Fluorinated ionic surfactant microemulsions in hydrofluorocarbon 134a (HFC 134a)

Area of Science:

• Physical Chemistry
• Colloid and Surface Science
• Materials Science

Background:

• Microemulsions are thermodynamically stable, isotropic liquid mixtures of immiscible oil and water phases.
• Fluorinated surfactants offer unique properties for specialized applications, including propellant systems.
• Developing stable water-in-propellant microemulsions is crucial for advanced delivery systems.

Purpose of the Study:

• To investigate the factors influencing the formation of water-in-134a microemulsions.
• To determine the efficacy of fluorinated ionic surfactants in creating these systems.
• To assess the potential for solubilizing water-soluble drugs within these microemulsions.

Main Methods:

• Utilized ammonium perfluorooctanoate, ammonium perfluoroheptanoate, and sodium perfluorooctanoate as fluorinated ionic surfactants.
• Employed short-chain fluoro- or hydrocarbon alcohols as cosurfactants.
• Characterized microemulsion formation and stability using photon correlation spectroscopy (PCS).

Main Results:

• Single fluorinated ionic surfactants could not form clear microemulsions; cosurfactants were necessary.
• Clear microemulsion systems were achieved with surfactant:cosurfactant weight-mixing ratios (K(m)) from 1:2 to 2:1.
• Photon correlation spectroscopy confirmed the presence of microemulsion droplets and successful solubilization of terbutaline sulfate.

Conclusions:

• Water-in-134a microemulsions can be successfully prepared using fluorinated ionic surfactants in conjunction with cosurfactants.
• These microemulsions demonstrate the capability to solubilize water-soluble drugs like terbutaline sulfate.
• This research validates a novel approach for creating drug delivery systems utilizing propellant-based microemulsions.