Interaction between acetylsalicylic acid and a cationic amphiphile model: an experimental approach using surface techniques

Abstract

Mechanical and morphological effects of monolayers of octadecylamine upon aspirin adsorption are monitored by Langmuir isotherms measurements and Brewster angle microscopy. Aspirin induced a notable expansion of the corresponding isotherms and a concentration-dependence of the mechanical stability of the films as a consequence of the subtle balance between the solubility of the amine and the monolayer stabilization induced by the ion-pairs, as corroborated by Brewster Angle Microscopy images. The incorporation of the aspirin into the interface was confirmed by UV–vis reflection spectroscopy. Some comments on the feasibility of using aliphatic amines for drug delivery of anionic species are presented.