Claims for Patent: 8,877,255

Summary for Patent: 8,877,255

Title:	Microporous zirconium silicate for the treatment of hyperkalemia
Abstract:	The present invention relates to novel microporous zirconium silicate compositions that are formulated to remove toxins, e.g. potassium ions, from the gastrointestinal tract at an elevated rate without causing undesirable side effects. The preferred formulations are designed avoid increase in pH of urine in patients and/or avoid potential entry of particles into the bloodstream of the patient. Also disclosed is a method for preparing high purity crystals of ZS-9 exhibiting an enhanced level of potassium exchange capacity. These compositions are particularly useful in the therapeutic treatment of hyperkalemia.
Inventor(s):	Keyser; Donald Jeffrey (Southlake, TX), Guillem; Alvaro F. (Lantana, TX)
Assignee:	ZS Pharma, Inc. (Coppell, TX)
Application Number:	14/060,279
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,877,255
Patent Claims:	1. A zirconium silicate composition comprising zirconium silicate of formula (I): A.sub.pM.sub.xZr.sub.1-xSi.sub.nGe.sub.yO.sub.m (I) where A is a potassium ion, sodium ion, rubidium ion, cesium ion, calcium ion, magnesium ion, hydronium ion or mixtures thereof, M is at least one framework metal, wherein the framework metal is hafnium (4+), tin (4+), niobium (5+), titanium (4+), cerium (4+), germanium (4+), praseodymium (4+), terbium (4+) or mixtures thereof, "p" has a value from about 1 to about 20, "x" has a value from 0 to less than 1, "n" has a value from 1 to about 12, "y" has a value from 0 to about 12, "m" has a value from about 3 to about 36 and 1.ltoreq.n+y.ltoreq.12, wherein the composition comprises ZS-9 and ZS-7 and lacks detectable amounts of ZS-8. 2. The composition of claim 1, wherein the ZS-9 has an X-ray diffraction pattern of TABLE-US-00014 d (.ANG.) 5.9-6.7 5.3-6.1 2.7-3.5 2.0-2.8 1.6-2.4. 3. The composition of claim 1, wherein the ZS-7 has an X-ray diffraction pattern of TABLE-US-00015 d (.ANG.) 6.8-7.6 5.6-6.4 3.7-4.5 3.6-4.4 2.6-3.4 2.5-3.3 2.4-3.2. 4. The composition of claim 1, wherein the ZS-8 has an X-ray diffraction pattern of TABLE-US-00016 d (.ANG.) 12.0-13.2 3.9-4.7 2.8-3.6 2.3-3.1 2.2-3.0 2.1-2.9. 5. The composition of claim 1, wherein the composition comprises ZS-9 at a weight percent ranging from about 50% to about 75%. 6. The composition of claim 1, wherein the composition comprises ZS-7 at a weight percent ranging from about 25% to about 50%. 7. The composition of claim 1, wherein the ZS-9 exhibits a median particle size of greater than 3 microns and less than 7% of the particles in the composition have a diameter less than 3 microns, and the composition exhibits a sodium content below 12% by weight. 8. The composition of claim 1, wherein the ZS-9 is partially protonated. 9. The composition of claim 1, wherein the protonated ZS-9 has a potassium exchange rate of greater than 3.1 meq/g. 10. The composition of claim 1, wherein the protonated ZS-9 has a potassium exchange rate in the range of 3.2 to 3.5 meq/g. 11. The composition of claim 1, wherein the protonated ZS-9 has a potassium exchange rate of >2.46 meq/g. 12. The composition of claim 1, wherein the protonated ZS-9 has a sodium content of less than 12%. 13. An zirconium silicate composition comprising zirconium silicate of formula (I): A.sub.pM.sub.xZr.sub.1-xSi.sub.nGe.sub.yO.sub.m (I) where A is a potassium ion, sodium ion, rubidium ion, cesium ion, calcium ion, magnesium ion, hydronium ion or mixtures thereof, M is at least one framework metal, wherein the framework metal is hafnium (4+), tin (4+), niobium (5+), titanium (4+), cerium (4+), germanium (4+), praseodymium (4+), terbium (4+) or mixtures thereof, "p" has a value from about 1 to about 20, "x" has a value from 0 to less than 1, "n" has a value from 1 to about 12, "y" has a value from 0 to about 12, "m" has a value from about 3 to about 36 and 1.ltoreq.n+y.ltoreq.12, wherein the zirconium silicate comprises ZS-9 at a weight percent ranging from about 50% to about 75%, and ZS-7 at a weight percent ranging from about 25% to about 50%. 14. The composition of claim 13, wherein the ZS-9 has an X-ray diffraction pattern of TABLE-US-00017 d (.ANG.) 5.9-6.7 5.3-6.1 2.7-3.5 2.0-2.8 1.6-2.4. 15. The composition of claim 13, wherein the ZS-7 has an X-ray diffraction pattern of TABLE-US-00018 d (.ANG.) 6.8-7.6 5.6-6.4 3.7-4.5 3.6-4.4 2.6-3.4 2.5-3.3 2.4-3.2. 16. The composition of claim 13, wherein the composition does not comprise a ZS-8 having an X-ray diffraction pattern of TABLE-US-00019 d (.ANG.) 12.0-13.2 3.9-4.7 2.8-3.6 2.3-3.1 2.2-3.0 2.1-2.9. 17. The composition of claim 13, wherein the composition comprises ZS-9 at a weight percent ranging from about 50% to about 75%. 18. The composition of claim 13, wherein the composition comprises ZS-7 at a weight percent ranging from about 25% to about 50%. 19. The composition of claim 13, wherein the ZS-9 exhibits a median particle size of greater than 3 microns and less than 7% of the particles in the composition have a diameter less than 3 microns, and the composition exhibits a sodium content below 12% by weight. 20. The composition of claim 13, wherein the ZS-9 is partially protonated. 21. The composition of claim 13, wherein the protonated ZS-9 has a potassium exchange rate of greater than 3.1 meq/g. 22. The composition of claim 13, wherein the protonated ZS-9 has a potassium exchange rate in the range of 3.2 to 3.5 meq/g. 23. The composition of claim 13, wherein the protonated ZS-9 has a potassium exchange rate of >2.46 meq/g. 24. The composition of claim 13, wherein the protonated ZS-9 has a sodium content of less than 12%.