Simultaneous Determination of Ramipril and Felodipine using Carbon Paste Electrode in Micellar Medium

Simple, precise, inexpensive and sensitive voltammetric method was developed for simultaneous determination of Ramipril (RAM) and felodipine (FLD) mixture in drug substance, drug product and human urine using carbon paste electrode (CPE). Effect of different surfactants on peak current was studied in acetate buffer solution of pH 4.8. Sodium dodecyl sulphate (SDS) is the optimum surfactant based on the enhancement of the peak current. The peak current varied linearly over the concentration ranges from 5×10-5 mol L-1 to 8×10-4 mol L-1 for both drugs. The quantification limits were 1.78×10-5 and 1.94×10-5 mol L-1 and detections limits were 4.5×10-6 and 2.7×10-6 mol L-1 for RAM and FLD, respectively. The proposed voltammetric method was successfully applied to determine RAM and FLD mixture in drug product and human urine. The results of the proposed method were statistically compared with those of the reported method and showed no significant difference. Thus, it can be applied for quality control of both drugs.