Solubilization of nutraceuticals into reverse hexagonal mesophases.

Area of Science:

• Materials Science
• Physical Chemistry
• Biophysics

Background:

• Reverse hexagonal (HII) liquid crystalline phases are complex self-assembled systems.
• Understanding bioactive molecule interactions within these phases is crucial for formulation development.

Purpose of the Study:

• To investigate the solubilization of four bioactive molecules with varying polarities within three distinct HII systems.
• To determine how molecule characteristics and HII structure influence phase behavior, swelling, and molecular location.

Main Methods:

• Small-angle X-ray scattering (SAXS) and optical microscopy for phase behavior determination.
• Differential scanning calorimetry (DSC) and Fourier-transform infrared (FT-IR) spectroscopy for thermal and functional group analysis.
• Investigation of glycerol monooleate (GMO)/tricaprylin/water HII systems, including fluid variants with Transcutol or ethanol.

Main Results:

• Bioactive molecule behavior (solubilization, location) was dictated by its polarity, geometry, and the specific HII structure.
• Ascorbic acid and ascorbyl palmitate acted as chaotropic agents, with distinct localization patterns.
• D-alpha-tocopherol and its acetate ester were incorporated into the lipid tails, with D-alpha-tocopherol nearer the interface.
• Partial migration of molecules was observed in fluid HII systems containing Transcutol or ethanol.

Conclusions:

• The HII system's composition and the guest molecule's properties are key determinants of solubilization and phase behavior.
• Specific molecular interactions govern the localization of bioactive molecules within the HII nanostructure.
• Fluid HII systems exhibit dynamic behavior upon guest molecule incorporation, suggesting potential for controlled release applications.