Factor Space Analysis and Dual Wavelength Spectrophotometric Methods for Simultaneous Determination of Norfloxacin and Tinidazole in Tablet

Two new, simple, and accurate spectrophotometric methods; factor space partial least squares (PLS) and dual wavelength methods were developed, validated and applied to the simultaneous determination of norfloxacin and tinidazole in their binary mixtures and tablet. A training set of ten binary mixtures in different combinations containing 2-9 μg/mL norfloxacin and 6-40 μg/mL tinidazole in 0.01 M HCl was used to develop the PLS calibration. The UV absorption spectra of the training and validation sets were recorded in the range of 290-300 nm at 1 nm intervals. Dual wavelength method measured the absorbance difference between 277.2 nm and 336.2 nm for determination of norfloxacin and between 309 nm and 254.6 nm for determination of tinidazole. Linearity ranges were found to be 2-10 μg/mL and 4-40 μg/mL for norfloxacin and tinidazole, respectively. The developed methods were validated and successfully applied to the simultaneous determination of both drugs in their tablet. The mean percentage recovery ± S.D. values were found to be 97.659 ± 0.249 and 99.053 ± 1.009 for PLS method and 97.691 ± 0.557and 98.582 ± 1.228 for dual wavelength method for norfloxacin and tinidazole, respectively. The assay results obtained by using the factor space PLS method and dual wavelength method were statistically compared to those obtained by a reported method and good agreement was observed.