Ranitidine and metronidazole have been successfully used in combination therapy with antibiotics for the treatment of gastric Helicobacter Pylori infections. Ranitidine and metronidazole have low plasma protein binding (20%) and their effective plasma concentrations are 100 ng/ml and 6 mglml, respectively. Due to the critical roles of ranitidine and metronidazole in the pharmaceutical industry, their determination is important in biological fluids and drug formulations. The metronidazole and ranitidine contain a nitro group, which is the electrochemically active reducible center. In this study GC electrode modified with SWCNTs have been used for detection metronidazole and ranitidine. The results indicated that CNT rnociified glassy carbon electrode exhibited etliciently electrocatalytic reduction fbr ranitidine and metronidazole with relatively high sensitivity, stability and long life. Under conditions of cyclic voltammetry, the potential for reduction of’ selected analytes is lowered by approximately 1 50 mV and current is enhanced signif andy (7 times) in comparison to the bare glassy carbon electrode. Under optimized condition in amperometry method the concentration calibration range, detection limit and sensitivity were about, 0.1-300 tM , detection limit (S/N 3 ) 6.3 10 8 mol.l’ and sensitivity 40 nAJiM for metronidazole and 0.3-270 p.M 7.73 -<10 -8 mol.I and 25 nAJpfvI for ranitidine. In addition, the ability of the modified electrode for simultaneous determination of’ ranitidine and metronidazole was evaluated. The proposed method was successfully applied to ranitidine and metronidazole determination in tablets.
