Toxicological screening of human plasma by on‐line SPE‐HPLC‐DAD: identification and quantification of basic drugs and metabolites

Abstract

An automated multi-analyte screening method for the identification and quantification of 92 drugs and metabolites based on on-line solid-phase extraction-high-performance liquid chromatography-diode array detection technique was developed and successfully validated. In addition, a database with 870 entries including UV-spectra, relative/retention times and response factors of toxicologically relevant compounds was created. Plasma samples (0.2 mL) were treated with methanol, diluted with buffer and on-line extracted (Strata X, 20 ×2 mm, 25 µm) at pH 9. Analytical separation was carried out on a Gemini NX column (150 ×4.6 mm, 3 µm) using gradient elution with acetonitrile-water (90:10,v/v) and 0.05 m potassium dihydrogen phosphate buffer (pH 2.3). Linear calibration curves with correlation coefficients ≥0.9950 were obtained for 78 analytes. As an additional benefit, the newly developed method allows the quantification of 42 analytes (e.g. antidepressants, neuroleptics and anticonvulsants) in a concentration range suitable for therapeutic drug monitoring. Limits of quantitation ranged from 0.02 mg/L (chlordiazepoxide) to 3.4 mg/L (mexiletine). Inter- and intra-day precisions of quality control samples (low/high) were better than 15% (zolpidem) and accuracy (bias) ranged from -11% (opipramol, venlafaxine) to 11% (venlafaxine, trazodone). Tests for carry-over and sample stability under different storage conditions were also performed and stability was adequate. Four cases of poisoning analysis are presented.

A fast and simple approach for the quantification of 40 illicit drugs, medicines, and pesticides in blood and urine samples by UHPLC‐MS/MS

“…The values were in the range of 0.5 and 20 ng mL −1 . These results were considered more significant than the values reported by Steuer et al and Sempio et al In our study, we determined that LLOQs for whole blood ranged from 0.5 to 10 ng mL −1 for benzodiazepines and antidepressants, while Mut et al reported values of 40 ng mL −1 . The LLOQs in urine analysis were considered adequate for all analytes once the RSD (%) was lower than 15%.…”

Toxicological screening of human plasma by on‐line SPE‐HPLC‐DAD: identification and quantification of acidic and neutral drugs

“…(b). The following drugs and metabolites concentrations were determined in the patient's plasma sample, quantified using the method described elsewhere (Mut et al ., ): analyte [concentration in mg/L, upper or therapeutic concentration (range) in mg/L], nordazepam (0.17, 0.02–0.8), diazepam [positive <LOQ (0.04), 0.13–0.4], lorazepam [positive <LOQ (0.05), 0.02–0.25], 4‐methylaminoantipyrine and an active metabolite of metamizole (39.8, 5.00); and [concentration in mg/L, below therapeutic concentration (range) in mg/L], quetiapine (0.06, 0.10–050) and duloxetine [positive <LOQ (0.04), 0.03–0.12]. Additionally, codeine was identified qualitatively.…”

“…The on-line SPE-HPLC-DAD model was similar to prior approaches (Grobosch et al, 2009;Mut et al, 2011Mut et al, , 2015. For on-line SPE the following eluents were used: A (acetonitrile-water, 90:10, v/v) as the mobile phase, E (0.01 M potassium dihydrogen phosphate buffer, pH 6) for loading and equilibration and D (water) for rinsing and purging of the SPE column.…”

“…Consequently, the aim of this project was to develop and integrate a multi‐analyte screening method for the quantitative determination of toxicologically relevant acidic/neutral drugs and metabolites in human plasma using the same analytical system (Mut et al ., ). The chemical properties of compounds as well as the therapeutic and critical concentration ranges of the compounds were used as the criteria for the analytical method.…”

“…LogP and pK a values were used from http://www.drugbank.ca, except for clomethiazole and salicylic acid, and taken from Klopp (2010). (Mut et al, 2015). The chemical properties of compounds as well as the therapeutic and critical concentration ranges of the compounds were used as the criteria for the analytical method.…”