Determination of Leflunomide in Pharmaceutical Tablets by Flow‐Injection Analysis

Abstract

A flow injection analysis (FIA) of leflunomide using UV‐detection is described, in this study. The most suitable carrier solvent was found to be an aqueous solution of ethanol (25%, v/v). Leflunomide was determined at the optimum conditions, such as flow rate of 0.8 mL · min−1 and detection wavelength of 260 nm. The method has been validated and linearity was examined in the range of 2.75×10−6−1.10×10−4 M. The limit of detection (LOD) and quantitation (LOQ) were calculated to be 2.60×10−7 M (S/N=3.3) and 7.87×10−7 M (S/N=10), respectively. The application of the proposed method has been performed in pharmaceutical tablets of leflunomide and excellent results were obtained. The results were compared with those obtained from UV‐spectrophotometry. Insignificant difference was found between the methods. As a result, the FIA method for the determination of leflunomide in pharmaceutical tablets can be proposed as a precise, accurate, sensitive, and cheap method for routine analysis laboratories.