Evaluation of stability of cefuroxime axetil in solid state.

The effect of temperature and relative atmospheric humidity on the stability of the crystalline form of cefuroxime axetil (CFA) in solid state was investigated. CFA is a mixture of diastereomers A and B. Changes in the concentration of the two diastereomers (A and B) of CFA were recorded by means of HPLC with UV detection. The degradation of diastereomers of CFA occurring at 0% relative humidity (RH) of the ambient air is a reversible first order reaction, while that occurring in humid air (RH>50%) is an autocatalytic first order reaction relative to substrate concentration. Although it has been found, that diastereomer B is the more stable isomer, humidity has a stronger effect on this very diastereomer.