Fluorinated ionic surfactant microemulsions in hydrofluorocarbon 134a (HFC 134a).
The factors influencing the formation of water-in-134a-propellant microemulsions using the fluorinated ionic surfactants ammonium perfluorooctanoate, ammonium perfluoroheptanoate, and sodium perfluorooctanoate has been determined. None of the fluorinated ionic surfactants could be used to prepare clear, one-phase systems when used as sole surfactant, but they could be when combined with a short-chain fluoro- or hydrocarbon alcohol in surfactant:cosurfactant weight-mixing ratios (K(m)) in the range 1:2 to 2:1. When hydrocarbon alcohols were used this clear region extended over a wide range of compositions and was confirmed by means of photon correlation spectroscopy (PCS) to contain microemulsion droplets in the propellant-rich part of the phase diagram. PCS studies performed in the presence of the water-soluble drug terbutaline sulfate showed that it was possible to solubilize the drug within water-in-propellant microemulsion droplets. These studies confirm for the first time that it is possible to prepare water-in-propellant 134a microemulsions using fluorinated ionic surfactants and to solubilize water-soluble drugs within these systems.
Patel
Nilesh
N
Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, SE1 9NN, London, United Kingdom.
Marlow
Maria
M
Lawrence
M Jayne
MJ
D016503:Drug Delivery Systems / Q000379:methods; D004655:Emulsions; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
D004655:Emulsions; D006845:Hydrocarbons, Fluorinated; D013501:Surface-Active Agents