Individual degradation rate constants for cefotaxime, deacetylation profile.

The individual degradation rate constants for cefotaxime in aqueous solution were calculated within a pH range of 1.6-10.0 at 37 degrees C from high performance liquid chromatography data. This allowed the general degradation profile of cefotaxime to be decomposed into a degradation profile attributed to the opening of the beta-lactam nucleus and a degradation profile attributed to the deacetylation. From the calculations of the individual rate constants, the activity of degraded cefotaxime solutions could be predicted. In the pH range of injectable solutions of cefotaxime 5-7, roughly equivalent amounts of inactive beta-lactam cleavage products and deacetylated compound which has a different spectrum of antibacterial activity are formed.