A comparative evaluation of sample preparation techniques for the therapeutic monitoring of carbamazepine in human plasma by RPLC/DAD

Abstract

Four sample preparation techniques, namely direct protein precipitation through a) trichloroacetic acid addition (PPA) or b) acetonitrile addition (PPO), c) liquid-liquid extraction in n-octanol followed by the direct injection of the organic layer, and d) supramolecular solvent extraction in a tetrahydrofuran/n-octanol/water coacervate (SUPRAS) were evaluated to be used for the RPLC/DAD assay of carbamazepine in human plasma samples, targeting therapeutic monitoring (TM) purposes. The chromatographic approach to separating carbamazepine from human plasma matrices was designed to be a simple gradient elution with an octadecyl chemically modified silica gel stationary phase, and a mobile phase composed of acetonitrile (organic) and HPLC grade water (aqueous), both with 0.1% formic acid. Monitoring at 290 nm allowed for the detection of carbamazepine. After optimizing both sample preparation procedures and chromatographic separation parameters, LOQ values of 3 µg/mL (PPA), 0.6 µg/mL (PPO), 12 ng/mL (LLE) and 50 ng/mL (SUPRAS) were determined. Detector response functions were studied over an interval up to 20 µg/mL (ULOQ).

Keywords:

• Carbamazepine
• human plasma
• in-situ SUPRAS extraction
• LLE in octanol
• sample preparation procedures
• therapeutic monitoring

Disclosure statement

No potential conflict of interest was reported by the author(s).