Rare earth metal compounds, methods of making, and methods of using the same

Abstract

Rare earth metal compounds, particularly lanthanum, cerium, and yttrium, are formed as porous particles and are effective in binding metals, metal ions, and phosphate. A method of making the particles and a method of using the particles is disclosed. The particles may be used in the gastrointestinal tract or the bloodstream to remove phosphate or to treat hyperphosphatemia in mammals. The particles may also be used to remove metals from fluids such as water.

1 . A composition comprising a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibiting a phosphate binding of at least 40% of the initial phosphate content after 10 minutes at pH of about 3. 
     
     
         2 . The composition according to  claim 1 , wherein the lanthanum oxycarbonate is La 2 O 2 CO 3 . 
     
     
         3 . The composition according to  claim 1 , wherein the lanthanum oxycarbonate is La 2 CO 5 . 
     
     
         4 . The composition as in any one of  claims 1 ,  2 , and  3  wherein the lanthanum oxycarbonate is in the form of particles of between 1 and 1000 microns in size. 
     
     
         5 . The composition according to  claim 4 , wherein the particles comprise individual crystals and wherein the crystals are between 20 nanometers and 10 microns in size. 
     
     
         6 . The composition as in any one of  claims 1 ,  2 , and  3  in the form of an orally ingestible form selected from the group consisting of liquid solutions, liquid suspensions, tablets, capsules, and gelcaps. 
     
     
         7 . A method of treating hyperphosphatemia in a mammal comprising administering an effective amount of a composition comprising a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibiting a phosphate binding of at least 40% of the initial phosphate concentration after 10 minutes at a pH of about 3. 
     
     
         8 . The method according to  claim 7 , wherein the lanthanum oxycarbonate is La 2 O 2 CO 3 . 
     
     
         9 . The method according  claim 7 , wherein the lanthanum oxycarbonate is La 2 CO 5 . 
     
     
         10 . The method as in any one of  claims 7 ,  8 , and  9  wherein the lanthanum oxycarbonate is in the form of particles between 1 and 1000 microns in size. 
     
     
         11 . The method according to  claim 10 , wherein the particles comprise individual crystals and wherein the crystals are between 20 nanometers and 10 microns in size. 
     
     
         12 . The method according to  claim 7 , wherein the composition is administered in the form of an orally ingestible form selected from the group consisting of liquid solutions, liquid suspensions, tablets, capsules, and gelcaps. 
     
     
         13 . A method of producing a lanthanum oxycarbonate comprising: reacting a lanthanum chloride with a carbonate at a temperature of 30 to 90 degrees centigrade, recovering the resulting precipitate, and thermally treating the precipitate at a temperature of 400 to 700 degrees centigrade to produce an anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g. 
     
     
         14 . The method of  claim 13 , wherein the reaction of the lanthanum chloride with a carbonate is conducted at a temperature of between 80 and 90 degrees centigrade. 
     
     
         15 . The method according to  claim 13  or  14 , wherein the carbonate comprises sodium carbonate. 
     
     
         16 . The method of  claim 15 , wherein the precipitate is heated to a temperature below 600 degrees centigrade. 
     
     
         17 . The method according to  claim 13  or  14 , wherein the lanthanum oxycarbonate is anhydrous La 2 O 2 CO 3 . 
     
     
         18 . The method of  claim 15 , wherein the lanthanum oxycarbonate is anhydrous La 2 O 2 CO 3 . 
     
     
         19 . The method of  claim 16 , wherein the lanthanum oxycarbonate is anhydrous La 2 O 2 CO 3 . 
     
     
         20 . The method of  claim 14 , wherein the lanthanum oxycarbonate is crystalline. 
     
     
         21 . The method of  claim 13 , wherein the lanthanum oxycarbonate is La 2 CO 5 . 
     
     
         22 . An orally ingestible form comprising: an effective amount of a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibits a phosphate binding of at least 40% of the initial phosphate content after 10 minutes at pH of about 3 and a vehicle in a liquid solution, liquid suspension, tablet, capsule, and gelcap. 
     
     
         23 . A method of binding a phosphate comprising: reacting a composition comprising a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibiting a phosphate binding of at least 40% of the initial phosphate content after 10 minutes at pH of about 3. 
     
     
         24 . The method according to  claim 23 , wherein the lanthanum oxycarbonate is La 2 O 2 CO 3 . 
     
     
         25 . The method according to  claim 23 , wherein the lanthanum oxycarbonate is La 2 CO 5 . 
     
     
         26 . The method as in any one of  claims 23 ,  24 , and  25  wherein the lanthanum oxycarbonate is in the form of particles between 1 and 1000 microns in size. 
     
     
         27 . The method according to  claim 26 , wherein the particles comprise individual crystals and wherein the crystals are between 20 nanometers and 10 microns in size. 
     
     
         28 . A device for removing phosphate from blood, wherein the device comprises a filter fluidically connected to a dialysis machine through which blood flows, and wherein the filter comprises a lanthanum compound, and wherein the lanthanum compound is a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibiting a phosphate binding of at least 40% of the initial phosphate content after 10 minutes at pH of about 3. 
     
     
         29 . The device according to  claim 28 , wherein the lanthanum oxycarbonate is selected from the group consisting of La 2 O 2 CO 3  and La 2 CO 5 . 
     
     
         30 . A method for removing phosphate from the bloodstream, the method comprising:
 positioning a device in the bloodstream, wherein the device comprises a filter and wherein the filter comprises a lanthanum compound, and wherein the lanthanum compound is a crystalline anhydrous lanthanum oxycarbonate having a BET specific surface area of at least about 10 m 2 /g and exhibiting a phosphate binding of at least 40% of the initial phosphate content after 10 minutes at pH of about 3.