Voltammetric behavior of amfepramone (diethylpropion) at the hanging mercury drop electrode and its analytical determination in pharmaceutical formulations

Abstract

This paper describes a systematic study of the voltammetric behavior of amfepramone at the hanging mercury drop electrode (HMDE) by cyclic (CV) and alternating current (AC) voltammetric methods. The studies showed the adsorptive behavior of amfepramone at the HMDE and were performed in H2SO 4 0.1 mol L-1 (pH 1.0) and Ringer buffer (pH 11.0) as supporting electrolytes. The linear range for the amfepramone determination by differential pulse voltammetry (DPV) was 0.05 to 2.0 mg L-1 (r = 0.998) in acidic medium and 0.25 to 4.0 mg L-1 (r = 0.994) in alkaline medium. The relative standard deviation calculated was 2.5% and 4.0 % for five measurements of 0.5 mg L-1 amfepramone in acidic and alkaline medium, respectively. The detection limits calculated for the amfepramone determination in acidic and alkaline medium were 0.035 e 0.18 mg L-1, respectively. The methods were applied for the determination of amfepramone by DPV in tablets and capsules of pharmaceutical formulations used in the treatment of obesity. Recoveries values ranging from 90.0 to 101.0% for amfepramone added to synthetic mixtures containing fenproporex, mazindol, sibutramine, fluoxetine, caffeine, diazepam, and metformin as interferents prove the applicability of the method for its determination in the presence of other drugs normally added illegally to pharmaceutical formulations commercialized as natural medicaments. ©2007 Sociedade Brasileira de Química.