Study on reactive extraction of certain betalactam antibiotics equilibrium and kinetics

Abstract

The beta-lactam antibiotics are well known for their antibacterial activity. The extensively used beta-lactam such as penicillins and cephalosporins constituents a large portion of the multimillion dollar antibiotics market. Since the discovery of penicillins by Fleming (1929) and cephalosporin-c (CPC) by Netwon and Abraham, (1955), the processes for production of natural and semisynthetic cephalosporins have undergone various modifications. The enzymatic process has several advantages over the chemical synthesis including the use of toxic organic solvent. In view of this, most of the commercially important natural beta-lactams are produced by biochemical method. Effective methods for extraction and purification of beta-lactam antibiotics are essential from both analytical and preparative purposes. Various methods of extraction and purification of beta-lactam antibiotics have been discussed in our recent reviews (Ghosh et al., 1996, 1997). The adsorption chromatography used for isolation and purification of hydrophilic beta-lactam (Voser, 1982) has the limitation of generating dilute solution. Recovery of the beta-lactam by this method involves capital and energy intensive operation. Certain beta-lactam antibiotics are amphoteric in nature and therefore, physical solvent extraction is difficult. Reactive extraction, accompanied by chemical reaction can provide an efficient method for separation and purification of beta-lactam antibiotics. Reactive extraction has been extensively studies for various biomolecules and penicillin-G (Likidis et al., 1987). The concept has been exploited to develop liquid membrance processes where facilitated transport could be realised to give high flux and selectivity of separation (Lee and Lee, 1992 ; Lee et al., 1993). In order to exploit the principle of reactive extraction for practical application, the knowledge of the data on equilibrium and kinetics is very much essential. However, such information is vary scanty in literature particularly for cephalosporin antibiotics. In...