Para-carboxy modified amphiphilic calixarene, self-assembly and interactions with pharmaceutically-relevant molecules

The self-assembly properties of the amphiphilic 5,11,17,23-tetra-carboxy-25,26,27,28-tetradodecyloxycalix[4]arene have been investigated at the air-water interface as monomolecular Langmuir layers and in water. The interactions of this amphiphile with salicylic acid (SA), acetyl-salicylic acid (ASA) and acetaminophene (APAP) have been studied at the air-water interface by means of the Langmuir balance technique. It has been demonstrated that the calix-arene molecules, when self-assembled as Langmuir monolayers, have the ability to interact with all the tested compounds. While APAP causes a stabilization of the monolayer, ASA and SA cause a slight loss of stability and a drastic change of the compressibility of the monolayer. The study of the self-assembly properties of the title compound in water revealed that this amphiphile can be self-assembled as solid lipid nanoparticles (SLNs). The atomic force microscopy investigations of the colloidal suspension, spread on a solid surface and dried, revealed the coexistence of the SLNs with layered structures.