New Method for the Monitoring of Antidepressants in Oral Fluid Using Dried Spot Sampling

The increase in the consumption of antidepressants is a public health problem worldwide, as these are a class of compounds widely used in the treatment of several illnesses, such as depression and anxiety. This work aimed to develop and optimize a method for the quantification of a number of antidepressants and their metabolites (fluoxetine, venlafaxine, O-desmethylvenlafaxine, citalopram, sertraline, and paroxetine) in 100 µL of oral fluid using the dried saliva spots (DSS) sampling approach and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The method was validated, presenting linearity within the studied range, with detection and quantification limits ranging between 10 and 100 ng/mL, and coefficients of determination (R²) of at least 0.99 for all analytes. Recoveries were between approximately 13 and 46%. The analysis of precision and accuracy presented acceptable coefficients of variation and relative errors, considering the criteria usually accepted in the validation of bioanalytical procedures. The method herein described is the first to be reported using DSS for the extraction of antidepressants, proving to be a sensitive, simple, and fast alternative to conventional techniques, and capable of being routinely applied in clinical and forensic toxicology scenarios.

Selective determination of some beta-blockers in urine and plasma samples using continuous flow membrane microextraction coupled with high performance liquid chromatography

In this work, an efficient method termed as continuous flow membrane microextraction coupled with high performance liquid chromatography is introduced for a highly selective determination of metoprolol and propranolol in the biological samples. According to this method, an aqueous source phase of the analytes (donor phase, 10 mL) is circulated into an extraction cell, which is separated from an aqueous acceptor phase (100 μL) by a small piece of polypropylene membrane sheet whose pores are impregnated by an organic solvent (1-octanol, 15 μL). The analytes are extracted from the donor phase into the organic solvent. They are subsequently selectively back-extracted into the acceptor solution due to the pH gradient. The proposed method is very convenient and has the capability of being fully automated. It provides a good preconcentration and an excellent repeatability. The extractant is an aqueous phase, and by prevention of the extraction of macromolecules through the membrane, the developed method provides a high sample clean-up. In order to maximize the extraction efficiency, the influential parameters including the type of mediator solvent, pH values for the donor and acceptor solutions, extraction time, ionic strength, stirring rate, and volume of the acceptor solution are optimized. The calibration curves were obtained with a reasonable linearity (r² = 0.999) in the range of 3-1000 ng mL^-1. The limits of detection were 0.5 and 1.0 ng mL^-1, and excellent relative standard deviations were obtained (between 3.2% and 4.0%). Finally, the reliability of the procedure is evaluated by determination of metoprolol and propranolol in the human urine and plasma samples, which indicates the suitability, sensitivity, and high sample clean-up of the proposed method.

Capillary electrophoresis for the analysis of antidepressant drugs: A review

Depression is a common mental disorder that may lead to major mental health problems, and antidepressant drugs have been used as a treatment of choice to mitigate symptoms of major depressive disorders by ameliorating the chemical imbalances of neurotransmitters in brain. Since abusing antidepressant drugs such as selective serotonin reuptake inhibitors and tricyclic antidepressant drugs can cause severe adverse effects, continuous toxicological monitoring of the parent compounds as well as their metabolites using numerous analytical methods appears pertinent. Among them, capillary electrophoresis has been popularly utilized since the method has a lot of advantages viz. using small amounts of sample and solvents, ease of operation, and rapid analysis. This review paper brings a survey of more than 30 papers on capillary electrophoresis of antidepressant drugs published approximately from 1999 until 2018. It focuses on the reported capillary electrophoresis techniques and their applications and challenges for determining antidepressant drugs and their metabolites. It is organized according to the commonly used capillary zone electrophoresis method, followed by non-aqueous capillary electrophoresis and micellar electrokinetic chromatography, with details on breakthrough findings. Where available, information is given about the background electrolyte used, detector utilized, and sensitivity obtained.

Dispersive liquid-liquid microextraction combined with acetonitrile stacking through capillary electrophoresis for the determination of three selective serotonin reuptake inhibitor drugs in body fluids

Dispersive liquid-liquid microextraction was combined with acetonitrile stacking in capillary electrophoresis for the identification of three selective serotonin reuptake inhibitors (citalopram, fluoxetine, and fluvoxamine) in human fluids such as urine and plasma. Parameters that affect the extraction and stacking efficiency, such as the type and volume of the extraction and disperser solvent, extraction time, salt addition for dispersive liquid-liquid microextraction, and sample matrices, pH, and concentration of the separation buffer for stacking, were investigated and optimized. Under optimum conditions, the enrichment factors were in the range of 1195-1441. Limits of detection ranged from 1.4 to 1.7 nM for the target analytes. Calibration graphs displayed satisfied linearity with R² greater than or equal to 0.9978, and relative standard deviations of the peak area analysis were in the range of 2.9-5.0% (n = 3). The recoveries of all tricyclic antidepressant drugs from urine and plasma were in the range of 77-117 and 79-106%, respectively. The findings of this study show that dispersive liquid-liquid microextraction acetonitrile-stacking capillary electrophoresis is a rapid and convenient method for identifying tricyclic antidepressant drugs in urine and plasma.

Recent progress of sample stacking in capillary electrophoresis (2014-2016)

The term "sample stacking" comprises a relatively broad spectrum of techniques that already form an almost inherent part of the methodology of CZE. Their principles are different but the effect is the same: concentration of a diluted analyte into a narrow zone and considerable increase of the method sensitivity. This review brings a survey of papers on electrophoretic sample stacking published approximately since the second quarter of 2014 till the first quarter of 2016. It is organized according to the principles of the stacking methods and includes chapters aimed at the concentration adjustment principle (Kohlrausch stacking), techniques based on pH changes, micellar methods, and other stacking techniques. Not reviewed are papers on transient ITP that are covered by another review in this issue.

Headspace Microextraction of Sulfonamides from Honey by Hollow Fibers Coupled with Ultrasonic Nebulization

A new method for the rapid simultaneous determination of five sulfonamides in honey was developed using ultrasonic nebulization-assisted extraction coupled with hollow fiber liquid-liquid-liquid microextraction prior to liquid chromatography. In the present method, the sample solution was nebulized by ultrasonication. Sulfonamides in the aerosol particles were extracted by 1-octanol impregnated in the pores of a hollow fiber and further into the acceptor phase (acid solution, pH 2.0) contained in the lumen of the hollow fiber. Several experimental parameters that affect the extraction efficiency were optimized. The present method provides good recoveries (88.9-114.2%) and acceptable precision (<10.7%), indicating the effective extraction. The detection limits were 4.6-6.8 μg/kg, lower than the maximum residue limits of sulfonamides in honeys. Compared to the traditional extraction methods, the present method requires less organic solvent and operation time, demonstrating excellent cleanup ability and good enrichment efficiency.

Determination of selective serotonin reuptake inhibitors in biological samples via magnetic stirring-assisted dispersive liquid–liquid microextraction followed by high performance liquid chromatography

This work reports an efficient, quick and low-cost procedure for the determination of serotonin reuptake inhibitors (SSRIs) in low concentration levels in biological fluids.