Azlocillin Opern-Ring Decarboxylation Impurity 4-Thiazolidinecarboxylic acid, 5,5-dimethyl-2-[[[2-[[(2-oxo-1-imidazolidinyl)carbonyl]amino]-2-phenylacetyl]amino]methyl]- Aloxicillin ring opening decarboxylation impurity Azlocillin Open-Ring Decarboxylation Impurity Aloxicillin opening decarboxylation impurity Abamectin Impurity 13