Methicillin polymerization

Kusuda M, Inada K, Ogawa TO, Yoshida T, Shiota T, Shiota S, Tsuchiya T, Hatano T. (2006) Polyphenolic constituents structures of Zanthoxylum piper-itum fruit and the antibacterial effects of its polymeric procyanidin on methicillin-resistant Staphylococcus aureus. Biosci Biotechnol Biochem 70 1423-1431. 

Polymerization of benzylpenicillin has been described by several authors (Batchelor et al. 1967 Stewart 1967 a de Weck et al. 1968 Butcher and Stewart 1969, 1970 Dewdney et al. 1971 Smith et al. 1971 Smith and Marshall 1971 Bungaard and Larsen 1977). Polymerization probably involves hydrolysis of the beta-lactam ring to form penicilloic acid, followed by acylation of the exposed thiazolidine nitrogen by another intact penicillin molecule or a benzyl-penicillenic acid derivative (Stewart 1973 Smith and Marshall 1971 Schneider and de Weck, 1970) (Fig. 8) Such polymers have been isolated by Sephadex gel chromatography (Smith et al. 1971) or by high-pressure liquid chromatography (Bundgaard 1977 b). Polymers have been isolated also from other semisynthetic penicillins such as hetacillin and carbenicillin (Smith et al. 1971), methicillin and pheneticillin (Butcher and Stewart 1970). 

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