Simultaneous Spectrophotometric Estimation of Norfloxacin and Tinidazole from Combined Tablet Dosage Form.

Two simple, sensitive, accurate, precise, rapid and economical methods were developed for the estimation of Norfloxacin and Tinidazole from combined tablet dosage form. First method is based simultaneous equations and second method is based on Q-analysis (absorbance ratio method). Norfloxacin and Tinidazole show absorbance maxima at 277nm and 308nm in 0.1N Methanolic-HCI (30:70), respectively. The linearity was obtained in the concentration ranges of 4–14 μg/ml for Norfloxacin and 6–24 μg/ml for Tinidazole. In the first method concentration and subsequently amount of drug determined by using simultaneous equations and in second method concentration and amount of drugs determined by using ratio of absorbance at iso-absorptive point and at λmax of one of the drug. The results of analysis have been validated statistically and by assay and recovery studies.