Ecofriendly bioanalytical validated RP-HPLC method for simultaneous determination of COVID-19 co-prescribed drugs employing quality by design and green chemistry

Molnupiravir, dexamethasone, ertapenem, and remdesivir are among the most frequently co-prescribed drugs used for COVID-19 virus treatment. For the first time, a simple isocratic reversed phase-high performance liquid chromatographic (RP-HPLC) method employing a photodiode array detector has been developed and validated for their simultaneous determination in spiked human plasma using rivaroxaban as an internal standard by the aid of quality by design and in accordance with the criteria of green chemistry. The separation was carried out utilizing a BDS Hypersil (R) C18 column (300 x 4.6 mm), 5 mu m particle size as the stationary phase using mobile phase consisted of methanol: acidified water; adjusted at pH 4.0 with 0.1 M orthophosphoric acid; with ratio (70:30, v:v) delivered at flow rate 0.6 mL/min, temperature adjusted at 20 degrees C, photodiode array detector maintained at 240 nm. The method was validated according to bioanalytical FDA guidelines with respect to linearity, accuracy, precision, selectivity, recovery, and stability. The method was found to be linear in the range of 4.00-120.00 mu g/mL for molnupiravir, 10.00-140.00 mu g/mL for dexamethasone, 10.00-160.00 mu g/mL for ertapenem and 4.00-120.00 mu g/mL for remdesivir. It is worth mentioning that the previously mentioned ranges covered the C-max of the drugs. Finally, the green analytical score has been evaluated, and it was found to be an excellent green analytical method based on analytical eco-scale system penalty points. Moreover, it was assessed by analytical GREEnness metric approach and green analytical procedure index tool.