Development of a Simple and Efficient Method for Preconcentration and Determination of Trace Levels of Fexofenadine in Plasma and Urine Samples

A simple, inexpensive and sensitive three-phase hollow fiber liquid-phase microextraction (HFLPME) coupled with high performance liquid chromatography (HPLC) with UV detection was successfully developed for determination of trace level of an anti-Histamine drug, fexofenadine, in human plasma and urine. The analyte was extracted into n-octanol that was immobilized in the wall of a porous hollow fiber from 15 mL of aqueous sample, with pH 4 (donor phase), and was back extracted into the acceptor phase with pH 9 located in the lumen of the hollow fiber. The extraction occurred due to a pH gradient between the sides of the hollow fiber. Several parameters affecting the extraction process such as type of extraction solvent, pH, salt concentration, extraction time, and stirring speed were optimized. Under the optimized conditions enrichment factor of 65, linear dynamic range (LDR) of 1.8-200 ng/mL and limit of detection (LOD) 0.6 ng/mL were obtained. The percent relative intraday and interday standard deviations (RSD%) based on 3 replicate determinations were 7.1% and 7.6% respectively.