Lanthanum carbonate hydroxide, lanthanum oxycarbonate and methods of their manufacture and use
Inventors
Gore, Ashok Yeshwant • Schauer, Edward A. • Stewart, Matthew • Singh, Ramsharan
Assignees
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Publication Number
US-8961917-B2
Publication Date
2015-02-24
Expiration Date
Abstract
The present invention is a method of producing a lanthanum carbonate hydroxide or lanthanum oxycarbonate which has improved properties. The method involves the use of a water soluble lanthanum and a water soluble non-alkali metal carbonate or bicarbonate. The resulting material can be used as a phosphate binder individually or for treating patients with hyperphosphatemia.
Core Innovation
The invention relates to a method of producing a lanthanum carbonate compound by reacting a soluble salt of lanthanum chloride with ammonium carbonate in a solvent at a reaction temperature from between about 75 degrees C. to about 90 degrees C. and at a pH of from about 6.0 to 7.5. The reaction product is precipitated as lanthanum carbonate hydroxide that includes about 0.5% by weight or less of sodium.
The invention further includes converting lanthanum carbonate hydroxide to lanthanum dioxycarbonate by calcining the reaction product at about 400 degrees C. to about 700 degrees C. for at least two hours, producing lanthanum oxycarbonate/lanthanum dioxycarbonate (LDOC). The produced LDOC includes polymorphs of La2O2CO3 as a major component and La2CO5 as a limited component, while maintaining low sodium/alkali content.
The disclosure emphasizes low sodium/alkali-metal content in the lanthanum carbonate hydroxide and the LDOC, and provides characterization support including PXRD polymorph control and a PXRD pattern matching ICDD card 26-815. Comparative property improvements include higher BET surface area, improved porosity/pore volume, and improved phosphate binding kinetics under higher pH conditions.
Claims Coverage
The claims cover low-sodium lanthanum carbonate hydroxide precipitation under defined temperature and pH using lanthanum chloride and ammonium carbonate, with optional conversion to lanthanum dioxycarbonate and limits on sodium and polymorph composition. Four inventive features are identified across the independent claim and dependent refinements.
Low-sodium lanthanum carbonate hydroxide precipitation from lanthanum chloride and ammonium carbonate
Reacting a soluble salt of lanthanum chloride with ammonium carbonate in a solvent at a reaction temperature from between about 75 degrees C. to about 90 degrees C. and at a pH of from about 6.0 to 7.5, and precipitating the reaction product as lanthanum carbonate hydroxide including about 0.5% by weight or less of sodium.
IcdD pattern matching of lanthanum carbonate hydroxide
Producing lanthanum carbonate hydroxide that includes a diffraction/pattern matching ICDD card 26-815.
Optional calcination to form lanthanum dioxycarbonate with polymorph and sodium constraints
Calcining the reaction product at about 400 degrees C. to about 700 degrees C. for at least two hours to produce lanthanum dioxycarbonate including polymorphs of La2O2CO3 and La2CO5, and including about 0.75 wt% or less of sodium.
Polymorph fraction limiting for La2CO5 in lanthanum dioxycarbonate
Producing lanthanum dioxycarbonate containing no more than about 5% by weight of the polymorph of formula La2CO5.
The claims focus on producing low-sodium lanthanum carbonate hydroxide by precipitation under defined conditions, optionally verifying the product by ICDD pattern matching, and converting it by calcination to lanthanum dioxycarbonate with controlled polymorph composition and tightened sodium limits.
Stated Advantages
Higher BET surface area.
Higher porosity and pore volume.
Improved phosphate binding kinetics at higher pH conditions, including intestine-like pH ~6.5.
Lower sodium/alkali-metal content in the lanthanum carbonate hydroxide and LDOC versus embodiments using sodium carbonate.
Documented Applications
Phosphate binding for conditions involving hyperphosphatemia, including chronic kidney disease (CKD)-related high phosphate.
Pharmaceutical compositions and dosage forms including tablets, chewables, suspensions, and sprinkle powders containing the lanthanum carbonate compound or phosphate binder.
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