Development of a stable isotope dilution UPLC‐MS/MS method for quantification of dexmedetomidine in a small amount of human plasma

Abstract

Dexmedetomidine (Dex) is a selective central α2-agonist with anesthetic properties and has been used in clinical practice for sedation in the intensive care unit (ICU) after operations. In this study, an analytical assay for the determination of Dex in a small amount of plasma was developed for the application to pediatric ICU trials. The quantification of Dex was constructed using the original stable isotope Dex-d3 for electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in the selected reaction monitoring mode. A rapid ultra-performance liquid chromatography technique was adopted using ESI-MS/MS with a runtime of 3 min. Efficacious concentration levels (50 pg/mL to 5 ng/mL) could be evaluated using a very small amount of plasma (10 μL) from patients. The lower limit of the quantification was 5 pg/mL in the plasma (100 µL). For sample preparation, a solid-phase extraction was used along with the OASIS-HLB cartridge type. Recovery values ranged from 98.8 to 100.3% for the intra- [relative standard deviation (RSD), 0.9-1.3%] and inter- (RSD, 0.9-1.5%) day assays. A stable test had recovery values that ranged from 97.8 to 99.7% with an RSD of 1.0-1.9% for the process/wet extract, bench-top, freeze-thaw and long-term tests. This method was used to measure the Dex levels in plasma from pediatric ICU patients. In the clinical ICU trial, the small amount of blood (approximate plasma volume, 200 μL) remaining from blood gas analysis was reused and targeted for the clinical analysis of Dex in plasma.

Stable isotope dilution HILIC‐MS/MS method for accurate quantification of glutamic acid, glutamine, pyroglutamic acid, GABA and theanine in mouse brain tissues

“…In choosing the stable isotope standard, labels such as 13 C and 15 N are preferred to 2 H labeling because the 2 H‐labeled standards may not sufficiently co‐elute with the analyte, causing differences in the ion artifact effects from the analyte and the internal standard during the usual reversed‐phase mode (Hewavitharana, ). The internal standard that increased with the number of 2 H substitutes was found to have a slightly earlier elution from a previous LC‐MS/MS method (Inoue et al ., ). On the other hand, stable isotope standards of five 2 H substitutes for the Glu analogs are commercially available.…”

Relationship between dexmedetomidine dose and plasma dexmedetomidine concentration in critically ill infants: a prospective observational cohort study

“…Arterial blood samples were numbered and no clinical information, including on whether dexmedetomidine had been administered, was provided to the investigators performing the assays. We have established a method to measure dexmedetomidine concentration using only 10 µl of plasma [18]. Briefly, dexmedetomidine was quantified using the original stable dexmedetomidine- d 3 for electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in the selected reaction monitoring mode.…”

Derivatization-based High-throughput Bioanalysis by LC-MS

“…[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] However, the sensitive determination of negatively charged molecules, such as carboxylic acids, is not always promising in spite of the highly sensitive MS detection. 52,53 In such a case, the derivatization technique, which generally uses a basic reagent possessing amine(s), is effective for increasing the detection sensitivity and separation efficiency of reversed-phase chromatography, 54 because the resulting derivatives are easily charged as a cation by acidic mobile-phase containing formic and acetic acids.…”