Drug induced micelle-to-vesicle transition in aqueous solutions of cationic surfactants?

RSC Advances Pub Date: 2017-01-13 DOI: 10.1039/C6RA25577A

Abstract

The effects of the anti-inflammatory drug diclofenac sodium (DS) on the morphology of aqueous micellar aggregates of two ionic liquid-based surfactants (ILBSs), 1-hexadecyl-3-vinylimidazolium bromide, C16VnImBr, 1-hexadecyl-3-methylimidazolium bromide C16MeImBr, and (conventional) cetyltrimethylammonium bromide, C16Me3ABr (Vn, Im, Me, A = vinyl, imidazolium, methyl and ammonium, respectively) were studied at 25 °C. To probe the morphology changes of the formed aggregates, we employed turbidity, viscosity, dynamic light scattering, and transmission electron microscopy. Depending on [DS], the transitions observed were from spherical micelles → worm-like micelles → vesicles. Viscosity data indicated that the first transition occurred at lower [DS] for C16VnImBr compared to C16MeImBr and C16Me3ABr; indicating stronger interaction between (C16VnIm)+ and DS?. Light scattering results revealed that the DS/C16VnImBr system contained larger vesicles, as compared to DS/C16MeImBr and DS/C16Me3ABr. The changes in morphology agree with the expected effects of DS on the packing parameter of the colloidal aggregates.

Graphical abstract: Drug induced micelle-to-vesicle transition in aqueous solutions of cationic surfactants
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