Quantitative determination of fentanyl in newborn pig plasma and cerebrospinal fluid samples by HPLC-MS/MS

Lipemia in the Plasma Sample Affects Fentanyl Measurements by Means of HPLC-MS2 after Liquid-Liquid Extraction

Examination of fentanyl levels is frequently performed in certain scientific evaluations and forensic toxicology. It often involves the collection of very variable blood samples, including lipemic plasma or serum. To date, many works have reported the methods for fentanyl detection, but none of them have provided information about the impact on the assay performance caused by an excessive amount of lipids. This aspect may be, however, very important for highly lipophilic drugs like fentanyl. To address this issue, we developed the liquid chromatography method with mass spectrometry detection and utilized it to investigate the impact of lipids presence in rabbit plasma on the analytical method performance and validation. The validation procedure, conducted for normal plasma and lipemic plasma separately, resulted in good selectivity, sensitivity and linearity. The limits of detection and quantification were comparable between the two matrices, being slightly lower in normal plasma (0.005 and 0.015 µg/L) than in lipemic plasma (0.008 and 0.020 µg/L). Liquid–liquid extraction provided a low matrix effect regardless of the lipid levels in the samples (<10%), but pronounced differences were found in the recovery and accuracy. In the normal plasma, this parameter was stable and high (around 100%), but in the lipemic matrix, much more variable and less efficient results were obtained. Nevertheless, this difference had no impact on repeatability and reproducibility. In the present work, we provided reliable, convenient and sensitive method for fentanyl detection in the normal and lipemic rabbit plasma. However, construction of two separate validation curves was necessary to provide adequate results since the liquid-liquid extraction was utilized. Therefore, special attention should be paid during fentanyl quantification that involves lipemic plasma samples purified by this technique.

Quantitative analysis of 20 fentanyl analogues by modified QuEChERS-LC-MS/MS in health products and transdermal patches

The spreading of narcotics especially illicit novel psychoactive substances is a continuing problem in recent years. In response to reduce the morbidity and crime related to fentanyl analogues, the accurate measurement of fentanyl analogues concentrations is significantly important in the analytical laboratories for customs checks and clinical application. In this work, ethyl acetate was selected as extraction solvent, 50 mg of PSA, 100 mg of C18, and 10 mg of GCB were optimized for purification. A modified QuEChERS extraction method followed by high performance liquid chromatography-tandem mass spectrometry with the mode of multiple reaction monitoring has been developed for the simultaneous determination of 20 fentanyl analogues in collagen peptides, slimming capsules and fentanyl transdermal patches. The limits of detection (LODs) varied from 0.004 to 0.02 μg L^-1 with relative standard deviations of 4.89-11.4 % and showed good linearity in the range of 0.02-10 μg L^-1 and 0.01-1.00 mg L^-1, respectively. The recoveries for 20 fentanyl analogues in the low (at μg L^-1 level) and high (at mg L^-1 level) concentration spiked samples were in the range of 77.7-114 % and 83.9-116 %, which demonstrated the application potential of the proposed method for the determination of fentanyl analogues with low and high concentration in real case samples. In addition, the matrix effect and the cross-reactivity were also proved to not interfere with quantitation of targeted fentanyl analogues. Thus, the developed method showed high sensitivity and good accuracy, which makes it suitable for the rapid detection of fentanyl analogues for customs and border service as well as pharmaceuticals.

Higher naloxone dosing in a quantitative systems pharmacology model that predicts naloxone-fentanyl competition at the opioid mu receptor level

Rapid resuscitation of an opioid overdose with naloxone, an opioid antagonist, is critical. We developed an opioid receptor quantitative systems pharmacology (QSP) model for evaluation of naloxone dosing. In this model we examined three opioid exposure levels that have been reported in the literature (25 ng/ml, 50 ng/ml, and 75 ng/ml of fentanyl). The model predicted naloxone-fentanyl interaction at the mu opioid receptor over a range of three naloxone doses. For a 2 mg intramuscular (IM) dose of naloxone at lower fentanyl exposure levels (25 ng/ml and 50 ng/ml), the time to decreasing mu receptor occupancy by fentanyl to 50% was 3 and 10 minutes, respectively. However, at a higher fentanyl exposure level (75 ng/ml), a dose of 2 mg IM of the naloxone failed to reduce mu receptor occupancy by fentanyl to 50%. In contrast, naloxone doses of 5 mg and 10 mg IM reduced mu receptor occupancy by fentanyl to 50% in 5.5 and 4 minutes respectively. These results suggest that the current doses of naloxone (2 mg IM or 4 mg intranasal (IN)) may be inadequate for rapid reversal of toxicity due to fentanyl exposure and that increasing the dose of naloxone is likely to improve outcomes.

Ten Years of Fentanyl-like Drugs: a Technical-analytical Review

Synthetic opioids, such as fentanyl and its analogues, are a new public health warning. Clandestine laboratories produce drug analogues at a faster rate than these compounds can be controlled or scheduled by drug agencies. Detection requires specific testing and clinicians may be confronted with a sequence of severe issues concerning the diagnosis and management of these contemporary opioid overdoses. This paper deals with methods for biological sample treatment, as well as the methodologies of analysis that have been reported, in the last decade, in the field of fentanyl-like compounds. From this analysis, it emerges that the gold standard for the identification and quantification of 4-anilinopiperidines is LC-MS/MS, coupled with liquid-liquid or solid-phase extraction. In the end, the return to the scene of illicit fentanyls can be considered as a critical problem that can be tackled only with a global multidisciplinary approach.

Bioanalytical methods for the quantification of hydromorphone, fentanyl, norfentanyl, morphine, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma

The aim of this study was to develop an assay for the quantification of hydromorphone, morphine, fentanyl and the metabolites norfentanyl, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma to support pharmacokinetic studies investigating the large interpatient variability in response to opioid treatment. For the quantitation of hydromorphone, morphine, fentanyl and its metabolite norfentanyl aliquots of 200μL human potassium EDTA plasma were deproteinized with deuterated internal standards in a mixture of acetonitrile and acetone, followed by a liquid-liquid extraction with 4% ammonium hydroxide and ethyl acetate. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were extracted by a solid phase extraction using 10mM ammonium carbonate pH 8.8 and a deuterated internal standards solution. Morphine, hydromorphone, fentanyl and norfentanyl were separated on an Aquity UPLC^® BEH C18 column 1.7μm, 100mm×2.1mm at 50°C. Separation, was achieved on a gradient of methanol with an overall run time of 6min. The compounds were quantified by triple-quadrupole mass spectrometry in the positive ion electrospray ionization mode. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were separated on a VisionHT C18-P; 3μm 2.1×50mm, column at 40°C on a gradient of acetonitrile, with an overall run time of 10min. Both methods were precise and accurate, with within-run and between-run precisions within acceptable limits and accuracy ranging from 84.0 to 105.5%. The methods were successfully applied to support clinical pharmacological studies in patients treated with opioids for the treatment of moderate to severe cancer-related pain.