Method for the preparation of liposome encapsulated vincristine for therapeutic use

1. A method of preparing a pharmaceutically acceptable liquid composition comprising liposome-encapsulated vincristine which is free of substantial degradation products, the method comprising:

(a) constituting in a single vial (i) a first solution comprising vincristine sulfate at a concentration of about 1 mg/ml to about 5 mg/ml, wherein the first solution has a pH of about 3.5 to about 5.5; and (ii) a second solution comprising sphingomyelin/cholesterol liposomes at a low pH;

(b) raising the pH of the constituting solution in the single vial to a pH of about 7.0 to 7.5;

(c) heating the single vial comprising the constituting solution in a dry heat block equilibrated at about 75° C. for at least about 13 to about 18 minutes, wherein said heat block comprises one or more bores about 1-5% larger than the average length or diameter of the single vial to produce a solution comprising constituted liposome encapsulated vincristine; and

(d) equilibrating the constituted solution to room temperature.

2. The method of claim 1 , wherein the pH of the second solution comprising the liposomes is about 4.0.

3. The method of claim 2 , wherein the second solution further comprises a citrate buffer.

4. The method of claim 1 , wherein the pH of the constituting solution is raised by the addition of a third solution comprising a buffer at a pH of about 9.0.

5. The method of claim 4 , wherein the third solution comprises sodium phosphate buffer.

6. The method of claim 1 , wherein the constituting solution comprises a concentration of about 0.1/1.0 to about 0.2/2.0 vincristine sulfate to lipid.

7. The method of claim 6 , wherein the concentration of vincristine sulfate in the constituted solution is about 0.1 mg/mL to about 0.5 mg/mL.

8. The method of claim 7 , wherein the concentration of vincristine sulfate in the constituted solution is about at about 0.15 mg/mL to about 0.2 mg/mL.

9. The method of claim 4 , wherein the first solution comprises vincristine sulfate USP (5 mg/5 mL), which is equivalent to 4.5 mg/5 mL vincristine free base, and 500 mg/5 mL mannitol, the second solution comprises sphingomyelin/cholesterol liposomes consisting of 73.5 mg/mL sphingomyelin, 29.5 mg/mL cholesterol, 33.6 mg/mL citric acid, 35.4 mg/mL sodium citrate, and the third solution comprises 355 mg/25 mL dibasic sodium phosphate and 225 mg/25 mL sodium chloride.

10. The method of claim 1 , wherein the ratio of sphingomyelin to cholesterol in the liposome is between about 75/25 mol %/mol % sphingomyelin/cholesterol to 30/50 mol %/mol % sphingomyelin/cholesterol.

11. The method of claim 1 , wherein the liposomes have a size range of about 0.05-0.5 microns.

12. A method of treatment comprising administering the liposome-encapsulated vincristine made by the method of claim 1 , wherein a patient with cancer is administered the liposome encapsulated vincristine at a dose of about 1.5to about 2.4 mg/m 2.

13. The method of claim 12 , wherein the cancer is selected from the group consisting of lymphoma, leukemia, myeloma, brain cancer and neuroblastoma.

14. The use of claim 12 , wherein the pharmaceutically acceptable liquid composition comprising liposome-encapsulated vincristine is administered by intravenous infusion over a period of about 30 to 60 minutes.

15. The method of claim 12 , wherein the pharmaceutically acceptable liquid composition comprising liposome-encapsulated vincristine is administered by intravenous infusion once every 7-28 days.