Low molecular weight polymers

• US 20050238618A1
• Filed: 04/25/2005
• Published: 10/27/2005
• Est. Priority Date: 04/23/2004
• Status: Abandoned Application

• Current Assignee: Amgen Inc.
• Original Assignee: Amgen Inc.
• Inventors: Huang, Yujin
• Application Number:
  US11/114,429
• Publication Number:
  US 20050238618A1
• Time in Patent Office: Days
• US Class Current: 424/78.370
• CPC Class Codes: A61K 31/765 Polymers containing oxygen
• CPC Class Codes: A61K 47/34 Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyesters, polyamino acids, polysiloxanes, polyphosphazines, copolymers of polyalkylene glycol or poloxamers A61K47/10 takes precedence
• CPC Class Codes: A61K 9/1647 Polyesters, e.g. poly(lactide-co-glycolide)
• CPC Class Codes: A61K 9/5031 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poly(lactide-co-glycolide)
• CPC Class Codes: C08G 63/08 Lactones or lactides
• CPC Class Codes: C08G 63/90 Purification; Drying

Abstract

The invention relates to a procedure for purifying low molecular weight polylactic acid polymers by use of reduced temperature liquid-liquid phase separation of the polymers in methanol, ethanol or isopropanol based solvents, compositions comprising the polymers and methods of using the same.

Claims

1. A method of fractionating low molecular weight polylactic acid (PLA) polymers comprising the steps of:

A) dissolving the PLA polymer in a solvent, wherein the solvent is a mixture that contains methanol, ethanol or isopropanol;

B) cooling the solution of step A to induce liquid-liquid phase separation; and

C) separating the upper and lower layers of step B.

2. The method of claim 1, further comprising the steps of:

D) adding solvent to the separated top and/or bottom layer;

E) allowing the mixtures of step D to form a solid, and

F) isolating the solids from each layers.

3. The method of claim 1, wherein the solvent is comprised of a solvent selected from the group consisting of methanol, ethanol or isopropanol.

4. The method of claim 1, wherein the solvent is comprised of methanol.

5. The method of claim 1, wherein the solvent is comprised of ethanol.

6. The method of claim 1, wherein the solvent is comprised of isopropanol.

7. The method of claims 3, 4, 5 or 6, further comprising the steps of repeating steps A-C.

8. A solid polymer isolated from a layer of any of claims 1 or 2.

9. A solid polymer made by the method of claim 7.

10. The polymer of claim 9, wherein the polydispersity is less than 1.6.

11. The polymer of claim 10, wherein the polydispersity is less than 1.3.

12. The polymer of claim 8, wherein the number average molecular weight of the polymer is between 800 and 2,500.

13. A pharmaceutically acceptable composition comprising the purified polymer of claim 2.

14. A solid PLA polymer, wherein the polydispersity is less than 1.6.

15. The polymer of claim 14, wherein the polydispersity is less than 1.3.

16. A method of treating a condition comprising administering an effective amount of a pharmaceutical composition comprising a microparticle, wherein the microparticle is made from the PLA polymer of claim 14.