Granted Patent B2

US 8,084,056 · App. 10/667,931 · Granted Dec 27, 2011

Abstract

Claims (47)

1. A process for preparing a lipid suspension for use with a perfluorocarbon gas as an ultrasound contrast agent, the method comprising:

(a) contacting phospholipids with a first non-aqueous solvent which causes the phospholipids to dissolve and form a lipid solution, wherein the contacting comprises the sequential addition of individual phospholipids to the first non-aqueous solvent wherein the phospholipids are 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phosphotidic acid, mono sodium salt (DPPA) and N-(methoxypolyethylene glycol 5000 carbamoyl)-1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine, mono sodium salt (MPEG5000-DPPE), or combining said phospholipids with each other prior to their addition to the first non-aqueous solvent;

(b) contacting the non-aqueous lipid solution of (a) with a second non-aqueous solvent which causes the phospholipids to precipitate out as a solid lipid blend;

(c) collecting the solid lipid blend;

(d) contacting the solid lipid blend with a third non-aqueous solvent which causes the lipid blend to dissolve to form a lipid blend solution;

(e) contacting the lipid blend solution with an aqueous solution to yield a lipid suspension comprising the third non-aqueous solvent.

2. The process of claim 1 , wherein each of the phospholipids has a gel to liquid crystalline phase temperature and wherein the lipid blend solution of step (d) is heated to a temperature that is about equal to or above the highest gel to liquid crystalline phase temperature of the phospholipids.

3. The process of claim 1 , wherein the first non-aqueous solvent is a mixture of methanol and toluene.

4. The process of claim 1 , wherein the second non-aqueous solvent is methyl t-butyl ether.

5. The process of claim 1 , wherein the third non-aqueous solvent is selected from propylene glycol, ethylene glycol, and polyethylene glycol 300.

6. The process of claim 5 , wherein the third non-aqueous solvent is propylene glycol.

7. The process of claim 1 , wherein the aqueous solution contains water, saline, a saline and glycerin mixture, or a saline and glycerin and non-aqueous solvent mixture.

8. The process of claim 7 , wherein the aqueous solution contains a saline and glycerin mixture.

9. The process of claim 7 , wherein the aqueous solution contains a saline, glycerin, and propylene glycol mixture.

10. The process of claim 1 , wherein the first non-aqueous solvent contains a mixture of methanol and toluene and wherein the second non-aqueous solvent is methyl t-butyl ether.

11. The process of claim 1 , wherein the third non-aqueous solvent is propylene glycol and wherein the aqueous solution contains a saline, glycerin, and propylene glycol mixture.

12. The process of claim 10 , wherein the third non-aqueous solvent is propylene glycol and wherein the aqueous solution contains a saline, glycerin, and propylene glycol mixture.

13. The process according to claim 12 , wherein sodium chloride, glycerin, propylene glycol, and about 0.75 to 1.0 mg/mL of the lipid blend are present in the lipid suspension.

14. The process according to claim 1 , wherein the third non-aqueous solvent is heated to a temperature of about 30 to 70° C. prior to contacting with the solid lipid blend.

15. The process according to claim 1 , wherein the third non-aqueous solvent is heated to a temperature of about 50 to 55° C. prior to contacting with the solid lipid blend.

16. The process according to claim 1 , wherein in step (d) the ratio of solid lipid blend to third non-aqueous solvent is from about 5 mg of solid lipid blend per mL of non-aqueous solvent to about 15 mg/mL of solid lipid blend per mL of non-aqueous solvent.

17. The process according to claim 16 , wherein the ratio of solid lipid blend to third non-aqueous solvent is about 10 mg/mL.

18. The process according to claim 1 , wherein in step (e), the aqueous solution is heated to a temperature of about 45 to 60° C. prior to contacting with the lipid blend solution.

19. The process according to claim 18 , wherein the aqueous solution is heated to a temperature of about 50 to 55° C. prior to contacting with the lipid blend solution.

20. The process according to claim 3 , wherein the lipid blend solution is heated to a temperature of at least about 67° C.

21. The process according to claim 3 , wherein step (d) of the process further comprises: filtering the lipid blend solution through a sterilizing filter to form a filtered lipid blend solution.

22. The process according to claim 21 , wherein step (d) of the process further comprises: filtering the filtered lipid blend solution through a second sterilizing filter to form a twice filtered lipid blend solution.

23. The process according to claim 22 , wherein the sterilizing filters are at a temperature of from about 70 to 80° C.

24. The process according to claim 23 , wherein 0.2 μm hydrophilic filters are used.

25. The process according to claim 21 , wherein the process further comprises: dispensing the filtered lipid blend solution into a vial.

26. The process according to claim 25 , wherein the process further comprises: exchanging the headspace gas of the vial with a perfluorocarbon gas.

27. The process according to claim 26 , wherein the perfluorocarbon gas is perfluoropropane.

28. The process according to claim 26 , wherein the process further comprises: sterilizing the vial.

29. The process according to claim 28 , wherein the vial is sterilized at about 126-130° C. for 1 to 10 minutes.

30. The process of claim 1 , wherein

i) the first non-aqueous solvent is a mixture of methanol and toluene;

ii) the second non-aqueous solvent is methyl t-butyl ether;

iii) the third non-aqueous solvent is propylene glycol;

iv) the aqueous solution contains a saline and glycerin and non-aqueous solvent mixture;

v) the third non-aqueous solvent is heated to a temperature of about 50-60° C. prior to contacting with the solid lipid blend;

vi) in step (d) the ratio of solid lipid blend to third non-aqueous solvent is from about 5 mg of solid lipid blend per mL of non-aqueous solvent to about 15 mg/mL of solid lipid blend per mL of non-aqueous solvent;

vii) in step (e), the aqueous solution is heated to a temperature of about 45 to 60° C. prior to contacting with the lipid blend solution;

viii) step (d) of the process optionally comprises filtering the lipid blend solution through a sterilizing filter to form a filtered lipid blend solution;

ix) the process comprises dispensing the filtered lipid blend solution into a vial;

x) wherein the process comprises exchanging the headspace gas of the vial with perfluoropropane; and

xi) the process comprises sterilizing the vial.

31. The process according to claim 30 , wherein sodium chloride, glycerin, propylene glycol, and about 0.75 to 1.0 mg/mL of the lipid blend are present in the lipid suspension.

Assignments (16)