Design of experiments and Derringer's desirability function in optimisation and validation of RP-HPLC method for the analysis of enrofloxacin and its impurities

Abstract Using the Design of Experiments methodology ( Response-Surface Methodology and Derringer's Desirability Function ), a simple, fast robust RP-HPLC method was developed for analysis enrofloxacin (EFC), its impurity A (fluoroquinolonic acid, FQ) B (ciprofloxacin, CPX). Gradient elution samples performed on Zorbax Eclipse XDB C18 column (150 × 4.6 mm, 3.5 μm) with mobile phase consisting 32 mM phosphate buffer pH – methanol (0 min-19.6% methanol; 15.5 29.5 min-80% 30 35 methanol), delivered at flow rate 1.5 mL min −1 , wavelength detection 278 nm (for EFX CFX) 265 FQ. good linear response achieved in range 15–35 μg (EFX) LOQ-150% impurities (CFX FQ). Other validation parameters were also tested: precision, accuracy, sensitivity robustness. The shown to be practical suitable EFC (CPX, veterinary drugs.