In vitro evaluation of temperature-dependent stability and antimicrobial activity of reconstituted cefovecin sodium

Cefovecin sodium is a long-acting third-generation cephalosporin widely used in dogs and cats. After reconstitution, refrigerated storage for a limited period is recommended; however, experimental data regarding the effects of alternative controlled storage temperatures on drug stability and antimicrobial activity are limited. This study evaluated, under in vitro conditions, the impact of storage temperature on the physicochemical stability and antimicrobial activity of reconstituted cefovecin sodium. Samples were stored at room temperature (25 ± 2°C), refrigerated conditions (4°C), or frozen conditions (-20°C) for up to 12 weeks. Visual appearance, absorbance at 360 nm, minimum inhibitory concentrations (MICs) against E. coli and Staphylococcus aureus, and cefovecin sodium concentrations determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) were assessed over time. Room temperature storage resulted in progressive discoloration, increased absorbance, elevated MIC values, and a significant decrease in drug concentration at later time points. Refrigerated storage delayed these changes, although mild increases in absorbance and MIC values were descriptively observed at later time points. In contrast, frozen storage preserved physicochemical properties, antimicrobial activity, and measured drug concentrations throughout the study period. These findings demonstrate that storage temperature influences the stability and in vitro antimicrobial activity of reconstituted cefovecin sodium in a condition-dependent manner. The results provide experimental reference data under controlled laboratory conditions and do not support clinical use outside the manufacturer's approved storage instructions.