A New Kinetic Approach. Stability of Cefquinome Sulfate under Variable pH and Temperature

Object: This study was evaluation of Cefquinome Sulfate (CS) long-term stability under different conditions of pH and temperature, so as to suggest the best conditions to perform its clinical application. Method: The CS stability was investigated at different values of pH (2.0-9.0) and temperature (4-370C). Kinetic parameters of CS degradation in alkaline environment were calculated adopting a new model that took into consideration the equilibrium between the active and a reversibly inactivated form of CS after long-time degradation. Result: All temperatures show increased CS instability,and this effect decreased in following sequence: 370C>250C>150C>40C, which describe typical Arrhenius behaviors with good correlation for Kd(R2= 0.941). Conclusion: The alkali-catalyzed degradation of CS was faster and stronger than the acidic one. The best conditions were met at a pH6.8 and 40C .