Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Local anesthetics of the homologous series of monohydrochlorides of [2-(alkoxy)phenyl]-2-(1-piperidinyl)ethyl esters of carbamic acid decrease the temperature of phase transitions L_β' → P_β (pretransition) and P_β → L_α (main transition) of 1,2-dipalmitoyl-sn-phosphatidylcholine in aqueous phase at pH 6.2. The efficiency of the anesthetics in decreasing the pretransition temperature increases with the number of carbon atoms n of the alkoxy substituent up to n = 6. For n > 6 no pretransition could be detected. The efficiency in decreasing the temperature of the main transition increases up to n = 8 - 9 while it starts decreasing at n = 10. Computer simulation of the thermograms has shown that the decrease of efficiency at n = 10 is caused by the dependence of the partition coefficients of the anesthetics K_P,G and K_P,LC between the aqueous phase and the P_β and L_α phases, respectively, on the length of the alkoxy substituent, thus: log K_P,LC = A_LC + B_LC n and log K_P,G = A_G + B_G n, where B_LC < B_G.