroxycodone and oxymorphone. However, we have previously shown that addition of a Nafion coating on top of the SWCNT electrode is essential for direct measurements in complex biological matrices. Thus, the Nafion/SWCNT electrode was further characterized and used for measuring clinically relevant concentrations of oxycodone in buffer solution. The limit of detection for oxycodone with the Nafion/SWCNT sensor was 85 nM, and the linear range was 0.5-10 µM in buffer solution. This study shows that the fabricated Nafion/SWCNT sensor has potential to be applied in clinical concentration measurements.

Supramolecular Sensors for Opiates and Their Metabolites.

The present study highlights a sensing approach for opiates using acyclic cucurbituril (aCBs) sensors comprising four glycouril units terminated on both ends with naphthalene fluorophore walls. The connectivity between the glycourils and naphthalene rings largely defines the opening size of the cucurbituril cavity and its diameter. The large hydrophobic binding cavity is flexible and is able to adapt to guests of various size and topology. The recognition event between the aCBs and guests results in modification of the fluorescence of the terminal walls, a fluorescence response that can be used to sense the drugs of abuse morphine, heroin, and oxycodone as well as their metabolites. Molecular dynamics is employed to understand the nature of the binding interactions. A simple three sensor cross-reactive array enables the determination of drugs and their metabolites in water with high fidelity and low error. Quantitative experiments performed in urine using a new three-way calibration model allows for determination of drugs and their metabolites using one sensor from a single fluorescence reading.

Candidate metrics for evaluating the impact of prescriber education on the safe use of extended-release/long-acting (ER/LA) opioid analgesics.

OBJECTIVE: The objective of this study was to develop metrics to assess opioid prescribing behavior as part of the evaluation of the Extended-Release/Long-Acting (ER/LA) Opioid Analgesic Risk Evaluation and Mitigation Strategies (REMS). DESIGN: Candidate metrics were selected using published guidelines, examined using sensitivity analyses, and applied to cross-sectional rolling cohorts of Medicare patients prescribed with extended-release oxycodone (ERO) between July 2, 2006 and July 1, 2011. Potential metrics included prescribing opioid-tolerant-only ER/LA opioid analgesics to non-opioid-tolerant patients, prescribing early fills to patients, and ordering drug screens. RESULTS: Proposed definitions for opioid tolerance were seven continuous days of opioid usage of at least 30 mg oxycodone equivalents, within the 7 days (primary) or 30 days (secondary) prior to first opioid-tolerant-only ERO prescription. Forty-four percent of opioid-tolerant-only ERO episodes met the primary opioid tolerance definition; 56% met the secondary definition. Fills were deemed "early" if a prescription was filled before 70% (primary) or 50% (secondary) of the prior prescription's days' supply was to be consumed. Five percent (primary) and 2% (secondary) of episodes had more than or equal to two early fills during treatment. At least one drug screen was billed in 14% of episodes. Stratified analyses indicated that older patients were less likely to be opioid tolerant at the time of the first opioid-tolerant-only ERO prescription. CONCLUSIONS: Investigators propose three metrics to monitor changes in prescribing behaviors for opioid analgesics that might be used to evaluate the ER/LA Opioid Analgesics REMS. Low frequencies of patients, particularly those >85 years, were likely to be opioid tolerant prior to receiving prescriptions for opioid-tolerant-only ERO.

Suspected North Carolina counterfeit pill-involved deaths, 2020-2022.

The NC Office of the Chief Medical Examiner regularly assumes jurisdiction over deaths that are suspicious, unusual or unattended by a medical professional. In recent years, the presence of counterfeit pills is occasionally suggested by investigatory notes and/or scene findings that document reported consumption of prescription drugs, or prescription drugs on scene, which are not reflected in the final autopsy findings after toxicological analysis of the decedent's blood samples. Counterfeit pill consumption is a major public health hazard worthy of attention from the forensic toxicology community. Seventy-five cases from January 2020 to December 2022 serve as a convenience sample of cases where prescription pills including formulations of alprazolam, oxycodone and hydrocodone were specifically referenced during the death scene investigation as recently consumed, yet an unexpected substance was found during toxicological analysis rather than the expected pharmaceutical drug. Of note, novel benzodiazepines detected included flualprazolam, etizolam, clonazolam metabolite (8-aminoclonazolam), bromazolam, flubromazolam and desalkylflurazepam. Decedents' ages ranged from 16 to 69, across 33 different NC counties. Case notes indicated that eight of the decedents obtained pills through direct personal relationships, six decedents obtained them from "the street" and one decedent likely purchased pills online. Pills were largely consumed orally or through insufflation. Seven case reports contained indication that decedents knew or suspected the counterfeit nature of their pills. This study describes the context and characteristics of 2020-2022 suspected counterfeit pill-involved deaths in NC to further the understanding of the forensic science community, law enforcement partners, public health stakeholders and those potentially at risk through the consumption of counterfeit pills.

Analysis of pharmaceutical compounds from glass, fabric, steel, and wood surfaces at atmospheric pressure using spatially resolved, nonresonant femtosecond laser vaporization electrospray mass spectrometry.

Laser electrospray mass spectrometry (LEMS) is demonstrated for pharmaceutical samples at atmospheric pressure. A nonresonant, femtosecond duration laser pulse vaporizes native samples at atmospheric pressure into an electrospray plume for ionization with subsequent transfer into a time-of-flight mass spectrometer. The active ingredients in pharmaceutical tablets were detected in the presence of binders and fillers in intact formulations using LEMS. Mass spectra were also obtained for microgram amounts of the pharmaceutical compounds loratadine, oxycodone, and atenolol deposited on glass, wood, steel, and polyester fabric. The neutral capture efficiency by the electrospray plume for nonresonant laser vaporization of oxycodone and atenolol desorbed from steel is 2.4% +/- 1.5% and 0.25% +/- 0.18%, respectively. LEMS imaging of the spatial distribution of an oxycodone spot on a metal slide with resolution of 250 mum is also presented.

Measurement of multiple drugs in urine, water, and on surfaces using fluorescence covalent microbead immunosorbent assay.

There are a range of applications that require the measurement of multiple drugs such as urine analysis, drug determination in water, and screening for drug contamination on surfaces. Some of the procedures used such as enzyme-linked immunosorbent assay (ELISA) are simple but can only determine one drug at a time, and others such as GC-MS or LC-MS are complex, time-consuming, and expensive. In this study, fluorescence covalent microbead immunosorbent assay (FCMIA) was investigated as a simple method for the measurement of multiple drugs simultaneously in three matrices: diluted urine, water, and on surfaces. Five different drugs of abuse or their metabolites (methamphetamine, caffeine, benzoylecgonine (a metabolite of cocaine), tetrahydrocannabinol (THC), the active ingredient in marijuana, and oxycodone) were studied over the range 0-15 ng/ml. There was no measureable cross-reactivity among the drugs at the concentrations studied. Urine dilutions from 1/50 to 1/2.5 were studied and dilutions less than 1/20 had a significant effect on the methamphetamine assay but limited effects on the benzoylecgonine and oxycodone assays and almost no effect on the THC assay. For assays performed in 1/20 urine dilution, water, and diluted surface sampling buffer, least detectable doses (LDD) were 1 ng/ml or less for the drugs. Surfaces spiked with drugs were sampled with swabs wetted with surface sampling buffer and recoveries were linear over the range 0-100 ng/100 cm(2) surface loading for all drugs. FCMIA has potential to be used for the measurement of multiple drugs in the matrices studied.

Detection of Fentanyl Analogs and Synthetic Opioids in Real Hair Samples.

Novel synthetic opioids include various analogs of fentanyl and emerging non-fentanyl compounds with different chemical structures, such as AH-7921, MT-45 and U-47700. In recent years, these drugs have rapidly emerged on the drug market, and their abuse has been increasing worldwide. The motivations for use of these new compounds include their legal status, ready availability, low cost, users' curiosity or preference for their particular pharmacological properties and the intention to avoid detection. Furthermore, more common drugs like heroin are now increasingly being replaced or cut with fentanyl or new designer opioids; thus, many drug users are unintentionally or unknowingly using synthetic fentanyl analogs. In this scenario, the detection of new psychoactive substances in hair can provide insight into their current diffusion among the population and social characteristics of these synthetic drug users. In this manuscript, we describe a simple, fast, specific and sensitive UHPLC-MS-MS method able to detect 13 synthetic opioids (including fentanyl analogs) and metabolites in hair samples. Furthermore, the method includes the detection of 4-anilino-N-phenethyl-piperidine (4-ANPP), which is considered both a precursor and a metabolite of several fentanyl analogs. The method was applied to 34 real hair samples collected in New York City from subjects who had reported past-year non-medical opioid and/or heroin use. In total, 17 samples tested positive for at least one target analyte, with oxycodone (nine samples) and tramadol (eight samples) being the most common. Among these, the method was able to quantify furanyl-fentanyl and fentanyl in the pg/mg range in two samples. Simultaneously, also 4-ANPP was detected, giving evidence for the first time that this compound can be selected as a marker of fentanyl analogs use via hair testing. In conclusion, this study confirmed the increasing diffusion of new synthetic opioids and "fentalogs" with high potency among non-medical opioid users.

Opioid Deaths in Milwaukee County, Wisconsin 2013-2017: The Primacy of Heroin and Fentanyl.

Heroin and fentanyl are the overwhelming and increasing cause of opioid deaths in Milwaukee County, Wisconsin. We reviewed all drug and opioid deaths from 2013 to 2017 to delineate the specific opioid drugs involved and changes in their incidence. From 2013 to 2017, 980 deaths were due to opioids, rising from 184 in 2013 to 337 in 2017. In 2017, opioid deaths exceeded combined non-natural deaths from homicide and suicide. Illicit heroin and fentanyl/analogs caused 84% of opioid deaths and 80% of drug deaths, with no increase in deaths due to oral prescription drugs such as oxycodone and hydrocodone. Any approach to decreasing this dramatic increase in opioid deaths should first focus on interdicting the supply and cheap availability of these illicit opioids. Fentanyl and its analogs represent the most deadly opioids and the greatest threat to human life in our population.

Positivity rates of drugs in patients treated for opioid dependence with buprenorphine: A comparison of oral fluid and urine using paired collections and LC-MS/MS.

BACKGROUND: Drug testing is recommended as part of comprehensive monitoring for medication-assisted treatment. Alternative matrices including oral fluid offer a number of advantages when compared with conventional urine testing but are not as well characterized. This study aims to compare positivity rates of drugs and drug classes in oral fluid and urine as a measure of the clinical utility of oral fluid in the evaluation and treatment of patients with opioid use disorders. METHODS: A retrospective review of paired oral fluid and urine test results from Millennium Health's laboratory database was performed for 2746 patients with reported prescriptions for buprenorphine products used in the treatment of opioid dependence. Specimens were tested using quantitative LC-MS/MS for 34 medications, metabolites and illicit drugs. RESULTS: A number of medications and illicit drugs were detected at comparable or higher rates in oral fluid vs. urine such as cocaine (15.7% vs. 7.9%), opiates (13.4% vs. 10.0%), oxycodone (8.6% vs. 3.7%), hydrocodone (3.0% vs. 1.2%) and others. Lower detection rates were observed in oral fluid vs. urine for benzodiazepines (6.6% vs. 8.7%), cannabinoids (15.5% vs. 19.5%), oxymorphone (1.8% vs. 3.1%) and hydromorphone (0.8% vs. 4.5%). CONCLUSIONS: Clinicians may find oral fluid advantageous for detection of specific drugs and medications in certain clinical situations. Understanding the relative differences between urine and oral fluid can help clinicians carefully select tests best suited for detection in their respective matrix. To our knowledge, this is the largest inter-matrix patient comparison study using paired collections and direct to definitive testing.

Development of a Quantitative LC-MS-MS Assay for Codeine, Morphine, 6-Acetylmorphine, Hydrocodone, Hydromorphone, Oxycodone and Oxymorphone in Neat Oral Fluid.

Recent advances in analytical capabilities allowing for the identification and quantification of drugs and metabolites in small volumes at low concentrations have made oral fluid a viable matrix for drug testing. Oral fluid is an attractive matrix option due to its relative ease of collection, reduced privacy concerns for observed collections and difficulty to adulterate. The work presented here details the development and validation of a liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the quantification of codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone and oxymorphone in neat oral fluid. The calibration range is 0.4-150 ng/mL for 6-acetylmorphine and 1.5-350 ng/mL for all other analytes. Within-run and between-run precision were <5% for all analytes except for hydrocodone, which had 6.2 %CV between runs. Matrix effects, while evident, could be controlled using matrix-matched controls and calibrators with deuterated internal standards. The assay was developed in accordance with the proposed mandatory guidelines for opioid confirmation in federally regulated workplace drug testing. The use of neat oral fluid, as opposed to a collection device, enables collection of a single sample that can be split into separate specimens.

Oxycodone-induced tolerance to respiratory depression: reversal by ethanol, pregabalin and protein kinase C inhibition.

BACKGROUND AND PURPOSE: Oxycodone, a prescription opioid, is a major drug of abuse, especially in the USA, and contributes significantly to opioid overdose deaths each year. Overdose deaths result primarily from respiratory depression. We have studied respiratory depression by oxycodone and have characterized how tolerance develops on prolonged exposure to the drug. We have investigated the role of PKC in maintaining tolerance and have examined whether ethanol or pregabalin reverses oxycodone-induced tolerance. EXPERIMENTAL APPROACH: Respiration was measured in male CD-1 mice by whole-body plethysmography. Mice were preinjected with oxycodone then implanted with mini-pumps (s.c.) delivering 20, 45 or 120 mg·kg-1 ·day-1 oxycodone for 6 days and subsequently challenged with oxycodone (3 mg·kg-1 , i.p.) or morphine (10 mg·kg-1 , i.p.) to assess the level of tolerance. KEY RESULTS: Oxycodone-treated mice developed tolerance to oxycodone and cross tolerance to morphine-induced respiratory depression. Tolerance was less with 20 mg·kg-1 ·day-1 than with 45 or 120 mg·kg-1 ·day-1 oxycodone treatment. At doses that do not depress respiration, ethanol (0.3 g·kg-1 ), pregabalin (20 mg·kg-1 ) and calphostin C (45 µg·kg-1 ) all reversed oxycodone-induced tolerance resulting in significant respiratory depression. Reversal of tolerance was less in mice treated with oxycodone (120 mg·kg-1 ·day-1 ). In mice receiving ethanol and calphostin C or ethanol and pregabalin, there was no greater reversal of tolerance than seen with either drug alone. CONCLUSION AND IMPLICATIONS: These data suggest that oxycodone-induced tolerance is mediated by PKC and that reversal of tolerance by ethanol or pregabalin may be a contributory factor in oxycodone overdose deaths.

Determination of meperidine, tramadol and oxycodone in human oral fluid using solid phase extraction and gas chromatography-mass spectrometry.

Analytical procedures for the determination of meperidine, tramadol and oxycodone in oral fluid have been developed and validated using gas chromatography-mass spectrometry (GC/MS) following initial screening with enzyme linked immunosorbent assay (ELISA). The oral fluid samples were collected using the Quantisal device, and any drugs present were quantified using mixed mode solid-phase extraction and electron impact GC/MS. For confirmation, three ions were monitored and two ion ratios determined, which were within 20% of those of the known calibration standards. The limits of quantitation were 10 ng/mL; the intra-day precision of the assays (n=5) was 2.33%, 1.00% and 7.61%; inter-day precision 2.48%, 2.44% and 5.8% (n=10) for meperidine, tramadol and oxycodone, respectively. The percentage recovery of the drugs from the collection pads was 86.7%, 87.7% and 96.6%, respectively (n=6). The methods were applied to specimens obtained during research studies in the USA.

Simultaneous determination of codeine, morphine, hydrocodone, hydromorphone, oxycodone, and 6-acetylmorphine in urine, serum, plasma, whole blood, and meconium by LC-MS-MS.

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for simultaneous analysis of six major opiates in urine, serum, plasma, whole blood, and meconium is described. The six opiates included are codeine, morphine, hydrocodone, hydromorphone, oxycodone, and 6-acetylmorphine (6-AM). The method was compared to an in-house gas chromatography (GC)-MS method and an LC-MS-MS method performed by another laboratory. The sample preparation time was decreased by eliminating the glucuronide hydrolysis and derivatization required for GC-MS analysis, as well as by adapting the solid-phase extraction to elute directly into autosampler vials. These improvements illustrate the advantages of an LC-MS-MS method over a GC-MS method for opiates. The structural similarity of these six opiates and others in the opiate class causes a high potential for interference and false-positive results. Twelve opiate analogues and metabolites were evaluated for interference. The potential for interference was reduced by altering the MRM transitions chosen for the six opiates. The increased specificity of LC-MS-MS decreased the interference rate in urine to 3.9% compared to 13.6% on the in-house GC-MS method. The rate of positivity for 6-AM in meconium is described for the first time. In urine, 11.0% of morphine positive specimens were also positive for 6-AM compared to 8.3% in serum/plasma and 0.9% in meconium. Although 6-AM is infrequent in meconium, it provides a definitive proof of illegal heroin abuse by the pregnant mother. This method has been routinely used in our laboratory over the last 6 months on more than 1500 patient specimens.

An estimate of the proportion of drug-facilitation of sexual assault in four U.S. localities.

In recent years, drugs including flunitrazepam, gamma-hydroxybutyrate, ketamine, and ethanol, have become popularly associated with drug-facilitated sexual assault. Other drugs are also candidates as factors in "drug facilitated sexual assault" (DFSA). The true extent of DFSA is not known, and is difficult to estimate. We recruited sexual assault complainants at four clinics in different parts of the U.S. to anonymously provide urine and hair specimens, and to answer questions about suspected drugging, drug use, and the sexual assault incident. Urine and hair specimens were tested for 45 drugs, including ethanol, and those pharmacologically capable of inducing sedation, amnesia, or impairment of judgment. Analytical test results were used to estimate the proportion of subjects, and the proportion of all complainants to the clinic in the same time period, who were victims of DFSA. Overall, cases of 43% of 144 subjects, and 7% of 859 complainants, were characterized as DFSA. Subjects underreported their use of drugs. The role of toxicological results and history in characterizing DFSA cases is discussed.

Predictive Value of Positive Drug Screening Results in an Urban Outpatient Population.

Urine drug testing (UDT) has become an essential component in the management of patients prescribed opioid analgesics for the treatment of chronic non-malignant pain. Several laboratory methods are available to monitor adherence with the pharmacological regimen and abstinence from illicit or unauthorized medications. Immunochemical screening methods are rapid and economical, but they have limitations, including lack of specificity, and confirmatory methods are often necessary to verify presumptive positive results. We analyzed the results of confirmatory assays in an outpatient setting to determine the predictive value of presumptive positive urine drug screen results using an automated immunoassay for eight common drugs or drug classes. Positive predictive values (PPVs), in descending order, were as follows: cannabinoids (100%), cocaine (100%), opiates (86.8%), benzodiazepines (74.6%), oxycodone (67.6%), methadone (44.1%) and amphetamines (9.3%). The number of positive barbiturate results was too small to be included in the statistical analysis.

The detection of oxycodone in meconium specimens.

A procedure for the determination of oxycodone in meconium using direct ELISA microplate technology followed by electron impact gas chromatography-mass spectrometry (GC-MS) is described for the first time. The abuse of oxycodone (OxyContin) has been widely discussed in mainstream media, and it has been described as a cheap form of heroin. Oxycodone has been reported as having a high degree of abuse and potential complications in neonates from maternal drug use. Using a standard enzyme multiplied immunoassay screening technology, the cross-reactivity of oxycodone to the morphine antibody is only 5-6%. A positive screening value would require a high concentration of drug to be present, so a protocol for the detection of oxycodone in meconium using a direct ELISA microplate immunoassay followed by GC-MS was developed. The assay is now routinely used in our laboratory.

The Disposition of Oxycodone and Metabolite in Human Hair.

The disposition of oxycodone (OC) and metabolites in hair remains poorly characterized. We present a case involving a pharmacist in an impaired professionals' monitoring program in whom hair testing yielded OC on two occasions. On both occasions, his hair was negative for the oxymorphone (OM) metabolite at the cutoff concentration of 100 pg/mg. He claimed that, absent the detection of metabolite, the OC necessarily represented external contamination. This prompted a review of the laboratory's OC-positive hair results for the quarter April-June 2014. Overall, 466 specimens contained OC, with a mean (median) concentration of 2,375 (1,060) pg/mg. Of these OC-positive specimens, only 47 (10%) contained detectable OM. When OC was present at or below the mean (median) concentration, only 2.2% (1.3%) of specimens were OM-positive. In the setting of OC administration, the detection of OM in hair is unlikely at a cutoff concentration of 100 pg/mg. More consistent demonstration of OC metabolite(s) in hair will require the validation of methods to detect OM at lower concentrations and/or methods to detect noroxycodone.

Approximating the detection limit of an infrared spectroscopic imaging microscope operating in an attenuated total reflection (ATR) modality: theoretical and empirical results for an instrument using a linear array detector and a 1.5 millimeter germanium hemisphere internal reflection element.

Theoretical and empirical detection limits have been estimated for aripiprazole (analyte) in alpha lactose monohydrate (matrix model pharmaceutical formulation) using a micro-attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic imaging instrument equipped with a linear array detector and a 1.5 mm germanium hemisphere internal reflection element (IRE). The instrument yielded a theoretical detection limit of 0.0035% (35 parts per million (ppm)) when operating under diffraction-limited conditions, which was 49 times lower than what was achieved with a traditional macro-ATR instrument operating under practical conditions (0.17%, 1700 ppm). However, these results may not be achievable for most analyses because the detection limits will be particle size limited, rather than diffraction limited, for mixtures with average particle diameters greater than 8.3 µm (most pharmaceutical samples). For example, a theoretical detection limit of 0.028% (280 ppm) was calculated for an experiment operating under particle size-limited conditions where the average particle size was 23.4 µm. These conditions yielded a detection limit of 0.022% (220 ppm) when measured empirically, which was close to the theoretical value and only eight times lower than that of a faster, more simplistic macro-ATR instrument. Considering the longer data acquisition and processing times characteristic of the micro-ATR imaging approach (minutes or even hours versus seconds), the cost-benefit ratio may not often be favorable for the analysis of analytes in matrices that exhibit only a few overlapping absorptions (low-interfering matrices such as alpha lactose monohydrate) using this technique compared to what can be achieved using macro-ATR. However, the advantage was significant for detecting analytes in more complex matrices (those that exhibited several overlapping absorptions with the analyte) because the detection limit of the macro-ATR approach was highly formulation dependent while that of the micro-ATR imaging technique was not. As a result, the micro-ATR imaging technique is expected to be more valuable than macro-ATR for detecting analytes in high-interfering matrices and in products with unknown ingredients (e.g., illicit tablets, counterfeit tablets, and unknown powders).