Claims for Patent: 5,192,535

Summary for Patent: 5,192,535

Title:	Ophthalmic suspensions
Abstract:	Lightly crosslinked polymers, preferably ones prepared by suspension or emulsion polymerizing at least about 90% by weight of a carboxyl-containing monoethylenically unsaturated monomer such as acrylic acid with from about 0.1% to about 5% by weight of a polyfunctional, and preferably difunctional, crosslinking agent such as divinyl glycol (3,4-dihydroxy-1,5-hexadiene), having a particle size of not more than about 50 .mu.m in equivalent spherical diameter, when formulated with an ophthalmic medicament, e.g., fluorometholone, into suspensions in aqueous medium in which the amount of polymer ranges from about 0.1% to about 6.5% by weight, based on the total weight of the aqueous suspension, the pH is from about 3.0 to about 6.5, and the osmotic pressure (osmolality or tonicity) is from about 10 mOsM to about 400 mOsM, provide new topical ophthalmic medicament delivery systems having suitably low viscosities which permit them to be easily administered to the eye in drop form, and hence be comfortably administrable in consistent, accurate dosages. These suspension will rapidly gel in the eye after coming into contact with the eye's tear fluid to a substantially greater viscosity than that of the originally-introduced suspension and thus remain in place for prolonged periods of time to provide sustained release of the ophthalmic medicament.
Inventor(s):	Davis; Jeffrey P. (Madison, WI), Chandrasekaran; Santosh K. (Moraga, CA), Su; Yansheng (Shandong, CN), Archibald; Roy D. (Fremont, CA), Robinson; Joseph R. (Madison, WI)
Assignee:	InSite Vision Incorporated (Alameda, CA)
Application Number:	07/544,518
Patent Claims:	1. A sustained release topical ophthalmic medicament delivery system, comprising: an aqueous suspension at a pH of from about 3 to about 6.5 and an osmotic pressure of from about 10 to about 400 mOsM containing from about 0.1% to about 6.5% by weight, based on the total weight of the suspension, of a carboxyl-containing polymer prepared by polymerizing one or more carboxyl-containing monoethylenically unsaturated monomers and less than about 5% by weight of a crosslinking agent, such weight percentages of monomers being based on the total weight of monomers polymerized, said suspension having a viscosity of from about 1,000 to about 30,000 centipoises and being administrable to the eye in drop form, said polymer having average particle size of not more than about 50 .mu.m in equivalent spherical diameter and being lightly cross-linked such that although the suspension is administrable in drop form, upon contact of the lower pH suspension with the higher pH tear fluid of the eye, the suspension is rapidly gellable to a substantially greater viscosity than the viscosity of the suspension as originally administered in drop form, whereby the resulting more viscous gel can remain in the eye for sustained release of a medicament contained therein. 2. A topical medicament delivery system as in claim 1 in which said polymer is one prepared from at least 50% weight of one or more carboxyl-containing monoethylenically unsaturated monomers. 3. A topical ophthalmic medicament delivery system as in claim 1 containing an ophthalmic medicament. 4. A topical ophthalmic medicament delivery system as in claim 3 in which said polymer has a particle size of not more than about 30 .mu.m. 5. A topical ophthalmic medicament delivery system as in claim 1, claim 2 or claim 3 in which said polymer is a monodispersion of particles. 6. A topical ophthalmic medicament delivery system as in claim 5 wherein at least about 80% of the particles are within a no more than about 10 .mu.m band of major particle size distribution and no more than about 20% of the total particles are fines. 7. The topical ophthalmic medicament delivery system as in claim 5 wherein at least about 90% of the particles are within a no more than about 10 .mu.m band of major particle size distribution, and no more than about 10% of the total particles are fines. 8. The topical ophthalmic medicament delivery system as in claim 5 wherein at least about 95% of the particles are within a no more than about 10 .mu.m band of major particle size distribution, and no more than about 5% of the total particles are fines. 9. The topical ophthalmic medicament delivery system as in claim 6 wherein the band of major particle distribution is from about 1 to about 5 .mu.m. 10. The topical ophthalmic medicament delivery system as in claim 1 wherein the polymer is one in which up to about 40% by weight of said carboxyl-containing monoethylenically unsaturated monomers has been replaced by one or more non-carboxyl-containing monoethylenically unsaturated monomers. 11. A topical ophthalmic medicament delivery system as in claim 4 in which said polymer is one prepared from at least about 90% by weight of one or more carboxyl-containing monoethylenically un-saturated monomers. 12. A topical ophthalmic medicament delivery system as in claim 3 in which said polymer is one prepared by suspension or emulsion polymerizing acrylic acid and a non-polyalkenyl polyether difunctional crosslinking agent to a particle size of not more than about 50 .mu.m in equivalent spherical diameter. 13. A topical ophthalmic medicament delivery system as in claim 12 in which said crosslinking agent is divinyl glycol. 14. A topical ophthalmic medicament delivery system as in claim 13 in which said osmotic pressure is achieved using a physiologically and ophthalmologically acceptable salt in an amount of from about 0.01% to about 1% by weight, based on the total weight of the suspension. 15. A topical ophthalmic medicament delivery system as in claim 14 in which said salt is sodium chloride. 16. A topical ophthalmic medicament delivery system as in claim 15 in which said medicament is present in an amount of from about 0.005% to about 10% by weight, based on the total weight of the suspension. 17. A topical ophthalmic medicament delivery system as in claim 16 in which said medicament is fluorometholone. 18. A topical ophthalmic medicament delivery system as in claim 16 in which said medicament is pilocarpine. 19. A method of delivering an ophthalmic medicament to the eye which comprises: preparing an aqueous suspension at a pH of from about 3 to about 6.5 and an osmotic pressure of from about 10 to about 400 mOsM containing an ophthalmic medicament and from about 0.1% to about 6.5% by weight, based on the total weight of the suspension, of a carboxyl-containing polymer prepared by polymerizing one or more carboxyl-containing monoethylenically unsaturated monomers and from less than about 5% by weight of a cross-linking agent, such weight percentages of monomers being based on the total weight of monomers polymerized, said suspension having a viscosity of from about 1,000 to about 30,000 centipoises, and said polymer having an average particle size of not more than about 50 .mu.m in equivalent spherical diameter and being lightly crosslinked, administering said suspension to the eye in drop form to cause the suspension, upon contact with the higher pH tear fluid of the eye, to rapidly gel to a substantially greater viscosity than the viscosity of the suspension as originally administered in drop form, whereby the resulting more viscous gel remains in the eye for sustained release of the medicament contained therein. 20. A method of claim 19 in which said polymer is one prepared from at least 50% weight of one or more carboxyl-containing monoethylenically unsaturated monomers. 21. A method as in claim 19 or claim 20 in which said polymer has a particle size of not more than about 30 .mu.m. 22. A method as in claim 19 or claim 20 in which said polymer is one in which up to about 40% by weight of said carboxyl-containing monoethylenically unsaturated monomers has been replaced by one or more non-carboxyl-containing monoethylenically unsaturated monomers containing only physiologically and ophthalmologically innocuous substituents. 23. A method as in claim 19 in which said polymer is one prepared by suspension or emulsion polymerizing acrylic acid and a non-polyalkenyl polyether difunctional crosslinking agent to a particle size of not more than about 50 .mu.m in equivalent spherical diameter. 24. A method as in claim 23 in which said cross-linking agent is divinyl glycol. 25. A method as in claim 24 in which said osmotic pressure is achieved using a physiologically and ophthalmologically acceptable salt in an amount of from about 0.01% to about 1% by weight, based on the total weight of the suspension. 26. A method as in claim 25 in which said salt is sodium chloride. 27. A method as in claim 26 in which said medicament is present in an amount of from about 0.005% to about 10% by weight, based on the total weight of the suspension. 28. A method as in claim 27 in which said medicament is fluorometholone. 29. A method as in claim 28 in which said medicament is pilocarpine. 30. A method as in claim 19, claim 20 or claim 21 in which said polymer is a monodispersion of particles. 31. A method as in claim 30 wherein at least about 80% of the particles are within a no more than about 10 .mu.m band of major particle size distribution and no more than about 20% of the total particles are fines. 32. A method as in claim 30 wherein at least about 90% of the particles are within the 10 .mu.m band of major particle size distribution, and no more than about 10% of the total particles are fines. 33. A method as in claim 30 wherein at least about 95% of the particles are within a no more than about 5 .mu.m band of major particle size distribution and no more than about 20% of the total particles are fines. 34. A method as in claim 31 wherein the band of major particle distribution is from about 1 to about 5 .mu.m. 35. A method of preparing a sustained release topical ophthalmic delivery systems, comprising: preparing an aqueous suspension at a pH of from about 3 to about 6.5 and an osmotic pressure of from about 10 to about 400 mOsM and containing from about 0.1% to about 6.5% by weight, based on the total weight of the suspension, of a carboxyl-containing polymer prepared by polymerizing one or more carboxyl-containing monoethylenically unsaturated monomers and less than about 5% by weight of a crosslinking agent, such weight percentages of monomers being based on the total weight of monomers polymerized, and packaging the suspension, at a viscosity of from 1,000 to about 30,000 centipoises, for administration to the eye in drop form, said polymer having average particle size of not more than about 50 .mu.m in equivalent spherical diameter and being lightly cross-linked such that although the suspension is administrable in drop form, upon contact of the lower pH suspension with the higher pH tear fluid of the eye, the suspension is rapidly gellable to a substantially greater viscosity than the viscosity of the suspension as originally administered in drop form.