Hydrophilic filtration during manufacture of vaccine adjuvants

Abstract

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 - 3 . (canceled) 
     
     
         4 . A method for the manufacture of a squalene-containing oil-in-water emulsion, comprising the 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;   (iii) prefiltering the second emulsion through a first hydrophilic polyethersulfone membrane; and   (iv) filtering the second emulsion using a second hydrophilic polyethersulfone membrane.   
     
     
         5 . The method according to  claim 4 , wherein the first average oil droplet size is 5000 nm or less. 
     
     
         6 . The method according to  claim 4  or  claim 5 , wherein the number of oil droplets having a size of >1.2 μm in the first emulsion is 5×10 11 /ml or less. 
     
     
         7 . The method according to  claim 6 , wherein the second average oil droplet size is 500 nm or less. 
     
     
         8 . The method according to  claim 7 , wherein the number of oil droplets having a size of >1.2 μm in the second emulsion is 5×10 10 /ml or less. 
     
     
         9 . A method for manufacture of a squalene-containing oil-in-water emulsion, comprising the steps of:
 (i) forming a squalene-containing emulsion having an average oil droplet size of 500 nm or less;   (ii) filtering the squalene-containing emulsion using a hydrophilic polyethersulfone filter which has a first membrane layer with larger pores and a second membrane layer with smaller pores.   
     
     
         10 . The method according to  claims 4  or  9 , wherein the average oil droplet size after filtration is less than 220 nm. 
     
     
         11 . The method according to  claims 4  or  9 , wherein the number of oil droplets having a size of >1.2 μm after filtration is 5×10 8 /ml or less. 
     
     
         12 .- 14 . (canceled) 
     
     
         15 . The method according to  claims 4  or  9 , wherein the filtration membrane is asymmetric and/or porous. 
     
     
         16 . The method according to  claims 4  or  9 , wherein the filtration membrane, and optionally the prefiltration membrane, comprises a polymeric support material. 
     
     
         17 . The method according to  claims 4  or  9 , wherein (i) the first membrane has a pore size ≥0.3 μm, and/or (ii) the second membrane has a pore size <0.3 μm. 
     
     
         18 . A method for preparing a vaccine composition, comprising preparing an emulsion according to  claims 4  or  9 , preparing an emulsion adjuvant comprising the emulsion, and combining the emulsion adjuvant with an antigen. 
     
     
         19 . A method for preparing a vaccine kit comprising preparing an emulsion according to  claims 4  or  9 , preparing an emulsion adjuvant comprising the emulsion, and packaging the emulsion adjuvant into a kit as a kit component together with an antigen component. 
     
     
         20 . The method of  claim 19 , wherein the kit components are in separate vials. 
     
     
         21 . The method of  claim 20 , wherein the vials are made from borosilicate glass. 
     
     
         22 . The method of  claim 18 , wherein the emulsion adjuvant is a bulk adjuvant and the method comprises extracting unit doses from the bulk adjuvant for packaging as kit components. 
     
     
         23 . The method of  claim 18 , wherein the antigen is an influenza virus antigen. 
     
     
         24 . The method of  claim 23 , 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. 
     
     
         25 . The method of  claim 23 , 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. 
     
     
         26 . A method for the manufacture of a squalene-containing oil-in-water emulsion, comprising the 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 through a hydrophilic double-layer filter, wherein the double-layer filter comprises a first hydrophilic polyethersulfone membrane layer with larger pores and a second hydrophilic polyethersulfone membrane layer with smaller pores.   
     
     
         27 . (canceled) 
     
     
         28 . The method of  claim 4 , wherein the prefiltration and filtration steps are carried out using a double-layer filter. 
     
     
         29 . The method according to  claims 4  or  9 , wherein the prefiltration membrane is asymmetric and/or porous. 
     
     
         30 . The method of  claim 9 , wherein the filtration is carried out using a double-layer filter.