CLVII. Chromatographic Properties of Pentacaine, Carbisocaine, Heptacaine, and Its 3-, and 4-Positional Isomers in the RP HPLC System The present study aimed to find a suitable HPLC systém for the determination of the values of the capacity factor of k' pentacaine, carbisocaine, heptacaine, and its 3-, and 4-positional isomers. The column Separon SG X C-18 and a mobile phase consisting of 90 % methanol and 10 % water (with 0.5 moUl of sodium acetate) esere demonstrated to be suitable for the separation of these potential local anaesthetics from the group of phenylcarbamic acid derivatives. In this systém, k'o for pentacaine is 22.9, for carbisocaine 8.6, for heptacaine 8.1, and for 3-positional derivative of heptacaine, 13.0, and 4-isomer, 18.4. It results from the data tkat log k' of these drugs is in the interval 2-5 and even minor changes in the concentration of sodium acetate (c=0,5±0.05 moUl) do not change it markedly.

        Key words: pentacaine - carbisocaine - heptacaine - capacity factor k', HPLC