1Department of Chemical Theory of Drugs, 2Department of Physical Chemistry of Drugs and 3Department of Cell and Molecular Biology of Drugs,

A series of new monomeric amphiphilic surfactants with variable length of side chain, derived from N-(2-dimethylamino)ethylbenzenecarboxamide was prepared. The critical micelle concentration (cmc) of the studied surfactants was determined in the water based solutions by measuring their electrical conductance. From cmc values some of essential characteristics of micelles, e.g. the micelle ionization degree (α), the micelle association degree (β) and the physico-chemical parameter, free energy of micellisation (ΔGo) were evaluated. The antimicrobial efficacy of the synthesized compounds expressed as the minimum inhibitory concentration (MIC) was determined using two bacterial strains (Staphylococcus aureus 4516, Escherichia coli 377/79 EN) and one yeast strain Candida albicans 8186. The antimicrobial activity was compared to the commercially used disinfectants Septonex ® and Ajatin®. Relationships between structure, physicochemical properties and antimicrobial activity of prepared and related compounds is discussed. Key words: antimicrobial activity – 2-(benzenecarbamoyl)ethyl-N,N-dimethyl-N-alkylammonium bromides – critical micelle concentration – cut-off effect – electrical conductivity – minimum inhibitory concentration – N-(2-dimethylamino)ethylbenzenecarboxamid