Ecological assessment and development of analytical methods for concurrent quantification of valsartan and sacubitril: whiteness comparative study based on relative scoring.

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.

Development of hybrid spectrofluorimetric method for simultaneous determination of Valsartan and Sacubitril in LCZ696 tablets.

A hybrid Spectrofluorimetric method was developed for the simultaneous determination of binary mixtures, without prior separation steps. It coupled synchronous spectrofluorimetry with derivative ratio mathematical treatment. The method was applied successfully to quantify a new model binary mixture consisting of Valsartan (VAL) and Sacubitril (SAC). This mixture was recently approved by FDA as LCZ696. It added a great value in reducing morbidity and mortality in resistant heart failure (HF) patients. First derivative ratio synchronous fluorescence was measured at 258-295 (peak-to-peak) and 204 nm for VAL and SAC, respectively. ICH guidelines were fulfilled for the method validation. VAL and SAC showed linear responses in the range of 60-200 and 20-200 ng mL-1, respectively. The proposed method was compared, in details, with the reported ones. Its high accuracy, selectivity, simplicity and affordable cost recommend method application in large-scale routine analysis of LCZ696 tablets. Moreover, reliable application of this new integrated spectrofluorimetric method suggests expansion of its application for various therapeutic combinations and different matrices.

Gradient HPLC-DAD method for quantification of novel oral anticoagulant "Edoxaban" in plasma: Its selective determination in presence of sixteen co-administered drugs.

As an anticoagulant, Edoxaban (EDX) is a high risk drug that may cause a life-threatening bleeding. Also, it is prescribed as a chronic therapy for atrial fibrillation and venous thromboembolism patients. They are special population that needs appropriate care and optimum dosing of EDX. Hence, its monitoring in the patient plasma is fundamental, especially in emergency and special circumstances. However, such patient mostly receives many drugs of different pharmacological classes, side by side with EDX. This study represents the first attempt to quantify EDX in plasma without interference of the plasma matrix or concomitant medications. An accurate RP-HPLC-DAD method was developed for this purpose. It succeeded to monitor EDX level, selectively, without interference of plasma matrix or 16 of its frequently co-administered drugs. All drugs were extracted from plasma samples by protein precipitation followed by evaporation and concentration. EDX was well resolved from the co-administered drugs on C8 column using linear gradient elution of methanol and phosphate buffer (pH 4), at a flow rate of 1 mL/min. EDX appeared at retention time 9.6 min and was quantified at its λmax (290 nm). It exhibited a linear response over the concentration range of 0.15-2.2 µg/mL plasma which covers the reported therapeutic concentration. The suggested method fulfilled the US FDA guidelines for bioanalytical method validation. The developed method is fully discussed in comparison with the reported techniques. An in vivo study was performed to ensure applicability of the method on real plasma samples without interference from plasma matrix, co-administered drugs or the expected metabolites. It presented a unique selectivity of the method that guarantees accurate laboratory monitoring of EDX in plasma in almost all combined treatments including such novel oral anticoagulant drug.