Manufacturing of bupivacaine multivesicular liposomes

1. A process for preparing bupivacaine encapsulated multivesicular liposomes (MVLs), the process comprising, comprising:

(a) mixing a first aqueous solution comprising phosphoric acid with a volatile water-immiscible solvent solution to form a water-in-oil first emulsion, wherein the volatile water-immiscible solvent solution comprises bupivacaine, 1, 2-dierucoylphosphatidylcholine (DEPC), 1, 2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), cholesterol, and at least one neutral lipid, and wherein a mixing time in step (a) is about 65 minutes to about 75 minutes;

(b) mixing the water-in-oil first emulsion with a second aqueous solution to form a water-in-oil-in-water second emulsion, wherein the second aqueous solution comprises lysine and dextrose, and wherein a mixing time in step (b) is about 60 seconds to about 65 seconds;

(c) diluting the water-in-oil-in-water second emulsion with additional second aqueous solution to form a diluted water-in-oil-in-water second emulsion;

(d) removing the volatile water-immiscible solvent from the diluted water-in-oil-in-water second emulsion to form a first aqueous suspension of bupivacaine encapsulated MVLs having a first volume;

(e) reducing the first volume of the first aqueous suspension of bupivacaine encapsulated MVLs by microfiltration to provide a second aqueous suspension of bupivacaine encapsulated MVLs having a second volume;

(f) exchanging the aqueous supernatant of the second aqueous suspension with a saline solution by diafiltration to provide a third aqueous suspension of bupivacaine encapsulated MVLs having a third volume; and

(g) further reducing the third volume of the third aqueous suspension by microfiltration to provide a final bulk aqueous suspension of bupivacaine encapsulated MVLs having a volume of about 100 L to about 250 L, and a bupivacaine concentration from about 11.3 mg/mL to about 17.0 mg/mL;

wherein all steps are carried out under aseptic conditions.

2. The process of claim 1 , wherein the mixing in step (a) is performed using a mixer at a high shear speed from about 1100 rpm to about 1200 rpm.

3. The process of claim 2 , wherein the mixer in step (a) is a non-static mixer having a blade diameter of between about 8 inch to about 10 inch.

4. The process of claim 2 , wherein the mixing in step (a) is performed at a temperature of about 21° C. to about 23° C.

5. The process of claim 1 , wherein the mixing in step (b) is performed using a mixer at a low shear speed from about 450 rpm to about 510 rpm.

6. The process of claim 5 , wherein the mixer in step (b) is a non-static mixer having a blade diameter of between about 10 inch to about 15 inch.

7. The process of claim 5 , wherein the mixing in step (b) is performed at a temperature of about 21° C. to about 23° C.

8. The process of claim 1 , wherein the at least one neutral lipid in the volatile water-immiscible solvent solution is tricaprylin.

9. The process of claim 1 , wherein the volume ratio of the second aqueous solution to the water-in-oil first emulsion in step (b) is about 2.5:1.

10. The process of claim 9 , wherein the volume ratio of the total volume of the second aqueous solution to the volume of the water-in-oil first emulsion after step (c) is about 20:1.

11. The process of claim 1 , wherein the diafiltration in step (f) comprises a plurality of independently operating crossflow modules, each crossflow module comprises at least one filter array, each filter array comprising a plurality of hollow fiber filters.

12. The process of claim 11 , wherein each crossflow module comprises two filter arrays, and each filter array comprises six hollow fiber filters.

13. The process of claim 1 , further comprising transferring the final bulk aqueous suspension of bupivacaine encapsulated MVLs into a sterilized holding vessel.

14. The process of claim 13 , further comprising filling the bulk aqueous suspension of bupivacaine encapsulated MVLs into individual vials each containing a composition of bupivacaine encapsulated MVLs.

15. The process of claim 14 , wherein the concentration of bupivacaine in the composition is about 13.3 mg/mL.

16. The process of claim 15 , wherein the composition comprises about 5% or less by weight of free bupivacaine when measured after the composition is stored at 2-8° C. for about 24 months.

17. The process of claim 15 , wherein the composition comprises about 4% or less by weight of free bupivacaine when measured after the composition is stored at 2-8° C. for about 24 months.

18. The process of claim 17 , wherein the composition comprises at least 0.03 mg/mL encapsulated lysine.

19. The process of claim 1 , wherein an average erucic acid concentration of at least three batches of bupivacaine encapsulated MVLs prepared by the process is about 105 μg/mL or less when measured after storage at about 25° C. for six months.

20. The process of claim 19 , wherein an average erucic acid concentration of at least three batches of bupivacaine encapsulated MVLs prepared by the process is about 99 μg/mL or less when measured after storage at about 25° C. for six months.

21. A method of providing local or regional analgesia to a subject in need thereof, comprising administering a composition of bupivacaine encapsulated MVLs prepared by the process of claim 14 to the subject.

22. The method of claim 21 , wherein the administration is via local infiltration to a surgical site to provide postsurgical local analgesia.

23. The method of claim 21 , wherein the administration is via a nerve block to provide postsurgical regional analgesia.

24. The method of claim 23 , wherein the nerve block is interscalene brachial plexus nerve block or femoral nerve block.

25. The method of claim 21 , wherein the composition has a volume of 10 mL or 20 mL for a single-dose administration.

26. The method of claim 21 , wherein the concentration of bupivacaine in the composition is about 13.3 mg/mL.

27. The method of claim 21 , wherein the composition comprises about 5% or less by weight of free bupivacaine when measured after the composition is stored at 2-8° C. for about 24 months.

28. The method of claim 21 , wherein the composition comprises at least 0.03 mg/mL encapsulated lysine.

29. The process of claim 1 , wherein the final bulk aqueous suspension of bupivacaine encapsulated MVLs has a volume of about 110 L to about 250 L.

30. The process of claim 29 , further comprising filling the bulk aqueous suspension of bupivacaine encapsulated MVLs into individual vials each containing a composition of bupivacaine encapsulated MVLs.

31. The process of claim 30 , wherein the composition comprises at least 0.03 mg/mL encapsulated lysine.

32. The process of claim 1 , wherein the final bulk aqueous suspension of bupivacaine encapsulated MVLs has a volume of about 150 L to about 250 L.

33. The process of claim 32 , further filling the bulk aqueous suspension of bupivacaine encapsulated MVLs into individual vials each containing a composition of bupivacaine encapsulated MVLs.

34. The process of claim 33 , wherein the composition comprises at least 0.03 mg/mL encapsulated lysine.

35. A method of providing local or regional analgesia to a subject in need thereof, comprising administering a composition of bupivacaine encapsulated MVLs prepared by the process of claim 30 to the subject.

36. The method of claim 35 , wherein the administration is via local infiltration to a surgical site to provide postsurgical local analgesia, or via a nerve block to provide postsurgical regional analgesia.

37. The method of claim 36 , wherein the nerve block is interscalene brachial plexus nerve block or femoral nerve block.

38. The method of claim 35 , wherein the composition has a volume of 10 mL or 20 mL for a single-dose administration.

39. A method of providing local or regional analgesia to a subject in need thereof, comprising administering a composition of bupivacaine encapsulated MVLs prepared by the process of claim 33 to the subject.

40. The method of claim 39 , wherein the administration is via local infiltration to a surgical site to provide postsurgical local analgesia, or via a nerve block to provide postsurgical regional analgesia.

41. The method of claim 40 , wherein the nerve block is interscalene brachial plexus nerve block or femoral nerve block.

42. The method of claim 39 , wherein the composition has a volume of 10 mL or 20 mL for a single-dose administration.