Physical-chemical and toxicological properties of osmolyte-based cationic surfactants and spontaneously formed low-toxic catanionic vesicles out of them

In the context of efficient drug delivery systems, catanionic vesicles offer several advantages, such as spontaneous formation and long-term stability. However, especially the cationic component of such vesicles is often toxic. Thus, the search for less toxic, biocompatible amphiphiles, while maintaining the desirable aggregation properties is crucial. In this work, we present cytotoxicity towards the human cell line Hela as well as biodegradability data of some cationic surfactants based on the natural osmolytes choline and ectoine. The synthesis, aggregation and solubility behaviour as well as the stability in water of these compounds is discussed. In order to induce the spontaneous formation of vesicles, several of these cationic surfactants are combined with choline carboxylates with varying chain length in different mixing ratios and characterised with cryo-TEM. Further, the cytotoxic effect of such novel catanionics is evaluated as a function of the cationic-anionic ratio and compared to that of classical combinations of sodium dodecylsulfate and dodecyltrimethylammonium bromide.