ALTERATION OF PERMEABILITY OF NEUTRAL AND ELECTRONEGATIVELY CHARGED LIPOSOMES BY ALKYL SULFATE SURFACTANTS

The partition coefficients have been determined for a series of anionic alkyl sulfate surfactants (alkyl chain lengths C-10, C-12, and C-14) partitioning between the aqueous phase and the lipid bilayer of neutral or electronegatively charged liposomes. The release of the fluorescent agent 6-carboxyfluorescein induced by the surfactants was studied before these surfactants perturbed the bilayer architecture. Unilamellar liposomes formed by egg phosphatidyl choline plus or minus phosphatidic acid were used. From there results obtained we assume that there was a strong correlation between the partition coefficients and the ability of the different surfactants to modify the permeability of liposomes. Likewise, the results suggest that the hydrophobic interactions are the main forces involved in the alteration of the permeability of lipid bilayers although the electrostatic forces play a significant role in the modification of this parameter.