Aqueous sodium dehydrocholate–sodium deoxycholate mixtures at low concentration

The behavior of the sodium dehydrocholate (NaDHC)–sodium deoxycholate (NaDC) mixed system was studied by a battery of methods that examine effects caused by the different components of the system: monomers, micelles, and both components. The behavior of the mixed micellar system was studied by the application of Rubingh's model. The obtained results show that micellar interaction was repulsive when the aggregates were rich in NaDHC. The gradual inclusion of NaDC in micelles led to a structural transformation in the aggregates and the interaction became attractive. The bile salts' behavior in mixed monolayers at the air–solution interface was also investigated. Mixed monolayers are monotonically rich in NaDC, giving a stable and compact adsorbed layer. Results have shown that the interaction in both micelles and monolayer is not ideal and such behavior is assumed to be due to a structural factor in their hydrocarbon backbone. In addition to their physiological roles, bile salts mixed micelles are promising systems for drug delivery. The purpose of this research was to attempt to shed further light on the process of bile salts mixed micelles and mixed monolayer formation. These kinds of systems could be considered the simplest model to get molecular information and hence, this study is the first step to understand the properties and the behavior of macromolecular assemblies.