Novel UV spectrophotometer methods for quantitative estimation of metronidazole and furazolidone using mixed hydrotropy solubilization

Two simple, accurate, novel, safe and precise methods were developed for the simultaneous estimation of poorly water-soluble drugs Metronidazole (MTR) and Furazolidone (FZ) in a tablet dosage form using 2 M sodium acetate and 8 M urea solution (50:50%V/V) as a mixed hydrotropic solution. MTR and FZ show maximum absorbances at 319 and 364 nm, respectively. Sodium acetate and urea solution did not show any absorbance above 240 nm and thus no interference in the estimation of drugs was seen. MTR and FZ follow Beer's law in the concentration range of 10-50 μg/ml and 5-25 μg/ml (r2 = 0.9992 and 0.9996). Method-A employs the simultaneous equation method using 319 and 364 nm as two analytical wavelengths, method-B employs the absorption ratio method, which uses 339.2 and 364 nm as two analytical wavelengths for estimation of MTR and FZ. The mean percent label claims of tablet dosage were found to be 98.715 ± 1.012 and 98.74 ± 0.912 in method A, 98.99 ± 0.872 and 97.89 ± 0.903 in method B for MTR and FZ, respectively. The developed methods were validated according to ICH guidelines and values of accuracy, precision and other statistical analysis were found to be in good accordance with the prescribed values therefore both methods can be used for routine monitoring of MTR and FZ in industry in the assay of bulk drug and tablets.