Determination of dexmedetomidine by UHPLC–MS/MS and its application to evaluate the effect of dexmedetomidine concentration on the target-controlled infusion concentration of propofol

Rapid quantitative determination of blood propofol concentration throughout perioperative period by negative photoionization ion mobility spectrometer with solvent-assisted neutral desorption

Rapid and quantitative determination of blood propofol concentration is important for anesthesiologists to accurately control intraoperative propofol dose, timely monitor physiological statuses of patients and greatly improve the safety of surgery. Herein, a dopant-assisted negative photoionization ion mobility spectrometer with the optimized ionization region structure and the three-way inlet design was developed, increasing the generation ratio of the reactant ions O₂^-, and improving the ionization efficiency of propofol molecules. Besides, the addition of methanol-anisole solution during injection promoted the neutral desorption of propofol in blood, further improving the detection sensitivity by an order of magnitude, eliminating any sample pretreatment and effectively reducing the single analysis time to less than 1 min compared to the previous article. The dual calibration quantitative method, i.e. the method of calibrating the O₂^- concentration and the sample concentration changes during the entire process of detecting propofol through the integral value of M·O₂^- and the maximum signal intensity of O₂^-, successfully achieved accurate quantification of blood propofol. And the linear calibration curve of propofol was obtained with the range of 0.1-15 ng μL^-1 and with the limit of detection of 0.03 ng μL^-1, which was fulfilled to conduct propofol determination throughout the perioperative period. Finally, this method was applied to clinically measure the blood propofol concentration in patients newly regained consciousness with concentrations ranging from 0.2 ng μL^-1 to 3 ng μL^-1, and it turned out that the older patient had the lower propofol concentration in blood.

An improved ultra-high-performance liquid chromatography-tandem mass spectrometric method for the quantitation of dexmedetomidine in small volume of pediatric plasma

Dexmedetomidine (Dex), a highly selective α₂ -adrenergic agonist, is used primarily for the sedation and anxiolysis of adults and children in the intensive care setting. A sensitive and selective assay for Dex in pediatric plasma was developed by employing ultra-high-performance liquid chromatography-tandem mass spectrometry with d4-Dex as an internal standard. Dex was extracted from 0.1 mL of plasma by micro-elution solid-phase extraction. Separation was achieved with a Waters XBridge C₁₈ column with a flow rate of 0.3 mL/min using a mobile phase comprising 5 mm ammonium acetate buffer with 0.03% formic acid in water and methanol-acetonitrile (50:50, v/v). The intra-day precision (coefficient of variation) and accuracy for quality control samples ranged from 1.32 to 8.91% and from 92.8 to 108%, respectively. The inter-day precision and accuracy ranged from 2.13 to 8.45% and from 97.0 to 104%, respectively. The analytical method showed excellent sensitivity using a small sample volume (0.1 mL) with a lower limit of quantitation of 5 pg/mL. This method is robust and has been successfully employed in a pharmacokinetic study of Dex in neonates and infants postoperative from cardiac surgery.