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

The stability of mezlocillin sodium solutions in water with either phosphate buffers or other ingredients used in intravenous admixtures (dextrose, fructose, and sodium chloride) has been studied using a stability-indicating high-performance liquid chromatographic method. This assay shows a relative standard deviation of 1.42% based on six injections. The optimum stability was shown at an approximate pH of 4.8, and solutions in dextrose (5%) and sodium chloride (0.9%) were stable for up to 4 days at 25 degrees, 36 days at 5 degrees, and for 60 days at -10 degrees. When refrigerated, the solutions in 5% fructose and 10% dextrose were as stable as those in 5% dextrose.