Ethoxylated copolymersurfactants for the HFA134a–water interface: interfacial activity, aggregate microstructure and biomolecule uptake

Applications of the Atomic Force Microscope in the Development of Propellant-based Inhalation Formulations

“…However, the range of suitable fluorinated surfactants is limited due to their potential toxicity 40,43) . Water-in-HFA227 microemulsions have been recently reported in the presence of an ethoxylated triblock copolymer and ethanol 36) . The uptake of biomolecules and anticancer therapeutics, and the aerosol characteristics of the corresponding formulations have been investigated 36) .…”

“…Water-in-HFA227 microemulsions have been recently reported in the presence of an ethoxylated triblock copolymer and ethanol 36) . The uptake of biomolecules and anticancer therapeutics, and the aerosol characteristics of the corresponding formulations have been investigated 36) . Microemulsions may serve as an alternative to traditional solution/dispersion-based formulations of high-potency systems as the active component remains solubilized within the core of the aggregate, preventing its interaction with the container walls and other parts of the device that may significantly reduce the dosage 41,42) .…”

“…36) The presence of such low-volatility excipients can reduce the vapor pressure of the aerosol mixture, thus negatively affecting the efficiency of the aerosol 36) . A significant body of work from AFM-related techniques provided the insight for the design of amphiphiles containing highly HFA-philic groups, which are required for the formation and stabilization of such aqueous aggregates 34,35) .…”

“…The emulsion-based formulations can be potentially used for the local or systemic delivery of therapeutics to and through the lungs. W/HFA microemulsions have also been suggested as a potential formulation for the pulmonary delivery of therapeutics (both small molecules and large biomolecules) 36) . Fluorinated ionic and non-ionic amphiphiles can form microemulsions of water in propellant HFA 41,42) .…”

“…Ef for ts in the development of novel propellant-based inhalation formulations can be classified with respect to the nature of the dispersed phase: aqueous-(emulsions/ microemulsions) and nonaqueous(solid)-based systems 23,35) . Aqueous-based dispersions can be stabilized in the form of emulsions (micron size and kinetically stable) 22) or microemulsions (nanometer in size -transparent, and thermodynamically stable) 36,37) provided a suitable amphiphile is identified. Poly(lactide)- 38) , poly(propylene oxide)- 39) and fluorine-based 40) nonionic amphiphiles have been shown to be effective in stabilizing reverse water-in-HFA (W/HFA) emulsions.…”