Eudragit E100 surface activity and lipid interactions

ALASINO RV; LEONHARD V; BIANCO ID; BELTRAMO DM

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012 p. 84 - 89

0927-7765

Eudragit E100 (E100) is a cationic metacrylate polymer that interact with viral and cell membranes. We studied the effect of pH, ionic strength and the presence of lipids monolayers on the surface activity of the polymer. E100 forms stable monolayers at the air-water interface, either by spreading or when is added into the subphase. This behaviour is strongly affected by the pH and saline concentration of the subphase. At pH 5 or higher, the adsorption of the polymer to the air-water interface begins immediately after its injection into the subphase, while at pH below 5 E100 remains into the subphase with a very slow adsorption to the interface.  Besides, low ionic strength (10 mM) in the subphase result in a fast adsorption of the polymer to the interface, even at pH under 5. On the other hand, in presence of non-ionic (cholesterol) or anionic (monosialoganglioside) lipid monolayers, E100 shows a fast adsorption to the interface reaching surface pressures of 25 and 36 mN.m-1, respectively. However, E100 barely interacts with monolayers of a zwitterionic lipid (hydrogenated soy lecithin) with a cut-off pressure of 11 mN.m-1. The interaction of E100 with GM1 micelles in the subphase reduced its surface activity. Altogether these results show that E100 can effectively penetrate into model membranes and that its amphipatic character is strongly dependent on the chemical composition of the aqueous environment and the lipid composition of the membrane.