Transport studies of β-lactam antibiotics and their degradation products across electrified water/oil interface

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 19; no. 1; pp. 183 - 192
• Main Authors: Basáez, Luis, Vanýsek, Petr
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.02.1999
• Subjects: Ampicillin; Ampicillin - analysis; Anti-Bacterial Agents - analysis; Anti-Bacterial Agents - chemistry; Cephalexin; Cephalexin - analysis; Cephalosporin; Electroanalysis; Electrochemistry; Electrodes; Electrolytes; Hydrogen-Ion Concentration; Hydrolysis; Hydrolysis products; Indicators and Reagents; Ion transfer; ITIES; Oils; Penicillin; Photometry; Spectrophotometry, Ultraviolet; Water; β-Lactam antibiotics; Electroanalysis; β-Lactam antibiotics; Ampicillin; Ion transfer; Cephalexin; ITIES; Hydrolysis products; Penicillin; Cephalosporin
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/S0731-7085(98)00147-2

An electrochemical method for quantifying β-lactam antibiotics (cephalexin and ampicillin) and their hydrolysis products is described. Cyclic voltammetry at the water/nitrobenzene interface in a four-electrode system was used. The zwitterionic compounds were ionized to the necessary electrochemical form by pH adjustment. The pH change, however, resulted also in hydrolysis of the antibiotics. Hydrolysis products were characterized across UV-vis spectrum. The various hydrolysis products as well as the ionized antibiotics were studied in voltammetric transfer from water to nitrobenzene using the method of the interface between two immiscible electrolyte solutions (ITIES). It was concluded that this electrochemical method is suitable for the quantification of β-lactam antibiotics and their hydrolysis products.