Claims for Patent: 6,174,524

Summary for Patent: 6,174,524

Title:	Gelling ophthalmic compositions containing xanthan gum
Abstract:	Ophthalmic drug delivery vehicles which are administrable as a liquid and which gel upon contact with the eyes are disclosed. The vehicles contain xanthan gum.
Inventor(s):	Bawa; Rajan (Fort Collins, CO), Hall; Rex E. (Fort Worth, TX), Kabra; Bhagwati P. (Arlington, TX), Teague; James E. (Arlington, TX)
Assignee:	Alcon Laboratories, Inc. (Fort Worth, TX)
Application Number:	09/277,102
Patent Claims:	1. An improved ophthalmic composition comprising xanthan gum, wherein the improvement comprises the composition having a total ionic strength of about 120 mM or less and the xanthan gum having an initial bound acetate content of at least about 4% and an initial bound pyruvate content of at least about 2.5%, provided that the composition does not contain locust bean gum. 2. The composition of claim 1 wherein the amount of xanthan gum is from about 0.1 to about 1% (w/w). 3. The composition of claim 1 further comprising an ophthalmic drug. 4. The composition of claim 3 wherein the drug is selected from the group consisting of anti-glaucoma agents; anti-infective agents; non-steroidal and steroidal anti-inflammatory agents; growth factors; immunosuppressant agents; and anti-allergic agents. 5. The composition of claim 4 wherein the drug is selected from the group consisting of timolol; brimonidine; tobramycin; ciprofloxacin; rimexolone; olopatadine; latanoprost; 15-keto-latanoprost; fluprostenol isopropyl ester; isopropyl [2R(1E,3R),3S(4Z),4R]-7-[tetrahydro-2-[4-(3-chlorophenoxy)-3-hydroxy-1-but enyl]-4-hydroxy-3-furanyl]-4-heptenoate; and the pharmaceutically acceptable salts thereof. 6. The composition of claim 1 further comprising one or more agents selected from the group consisting of buffering agents; preservatives; tonicity-adjusting agents; surfactants; solubilizing agents; stabilizing agents; comfort-enhancing agents; emollients; pH-adjusting agents; lubricants; and drug carrier substrates. 7. The composition of claim 1 wherein the xanthan gum forms a gel having an elastic modulus (G') of approximately 130 Pa when measured in the Lysozyme Gel Strength Test. 8. The composition of claim 1 wherein the composition has a total ionic strength of about 94 mM or less. 9. The composition of claim 1 wherein the composition comprises tobramycin or a pharmaceutically acceptable salt of tobramycin, a preservative, a pH-adjusting agent, a tonicity adjusting agent, and xanthan gum. 10. The composition of claim 1 wherein the composition comprises timolol or a pharmaceutically acceptable salt of timolol, a preservative, a pH-adjusting agent. 11. The composition of claim 10 wherein the composition comprises timolol maleate, benzododecinium bromide, tromethamine, boric acid, mannitol, and polysorbate 80. 12. The composition of claim 1 wherein the composition is intended for treating dry eye and comprises a pH-adjusting agent and a tonicity adjusting agent. 13. The composition of claim 12 wherein the amount of xanthan gum is 0.4-0.8% (w/w).