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 a large-scale manufacture of a squalene-containing oil-in-water emulsion, comprising steps of:
(i) forming providing a first emulsion having a first average oil droplet size, wherein the first average oil droplet size is 5000 nm or less and/or wherein the number of oil droplets having a size of >1.2 μm in the first emulsion is 5×10 11 /ml or less;
(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, wherein the number of oil droplets having a size of >1.2 μm in the second emulsion is 5×10 10 /ml or less; and
(iii) filtrating the second emulsion using 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 squalene-containing oil-in-water emulsion,
wherein at least one of the first and the second hydrophilic polyethersulfone membrane layers is an asymmetric membrane,
wherein the squalene-containing oil-in-water emulsion has a volume of more than or equal to 50 liters; and,
(iv) filling the oil-in-water emulsion into one or more sterile closed systems.
2. The method according to claim 1 , wherein the second average oil droplet size is 500 nm or less.
3. The method according to claim 1 , wherein the second emulsion is prefiltered through a membrane prior to filtration.
4. The method of claim 3 , wherein the prefiltration and filtration steps are carried out using a double-layer filter.
5. The method of claim 3 , wherein the filtration membrane, and optionally the prefiltration membrane, comprises a polymeric support material.
6. The method of claim 1 , wherein the squalene-containing oil-in-water emulsion obtained after step (iii) is characterized in that the number of oil droplets having a size of >1.2 μm is 5×10 8 /ml or less.
7. The method of claim 1 , wherein the filtering step (iii) comprises a double layer polyethersulfone membrane.
8. The method of claim 1 , wherein the squalene-containing oil-in-water emulsion comprises, by volume, about 5% squalene, about 0.5% polysorbate 80 and about 0.5% sorbitan trioleate.
9. The method of claim 1 , wherein the squalene-containing oil-in-water emulsion contains between 2-20% of oil by volume.
10. The method of claim 1 , wherein the sterile closed system is selected from the group consisting of: glass bottles, flexible, bags, vials and disposable syringes.
11. A method for a large-scale manufacture of a squalene-containing oil-in-water emulsion, comprising steps of:
(i) subjecting a first emulsion having a first average oil droplet size, wherein the first average oil droplet size is 5000 nm or less and/or wherein the number of oil droplets having a size of >1.2 μm in the first emulsion is 5×10 11 /ml or less to microfluidization to form a second emulsion having a second average oil droplet size which is less than the first average oil droplet size, wherein the number of oil droplets having a size of >1.2 μm in the second emulsion is 5×10 10 /ml or less;
(ii) filtrating the second emulsion using 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 squalene-containing oil-in-water emulsion, wherein at least one of the first and the second hydrophilic polyethersulfone membrane layers is an asymmetric membrane
wherein the squalene-containing oil-in-water emulsion has a volume of more than or equal to 50 liters; and
(iv) filling the oil-in-water emulsion into one or more sterile closed systems.