5. Development and validation of spectrophotometric methods for simultaneous estimation of norfloxacin and tinidazole in combined dosage form

The present work relates with two simple, accurate and reproducible spectrophotometric methods have been developed for the simultaneous estimation of Norfloxacin and Tinidazole in pharmaceutical dosage forms. The first method involves determination using the AUC (Area under Curve) method; the sampling wavelengths selected are 272-282nm and 313-323nm over the concentration ranges of 2-12μg/mL and 3-18μg/mL for Norfloxacin and Tinidazole, respectively. The second method involves determination using the Q-analysis method (Absorbance Ratio Method); the sampling wavelengths selected are 277nm and 318nm over the concentration ranges of 2-12μg/mL and 3-18μg/mL for Norfloxacin and Tinidazole, respectively. The % recovery was between 98-102% indicating high degree of accuracy of the proposed methods. The results of the analysis were validated statistically and recovery studies were carried out as per ICH guidelines. The developed methods are simple, rapid, precise, accurate and can be employed for the routine estimation of NF and TZ in both bulk and tablet dosage form.