Electrochemical determination of a hemorheologic drug, pentoxifylline at a multi-walled carbon nanotube paste electrode

The electrochemical oxidation of a hemorheologic drug, pentoxifylline was investigated at a multi-walled carbon nanotubes-paraffin oil paste electrode using cyclic and differential pulse voltammetry. The oxidation process was irreversible over the pH range studied and exhibited an adsorption-controlled behavior. All experimental parameters have been optimized. Under the optimum conditions, the oxidation peak current was linearly proportional to the concentration of pentoxifylline in the range of 3.0 x 10(-5) to 2.0 x 10(-4) M with a detection limit of 1.69 x 10(-7) M by differential pulse voltammetry with 180 s accumulation. The proposed method was successfully applied to pentoxifylline determination in pharmaceutical and urine samples. Satisfactory recoveries of the analyte from the real samples and a good agreement between the concentration ranges studied and the real ranges encountered in the urine samples, when treated with the drug make the developed method applicable in clinical analysis. This method can also be employed in quality control and routine determination of drugs in pharmaceutical formulations. (C) 2011 Elsevier B.V. All rights reserved.