Active Macromolecular Contaminants of Penicillins

The protein contaminants in benzylpenicillin derive from the fermentation manufacturing processes used in production of the antibiotic. During the course of fermentation, proteins of the medium become penicilloylated and may be extracted in minute amounts into the final preparations. The semisynthetic penicillins are prepared from 6-APA, which in turn is obtained through either enzymatic or chemical removal of the side chain in benzylpenicillin (Carrington 1971). Penicil- 

The amounts of penicilloylated proteins in commercial benzylpenicillin and semisynthetic penicillins seem to vary considerably. Whereas up to 200-300 parts/ 10 of penicilloy 1-protein in benzylpenicillin preparations were reported by Batchelor et al. (1967) and also by Butcher and Stewart (1970), other groups have only detected less than 10 parts/10 of proteinaceous impurities in commercial benzylpenicillin (Dursch 1968 Preud homme and Lunel 1969 Weidenmuller and Ziegler 1970 Walsh et al. 1971 Ottens et al. 1971 Vilim et al. 1976). As described by Ottens et al. (1971), the methods used for the determinations, i.e., dialysis, membrane filtration, and gel filtration followed by penicilloyl and protein analysis, have several drawbacks. Penicillin degradation products and polymers were found to influence the determinations, making these somewhat unreliable. 

The presence of protein in ampicillin has been shown to have a significant effect upon the immunogenicity of the antibiotic (Knudsen et al. 1970). Removal of protein markedly reduced the immunogenicity as well as the antigenicity. Immunogenicity was, however, not completely abolished and low levels of antibody were detected in the rabbits used in the immunization experiments. A similar reduction in immunogenicity and antigenicity of ampicillin preparations (and 6-APA preparations) by reduction of protein levels was shown by Shaltiel et al. (1970, 1971). 

---