Docosahexaenoic acid triglyceride-based microemulsions with an added dendrimer - Structural considerations

Area of Science:

• Colloid and Surface Science
• Materials Science
• Biochemistry

Background:

• Omega-3 fatty acids, like triglyceride of docosahexaenoic acid (TG-DHA), are vital nutraceuticals but face delivery challenges due to poor water solubility.
• Dendrimers, such as poly(propyleneimine) dendrimers (PPI-G2), are recognized for their potential as drug carriers and permeation enhancers across biological membranes.

Purpose of the Study:

• To investigate the interactions between TG-DHA and PPI-G2 within a microemulsion (ME) system.
• To understand how these interactions influence the structural transitions and properties of the ME.
• To explore the potential of ME systems containing TG-DHA and PPI-G2 for future targeted delivery applications.

Main Methods:

• Electron paramagnetic resonance (EPR) spectroscopy.
• Pulsed-gradient spin-echo nuclear magnetic resonance (PGSE-NMR) spectroscopy.
• Differential scanning calorimetry (DSC) and other analytical techniques were employed to analyze ME properties along the water dilution line.

Main Results:

• Water dilution decreased microviscosity, order parameter, and micropolarity in the studied systems.
• TG-DHA incorporation reduced microviscosity, order, and micropolarity.
• PPI-G2 addition increased these parameters, with a more pronounced effect at higher concentrations (1 and 5 wt%) due to interactions with surfactant headgroups. Macroviscosity changes varied between TG-DHA and PPI-G2 in the bicontinuous region.

Conclusions:

• The study elucidates the distinct effects of TG-DHA and PPI-G2 on ME structure and dynamics.
• PPI-G2 is readily intercalated at the interface in the presence of TG-DHA, as indicated by DSC.
• These findings provide insights into designing advanced ME-based delivery systems for nutraceuticals and drugs.