Influence of temperature on the kinetics of adsorption and desorption of clavulanic acid by ionic exchange

Beta-lactamases are enzymes that deactivate penicillins and cephalosporins by hydrolyzing their beta-lactam rings, producing penicilloic acid derivatives and, in the case of cephalosporins, analogous degradation products. Clavulanic acid (CA) is a beta-lactam antibiotic produced by Streptomyces clavuligerus, which has a potent beta-lactamase inhibiting activity. This antibiotic displays only weak antibacterial activity, therefore rendering it unsuitable for use by itself. However, its use in combination with certain penicillins (amoxycillin and ticarcillin) is effective in clinical use. The recovery process of CA involves steps such as adsorption, ion exchange chromatography or liquid-liquid extraction, but with low yields. Thus, in the case of CA, an investigation of the influence of temperature on the adsorption process is very important because of the unstable structure of this antibiotic, which degrades rapidly under normal processing conditions. In the work reported on herein, the influence of temperature on the CA adsorption process was investigated, involving equilibrium and kinetic studies and carrying out batch shake experiments with the ion exchanger resin Amberlite IRA 400 at four different temperatures. A model of the CA adsorption process, taking into account mass transfer limitation, is proposed. An estimate of the thermodynamics of the adsorption process was made based on van't Hoff's equation. (C) 2002 Elsevier Science B.V. All rights reserved.