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 pharmaceutical composition comprising a La 2 O 2 CO 3  compound and a pharmaceutically acceptable vehicle or diluent. 
     
     
         2 . The pharmaceutical composition of  claim 1 , wherein the La 2 O 2 CO 3  compound has a phosphate binding capacity of at least 45 mg phosphate per gram of compound. 
     
     
         3 . The pharmaceutical composition of  claim 2 , wherein the La 2 O 2 CO 3  compound has a phosphate binding capacity of at least 50 mg phosphate per gram of compound. 
     
     
         4 . The pharmaceutical composition of  claim 3 , wherein the La 2 O 2 CO 3  compound has a phosphate binding capacity of at least 75 mg phosphate per gram of compound. 
     
     
         5 . The pharmaceutical composition of  claim 4 , wherein the La 2 O 2 CO 3  compound has a phosphate binding capacity of at least 100 mg phosphate per gram of compound. 
     
     
         6 . The pharmaceutical composition of  claim 2 , wherein the La 2 O 2 CO 3  compound has a BET surface area of at least about 10 m 2 /g. 
     
     
         7 . The pharmaceutical composition of  claim 6 , wherein the La 2 O 2 CO 3  compound has a BET surface area of at least about 20 m 2 /g. 
     
     
         8 . The pharmaceutical composition of  claim 7 , wherein the La 2 O 2 CO 3  compound has a BET surface area of at least 35 m 2 /g. 
     
     
         9 . The pharmaceutical composition of  claim 3 , wherein the La 2 O 2 CO 3  compound is made according to the following steps:
 a) providing a lanthanum acetate or lanthanum chloride solution;   b) mixing a carbonate solution with the lanthanum acetate or lanthanum chloride solution to form a precipitate comprising La 2 O 2 CO 3 ;   c) filtering the precipitate to form a filter cake; and,   d) drying the filter cake to provide the La 2 O 2 CO 3  compound.   
     
     
         10 . The pharmaceutical composition according to  claim 9 , wherein the carbonate solution is mixed with the lanthanum acetate or lanthanum chloride solution at a temperature between about 30° C. and about 90° C. 
     
     
         11 . The pharmaceutical composition according to  claim 10 , wherein the carbonate solution is mixed with the lanthanum acetate or lanthanum chloride solution at a temperature of 80° C. 
     
     
         12 . The pharmaceutical composition according to  claim 10 , wherein the filter cake is dried at a temperature between about 400° C. and about 700° C. 
     
     
         13 . The pharmaceutical composition according to  claim 1 , wherein the La 2 O 2 CO 3  compound and the vehicle or diluent are formulated to provide an orally ingestible form. 
     
     
         14 . The pharmaceutical composition according to  claim 13 , wherein the orally ingestible form is selected from the group consisting of liquid solution, liquid suspension, tablet, capsule, and gelcap. 
     
     
         15 . The pharmaceutical composition of  claim 1 , wherein the pharmaceutically acceptable vehicle or diluent is cellulose or carboxymethyl cellulose.