Investigation of linezolid degradation kinetics using a validated UV/Vis spectrophotometer method

Abstract

This study focuses on the development and validation of a simple, precise, and cost-effective UV/Visible spectrophotometric method for the quantitative estimation of linezolid, a synthetic antibiotic used to treat serious Gram-positive bacterial infections. Emphasizing pharmaceutical quality control, the method adheres to International Council for Harmonisation (ICH) guidelines for analytical method validation and forced degradation studies. The method demonstrated excellent linearity over a concentration range of 2-20 μg/mL, with a maximum absorbance at 251 nm, and exhibited high precision, accuracy, sensitivity (LOD of 8.684 × 10⁻³ μg/mL), and robustness under slight variations in analytical conditions. Forced degradation under thermal stress conditions confirmed the method’s stability-indicating capability by clearly distinguishing linezolid from its degradation products. The kinetic degradation study at multiple temperatures revealed that the degradation rate increased with temperature, and an Arrhenius plot was used to predict a shelf life of approximately 2.64 years at room temperature (25 °C). These findings validate the method’s suitability for routine stability testing and shelf-life prediction of linezolid in pharmaceutical formulations, thereby supporting regulatory compliance and quality assurance in drug development.