Hydrophilic filtration during manufacture of vaccine adjuvants
An improved method for the manufacture of an oil-in water emulsion involves three procedures: (i) preparation of a preliminary emulsion; (ii) micro fluidization of the preliminary emulsion to reduce its droplet size; and (iii) filtration, of the microfluidized emulsion through a hydrophilic membrane. The emulsions are useful as vaccine adjuvants.
1. A method for manufacture of a squalene-containing oil in water emulsion, comprising steps of:
(i) forming a first emulsion having a first average oil droplet size;
(ii) microfluidizing the first emulsion to form a second emulsion having a second average oil droplet size which is less than the first average oil droplet size; and
(iii) filtering the second emulsion using a hydrophilic double-layer filter which has a first hydrophilic polyethersulfone membrane layer having a pore size ≥0.3 μm, and a second hydrophilic polyethersulfone membrane layer having a pore size <0.3 μm, thereby providing a vaccine adjuvant.
2. The method according to claim 1 , wherein the average oil droplet size of the emulsion prepared in step (i) is 5000 nm or less.
3. The method according to claim 1 , wherein the number of oil droplets having a size of >1.2 μm in the first emulsion is 5×10 11 /ml or less.
4. The method according to claim 1 , wherein the second average oil droplet size is 500 nm or less.
5. The method according to claim 1 , wherein the number of oil droplets having a size of >1.2 μm in the second emulsion is 5×10 10 /ml or less.
6. The method according to claim 1 , wherein the average oil droplet size after filtration is less than 220 nm.
7. The method according to claim 1 , wherein the number of oil droplets having a size of >1.2 μm after filtration is 5×10 8 /ml or less.
8. The method according to 1 , wherein the first hydrophilic polyethersulfone membrane layer is asymmetric and/or porous.
9. The method according to claim 1 , wherein the second hydrophilic polyethersulfone membrane layer is asymmetric and/or porous.
10. The method according to claim 1 , wherein the second hydrophilic polyethersulfone membrane layer, and optionally the first hydrophilic polyethersulfone membrane layer, comprises a polymeric support material.
11. A method for preparing a vaccine composition, comprising preparing an emulsion adjuvant according to claim 1 and combining the emulsion adjuvant with an antigen.
12. A method for preparing a vaccine kit comprising preparing an emulsion adjuvant according to claim 1 and packaging the emulsion adjuvant into a kit as a kit component together with an antigen component.
13. The method of claim 12 , wherein the kit components are in separate vials.
14. The method claim 12 , wherein the emulsion adjuvant is a bulk adjuvant and the method comprises extracting unit doses from the bulk adjuvant for packaging as kit components.
15. The method of claim 12 , wherein the antigen is an influenza virus antigen.
16. The method of claim 15 , wherein the combination of the emulsion and the antigen forms a vaccine composition and wherein the vaccine composition includes about 15 μg, about 10 μg, about 7.5 μg, about 5 μg, about 3.8 μg, about 3.75 μg, about 1.9 μg, or about 1.5 μg of hemagglutinin per influenza virus strain.
17. The method of claim 15 , wherein the combination of the emulsion and the antigen forms a vaccine composition and wherein the vaccine composition includes a thiomersal or 2 phenoxyethanol preservative.
18. The method of claim 11 , wherein the antigen is an influenza virus antigen.
19. A method of preparing an oil-in-water emulsion vaccine adjuvant which comprises using a hydrophilic double-layer filter which has a first hydrophilic polyethersulfone membrane layer having a pore size ≥0.3 μm, and a second hydrophilic polyethersulfone membrane layer having a pore size <0.3 μm.
20. A method for manufacture of a squalene-containing oil in water emulsion, comprising steps of:
(i) forming a first emulsion having a first average oil droplet size;
(ii) microfluidizing the first emulsion to form a second emulsion having a second average oil droplet size which is less than the first average oil droplet size; and
(iii) filtering the second emulsion using a hydrophilic double-layer filter which has a first hydrophilic polyethersulfone membrane layer having a pore size >0.3 μm, and a second hydrophilic polyethersulfone membrane layer having a pore size <0.3 μm, thereby providing a vaccine adjuvant
wherein the squalene-containing oil in water emulsion has a volume that is equal to or greater than about 50 liters.
21. The method according to claim 20 , wherein the volume of the squalene-containing emulsion is equal to or greater than about 100 liters.