Microstructural elucidation of self-emulsifying system: effect of chemical structure

Area of Science:

• Pharmaceutical Sciences
• Materials Science

Background:

• Self-emulsifying systems (SES) spontaneously form oil-in-water emulsions upon contact with aqueous phases.
• The self-emulsification process is critical for emulsion formation and final formulation performance.

Purpose of the Study:

• To investigate the internal structuration of SES during controlled hydration.
• To determine the influence of additives on SES microstructure and final droplet size.
• To correlate microstructure with the performance of ibuprofen-based formulations.

Main Methods:

• Determination of droplet size for ibuprofen analogue formulations.
• Microstructural analysis of hydrated SES using small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and rheology.

Main Results:

• An inverse relationship was observed between formulation droplet size and the Log P values of ibuprofen analogues.
• Formation of local lamellar structures was identified in intermediate hydrated regimes.
• Microstructural alterations in lamellae significantly correlated with final droplet size.
• In vitro studies showed enhanced dissolution rates for lipophilic drugs formulated as SES.

Conclusions:

• Tailor-made drug formulations can be achieved by precisely controlling the properties of intermediate SES regimes.
• Understanding and manipulating SES microstructure is crucial for optimizing drug delivery systems.