Claims for Patent: 8,101,582

Summary for Patent: 8,101,582

Title:	Topical ophthalmic compositions containing tobramycin and dexamethasone
Abstract:	Ophthalmic pharmaceutical compositions containing tobramycin, dexamethasone and deacetylated xanthan gum are described. The compositions provide longer ocular retention for enhanced ocular bioavailability of tobramycin and dexamethasone. In a preferred embodiment, the compositions also provide for improved suspension of dexamethasone. The concentration of ionizable species in the compositions is controlled so as to prevent precipitation of the xanthan gum as a result of ionic interactions between tobramycin and xanthan gum, while allowing for a restoration of viscosity upon topical application of the compositions to the eye. The use of deacetylated xanthan gum is disclosed, so as to avoid formulation instability caused by pH drift during storage.
Inventor(s):	Kabra; Bhagwati P. (Euless, TX)
Assignee:	Alcon Research, Ltd. (Fort Worth, TX)
Application Number:	12/841,414
Patent Claims:	1. A method of treating an eye affected with an ophthalmic inflammatory condition wherein either an infection or risk of infection exists, the method comprising: providing a therapeutically effective amount of a composition to the affected eye wherein the composition includes: i. 0.1 to 0.5 w/v % tobramycin; ii. 0.03 to 0.1 w/v % of dexamethasone; iii. an aqueous, ophthalmically acceptable vehicle containing deacetylated xanthan gum at a concentration of 0.3 to 0.9%; and iv. one or more ionizable species in an amount sufficient to limit ionic interactions between the tobramycin and the deacetylated xanthan gum, such that the in vitro viscosity of the composition is maintained within the range of 10 to 700 cps at a shear rate of 6 sec.sup.-1 and a temperature of 25.degree. C.; said composition having a pH of 5 to 6. 2. A method according to claim 1, wherein the one or more ionizable species is selected from the group consisting of inorganic electrolytes, organic buffering agents and combinations thereof. 3. A method according to claim 2, wherein the one or more ionizable species is selected from the group consisting of sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, sodium citrate, potassium citrate, sodium phosphate, potassium phosphate, sodium acetate, sodium borate, boric acid/mannitol complexes, boric acid/sorbitol complexes and combinations thereof. 4. A method according to claim 3, wherein the ionizable species is selected from the group consisting of sodium chloride, sodium sulfate, and combinations thereof. 5. A method according to claim 1, wherein the in vitro viscosity of the composition is within the range of 10 to 300 cps. 6. A method according to claim 5, wherein the composition has an initial viscosity of 25 to 175 cps. 7. A method according to claim 6, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65. 8. A method according to claim 7, wherein the one or more ionizable species is selected from the group consisting of inorganic electrolytes, organic buffering agents and combinations thereof. 9. A method according to claim 8, wherein the one or more ionizable species is selected from the group consisting of sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, sodium citrate, potassium citrate, sodium phosphate, potassium phosphate, sodium acetate, sodium borate, boric acid/mannitol complexes, boric acid/sorbitol complexes and combinations thereof. 10. A method according to claim 9, wherein the ionizable species is selected from the group consisting of sodium chloride, sodium sulfate, and combinations thereof. 11. A method of treating an eye affected with an ophthalmic inflammatory condition wherein either an infection or risk of infection exists, the method comprising: providing a composition to the affected eye wherein the composition includes: i. 0.1 to 0.5 w/v % tobramycin; ii. 0.03 to 0.1 w/v % of dexamethasone; iii. an aqueous, ophthalmically acceptable vehicle containing deacetylated xanthan gum at a concentration of 0.3 to 0.9%; and iv, one or more ionizable species in an amount sufficient to limit ionic interactions between the tobramycin and the deacetylated xanthan gum, such that the in vitro viscosity of the composition is maintained within the range of 10 to 300 cps at a shear rate of 6 sec.sup.-1 and a temperature of 25.degree. C.; said composition having a pH of 5 to 6; and wherein providing the composition to the affected eye includes topically applying a therapeutically effective amount of the composition to the affected eye. 12. A method according to claim 11, wherein the one or more ionizable species is selected from the group consisting of inorganic electrolytes, organic buffering agents and combinations thereof. 13. A method according to claim 12, wherein the ionizable species is selected from the group consisting of sodium chloride, sodium sulfate, and combinations thereof. 14. A method according to claim 11, wherein the composition has an initial viscosity of 25 to 175 cps. 15. A method according to claim 14, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65. 16. A method of treating an eye affected with an ophthalmic inflammatory condition wherein either an infection or risk of infection exists, the method comprising: topically applying a therapeutically effective amount of a composition to the affected eye wherein the composition includes: i. 0.1 to 0.5 w/iv % tobramycin; ii. 0.03 to 0.1 w/v % of dexamethasone; iii. an aqueous, ophthalmically acceptable vehicle containing deacetylated xanthan gum at a concentration of 0.3 to 0.9%; and iv, one or more ionizable species in an amount sufficient to limit ionic interactions between the tobramycin and the deacetylated xanthan gum, such that the in vitro viscosity of the composition is maintained within the range of 10 to 700 cps at a shear rate of 6 sec.sup.-1 and a temperature of 25.degree. C.; said composition having a pH of 5 to 6. 17. A method according to claim 16, wherein the one or more ionizable species is selected from the group consisting of inorganic electrolytes, organic buffering agents and combinations thereof. 18. A method according to claim 17, wherein the ionizable species is selected from the group consisting of sodium chloride, sodium sulfate, and combinations thereof. 19. A method according to claim 16, wherein the concentration of tobramycin is 0.3 w/v%. 20. A method according to claim 19, wherein the concentration of dexamethasone is 0.05 w/v%. 21. A method according to claim 20, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65. 22. A method according to claim 16 wherein the ocular inflammation resulted from trauma or ocular surgical procedures. 23. A method according to claim 1, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65. 24. A method according to claim 11, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65. 25. A method according to claim 16, wherein the composition has an in vitro/in vivo viscosity ratio of 0.01 to 0.65.