norfentanyl and despropionylfentanyl

A rapid and sensitive liquid chromatography/tandem mass spectrometric (LC-MS/MS) method for simultaneous quantification of fentanyl (F), norfentanyl (NF), despropionylfentanyl (DPF), and hydroxynorfentanyl (OHNF) in human plasma and urine specimens has been developed and validated according to international guidelines. Analytes were extracted from 250-μL plasma or urine by liquid-liquid extraction. OHNF in urine affords a second extraction step and analysis with a different column. Calibration curves in plasma were linear from 0.05-10 ng/mL for F, 0.07-0.5 ng/mL for NF, 0.02-1.0 ng/ml for DPF, and 0.67-3.0 ng/mL for OHNF; in urine, from 0.09-10.0, 0.17-50, 0.08-1.0, and 1.0-5.0 ng/mL for F, NF, DPF, and OHNF, respectively. Analytical bias and intra- and inter-assay imprecision were within ± 15 % of target, except for OHNF in plasma and DPF in urine at the respective lower quality control level. All analytes were stable in processed samples when stored for 24 h at room temperature. Recoveries and process efficiencies were above 82.9 and 75.1 % for all analytes in plasma and urine. The low level of DPF in plasma indicated with a matrix effect of 71.3 % moderate ion suppression, all other analytes in plasma and urine showed no matrix effects. The lower limit of quantification (LOQ) in plasma was 0.05, 0.07, 0.02 and 0.67 ng/mL for F, NF, DPF, and OHNF, respectively. In urine, the LOQ of F, NF, DPF, and OHNF were 0.09, 0.17, 0.08, and 1.28 ng/mL, respectively. This assay has been applied to human specimens collected during a clinical drug-drug interaction study.

Topics: Chromatography, Liquid; Fentanyl; Forensic Toxicology; Humans; Limit of Detection; Narcotics; Tandem Mass Spectrometry

Preterm and term neonates often require surgical procedures and analgesia. However, our knowledge about neonatal pharmacokinetics of fentanyl, the most commonly used drug for these procedures, and its metabolites is still incomplete. To facilitate pharmacokinetic studies of fentanyl and its metabolites in neonates and other children, we developed and validated an LC-MS/MS method based on minimally invasive, low blood volume sampling. LC-MS/MS was used for the simultaneous analysis of fentanyl, despropionyl fentanyl (DPF), and norfentanyl from dried blood samples (DBS) collected on filter paper. Positive ions were monitored using multiple reaction monitoring. Since the standard matrix for measuring fentanyl blood concentrations is plasma, the assay was developed and validated in plasma, whole blood, and then DBS. Our method was able to measure clinically relevant levels of fentanyl and its metabolites. In DBS, the lower limits of quantification were 100 pg/mL for fentanyl with a range of reliable response from 0.1 to 100 ng/mL (r(2)>0.99) and 250 pg/mL for both DPF and norfentanyl with a range of reliable response from 0.25 to 100 ng/mL (r(2)>0.99). In plasma and in DBS inter-day accuracy and precisions of fentanyl met predefined acceptance criteria and also indicated comparable assay performance in both matrices.

Topics: Blood Volume; Child; Chromatography, High Pressure Liquid; Fentanyl; Humans; Sensitivity and Specificity; Tandem Mass Spectrometry

This study was undertaken to determine if metabolites of fentanyl might be useful in the detection and monitoring of substance abuse. The presence of fentanyl and two of its metabolites in the urine and saliva of seven female patients receiving small doses (110 +/- 56 micrograms) of fentanyl was studied up to 96 h from the time of administration. Fentanyl and its two metabolites (norfentanyl and despropionylfentanyl) were extracted from samples and analyzed by gas chromatography/mass spectrometry. Unchanged fentanyl was detectable in urine in all patients immediately postoperatively and in 3 of 7 patients at 24 h. By 72 h, fentanyl was undetectable. Norfentanyl was present in larger quantities than fentanyl immediately postoperatively and was detected in all patients at 48 h and in 4 of 7 patients at 96 h. Despropionylfentanyl was not detected in any of the urine specimens tested. Neither fentanyl nor its metabolites could be detected consistently at any time in saliva. Saliva testing does not appear to be a viable alternative to urine testing based on this study. Urinary norfentanyl might be considered as the substance of choice when testing for fentanyl abuse.

Topics: Adult; Female; Fentanyl; Gas Chromatography-Mass Spectrometry; Humans; Saliva; Substance Abuse Detection; Time Factors