Details for Patent: 5,711,968
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| Title: | Composition and method for the controlled release of metal cation-stabilized interferon |
| Abstract: | This invention relates to a composition, and method of forming said composition, for the controlled release of interferon. The controlled release composition of this invention comprises a biocompatible polymer and particles of metal cation-stabilized interferon, wherein the particles are dispersed within the biocompatible polymer. The method of the invention, for producing a composition for the controlled release of interferon, includes dissolving a polymer in a polymer solvent to form a polymer solution, dispersing particles of metal cation stabilized-interferon particles in the polymer solution, and then solidifying the polymer to form a polymeric matrix containing a dispersion of the interferon particles. |
| Inventor(s): | Tracy; Mark A. (Arlington, MA), Bernstein; Howard (Cambridge, MA), Khan; M. Amin (Dowingtown, PA) |
| Assignee: | Alkermes Controlled Therapeutics, Inc. (Cambridge, MA) |
| Filing Date: | Jul 25, 1994 |
| Application Number: | 08/279,784 |
| Claims: | 1. A composition for the controlled release of interferon from a polymeric matrix, comprising: a) a biocompatible polymer; and b) particles of metal cation-complexed interferon, wherein said particles are dispersed within the biocompatible polymer and are in the substantial absence of protamine. 2. A controlled release composition of claim 1 wherein the metal cation-complexed interferon contains at least one type of biocompatible multivalent cation, wherein said cation is not significantly oxidizing to interferon. 3. A controlled release composition of claim 2 wherein said multivalent cation is selected from the group consisting of Zn.sup.+2, Ca.sup.+2, Cu.sup.+2, Mg.sup.+2 and any combination thereof. 4. A controlled release composition of claim 2 wherein the biocompatible polymer is biodegradable. 5. A controlled release composition of claim 4 wherein the biodegradable polymer is selected from the group consisting of poly(lactides), poly(glycolides), poly(lactide-co-glycolides), polycaprolactone, polycarbonates, polyesteramides, polyanhydrides, poly(amino acids), polyorthoesters, polyacetals, polycyanoacrylates, biodegradable polyurethanes, blends and copolymers thereof. 6. A controlled release composition of claim 5 wherein said polymer comprises poly(lactide-co-glycolide). 7. A controlled release composition of claim 2 wherein the biocompatible polymer is non-biodegradable. 8. A controlled release composition of claim 7, further comprising a pore forming agent which is dispersed within the non-biodegradable polymer. 9. A controlled release composition of claim 8 wherein the non-biodegradable polymer is selected from the group consisting of non-biodegradable polyurethanes, polyacrylates, poly(ethylene-vinyl acetates), poly(acyl-substituted cellulose acetates), polysaccharides, polystyrenes, polyvinyl chloride, polyvinyl fluoride, poly(vinyl imidazole), chlorosulphonated polyolefins, polyethylene oxides, blends and copolymers thereof. 10. A controlled release composition of claim 4 further comprising a second metal cation component, wherein the second metal cation component is not complexed to said interferon, and wherein the second metal cation component is dispersed within the biocompatible polymer to modulate the release of interferon from the polymeric matrix. 11. A controlled release composition of claim 10 wherein the second metal cation component inorganic salt is selected from the group consisting of Mg(OH).sub.2, MgCO.sub.3, CaCO.sub.3, ZnCO.sub.3, Mg(OAc).sub.2, Zn(OAc).sub.2, ZnSO.sub.4, MgCl.sub.2, ZnCl.sub.2, MgSO.sub.4, zinc citrate and magnesium citrate. 12. A method for forming a composition for the controlled release of interferon, comprising the steps of: a) dissolving a diocompatible polymer in a polymer solvent to form a polymer solution; b) dispersing metal cation-complexed interferon particles which are in the substantial absence of protamine, in the polymer solution; and c) solidifying the polymer to form a polymeric matrix containing a dispresion of said interferon particles. 13. A method of claim 12 wherein the metal cation of the metal cation-complexed interferon contains at least one type of biocompatible multivalent cation, which is not significantly oxidizing to interferon. 14. A method of claim 13 wherein the multivalent cation is selected from the group consisting of Zn.sup.+2, Ca.sup.+2, Mg.sup.+2, Cu.sup.+2 and a combination thereof. 15. A method of claim 14 wherein the biocompatible polymer is biodegradable. 16. A method of claim 15 wherein the biodegradable polymer is selected from the group consisting of poly(lactides), poly(glycolides), poly(lactide-co-glycolides), polycaprolactone, polycarbonates, polyesteramides, polyanhydrides, poly(amino acids), polyorthoesters, polyacetals, polycyanoacrylates, biodegradable polyurethanes, blends and copolymers thereof. 17. A method of claim 16 wherein the biodegradable polymer comprises poly(lactide-co-glycolide). 18. A method of claim 13 wherein the biocompatible polymer is non-biodegradable. 19. A method of claim 18, further comprising the step of dispersing a pore forming agent within the polymer solution. 20. A method of claim 19 wherein the non-biodegradable polymer is selected from the group consisting of non-biodegradable polyurethanes, polyacrylates, poly(ethylene-vinyl acetates), poly(acyl-substituted cellulose acetates), polysaccharides, polystyrenes, polyvinyl chloride, polyvinyl fluoride, poly(vinyl imidazole), chlorosulphonated polyolefins, polyethylene oxides, blends and copolymers thereof. 21. A method of claim 15 further comprising the step of dispersing a second metal cation component within the polymer solution, wherein the second metal cation component is not contained in said interferon particles. 22. A method of claim 21 wherein the second metal cation component is selected from the group consisting of Mg(OH).sub.2, MgCO.sub.3, CaCO.sub.3, ZnCO.sub.3, Mg(OAc).sub.2, Zn(OAc).sub.2, ZnSO.sub.4, MgCl.sub.2, ZnCl.sub.2, MgSO.sub.4, zinc citrate and magnesium citrate. 23. A method for forming interferon controlled release microspheres, comprising the steps of: a) dissolving a biocompatible polymer in a polymer solvent to form a polymer solution; b) dispersing metal cation-complexed interferon particles in the polymer solution to form a dispersion; c) dividing the dispersion into droplets, wherein a droplet contains metal cation-complexed interferon particles in the substantial absence of protamine; d) freezing the droplets to form microspheres; and e) contacting the microspheres with a liquid non-solvent, which is miscible with the polymer solvent, whereby the polymer solvent is extracted from the microspheres, thereby forming microspheres for the controlled release of interferon. 24. A method for forming a metal cation-stabilized interferon, comprising the steps of: a) forming a solution containing interferon; b) dispersing a multivalent metal cation component within the interferon solution under pH conditions suitable for complexing the multivalent metal cation with the interferon, thereby forming a metal cation-complexed interferon suspension; and c) lyophilizing said suspension to form the metal cation-stabilized interferon. 25. A method of claim 24 wherein the multivalent metal cation component contains cations selected from the group consisting of Zn.sup.+2, Ca.sup.+2 and any combination thereof. 26. A method of claim 25 wherein the multivalent metal cation component comprises zinc acetate. 27. A composition for the controlled release of interferon from a polymeric matrix, comprising: a) poly(lactide-co-glycolide) with a molecular weight between 5000 Daltons and 42,000 Daltons; b) particles of Zn.sup.+2 -complexed interferon, with a zinc-to-interferon molar ratio between 1:1 and 10:1, wherein said particles are dispersed within the poly(lactide-co-glycolide) and are in the substantial absence of protamine, and wherein the proportion of interferon in the controlled release composition is between 0.5 and 15 weight percent. 28. A composition for the controlled release of interferon from a polymeric matrix, comprising: a) poly(lactide-co-glycolide) with a molecular weight between 5000 Daltons and 42,000 Daltons; b) particles of Zn.sup.12 -complexed interferon, with a zinc-to-interferon molar ratio between 1:2 and 50:1, wherein said particles are dispersed within the poly(lactide-co-glycolide) and are in the substantial absence of protamine, and wherein the proportion of interferon in the controlled release composition is between 0.5 and 15 weight percent. 29. A composition for the controlled release of interferon from a polymeric matrix, comprising: a) poly(lactide-co-glycolide) with a molecular weight between 5000 Daltons and 42,000 Daltons; b) particles of Zn.sup.+2 -complexed interferon, with a zinc-to-interferon molar ratio of about 2:1, wherein said particles are dispersed within the poly(lactide-co-glycolide) and are in the substantial absence of protamine, and wherein the proportion of interferon in the controlled release composition is between 0.5 and 15 weight percent. |
