First derivative emission spectrofluorimetric method for the determination of LCZ696, a newly approved FDA supramolecular complex of valsartan and sacubitril in tablets.

LCZ696 (sacubitril/valsartan, Entresto™) is a therapy lately approved by United States Food and Drug Administration (US FDA) as a heart failure therapy. It is claimed to decrease the mortality rate and hospitalization for patients with chronic heart failure. This study is considered as the first report to investigate the fluorimetric behavior of sacubitril in addition to pursuing all the different conditions that may affect its fluorescence. Various conditions were studied, for example studying the effects of organized media, solvents and pH, which may affect the fluorescence behavior of sacubitril. For the simultaneous determination of the newly approved supramolecular complex of valsartan (VAL) and sacubitril (SAC) in their tablets, a sensitive and simple first derivative spectrofluorimetric method was developed. The method involved the measurement of native fluorescence at 416 nm and 314 nm (λex 249 nm) for VAL and SAC, respectively. The first (D1) derivative technique was applied to the emission data to resolve a partial overlap that appeared in their emission spectra. The proposed method was successfully applied for the assay of the two drugs in their supramolecular complex LCZ696 with no interference from common pharmaceutical additives. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines were followed in order to validate the proposed method.