RESUMO
Sustainable analytical chemistry is gaining great interest in global environmental pollution control. In addition, valsartan (VAS) and sacubitril (SAB) have been recently approved by the FDA as a fixed-dose combination "LCZ696". It showed efficacy and safety enough to extend its application from heart failure to hypertension control. VAS/SAB dual therapy is considered expensive; however, its prescription has increased significantly worldwide. This prescription increased the demand for developing sustainable analytical methods that simultaneously analyze VAS and SAB. Highly sensitive and selective spectrofluorimetric methods have been developed for this purpose. A synchronous spectrofluorimetric technique was applied. In one method, it was followed by spectral derivatization at the first-order level. The signals were recorded at 230 and 211 nm for VAS and SAB, respectively. Synchronous spectrofluorimetry was coupled to a dual-wavelength mathematical approach in the second method. Signals were derived by subtracting synchronous responses at 241 nm, 226 nm, and 239 nm from the response at 208 nm for VAS and SAB, respectively. Method validation was carried out following ICH guidelines. VAS showed linear calibration curves spanning the range of 60-200 and 80-600 ng mL-1 for the derivative and dual wavelength-assisted approaches, respectively. SAB achieved linear responses in the range of 17-190 and 30-350 ng mL-1 for the first and second methods, respectively. The green profile of the proposed methods was confirmed using the analytical eco-scale (AES), green analytical procedure index (GAPI), and analytical greenness metric (AGREE) tools. The proposed hybrid methods proved highly sustainable through the whiteness RGB 12 algorithm evaluation approach. Whiteness was comparatively assessed for the proposed and reported methods based on relative scoring depending on the parameters of each method. Despite this scoring approach being accurate as a relative score for comparative purposes, it gave rise to underestimated absolute scores. Therefore, to obtain a proper conclusion from the comparative whiteness study, all the methods were ranked according to their whiteness score, illustrating the excellent whiteness ranks of the proposed methods. Upon complete comparison with the reported methods, the suggested ones showed several advantages concerning analytical performance and the greenness level. The proven affordability and simplicity encourage their wide industrial application in developing countries.