The scale up of air-filled emulsion production

Abstract

An Air-Filled Emulsion (AFE) is a dispersion of particles, of colloidal size, which are generally characterised from sub-micron to ten microns in diameter. They are produced by unfolding proteins so that the disulphide bonds in the protein react with superoxide radicals to form ‘air cells’. These air cells are what form the non-aqueous phase in AFEs. The aim of this project was to see if the production of AFEs could be scaled up from bench to pilot scale. Results showed that recycle methods produced up to 98.7 % AFE yield with two out of three top-up methods (STUM) producing >90 % AFE yield. Other methods which were non-top-up (NoTUM) did not produce a high yield, but showed that air cells are robust enough to withstand multiple passes of sonication waves and heating. These methods yielded the first continuous method of AFE production. This was adapted to produce a novel way of isolating and concentrating formulation-ready AFE, which was concentrated up to 6-times previously found using a cross-flow filtration module. Work on the pilot scale produced the first AFE sample beyond the bench scale, and combined with the novel methods it provides a promising benchmark to take the production to larger scales in the future.