Analytical method development and validation of enrofloxacin and ciprofloxacin in marketed formulation by UV spectrophotometric method

This study focuses on the development and validation of a simple, rapid, and cost-effective UV–Visible spectrophotometric method for the simultaneous estimation of Enrofloxacin and Ciprofloxacin in pharmaceutical formulations. Both drugs, belonging to the fluoroquinolone class, are widely used in veterinary and human medicine, necessitating accurate and reliable analytical techniques for quality control. Existing methods such as HPLC and LC-MS/MS, although sensitive, are expensive and time-consuming, highlighting the need for alternative approaches. Pre-formulation studies confirmed the physicochemical suitability of both drugs for UV analysis, while FTIR spectroscopy verified their identity and purity. A solvent system comprising methanol and phosphate buffer (50:50 v/v) was optimized to ensure solubility and spectral clarity. The selected wavelengths were 278 nm for Enrofloxacin and 272 nm for Ciprofloxacin, enabling simultaneous estimation without interference.
Method validation was performed as per ICH Q2(R1) guidelines, demonstrating excellent linearity (r² > 0.999), accuracy (98–102%), precision (RSD < 2%), and robustness. The limits of detection and quantification confirmed adequate sensitivity for routine analysis. Application of the method to marketed formulations yielded assay values within pharmacopoeial limits, confirming its reliability. In conclusion, the proposed UV–Vis method offers a practical alternative to chromatographic techniques, especially in resource-limited settings, ensuring efficient pharmaceutical quality control.