An unexpected amide bond cleavage: poly (ethylene glycol) transport forms of vancomycin. 2

PEG-amide vancomycin derivatives (V(3) position) have been synthesized and found to behave as prodrugs in vivo, demonstrating anti-microbial activity in mice when challenged with Staphylococcus aureus. The corresponding PEG-carbamate derivatives do not manifest this in vivo activity, although both classes of compounds have similar in vitro rat plasma stability. Thus, it appears that extra vascular cleavage of the amide bond can occur if the condition of extended circulation of the conjugate is met, resulting in the release of vancomycin.