Five greenness assessments of novel RP-UPLC and MCR methods for concurrent determination of selected pharmaceutical drugs in comparison with the lean Six Sigma approach

Implementing the Lean Six Sigma methodology is highly recommended for minimizing analysis waste and improving efficiency and productivity. Developing green analytical UPLC and MCR methods to evaluate the solvent used and ensure safety and sustainability is also necessary. The current research work studies the development of analytical eco-scale, analytical greenness (AGREE), analytical greenness for sample preparation (AGREEprep), green analytical procedure index (GAPI), and complementary green analytical procedure index (ComplexGAPI) tools for greenness assessment of validated novel and simple RP-UPLC and MCR methods for simultaneous estimation and separation of Ciprofloxacin (CIP), Azithromycin (AZI), and Diclofenac sodium (DIC) in their pure and dosage form. The analytical method employed for the UPLC was isocratic and utilized a mobile phase consisting of ethanol and acidic water in a ratio of 75:25. The pH of the mobile phase was adjusted to 2.5, and detection was performed using UV at a wavelength of 210 nm. The flow rate was set at 0.3 mLmin−1, and a stationary phase RRHD C18 column (50 mm × 2.6 mm, 1.8 μm) was used. The column oven temperature was maintained at 25 °C throughout all the sequences. The Parameters affecting the separation and detection were optimized. The spectral overlapping of the drugs has been effectively resolved through the mean centering of ratio (MCR) spectra approach. This approach was used at 316.5, 240.7, and 208.6 nm for CIP, DIC, and AZI, respectively. Based on the calibration curves, it was found that the UPLC and MCR methods were linear in the (5–50 µgmL−1) and (5–30 µgmL−1) ranges for all drugs, with a correlation coefficient greater than 0.999. Additionally, the primary recovery of the method was calculated and yielded excellent results, with recovery rates ranging between 99.8 and 100.7%. The recommended technique has been validated per ICH recommendations.