Simultaneous determination of alfentanil and midazolam in human plasma using liquid chromatography and tandem mass spectrometry

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.

Impurity profiling of alfentanil hydrochloride by liquid chromatography/quadrupole time-of-flight high-resolution mass spectrometric techniques for drug enforcement

RATIONALE

Fentanyl and its analogues play important roles in the hospital and clinic setting as anesthetics. However, illicitly manufactured fentanyl as well as the new psychoactive substances (NPS) account for 30% of all deaths in the United States. Since fentanyl derivatives and NPS are designed to produce similar effects, their related substances are similar or even have the same active groups. A comprehensive analysis of the related substances of alfentanil hydrochloride can provide a basis for the identification and supervision of fentanyl derivatives and NPS.

METHODS

A liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (LC/QTOF-MS/MS) method was developed for the separation and characterization of related substances in alfentanil hydrochloride. Degradation studies were conducted according to the ICH-prescribed stress conditions. The compounds were identified mainly through positive electrospray ionization QTOF high-resolution mass spectrometric measurements of the accurate masses of the precursor and product ions and their calculated elemental compositions. Their formation mechanisms were also discussed.

RESULTS

Seventeen related substances were detected in alfentanil hydrochloride and its stressed samples. Among them, nine were process-related substances and the other eight were degradation products. The stress study results demonstrated that alfentanil hydrochloride was unstable under acid, alkaline, and oxidative stress conditions, while relatively stable under dry photolytic and thermal stress conditions. Alfentanil hydrochloride was most susceptible for degradation at the N-phenylpropanamide and piperidine sites.

CONCLUSIONS

Process-related alfentanil hydrochloride compounds are useful for determination of synthetic routes and entangling of fentanyl analogues. The stress study results can provide a sound scientific basis for the waste water monitoring of alfentanil. These results are important for routine quality control in the manufacturing and storage of alfentanil hydrochloride, as well as for drug enforcement of fentanyl and its analogues.

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.

Determination of four antiepileptic drugs in plasma using ultra-performance liquid chromatography with mass detection technique

Status epilepticus (SE) is considered the second most frequent neurological emergency. Its therapeutic management is performed using sequential antiepileptic drug regimens. Diazepam (DIA), midazolam (MID), phenytoin (PHT) and phenobarbital (PB) are four drugs of different classes used sequentially in the management of SE. A sensitive, selective, accurate and precise method was developed and validated for simultaneous determination of the four antiepileptic drugs in human plasma. Their separation and quantification were achieved using ultra-performance liquid chromatography (UPLC) with mass detection using carbamazepine as internal standard (IS). For the first three drugs and the IS, UPLC-MS/MS with electrospray ionization working in multiple reaction monitoring mode was used at the following transitions: m/z 285 → 193 for DIA; m/z 326 → 291 for MID; m/z 253 → 182 for PHT; and m/z 237 → 194, 237 → 192 for IS. For the fourth drug (PB), a molecular ion peak of PB [M + H] ⁺ at m/z 233 was used for its quantitation. The method was linear over concentration ranges 5-500 ng/mL for DIA and MID and 0.25-20 μg/mL for PHT and PB. Bioanalytical validation of the developed method was carried out according to European Medicines Agency guidelines. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies.

Development and validation of a sensitive assay for analysis of midazolam, free and conjugated 1-hydroxymidazolam and 4-hydroxymidazolam in pediatric plasma: Application to Pediatric Pharmacokinetic Study

Pharmacokinetic, pharmacodynamic and pharmacogenomic studies of midazolam are currently being performed in critically ill children to find suitable dose regimens. Sensitive assays using small volumes of plasma are necessary to determine the concentrations of midazolam and its respective metabolites in pediatric studies. Midazolam is metabolized to hydroxylated midazolam isomers, which are present as free as well as the corresponding glucuronide conjugates. A high-performance liquid chromatographic method with tandem mass spectrometry has been developed and validated for the quantification of midazolam, and free and total 1-hydroxymidazolam and 4-hydroxymidazolam metabolites in small volumes of plasma. Cleanup consisted of 96-well μ-elution solid phase extraction (SPE). The analytes were separated by gradient elution using a C₁₈ analytical column with a total run time of 5min. Multiple reaction monitoring was employed using precursor to product ion transitions of m/z 326.2→291.3 for midazolam, m/z 342.1→203.0 for 1-hydroxymidazolam, m/z 342.1→325.1 for 4-hydroxymidazolam and m/z 330.2→295.3 for ²H₄-midazolam (internal standard). Since authentic hydroxymidazolamglucuronide standards are not available, samples were hydrolyzed with β-glucuronidase under optimized conditions. Assay conditions were modified and optimized to provide appropriate recovery and stability because 4-hydroxymidazolam was very acid sensitive. Standard curves were linear from 0.5 to 1000ng/mL for all three analytes. Intra- and inter day accuracy and precision for quality control samples (2, 20, 200 and 800ng/mL) were within 85-115% and 15% (coefficient of variation), respectively. Stability in plasma and extracts were sufficient under assay conditions. Plasma samples were processed and analyzed for midazolam, and free 1-hydroxymidazolam and 4-hydroxymidazolam metabolites. Plasma samples that were hydrolyzed with β-glucuronidase were processed and analyzed for midazolam, and total 1-hydroxymidazolam and 4-hydroxymidazolam metabolites under the same assay conditions. The difference in concentration between the total and free hydroxymidazolam metabolites provided an estimate of conjugated hydroxymidazolam metabolites. The combination of 96-well μ-elution SPE and LC-MS/MS allows reliable quantification of midazolam and its metabolites in small volumes of plasma for pediatric patients. This assay is currently being successfully utilized for analysis of samples from ongoing clinical trials.

Sensitivity of intravenous and oral alfentanil and pupillary miosis as minimal and noninvasive probes for hepatic and first-pass CYP3A induction

Systemic and oral clearances of alfentanil (ALF) are in vivo probes for hepatic and first-pass cytochrome P450 (CYP) 3A. Both ALF single-point plasma concentrations and miosis are surrogates for area under the concentration-time curve (AUC) and clearance and are minimal and noninvasive CYP3A probes. This investigation determined ALF sensitivity for detecting graded CYP3A induction and compared it with that of midazolam (MDZ). Twelve volunteers (sequential crossover) received 0, 5, 10, 25, or 75 mg oral rifampin for 5 days. MDZ and ALF were given intravenously and orally on sequential days. Dark-adapted pupil diameter was measured with blood sampling. Graded rifampin decreased plasma MDZ AUCs to 83, 76, 62, and 59% (intravenous (i.v.)) and 78, 66, 39, and 24% (oral) of control. Hepatic and first-pass CYP3A induction were detected comparably by plasma MDZ and ALF AUCs. Single ALF concentrations detected all CYP3A induction, whereas MDZ was less sensitive. ALF miosis detected induction of first-pass but not hepatic CYP3A.