Stability of cefotaxime sodium as determined by high-performance liquid chromatography

The stability of cefotaxime sodium in water (with either hydrochloric acid, phosphate buffers, or other ingredients) dextrose, and sodium chloride has been studied using a stability-indicating high-performance liquid chromatographic method with a relative standard deviation of 1.9% based on six injections. The optimum pH range of stability was determined to be approximately 4.3-6.2. In this pH range, the decomposition process was catalyzed only by the solvent. At pH less than or equal to 3.4, the hydrogen ion also catalyzed the reaction while at pH greater than 6.2, the hydroxyl ion hastened the process of decomposition. The solutions in 5% dextrose and 0.9% NaCl injections were stable for at least 1, 22, and 112 d at 24 degrees C, 4 degrees C, and -10 degrees C, respectively. For both solutions, the loss in potency was less than 5% at -10 degrees C in 224 d, less than 9% at 4 degrees C in 42 d, and less than 3.1% at 24 degrees C in 1 d.