Improved Control over Particle Sizes and Stability of Concentrated Fluorocarbon Emulsions by Using Mixed Fluorocarbon/Hydrocarbon Molecular Dowels

Abstract

The use of a surfactant system consisting in equimolar amounts of egg yolk phospholipids and of a mixed fluorocarbon/hydrocarbon amphiphile (C8H₁₇CH=CHC₈F₁₇) allows the preparation of concentrated (90% w/v, i.e. 47% v/v) emulsions of perfluorooctyl bromide (perflubron), with average particle sizes ranging from 0.12 to 16 μm post-sterilization, depending on the surfactant/fluorocarbon ratio. Emulsion droplet diameters varied linearly as a function of the emulsifier's concentration, thus allowing easy pre-determination of the emulsion's average particle size. Excellent stability was observed for the dowel-containing emulsions for at least 6 months at 40°C over the whole domain of particle sizes investigated.