Electrochemical Determination of Tolfenamic Acid in Bulk, Tablets and Urine

A simple, precise, accurate and inexpensive voltammetric method was developed for the quantitative determination of tolfenamic acid at modified glassy carbon electrode in phosphate buffer of pH 7.2. Several factors such as type of buffer, type of surfactant; scan rate and accumulation time were studied to obtain the optimum conditions for the determination of tolfenamic acid. The proposed method shows linearity in concentration range of 6.0×10-7-6.0×10-6 mol L-1 with mean percentage recovery of 101.2±1.99. The limits of detection and quantification were 1.43×10-7 mol L-1 and 4.34×10-7 mol L-1, respectively. The proposed voltammetric method was successfully applied to determine tolfenamic acid in pharmaceutical formulations and human urine. The results of the proposed method were statistically compared with those of a reported method and showed no significant difference. Thus, it can be used as quality control for this drug in laboratories.