Direct analysis in real time-mass spectrometry for rapid quantification of five anti-arrhythmic drugs in human serum: application to therapeutic drug monitoring.

Therapeutic drug monitoring (TDM) is necessary for the optimal administration of anti-arrhythmic drugs in the treatment of heart arrhythmia. The present study aimed to develop and validate a direct analysis in real time tandem mass spectrometry (DART-MS/MS) method for the rapid and simultaneous determination of five anti-arrhythmic drugs (metoprolol, diltiazem, amiodarone, propafenone, and verapamil) and one metabolite (5-hydroxy(OH)-propafenone) in human serum. After the addition of isotope-labeled internal standards and protein precipitation with acetonitrile, anti-arrhythmic drugs were ionized by DART in positive mode followed by multiple reaction monitoring (MRM) detection.

Treatment of displaced radial neck fractures under ultrasonographic guidance in children.

Purpose: This study aimed to evaluate the feasibility of reduction under ultrasonographic (US) guidance with Kirschner wires (K-wires) and fixation with elastic stable intramedullary nails (ESINs) in the treatment of radial neck fractures (RNFs).

Methods: This retrospective study included 50 children treated for Judet types III and IV RNFs at our hospital from September 2015 to November 2018. Patients were divided into two groups: group A (without US) and group B (with US).

In situ calibration of Direct Analysis in Real Time-mass spectrometry for direct quantification: Urine excretion rate index creatinine as an example.

Ambient ionization in open environment brings a capability of a coupled mass spectrometry to detect target molecules in situ. However, it is limited to qualitative and semi-quantitative analysis. By coupling of an ambient ionization-based Direct Analysis in Real Time (DART) with high-resolution quadrupole time-of-flight mass spectrometry (QTOF/MS), we observe that, in one-chemical system, the target molecule displays a non-linear response in MS signal vs concentration, accompanying with large variation in MS signal, suggesting two obstacles for quantification to be overcome.

The direct analysis of drug distribution of rotigotine-loaded microspheres from tissue sections by LESA coupled with tandem mass spectrometry.

The direct analysis of drug distribution of rotigotine-loaded microspheres (RoMS) from tissue sections by liquid extraction surface analysis (LESA) coupled with tandem mass spectrometry (MS/MS) was demonstrated. The RoMS distribution in rat tissues assessed by the ambient LESA-MS/MS approach without extensive or tedious sample pretreatment was compared with that obtained by a conventional liquid chromatography tandem mass spectrometry (LC-MS/MS) method in which organ excision and subsequent solvent extraction were commonly employed before analysis. Results obtained from the two were well correlated for a majority of the organs, such as muscle, liver, stomach, and hippocampus.