The effect of piperidinoethylesters of n-alkoxyphenyl-carbamic acids on bacterial cells

The inhibitory effect of local anaesthetic agents of this type on the bacteria Escherichia coli were evaluated. The dependence between antimicrobial activity and structure (log 1/MIC = f/m) was studied with the use of a bilinear model. In the positional paraisomers a lower effect of spherical and electron effects than in the case of ortho- and meta-isomers is assumed. The efficacy of these agents depends on their lipophilicity. Membrane activity of these agents was confirmed. In subinhibitory concentrations they cause leakage of cytoplasmic material lysis of spheroplasts, they increase the permeability of the membrane for protons and inhibit dehydrogenase activity of cells. The mode of action of heptacainium chloride and its positional isomers on cells is identical and is similar as in organic ammonium salts and amine oxides.