New biamphiphilic surfactants (BS) based on the alkylmethylmorpholinium cation and deoxycholate anion (Mor-n(DC), n = 6, 8, 10, 12) have been synthesized. Using a range of physicochemical techniques, the aggregation behavior of BS in aqueous solutions was studied and their ability to act as nanocarriers for hydrophobic substrates was tested. It was found that an increase in alkyl tail length by two carbon atoms in the amphiphilic cation resulted in a decrease in the critical micelle concentration by approximately two times. In these systems, nanosized particles with hydrodynamic diameter from 2 to 300 nm were formed, depending on the tail length and concentration of the morpholinium cation. The transmission electron microscopy showed a variety of aggregate morphologies, including micelles, rod-like aggregates, and vesicular structures. In addition, the spectrophotometric method revealed a significant solubilization capacity of BS toward hydrophobic drugs, such as nimesulide, warfarin and amphotericin B. A significant increase in the solubilization ability was observed upon the transition from sodium deoxycholate surfactant (NaDC) to BS aggregates (Mor-n(DC)).
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