Process for the preparation of immunoglobulin G (IgG)
The present invention is directed to processes for extracting IgG from an unused waste precipitate produced during normal plasma fractionation processes via a separate fractionation process, thereby increasing the overall yield of IgG from blood plasma.
1. A method for extracting IgG from a waste precipitate fraction, the method comprising homogenizing the waste precipitate fraction with a suitable solvent for a period sufficient to extract IgG from the precipitate into the solvent, wherein the waste precipitate fraction is produced during plasma fractionation and separated from a main IgG manufacturing process stream, and wherein the suitable solvent is the same as a solvent used in a fractionation step which produced the waste precipitate wherein the extracted IgG comprises not less than 85% monomer and dimer and not more than 10 wt. % polymer and/or aggregate, and wherein the method for extracting IgG from the waste precipitate fraction does not involve any chromatographic steps.
2. A method according to claim 1 , wherein the waste precipitate fraction is produced during a fractionation step to produce a liquid fraction (supernatant) containing IgG.
3. A method according to claim 2 , wherein the liquid fraction is selected from the group consisting of Cohn supernatant III, Cohn supernatant I+III, Kistler & Nitschmann supernatant B, Kistler & Nitschmann supernatant B+I, modified Kistler & Nitschmann supernatant B, and modified Kistler & Nitschmann supernatant B+I.
4. A method according to claim 1 , wherein the waste precipitate fraction is selected from the group consisting of Cohn fraction III, Cohn fraction I+III, Kistler & Nitschmann precipitate B, Kistler & Nitschmann precipitate B+I, modified Kistler & Nitschmann precipitate B, and modified Kistler & Nitschmann precipitate B+I.
5. A method according to claim 1 , wherein the solvent is buffered aqueous ethanol.
6. A method according to claim 5 , wherein the solvent is an aqueous buffer containing about 13 vol. % to about 17 vol. % ethanol.
7. A method according to claim 5 , wherein the solvent is buffered using phosphate and/or acetate buffer.
8. A method according to claim 1 , wherein the ratio of waste precipitate fraction to solvent is from about 1:2 to about 1:10.
9. A method according to claim 1 , wherein the solvent containing extracted IgG is separated from any remaining waste precipitate solids.
10. A method according claim 9 , wherein the solvent containing extracted IgG is separated from remaining waste precipitate solids by filtration or centrifugation.
11. A method according to claim 1 , wherein the extracted IgG is combined with IgG obtained from the main IgG manufacturing process stream.
12. A method according to claim 1 , wherein the method for extracting IgG from the waste precipitate fraction does not involve any chromatographic steps.
13. A method according to claim 1 , wherein the extracted IgG obtained from the waste precipitate is further processed to produce a pharmaceutical IgG product.
14. A method according to claim 13 , wherein the further processing to produce a pharmaceutical IgG product comprises precipitation of the extracted IgG from the solvent.
15. A method according to claim 14 , wherein the precipitation is achieved by adjusting one or more of ethanol concentration, temperature and pH.
16. A method according to claim 14 , wherein the precipitation yields an IgG enriched Fraction II precipitate.
17. A method according to claim 14 , wherein the resulting precipitate is combined with an IgG rich fraction from the main IgG manufacturing process stream.
18. A method for the preparation of IgG comprising:
a) recovering precipitate and supernatant from a modified Kistler and Nitschmann B+I fractionation process;
b) homogenising the precipitate obtained in step a) and extracting IgG therefrom by mixing with 17 vol. % aqueous ethanol in acetate and/or phosphate buffer at 0° C. for 1 to 3 hours, and wherein extracting IgG does not involve any chromatographic steps; and then
c) separating the buffer containing extracted IgG from any remaining precipitate, wherein the extracted IgG comprises not less than 85% monomer and dimer and not more than 10 wt. % polymer and/or aggregate.
19. The method according to claim 18 , further comprising:
d) combining the buffer containing extracted IgG obtained in step c) with the modified Kistler and Nitschmann B+I supernatant obtained in step a).
20. The method according to claim 18 , wherein step c) is performed via filtration and wherein the method further comprises:
e) incubating the extracted IgG in aqueous ethanol according to the conditions for modified Kistler and Nitschmann Fraction II precipitation; and
f) recovering the resulting IgG-enriched Fraction II precipitate.
21. A method according to claim 1 , wherein the extracted IgG product comprises a purity of not less than 90% gammaglobulin.