Injectable rabies vaccine composition and method for preparing same

• US 4,252,792 A
• Filed: 09/21/1979
• Issued: 02/24/1981
• Est. Priority Date: 09/21/1979
• Status: Expired due to Term

• Current Assignee: Schering VET Incorporated
• Original Assignee: Douglas Industries Inc (Merck & Co., Inc.)
• Inventors: Blades, James E.
• Primary Examiner(s): Rose, Shep K.
• Application Number:
  US06/077,498
• Time in Patent Office: 522 Days
• Field of Search: 424/89
• US Class Current: 424/224.1
• CPC Class Codes: A61K 2039/5252 inactivated (killed)
• CPC Class Codes: A61K 2039/55511 Organic adjuvants
• CPC Class Codes: A61K 39/12 Viral antigens
• CPC Class Codes: A61K 39/205 Rhabdoviridae, e.g. rabies virus
• CPC Class Codes: A61K 39/39 characterised by the immunostimulating additives, e.g. chemical adjuvants
• CPC Class Codes: C12N 2760/20134 Use of virus or viral component as vaccine, e.g. live-attenuated or inactivated virus, VLP, viral protein

Abstract

A rabies vaccine composition is disclosed which comprises a sterilized suspension of proteineous suckling mice or rat brain particles of injectable particle size laden with an amount of inactivated rabies virus which is equivalent to a virus titer of from at least about 10⁵ to about 10⁷ MLD₅₀ per 0.01 milliliter thereof at a brain tissue concentration of from about 3 to about 6% by weight, in an aqueous buffer solution having a pH of between about 7.5 and about 8.4, and comprising an amount, dissolved therein, of between 0.03 and 0.08 moles per liter of a buffer composition comprising a mixture of an organic base of the formula ##STR1## wherein R₁ and R₂ each are hydrogen or CH₂ CH₂ OH and an acid addition salt thereof, preferably a mixture of tris (hydroxymethyl)amino methane and its hydrochloride. The vaccine composition exhibits a high potency and its pH value remains stable over a prolonged period of time.

Claims

1. A rabies vaccine composition comprising a sterilized suspension of proteineous suckling mice or rat brain particles of injectable particle size laden with an amount of inactivated rabies virus which is equivalent to a virus titer of from at least about 10⁵ to about 10⁷ MLD₅₀ per 0.01 milliliter thereof, at a brain tissue concentration of from about 3 to about 6% by weight, in an aqueous buffer solution having a pH of between about 7.5 and about 8.4, and comprising an amount, dissolved therein, of between 0.03 and 0.08 moles per liter of a buffer composition comprising a mixture of an organic base of the formula ##STR5## wherein R₁ and R₂ each are hydrogen or CH₂ CH₂ OH and an acid addition salt thereof with an acid the anion of which is compatible with virus replication.

14. The rabies vaccine composition as defined in claim 1, wherein the inactivated rabies virus is a rabies virus deactivated by Beta propiolactone.

2. A rabies vaccine composition comprising a sterilized suspension of a minor concentration by weight of proteineous suckling mice or rat brain particles of injectable particle size laden with inactivated rabies virus, in an aqueous buffer solution having a slightly basic pH value and an amount, dissolved therein, of a buffer composition sufficient to stabilize the pH at said value, said buffer composition comprising a mixture of an organic base of the formula ##STR6## wherein R₁ and R₂ each are hydrogen or CH₂ CH₂ OH, and an acid addition salt thereof with an acid the anion of which is compatible with virus replication.

3. The rabies vaccine composition as defined in claim 2, wherein the aqueous buffer solution is a 0.03 M to 0.08 M solution of said buffer composition.

4. The rabies vaccine composition as defined in claim 2, wherein the buffer composition comprises a mixture of tris (hydroxymethyl) amino methane and its hydrochloride.

5. The rabies vaccine composition as defined in claim 4, wherein the aqueous buffer solution is a 0.05 M solution of said buffer composition.

6. The rabies vaccine composition as defined in claim 4, wherein in the buffer composition the by weight ratio between tris (hydroxymethyl) amino methane and its hydrochloride is from about 1.18/6.35 to 4.03/2.64.

7. The rabies vaccine composition as defined in claim 6, wherein the by weight ratio is about 1.97/5.32.

8. The rabies vaccine composition as defined in claim 2, wherein said pH value is between about 7.5 and about 8.4.

9. The rabies vaccine composition as defined in claim 2, wherein said pH value at 25°

C. is between about 7.8 and about 8.0.

10. The rabies vaccine composition as defined in claim 2, wherein said brain particles are laden with an amount of said inactivated rabies virus which is equivalent to a virus titer of from at least about 10⁵ to about 10⁷ MLD₅₀ per 0.01 milliliter of said suspension.

11. The rabies vaccine composition as defined in claim 2, which comprises an amount of said brain particles of between about 2.5 and about 6 percent by weight.

12. The rabies vaccine composition as defined in claim 11, wherein the amount of brain particles is between about 2.5 and about 3.5 percent by weight.

13. The rabies vaccine composition as defined in claim 11, wherein the amount of brain paticles is between about 5 and about 6 percent by weight.

15. The rabies vaccine composition as defined in claim 2, which further comprises an indicator dye.

16. The rabies vaccine composition as defined in claim 15, wherein the indicator dye is phenol red.

17. The rabies vaccine composition as defined in claim 2, which further comprises a preservatively effective amount of an antibiotic.

18. The rabies vaccine composition as defined in claim 17, wherein the antibiotic is selected from the group consisting of penicillin, a streptomycin salt, amphotericin B and mixtures thereof.

19. The rabies vaccine composition as defined in claim 2, wherein the particle size of the brain particles is between about 1 and about 10 microns.

20. A process for preparing the rabies vaccine composition containing an antigenically effective concentration of proteineous viral laden brain particles as defined in claim 2, which comprises the steps of

(a) suspending a sufficient amount of viral laden suckling mice or rat brain tissue material in a sterilized aqueous buffer solution having a slightly basic pH value and an amount, dissolved therein, of a buffer composition sufficient to stabilize the pH at said value, said buffer composition comprising a mixture of an organic base of the formula ##STR7## wherein R₁ and R₂ each are hydrogen or CH₂ CH₂ OH, and an acid addition salt thereof with an acid the anion of which is compatible with virus replication, to obtain a concentrated suspension having suspended therein an amount of at least about 20 percent by weight of proteineous viral laden suckling mice or rat brain tissue material;

(b) comminuting the suspended viral laden suckling mice or rat brain tissue material within the concentrated suspension into particles of injectable particle size;

(c) diluting the concentrated suspension with a sufficient amount of said sterilized aqueous buffer solution to obtain a dilute suspension having a concentration of the proteineous virual laden brain particles of no greater than about 10 percent by weight;

(d) inactivating the dilute suspension; and

(e) adjusting the concentration of viral laden brain particles in the inactivated suspension to obtain the vaccine composition.

21. The process as defined in claim 20, wherein the amount of viral laden suckling mice or rat brain tissue material in the concentrated suspension in step (a) is from about 30 to about 60 percent by weight.

22. The process as defined in claim 20, wherein step (b) comprises subjecting the brain tissue material within the concentrated solution to high shear agitation.

23. The process as defined in claim 20, wherein the inactivating step (d) comprises combining the dilute suspension with an unhydrolyzed Beta propiolactone solution in an amount to provide a 1:

1,000 to 1;

10,000 dilution of Beta propiolactone in the combined product, and allowing the Beta propiolactone to hydrolize.

24. The process as defined in claim 23, wherein inactivation of the rabies virus is accomplished by maintaining said combined product at room temperature for a period of at least approximately 24 hours.

25. The process as defined in claim 24, wherein said combined product is periodically agitated during said period.

26. The process as claimed in claim 23, wherein said dilution of Beta propiolactone is approximately 1:

2500.

27. The process as defined in claim 20, which further comprises the step of adding a preservatively effective amount of an antibiotic to the aqueous buffer solution.

28. The process as defined in claim 27, wherein the antibiotic is selected from the group consisting of penicillin, a streptomycin salt, amphotericin B and mixtures thereof.

29. The process as defined in claim 20, wherein step (c) comprises diluting the suspension to a concentration of brain tissue of from about 2 to about 10 percent by weight.

30. The process as defined in claim 20, wherein said step (c) comprises diluting the suspension to a concentration of brain tissue of from about 2.5 to about 6 percent by weight.

31. The process as defined in claim 20, wherein in step (e) the concentration of viral laden brain particles is adjusted to from about 2.5 to about 6 percent by weight.

32. The process as defined in claim 20, wherein in step (e) the concentration of viral laden brain particles is adjusted to from about 2.5 to about 3.5 percent by weight.

33. The process as defined in claim 20, wherein in step (e) the concentration of viral laden brain particles is adjusted to from about 5 to about 6 percent by weight.

34. The process as defined in claim 20, wherein the buffer composition comprises a mixture of tris (hydroxymethyl) amino methane and its hydrochloride.

35. The process as defined in claim 34, wherein the aqueous buffer solution is a 0.05 M solution of said buffer composition.

36. The process as defined in claim 20, which further comprises the following steps for preparing the viral laden suckling mice or rat brain tissue material:

(1) intracerebrally inoculating a batch of disease free suckling animals which are mice or rats at an age of from two to five days with a working seed containing living, fully virulent rabies virus;

(2) allowing the thus inoculated suckling animals to develop typical rabies symptoms and to become moribund; and

(3) after a predetermined, minor percentage of the inoculated animals have died, withdrawing the viral laden brain tissue from the moribund animals.

37. The process as defined in claim 36, wherein step (3) comprises the steps of

freezing the moribund animals for subsequent, further processing;

thawing a batch of the frozen animals; and

withdrawing the viral laden brain tissue from the thawed animals.

38. The process as defined in claim 36, wherein said predetermined percentage of dead animals is from two to five percent of the inoculated animals.

39. The rabies vaccine composition as defined in claim 2, wherein the organic base is tris (hydroxymethyl) aminomethane, N-(2-hydroxyethyl) amino tris (hydroxymethyl) methane or N,N-bis (2-hydroxyethyl) amino tris (hydroxymethyl) methane.