Claims
- 1. A method for forming microparticles of a material from microdroplets of a solution of the material and a solvent, comprising the steps of:a) directing the microdroplets into a freezing section containing a liquefied gas, whereby the microdroplets freeze; and b) contacting the frozen microdroplets in an extraction section with a liquid non-solvent to extract the solvent into the non-solvent thereby forming said microparticles; wherein the freezing section and extraction section are separated, the non-solvent is in the liquid state throughout the method and the material comprises a poly(lactide-co-glycolide) polymer.
- 2. The method of claim 1 wherein the material further comprises a biologically active agent.
- 3. The method of claim 2 wherein said biologically active agent is selected from the group consisting of immunoglobulin proteins, interleukins, interferons, erythropoietin, antibodies, cytokines, hormones, antigens, growth factors, nucleases, tumor enzymes, tumor suppression genes, antisense molecules, anti-biotics, anesthetics, sedatives, cardiovascular agents, antitumor agents, antineoplastics, antihistamines and vitamins.
- 4. The method of claim 2 wherein the biologically active agent is a protein.
- 5. The method of claim 2 wherein the poly(lactide-co-glycolide) has a lactide: glycolide ratio of 1:1.
- 6. The method of claim 5 wherein the molecular weight of the poly(lactide-co-glycolide) is about 5000 Daltons to about 70,000 Daltons.
- 7. The method of claim 5 wherein the molecular weight of the poly(lactide-co-glycolide) is about 5000 to about 42,000 Daltons.
- 8. The method of claim 1 wherein the temperature of step (a) is lower than the temperature of step (b).
- 9. The method of claim 1 wherein the liquefied gas is sprayed into the freezing section.
- 10. The method of claim 1 wherein the microdroplets are formed by atomizing the solution of the material into the freezing section.
- 11. The method of claim 1 wherein the frozen microdroplets are collected at the bottom of the freezing section and directed into the extraction section.
- 12. A method for forming microparticles of a material from microdroplets of a solution of the material and a solvent, comprising the steps of:a) directing the microdroplets into a freezing vessel containing a liquefied gas, whereby the microdroplets freeze; and b) contacting the frozen microdroplets in an extraction vessel with a liquid non-solvent to extract the solvent into the non-solvent thereby forming said microparticles; wherein the freezing vessel and extraction vessel are separated, the non-solvent is in the liquid state throughout the method and the material comprises a poly(lactide-co-glycolide) polymer.
- 13. The method of claim 12 wherein the material further comprises a biologically active agent.
- 14. The method of claim 13 wherein said biologically active agent is selected from the group consisting of immunoglobulin proteins, interleukins, interferons, erythropoietin, antibodies, cytokines, hormones, antigens, growth factors, nucleases, tumor enzymes, tumor suppression genes, antisense molecules, anti-biotics, anesthetics, sedatives, cardiovascular agents, antitumor agents, antineoplastics, antihistamines and vitamins.
- 15. The method of claim 13 wherein the biologically active agent is a protein.
- 16. The method of claim 13 wherein the poly(lactide-co-glycolide) has a lactide:glycolide ratio of 1:1.
- 17. The method of claim 16 wherein the molecular weight of the poly(lactide-co-glycolide) is about 5000 Daltons to about 70,000 Daltons.
- 18. The method of claim 16 wherein the molecular weight of the poly(lactide-co-glycolide) is about 5000 Daltons to about 42,000 Daltons.
- 19. The method of claim 12 wherein the temperature of step (a) is lower than the temperature of step (b).
- 20. The method of claim 12 wherein the liquefied gas is sprayed into the freezing vessel.
- 21. The method of claim 12 wherein the microdroplets are formed by atomizing the solution of the material into the freezing vessel.
- 22. The method of claim 12 wherein the frozen microdroplets are collected at the bottom of the freezing vessel and directed into the extraction vessel.
RELATED APPLICATIONS
This application is a Continuation of U.S. patent application Ser. No. 09/305,413, filed on May 5, 1999, now U.S. Pat. No. 6,153,129 which is a Continuation of U.S. patent application Ser. No. 08/443,726, filed on May 18, 1995, now U.S. Pat. No. 5,922,253, the entire teachings of which are incorporated herein by reference.
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Foreign Referenced Citations (4)
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Date |
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May 1989 |
WO |
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Continuations (2)
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Number |
Date |
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Parent |
09/305413 |
May 1999 |
US |
Child |
09/587821 |
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US |
Parent |
08/443726 |
May 1995 |
US |
Child |
09/305413 |
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US |