Dexmedetomidine (DMET) is a sedative, analgesic and anxiolytic with minimum adverse respiratory effects. An LC–MS/MS bioanalytical method has been developed and validated to accurately measure DMET concentrations in samples of human plasma. The method overcomes difficulties in the extraction and quantification of DMET due to the fact that it binds strongly to glass and plastic tubes, as well as solid phase extraction (SPE) cartridges. Human plasma (50 μL) was mixed with the internal standard (IS) (DMET-d4) solution (100 μL) and 0.1% formic acid (50 μL) and extracted using Oasis HLB 1 CC (30 mg) solid phase extraction (SPE) cartridges (Waters^®). The glass tubes were coated with bovine serum albumin (BSA) 0.5% (20 μL) before eluting DMET and the IS. After evaporation under nitrogen at room temperature, the analytes were reconstituted in 20% acetonitrile in 0.1% formic acid in water and transferred to silanized glass vials. An electrospray ionisation (ESI) mass spectrometry method in positive mode was created and the precursor/product transitions (m/z) were 201.1 → 95.0 (DMET) and 204.9 → 99.0 (IS). The method was robust and fully validated based on the 2012 EMEA guideline for bioanalytical method validation in the concentration range of 0.5–20 ng/mL. Using this assay, we showed that DMET binds strongly to Extracorporeal Membrane Oxygenation (ECMO) circuits, consistent with expectations for small lipophilic compounds.

右美托咪定（DMET）具有镇静，镇痛和抗焦虑作用，对呼吸道的不利影响最小。已开发出LC-MS / MS生物分析方法，并经过验证可准确测量人血浆样品中的DMET浓度。该方法克服了DMET的萃取和定量困难，因为它与玻璃管和塑料管以及固相萃取（SPE）柱牢固结合。将人血浆（50μL）与内标（IS）（DMET-d4）溶液（100μL）和0.1％甲酸（50μL）混合，然后使用Oasis HLB 1 CC（30 mg）固相萃取（SPE）进行萃取）柱（沃特世^®）。在洗脱DMET和IS之前，玻璃管涂有0.5％（20μL）的牛血清白蛋白（BSA）。在室温下在氮气下蒸发后，将分析物在水中的0.1％甲酸的20％乙腈中重构，并转移至硅烷化玻璃瓶中。创建了正模式的电喷雾电离（ESI）质谱方法，前体/产物的跃迁（m / z）为201.1→95.0（DMET）和204.9→99.0（IS）。该方法是稳健的，并且根据2012年EMEA指南在0.5–20 ng / mL的浓度范围内进行生物分析方法验证而得到了充分验证。使用该测定法，我们表明DMET与体外膜氧合（ECMO）回路牢固结合，与对小型亲脂性化合物的期望一致。