On the basis of proposed six models of the dependence of local anaesthetic effectiveness of series of alkoxysubstituted derivatives of phenylcarbamic acid, this activity was studies in dependence on the capacity factor k’ as the parameter of lipophilicity. The most suitable models proved to be y = (Cx + Ci).k’ for surface anaesthesia, and y = Cx + Ci log k’ for infiltration anaesthesia, y being the value of the decadic logarithm of surface or infiltration local anaesthetic activity, Cx the coefficient characterizing the nitrogenous base, Ci the coefficient characterizing the individual alkoxygroups, and k’ the capacity factor from HPLC.

        Key words: local anaesthetic activity – derivatives of alkoxyphenylcarbamic acid – capacity factor k’ – dependence