Validated GC–MS analysis for the determination of residual fentanyl in applied Durogesic® reservoir and Durogesic® D-Trans® matrix transdermal fentanyl patches

Fentanyl transdermal patches: Extraction and evaluation of a novel disposal method using NarcX®

Currently, there is no known commercially available product for disposing of used fentanyl transdermal patches. To eliminate the potential for harm and abuse, a proper disposal method is needed-one that neutralizes the dangerous amount of residual fentanyl that remains after therapeutic use of the fentanyl patch. The patent-pending liquid solution of activated carbon, known as NarcX^® , was investigated as a potential fentanyl adsorbing agent. In order to determine the amount of fentanyl remaining after a patch is treated with NarcX^® , here, we utilized hexanes to first dissolve the patch adhesive and then followed with liquid-liquid extraction with methanol to recover the fentanyl. Using liquid chromatography coupled to tandem mass spectrometry (LC/MS-MS), the extracts obtained with this method yielded between 85% and 117% recovery of fentanyl from new and unused patches. Further optimization of this method allowed for a quantitative evaluation of NarcX^® -treated fentanyl patches. 100 µg/h Apotex brand fentanyl patches were exposed to NarcX^® for 1, 24, 48, and 72 h. NarcX^® was shown to adsorb fentanyl from the patches with varying degrees of success, demonstrating an average of 66.98 ± 0.75% fentanyl adsorption after 72 h. These findings suggest that more work is needed to successfully neutralize the fentanyl patches in their entirety using NarcX^® ; however, this work does demonstrate proof of concept.

A deadly trend in fentanyl fatalities (England, 1998-2017)

AIM

To identify trends in drug-related deaths associated with fentanyl and its derivatives, including novel variants, in England, 1998-2017.

METHODS

Case reports from the National Programme on Substance Abuse Deaths (NPSAD) where a pharmaceutical fentanyl or non-pharmaceutical fentanyl derivative (NPFD) was found at post-mortem and/or implicated in the death were extracted for analysis.

RESULTS

NPSAD has received case reports detailing 298 deaths in England from 1998-2017 where a fentanyl was found at post-mortem and/or implicated in the death. Hospital administered fentanyl is "very safe", whereas pharmaceutical fentanyls in the community, procured either legitimately via prescription or illegitimately, carry high risk of unintentional death. Deaths involving NPFDs, which possess extreme potencies in comparison to morphine, have drastically risen over the past three years, and correlate with an increasing number of available compounds. Males, and those with existing opioid abuse disorders, are particularly susceptible to death related to NPFD intake.

CONCLUSIONS

The increasing availability of both pharmaceutical fentanyls and NPFDs represents a serious risk to public health. Unintentional misuse of these compounds in England is contributing to the exponential increase in fentanyl-associated deaths that is being observed at the global scale.

Evaluation of a lateral flow immunoassay for the detection of the synthetic opioid fentanyl

In 2017, 47,600 overdose deaths were reported to be associated with the abuse of opioids, including prescription painkillers (e.g. oxycodone), opiates (e.g. heroin), or synthetic opioids (e.g. fentanyl) within the United States. The recent spike in the presence of synthetic opioids in lots of heroin distributed on the street present specific and significant challenges to law enforcement. Synthetic opioids are extremely toxic substances, which can easily be inhaled. This type of exposure can lead to accidental overdoses by law enforcement and other first responders answering calls involving illicit drugs containing these substances. Due to this extreme toxicity, it is important for these individuals to have tools that can be easily deployed for accurate presumptive field tests. Currently, there are only a limited number of presumptive tests available for fentanyl detection. In this study, we addressed this technology gap by evaluating newly developed lateral flow immunoassays (LFIs) designed for the detection of fentanyl and its derivatives. These LFIs were evaluated for effectiveness in different biofluid matrices, following an in vivo exposure, cross-reactivity with fentanyl analogs, and in case samples. This study demonstrates that LFIs have the potential to be used by law enforcement for the detection of synthetic opioids.

Evaluation of the analgesic and pharmacokinetic properties of transdermally administered fentanyl in goats

OBJECTIVE

Evaluate the analgesic properties and pharmacokinetics of transdermal fentanyl patches (TFPs) in goats.

DESIGN

Prospective, randomized study.

SETTING

Preclinical Testing Facility at a University Teaching Hospital.

ANIMALS

Thirty-four adult female Boer-cross goats.

INTERVENTIONS

Goats underwent surgery as part of a concurrent orthopedic research study. Twelve hours prior to surgery, each goat received a TFP (target dosage of 2.5 μg/kg/h), or a placebo patch with analgesia provided by buprenorphine (0.01 mg/kg, IM, q 6 h). Patches were removed after 72 hours. Blood was sampled at specified intervals, up to 84 hours following TFP placement. Plasma concentrations of fentanyl (FEN) were determined using liquid chromatography-mass spectrometry. Postoperative pain assessments were performed by two independent blinded observers.

MEASUREMENTS AND MAIN RESULTS

TFPs were applied at a mean (± standard deviation, SD) dose of 2.54 ± 0.36 μg/kg/h. No adverse events occurred. Pain scores between TFP and BUP groups were not significantly different at any time point. Mean plasma FEN concentration (± SD) 2 hours following patch application was 1.06 ± 0.85 ng/mL, and remained above 0.5 ng/mL for 40 hours. Maximum mean plasma FEN concentration (C_max ) was 1.84 (ranging from 0.81 to 3.35) ng/mL with average time to maximum concentration (T_max ) of 12 hours after patch application.

CONCLUSIONS

TFP resulted in consistent FEN absorption and plasma concentrations within the human and ovine therapeutic ranges. Pain scores for goats administered TFP were not different than those administered buprenorphine. Ease of administration, duration of analgesia, and decreased dosing frequency make TFPs an attractive option for pain management in goats.

Assisted suicide by fentanyl intoxication due to excessive transdermal application

Herein, we report a case of an assisted suicide committed by application of 34 matrix-based fentanyl-containing transdermal therapeutic systems (TTS) with different release rates. The TTS were supplied by the husband but administered by the deceased herself. Besides routine systematic toxicological analysis (STA), the concentrations of fentanyl and norfentanyl were determined in the blood (femoral and heart), urine, stomach content, brain, lung tissue, musculus iliopsoas, liver, kidney, bile and in some of the used TTS by LC-MS/MS. Blood levels of fentanyl were 60.6 μg/L in femoral blood and 94.1 μg/L in heart blood. These concentrations are in good concordance with levels described in cases with accidental or lethal suicidal fentanyl patch application. The organ distribution indicates an influence of post-mortem redistribution. The levels of residual fentanyl in the TTS were also determined. STA furthermore revealed supratherapeutic levels of bromazepam. Thus, the cause of death was a combination of fentanyl and bromazepam intoxication. However, considering the determined levels of fentanyl and norfentanyl in the entire set of specimens and the high toxicity in comparison to bromazepam, fentanyl was the leading toxic noxa.

Simple and rapid HPLC-UV method using an ultrafine particle octadecylsilane for determination of residual fentanyl in applied Durotep MT transdermal matrix patches and its clinical application

A few complicated and time-consuming methods are available for the determination of residual fentanyl in Durotep MT transdermal patches, however, their application to clinical settings is limited. The aim of this study was to develop a simple and rapid HPLC-UV method using an ultrafine particle octadecylsilane (ODS) for the determination of residual fentanyl in applied Durotep MT transdermal matrix patches. Patch extraction involved sonicating a shredded Durotep MT patch in acetonitrile for 15 min. Fentanyl separation was completed within 2 min using a 2.3-μm particle ODS column (50 × 4.6 mm i.d.) at a flow rate of 1.5 mL/min. No peaks interfering with fentanyl (1.27 min) and papaverine (0.89 min) as an internal standard were observed. The calibration curve for fentanyl was linear over the range of 0.015-9.0 mg as a Durotep MT patch. The intra- and inter-assay precisions and accuracies of each patch were within 5.3% and 103.9-110.5% and within 8.2% and 97.1-104.3%, respectively. The validated method was applied to determine residual fentanyl in Durotep MT patches used in 35 cancer patients. Although the plasma fentanyl concentration was significantly correlated with its measured absorption rate, the measured absorption rate normalized fentanyl concentration showed a large inter-individual variation. The validated simple and rapid HPLC-UV method established in the present study is helpful for evaluating the absorption rate of fentanyl in patients receiving Durotep MT patches.

Evaluation of transdermal fentanyl patch attachment in dogs and analysis of residual fentanyl content following removal

OBJECTIVE

To investigate whether the method used to attach matrix-type fentanyl patches influences the degree of skin attachment and the amount of active drug remaining in patches after use.

STUDY DESIGN

Prospective, randomised clinical study.

STUDY POPULATION

Fifteen adult dogs of mixed breeds.

METHODS

Two equally sized matrix-type fentanyl patches were attached to the dorsal third of the lateral thorax of fifteen dogs for 72 hours. The two patches were attached using different techniques: Method AD used an adhesive dressing in combination with a transparent film. Method TG used tissue adhesive applied to the edges of the patch. After 72 hours the patches were removed and the proportion of the patch attached at this time calculated. The residual content of the patches was analysed using a validated gas chromatography-mass spectrometery (GC-MS) analysis technique.

RESULTS

After 72 hours of continuous attachment, the mean proportion of drug uptake for method AD was 17.2 (SD ± 11.1)% and for method TG this was 16.9 (SD ± 7.3)%. The median proportion of attachment for method AD was 100% and for method TG was 95.6%.

CONCLUSIONS

The method of attachment did not significantly influence the uptake of fentanyl from matrix-type patches. The method of attachment resulted in a significant difference in the proportion of the patch attached 72 hours after placement, with method AD resulting in a greater median proportion of attachment than TG.

CLINICAL RELEVANCE

The method used to attach matrix-type fentanyl patches to dogs should not interfere with drug uptake. The residual fentanyl content remaining in these patches after 72 hours of continuous application is significant and could lead to intoxication if ingested by humans.

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.