Back to Search Start Over

Heterogeneous micellar solubilization within lyotropic liquid crystals interfaces.

Heterogeneous micellar solubilization within lyotropic liquid crystals interfaces.

Authors :
Goldmünz EY
Aserin A
Ottaviani MF
Shames AI
Garti N
Source :
Journal of colloid and interface science [J Colloid Interface Sci] 2024 Oct 15; Vol. 672, pp. 552-563. Date of Electronic Publication: 2024 May 24.
Publication Year :
2024

Abstract

The solubilization of sodium diclofenac (Na-DFC) in a glycerol monooleate-based emulsion triggers series of structural changes. Incorporation of Na-DFC, leads to formation of a reverse hexagonal mesophase between 2 and 5 wt% Na-DFC. Between 6 and 9 wt% Na-DFC, the hexagonal symmetry gradually transitions to a disordered lamellar mesophase. These structural shifts impact the system's storage modulus, structuring enthalpy, and structural diffusivity. Despite these transitions, the driving force for Na-DFC release remains consistent, leading to hypothesize that the interfacial structure remains unchanged during Na-DFC release. The nano-structural modifications imposed by the Na-DFC load and release were assessed by small-angle X-ray diffraction (SAXD), spin-probe electron paramagnetic resonance (EPR), and nuclear quadrupole resonance (NQR). The selective solubilization of Na-DFC was demonstrated by SAXD peak fittings, revealing an increase of hexagonally oriented rods at the expense of non-oriented micelles, rather than gradual micellar elongation. Computation of the EPR spectra also showcased the selective solubilization of Na-DFC at an enhanced free energy interface (γ), evidenced by step-wise variations in polarity, microviscosity, and order parameters. Additionally, NQR analysis highlighted a higher anisotropy for sodium compared to deuterium, linking the selective solubilization of Na-DFC to heterogeneous structural transformations. These findings underscore the heterogeneous nature of solubilization-release processes, driven by locally increased micellar free energy. Consequently, the loaded Na-DFC interfaces maintain a constant γ, ensuring a consistent release driving force despite the structural transitions affecting the matrix. The ability to selectively solubilize guest molecules may herald a new era in the utilization of selective molecular interfacial loading.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2024 Elsevier Inc. All rights reserved.)

Details

Language :
English
ISSN :
1095-7103
Volume :
672
Database :
MEDLINE
Journal :
Journal of colloid and interface science
Publication Type :
Academic Journal
Accession number :
38852356
Full Text :
https://doi.org/10.1016/j.jcis.2024.05.096