Deactivation and transformation products in biodegradability testing of beta-lactams amoxicillin and piperacillin.
Antibiotics have increasingly been detected in effluents and the environment. However, information on the degree of deactivation and mineralization, and the nature of possible formed dead-end transformation products is scarce but desirable for proper risk assessment. An important group of antibiotics is the beta-lactams. We studied the transformation of the closely structurally related beta-lactams piperacillin and amoxicillin in two OECD biodegradability batch tests. None of the antibiotics was biodegraded in the closed bottle test (CBT). However, primary abiotic elimination as monitored by HPLC-UV-VIS was 20% and 100% in the CBT within 14 days, respectively. With HPLC-UV-VIS and ion trap LC-MS/MS primary elimination was shown to be more than 94% for both antibiotics within seven days in the Zahn-Wellens test (ZWT). Both compounds were deactivated by hydrolysis. For piperacillin, a dead-end transformation product resulted after hydrolysis of the beta-lactam ring. For amoxicillin full mineralization of the transformation products was observed.
Längin
Andreas
A
Department of Environmental Health Sciences, Medical University Centre Freiburg, Breisacher Str., 115B, D-79106 Freiburg, Germany.
Alexy
Radka
R
König
Armin
A
Kümmerer
Klaus
K
D000658:Amoxicillin / Q000032:analysis* / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000032:analysis*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D010878:Piperacillin / Q000032:analysis* / Q000737:chemistry; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D014466:Ultraviolet Rays
D000900:Anti-Bacterial Agents; D000658:Amoxicillin; D010878:Piperacillin