Green direct and ratio-based spectrophotometric manipulated methods for tinidazole and ciprofloxacin hydrochloride concomitant assay in their tablet dosage form

• Direct and ratio-based spectrophotometric methods for tinidazole and ciprofloxacin. • Ratio based methods are first derivative and ratio difference. • Area under curve integrating zero order spectra due to significant overlapping. • The developed methods are simple, rapid, green and economic. • Assessment of greenness using the analytical eco-scale, complexMOGAPI, and AGREE. This study introduces three innovative green spectroscopic methods, each mathematically manipulated, for the simultaneous quantification of ciprofloxacin hydrochloride (CIP) and tinidazole (TIN) in their raw form and within a combined tablet product. Utilizing ratio spectra manipulation, CIP ratio spectra were derived by employing TIN at 8µg/mL as the divisor, and conversely, TIN ratio spectra were obtained using CIP at 4µg/mL as the divisor. The ratio difference spectrophotometric approach identified a correlation between the amplitude differences in the ratio spectra at ∆P 272nm-237nm , ∆P 331nm-273nm and the concentrations of CIP and TIN, respectively. Additionally, the first derivative of the ratio spectra was computed ( 1 DD), revealing that the peak amplitudes at 283 nm for CIP and 294.2 nm for TIN were directly related to their respective concentrations. The Area Under Curve (AUC) method involved integrating the area within zero order absorption spectra over selected wavelength intervals, specifically 268–288 nm for CIP and 300–330 nm for TIN. The proposed methods demonstrated linearity within the concentration ranges of 1–16 µg/mL for CIP and 2–20µg/mL for TIN. The proposed spectrophotometric methods were validated according to ICH guidelines and effectively applied to the simultaneous analysis of CIP and TIN in Tinifloxacin® tablets. A statistical comparison with the reported HPLC method was conducted using F and t -tests. The greenness of the methods was also assessed and verified using the Eco-scale, complex GAPI, and AGREE assessment tools. Graphical abstract