Fabric Phase Sorptive Extraction (FPSE) as an efficient sample preparation platform for the extraction of antidepressant drugs from biological fluids

The quantification and interpretation of drug concentrations in biological matrices to optimize pharmacotherapy and to perform the therapeutic drug monitoring (TDM) is particularly important for compounds with narrow therapeutic ranges, known to cause adverse effects. In these cases, the biomonitoring is essential to avoid the toxicity and side effects. In this study, an innovative Fabric Phase Sorptive Extraction (FPSE) followed by high performance liquid chromatography-photodiode array detection (FPSE–HPLC–PDA) method was optimized and validated for the extraction and quantitative evaluation of seven antidepressant drugs (ADs, venlafaxine, citalopram, paroxetine, fluoxetine, sertraline, amitriptyline, and clomipramine) in human whole blood, urine, and saliva samples.

The best chromatographic separation was obtained using a reverse phase column and ammonium acetate (50 mM, pH 5.5) and acetonitrile (AcN) as mobile phases, with 0.3% of triethylamine (TEA) for the best peak shape. The used sample preparation technique, FPSE, developed in 2014, has offered numerous advantages such as low consumption of organic solvents, no sample pretreatment, and reduced overall sample preparation time. Among all tested membranes, sol-gel carbowax (CW 20 M) sorbent, coated on cellulose FPSE media, was the most efficient. The developed method provides satisfactory limit of detection of 0.06 μg/mL for all analytes except for venlafaxine that was 0.04 μg/mL. Both RSD% and BIAS% gave values below ±15%, according to current guidelines. Finally, real samples analyzes were carried out, comparing the obtained data with the anamnestic data of the subjects, confirmed the validity of the method.