Cathodic stripping voltammetry of pipemidic acid and ofloxacin in pharmaceutical dosages and human urine

Sensitive cathodic stripping voltammetric methods have been developed for two quinolone antibacterial drugs, pipemidic acid (PIP) and ofloxacin (OFL) using hanging mercury drop electrode as working electrode vs. Ag/AgCl reference electrode. The methods were developed for the determination of drugs individually as well as simultaneously. 0.1 M and 0.01 M hydrochloric acid was used as medium for PIP and OFL, respectively, 0.1 M potassium chloride was used as base electrolyte. Reduction waves were observed for PIP within ?700 mV to ?800 mV and for OFL within ?1100 mV to ?1200 mV. Linear calibration ranges for PIP and OFL were observed within 10–100 μg ml^?1 with detection limits of 50 ng ml^?1 and 1 μg ml^?1, respectively. Relative standard deviations (RSD) for the analysis of 10 gµg ml^?1 of PIP and OFL (n = 6) were 0.5% and 1.4%, respectively. The presence of glucose, lactose, sorbitol, gum arabic, starch, magnesium stearate, methylparaben and propylparaben did not affect the determinations of both PIP and OFL. The methods were used for the analysis of pharmaceutical preparations and the results indicated relative deviation of 0.5–5.5% from labeled values with RSD within 0.49–2.5%. PIP and OFL could also be determined simultaneously, and were determined from spiked human urine.