Innovative spectrophotometric methods for the analysis of terbinafine and ketoconazole in pharmaceutical preparations with compliance to greenness and blueness metrics

Five simple, sensitive, and eco-friendly spectrophotometric techniques were developed for solving the highly overlapped spectra of Terbinafine HCl and Ketoconazole in their combined tablet formulation, for the first time without the common excipients interfering. The methods included third derivative spectrophotometry (D 3 ) (Method I), ratio spectra difference spectrophotometry (Method II), first derivative of ratio spectra (Method III), induced dual-wavelength (Method IV), and dual-wavelength resolution (Method V). The evaluation of the developed methods was based on correlation coefficients, relative standard deviations, and limits of detection and quantitation. Statistical tests, including the variance ratio F-test and Student t-test, showed no significant differences between the results obtained from the developed methods and those from the established reference methods. The techniques were efficiently applied to analyze the cited drugs in commercial tablet formulations with high % recoveries and low % RSD values. An assessment of the methods’ environmental impact, using the Analytical Eco-scale, the Green Analytical Procedure Index (GAPI), Analytical Greenness Approach (AGREE) and blue applicability grade index (BAGI) metrics demonstrated their sustainability. The developed spectrophotometric methods don’t require prior separation steps, large volumes of organic solvents, or sophisticated instruments; therefore, they are well-suited for routine analysis and quality control of the specified drugs in their dosage forms.