Process for the preparation of allergenic extracts
Disclosed herein are methods for the preparation of allergenic extracts. In one embodiment, the methods are carried out without having to adjust the pH of the extraction phase. The methods provide efficient recovery of allergenic extract from allergenic source material.
1. A process for the preparation of an allergenic intermediate, said process comprising:
contacting an allergenic source material with an extraction fluid, wherein the allergenic source material is contacted with the extraction fluid at a concentration ratio of about 1:15;
milling the allergenic source material after the source material is contacted with the extraction fluid;
extracting a biological material from the allergenic source material into the extraction fluid;
separating the biological material into a solid phase portion and a liquid phase portion to obtain a crude extract;
concentrating the crude extract using ultrafiltration to extract and to partially remove low molecular weight molecules of less than 5 kDa;
subjecting the concentrated extract to continuous diafiltration to remove remaining lower molecular weight molecules from the concentrated extract; and
lyophilizing the ultrafiltered and diafiltered extract to obtain the allergenic intermediate,
wherein said process is carried out without adjusting pH of the extraction fluid during said extracting or without requiring conductivity testing to determine the endpoint of ultrafiltration.
2. The process according to claim 1 further comprising:
reconstituting the allergenic intermediate and storing the reconstituted allergenic intermediate,
wherein during said storing the reconstituted allergenic intermediate has reduced precipitation potential compared to reconstituted allergenic intermediates prepared by other processes.
3. The process according to claim 1 , wherein the allergenic source material is selected from house dust mite allergen, insect allergen, venom allergen, animal hair and dander allergen, food allergen, and combinations thereof.
4. The process according to claim 3 , wherein said allergenic source material comprises house dust mite allergen.
5. The process according to claim 1 , wherein said extracting is carried out under conditions of continuous circulation through a mill.
6. The process according to claim 5 , wherein said extracting is carried out for 1-6 hours.
7. The process according to claim 5 , wherein said extracting is carried out at 20° C.-25° C.
8. The process according to claim 7 , wherein said subjecting the concentrated extract to continuous diafiltration is carried out using 10-14 diavolumes of buffer solution.
9. The process according to claim 3 , wherein said allergenic source material comprises animal hair and dander allergen.
10. The process according to claim 9 , wherein said allergenic source is contacted with said extraction fluid at a concentration ratio of about 1:6-7.
11. The process according to claim 9 , wherein said extracting is carried out for about 3-5 days.
12. The process according to claim 9 , wherein said extracting is carried out at 0° C.-5° C.
13. The process according to claim 9 , wherein said subjecting the concentrated extract to continuous diafiltration is carried out using 7 diavolumes of buffer solution.
14. The process according to claim 1 , wherein said separating is carried out using centrifugation.
15. The process according to claim 1 , wherein said separating is carried out using centrifugation and dead end filtration.
16. The process according to claim 1 , wherein said concentrating is carried out in the absence of a conductivity test.
17. The process according to claim 1 , wherein said subjecting the concentrated extract to continuous diafiltration is carried out using an aqueous ammonium bicarbonate solution.
18. A process for preparing an allergenic intermediate, said process comprising:
contacting an allergenic source material with an extraction fluid;
extracting biological material from the allergenic source into the extraction fluid;
recovering a crude extract from the extraction fluid in liquid phase by separating a solid phase from a liquid phase by cross flow microfiltration to remove particulates greater than 0.2 μm —0.8 μm in size;
flushing the solid phase with additional solution;
concentrating the crude extract using ultrafiltration to further extract and to partially remove low molecular weight molecules of less than 5 kDa;
subjecting the concentrated extract to continuous diafiltration to remove remaining lower molecular weight molecules in the concentrated extract; and
lyophilizing the diafiltered extract to obtain the allergenic intermediate,
wherein said process is carried out without adjusting pH of the extraction fluid.
19. The process according to claim 18 , wherein said recovering by cross flow microfiltration provides separation, clarification, and filtration in a single process.
20. The process according to claim 19 , wherein the cross flow microfiltration provides 0.2 μm—0.8 μm clarified crude liquid extract in a single step.
21. The process according to claim 18 , wherein the allergenic source material is selected from house dust mite allergen, insect allergen, venom allergen, animal hair and dander allergen, food allergen, and combinations thereof.
22. The process according to claim 21 , wherein said allergenic source material comprises house dust mite allergen.
23. The process according to claim 22 , wherein said allergenic source material is contacted with said extraction fluid at a concentration ratio of about 1:15.
24. The process according to claim 23 further comprising:
milling the allergenic source material after said contacting.
25. The process according to claim 24 , wherein said extracting is carried out under conditions of continuous circulation through a mill.
26. The process according to claim 25 , wherein said extracting is carried out for 1-6 hours.
27. The process according to claim 25 , wherein said extracting is carried out at 20-25° C.
28. The process according to claim 23 , wherein said subjecting the concentrated extract to continuous diafiltration is carried out using 10-14 diavolumes of buffer solution.
29. The process according to claim 18 further comprising:
reconstituting the allergenic intermediate and storing the reconstituted allergenic intermediate,
wherein during said storing the reconstituted allergenic intermediate has reduced precipitation potential compared to reconstituted allergenic intermediates prepared by other processes.
30. The process according to claim 18 , wherein said subjecting the concentrated extract to continuous diafiltration is carried out using an aqueous ammonium bicarbonate solution.