Arranging interaction and back pressure chambers for microfluidization
An improved method for the manufacture of an oil-in-water emulsion comprises using a microfluidisation device whose interaction chamber comprises a plurality of Z-type channels upstream of a back pressure chamber.
1. A microfluidization apparatus for microfluidizing a first oil-in-water emulsion to produce a second oil-in-water emulsion, said apparatus comprising an interaction chamber, at least one intensifier pump, and a back pressure chamber,
wherein:
the interaction chamber comprises a plurality of Z-type geometry channels,
the back pressure chamber comprises a plurality of fixed geometry channels and is located downstream of the interaction chamber, wherein said back pressure chamber is configured to reduce the average oil droplet size and/or the number of oil droplets with a size >1.2 μm in an emulsion that enters the back pressure chamber from the interaction chamber and exits from the back pressure chamber thereby producing the second emulsion; and
the oil-in-water emulsions comprise squalene and water.
2. The microfluidization apparatus according to claim 1 , wherein the second emulsion has an average oil droplet size of 500 nm or less.
3. The microfluidization apparatus according to claim 2 , wherein the oil-in-water emulsion further comprises polysorbate 80, and sorbitan trioleate.
4. The microfluidization apparatus of claim 1 , wherein the interaction chamber provides a shear rate in excess of 1×10 6 s −1 .
5. The microfluidization apparatus according to claim 1 , wherein the pressure of the emulsion components at the entrance to the interaction chamber is substantially constant for at least 85% of the time during which the emulsion is feed into the microfluidization apparatus.