Details for Patent: 7,488,495

Title:	Ion binding polymers and uses thereof
Abstract:	The present invention provides methods and compositions for the treatment of ion imbalances. In particular, the invention provides compositions comprising potassium binding polymers and pharmaceutical compositions thereof. Methods of use of the polymeric and pharmaceutical compositions for therapeutic and/or prophylactic benefits are disclosed herein. Examples of these methods include the treatment of hyperkalemia, such as hyperkalemia caused by renal failure and/or the use of hyperkalemia causing drugs.
Inventor(s):	Charmot; Dominique (Campbell, CA), Chang; Han Ting (Livermore, CA), Klaerner; Gerrit (San Jose, CA), Cope; Michael James (Berkeley, CA), Liu; Mingjun (Campbell, CA), Liu; Futian (Mountain View, CA), Buysse; Jerry (Los Altos, CA), Connor; Eric (Los Gatos, CA), Mong; Tony Kwok-Kong (Hsinchu, TW), Shao; Jun (Fremont, CA), Madsen; Deidre (Sunnyvale, CA)
Assignee:	Relypsa, Inc. (Santa Clara, CA)
Filing Date:	Oct 13, 2004
Application Number:	10/965,274
Claims:	1. A method of treating hyperkalemia in an animal subject, the method comprising administering to said animal subject an effective amount of a potassium-binding, cation-exchange polymer, the cation-exchange polymer comprising at least one polymer selected from a crosslinked carboxylic polymer, a crosslinked sulfonic polymer, a crosslinked sulfamic polymer, a crosslinked phosphonic polymer, and an anhydride thereof, the crosslinked polymer comprising an electron-withdrawing substituent attached to a carbon atom alpha or beta to an acid group of said polymer and being orally administered in a form having a combination of counterions selected from Ca.sup.2+, H.sup.+, NH.sub.4.sup.+, and Na.sup.+, whereby the potassium-binding, cation-exchange polymer binds and removes potassium from a gastrointestinal tract of said animal subject. 2. The method of claim 1 wherein the potassium-binding polymer has an in vitro potassium binding capacity of greater than 5 mmol/gm of said polymer at a pH of greater than 5.5. 3. The method of claim 1 wherein the potassium-binding polymer has an average in vivo potassium binding capacity of at least about 1.5 mmol/gm of said polymer. 4. The method of claim 1 wherein said potassium-binding polymer comprises at least one polymer selected from an optionally crosslinked carboxylic polymer, an optionally crosslinked sulfonic polymer, an optionally crosslinked sulfamic polymer, an optionally crosslinked phosphonic polymer, and an anhydride thereof. 5. The method of claim 1 wherein said potassium-binding polymer is a polystyrene sulfonate. 6. The method of claim 1 wherein less than 1% of said potassium-binding polymer is absorbed from the gastrointestinal tract of said animal subject. 7. The method of claim 1 wherein said treatment has a therapeutic or prophylactic benefit. 8. The method of claim 1 wherein said electron-withdrawing substituent is a hydroxyl group, an ether group, an ester group, or a halide group. 9. The method of claim 8 wherein said halide group is fluoride, chloride, or bromide. 10. The method of claim 4 wherein said potassium binding polymer comprises a poly-fluoroacrylic acid polymer, a poly-difluoromaleic acid polymer, or a combination thereof. 11. The method of claim 10 wherein said potassium binding polymer comprises 2-fluoroacrylic acid crosslinked with divinylbenzene, ethylene bisacrylamide, N,N'-bis(vinylsulfonylacetyl) ethylene diamine, 1,3-bis(vinylsulfonyl) 2-propanol, vinylsulfone, N,N'-methylenebisacrylamide, or a combination thereof. 12. The method of claim 11 wherein said potassium binding polymer comprises crosslinked 2-fluoroacrylic polymer or co-polymer, said polymer or co-polymer obtained by polymerization of an alkylester of 2-fluoroacrylic acid with divinylbenzene and followed by ester hydrolysis. 13. The method of claim 1 wherein said potassium-binding polymer is at least one polymer selected from an optionally crosslinked 2-fluroacrylate polymer, an optionally crosslinked vinyl sulfonic acid polymer, and an optionally crosslinked vinyl phosphonic acid polymer. 14. The method of claim 1 wherein the potassium-binding polymer comprises an enteric coating, said coating being capable of disintegrating in a colon. 15. The method of claim 1 wherein said potassium-binding polymer preferentially binds a potassium ion over a competing magnesium ion. 16. The method of claim 1, 2, or 3 wherein said potassium binding polymer is co-administered with a drug that promotes potassium retention. 17. The method of claim 1, 2, or 3 wherein said composition is co-administered with an ACE inhibitor, an angiotensin II receptor blocker (ARB), a potassium sparing diuretic, or any combination thereof. 18. The method of claim 1, 2, or 3 wherein said potassium-binding polymer is combined with at least one pharmaceutically acceptable excipient to form a pharmaceutical formulation. 19. The method of claim 18 wherein said pharmaceutical formulation is an oral formulation, and the cation exchange polymer is a crosslinked polymer comprising a repeat unit having acid groups in protonated, ionized or anhydride form. 20. The method of claim 19 wherein said oral formulation is a liquid formulation or a chewable tablet formulation.