Determination of Azithromycin in Biological Samples by LLLME Combined with LC

Abstract

A simple liquid–liquid–liquid microextraction (LLLME) technique combined with liquid chromatography (LC) was developed for the extraction and quantitative determination of azithromycin (AZI) in biological fluids. In this technique, AZI was extracted from 2.5 mL basic sample solution (donor phase) at pH 10.5 into an organic phase (90 μL), for 30 min. Then back-extracted into a 5 μL microdrop acidic aqueous solution (acceptor phase) at pH 2.5 immersed in the organic phase from the tip of a microsyringe for 20 min with a stirring rate of 800 rpm and donor phase temperature of 35 °C. After a prescribed time, the acceptor microdrop was returned into the microsyringe and injected into the LC. Optimization of experimental parameters on LLLME efficiency was investigated. Under optimized conditions, a preconcentration factor of 85 and limit of detection of 0.03 μg mL−1 were obtained. The calibration curve was linear (r 2 = 0.998) in the concentration range of 0.1–15 μg mL−1. Within-day relative standard deviation (RSD) (S/N = 3) and between-day RSD were 5.1 and 6.8%, respectively. Finally, the feasibility of the proposed method was evaluated by extraction and determination of AZI in plasma and urine samples and satisfactory results were obtained.