The stability of the amorphous form of cefuroxime axetil in solid state

The stability of the amorphous form of cefuroxime axetil was studied by means of the stress stability test. The degradation was evaluated using the HPLC method with UV detection (278 nm), as described in the monograph of Cefuroxime Axetil in European Pharmacopoeia. Liquid chromatography was performed with a H5 SAS Hypersil column (5 microm particle size, 250 mmx4 mm), the mobile phase consisted of a mixture of 38 volumes of methanol and 62 volumes of a 23 g l-1 solution of ammonium dihydrogen phosphate, a flow rate of 1.2 ml min-1, and the internal standard was a solution of acetanilide in a mixture (1:1) of acetonitrile and water at a concentration of 0.2 mg ml-1. At an increased temperature at RH=0%, the degradation of cefuroxime axetil (CFA) diastereoisomers is the reversible first-order reaction, while that occurring in humid air (RH>25%) is the reversible first-order autocatalytic reaction with Delta3-isomers and E-isomers of cefuroxime axetil and cefuroxime as the main products.