HK1111893B - Sachet formulation for amine polymers - Google Patents

Description

BACKGROUND OF THE INVENTION

Aliphatic amine polymers are effective as phosphate binders and have been described for the treatment of various conditions {see U.S. Patent Nos. 5,496,545 and 5,667,775 ). For example, sevelamer hydrochloride, a crosslinked poly(allylamine) polymer, is currently sold under the trademark of RENAGEL^® for removing phosphate from patients. Aliphatic amine polymers have also been described for the treatment of hypercholesterolemia {see U.S. Patent Nos. 5,624,963 and 5,679,717 and PCT Publication Nos. WO 98/29107 and WO 99/22721 ). For example, colesevelam, an alkylated, crosslinked poly(allylamine), is currently sold under the trademark of WELCHOL^® for reducing serum cholesterol.

However, as the above products are currently available only as tablets, certain patient groups may benefit from the availability of these products in other dosage forms.

International patent publication WO 2005/065291 (Genzyme Corp.) describes tablets, capsules, sachets, or papers having one or more aliphatic amine polymers which allow for the targeted release of the polymers at a specific region of the gastrointestinal tract, especially the small intestine. These tablets, capsules, sachets, or papers are useful in a method for lowering cholesterol in a mammal in need thereof. The tablet includes a tablet core having an aliphatic amine polymer, and an enteric coating for the core. The capsule, sachet or paper includes a plurality of beads where the beads have a bead core having an aliphatic amine polymer, an enteric coating therefor and optionally a water-soluble coating.

United States patent US 4172120 (Todd et al. ) describes a solid pharmaceutical composition comprising anhydrous cholestyramine, 0.6 to 1.7 parts by weight of low viscosity grade alginic acid/sodium alginate per weight of cholestyramine, the low viscosity grade alginic acid/sodium alginate having 0 to 75% of the acid groups neutralized, 0.1 to 0.3 parts by weight of citric acid per weight of sodium alginate, and sufficient sodium carbonate or bicarbonate mixtures thereof to neutralize the acid groups of the alginic and citric acids. The compositions may be used in the treatment of conditions associated with duodeno-gastric reflux of bile into the stomach.

United States patent publication US 2002/155091 (Huval et al. ) describes methods for treating hypercholesterolemia and atherosclerosis, and reducing serum cholesterol in a mammal. The methods comprise administering to a mammal a first amount of a bile acid sequestrant compound which is an unsubstituted polydiallylamine polymer and a second amount of a cholesterol-lowering agent. The first and second amounts together comprise a therapeutically effective amount. The invention further relates to pharmaceutical compositions useful for the treatment of hypercholesterolemia and atherosclerosis, and for reducing serum cholesterol. The pharmaceutical compositions comprise a combination of a first amount of an unsubstituted polydiallylamine polymer compound and a second amount of a cholesterol-lowering agent. The first and second amounts comprise a therapeutically effective amount. The pharmaceutical compositions may optionally contain a pharmaceutically acceptable carrier.

United States patent US 4439419 (Vecchio ) describes the new use of a known polymeric material for the neutralizing of gastric acidity and treating hyperacidity in humans having an excess of gastric acidity and the treatment of ulcers. The polymeric material is a copolymer of polyethylenepolyamine and a bifunctional substance. Oral pharmaceutical dosage forms and doses are shown.

United States patent US 5607669 (Mandeville et al. ) describes an amine polymer which includes first and second substituents bound to amines of the polymer. The first substituent includes a hydrophobic moiety. The second substituent includes a quaternary amine-containing moiety. A method for binding bile salts of bile acids in a mammal includes orally administering to the mammal a therapeutically-effective amount of the amine polymer.

International patent publication WO 2006050314 (Genzyme Corp.) describes a method for reducing serum phosphate in a subject in need thereof comprising administering once per day to said subject a phosphate binder, wherein the phosphate binder has a phosphate binding capacity of at least 52 mmole.

SUMMARY OF THE INVENTION

The present invention provides for, inter alia, new compositions and formulations of aliphatic amine polymers. One such formulation is a powder formulation that can be mixed with water and administered orally as a drink (solution or suspension), while providing acceptable properties to the patient such as mouth feel and taste. Applicants have found that in such formulations, a pharmaceutically acceptable anionic polymer, referred to herein as a "stabilizer", when mixed with the aliphatic amine polymer, can provide acceptable mouth-feel of an aliphatic amine polymer. Based on this discovery, a novel powder formulation for aliphatic amine polymer or a pharmaceutically acceptable salt thereof, a container containing the powder formulation and a method of treating a subject having hyperphosphatemia with the powder formulation are disclosed herein.

Accordingly, in its broadest sense, the present invention provided a powder composition as claimed in claim 1. The dependent claims set out features of certain preferred embodiments.

In one aspect, provided is a powder that comprises a pharmaceutically acceptable anionic stabilizer and an aliphatic amine polymer or a pharmaceutically acceptable salt thereof mixed with the anionic stabilizer. The powder is uncapsulated and free-flowing.

In another aspect, provided is a powder formulation comprising a pharmaceutically acceptable anionic stabilizer and an aliphatic amine polymer or a pharmaceutically acceptable salt thereof mixed with the pharmaceutically acceptable anionic stabilizer. Preferably, the only pharmaceutically active ingredient in the powder is the aliphatic amine polymer.

We also describe a method of treating a subject with hyperphosphatemia. The method comprises the step of orally administering to the subject the disclosed powder formulation.

DETAILED DESCRIPTION OF THE INVENTION

The disclosed powder formulation comprises an aliphatic amine polymer and a pharmaceutically acceptable anionic stabilizer formulated so as to provide an acceptable mouth-feel. The powder formulation is typically dissolved and/or suspended in an ingestible liquid such as water and therefore can be conveniently administered to a patient as a drink. The drink can be even more palatable with one or more sweeteners and/or flavorants. Such powder formulations may be conveniently packaged in a container, such as a sachet or tub. As used herein, the terms "powder" and "powder formulation" are used interchangeably.

The powder formulations of the present invention may further comprise flavorants, sweeteners, excipients, fillers, inert ingredients and the like.

As used herein, "a pharmaceutically acceptable anionic stabilizer" is a compound which comprises an acid functional group (e.g., a carboxylic acid, sulfonic acid, phosphonic acid and the like, or a pharmaceutically acceptable salt thereof), and may substantially improve the mouth-feel of aliphatic amine polymers. The acid functional group is optionally neutralized with one or more pharmaceutically acceptable organic or inorganic bases to form a pharmaceutically acceptable salt. When the pharmaceutically acceptable anionic stabilizer includes more than one acid functional group, the acid functional groups can be partially or completely neutralized. Optionally, some of the acid functional groups can be esterified to form an ester of the acid functional group. Examples of organic or inorganic bases are as described below.

The pharmaceutically acceptable anionic stabilizer typically has a solubility in water of greater than 1 mg/ml and a pKa value less than 9. The pharmaceutically acceptable anionic stabilizer should not interfere with the therapeutic activity of the aliphatic amine polymers, and should not cause unacceptable side effects at the dosages which are being administered.

The molecular weight of the pharmaceutically acceptable anionic stabilizer is not critical in the present invention as long as it has the features described above. Typically, the molecular weight of the pharmaceutically acceptable anionic stabilizer is greater than 1000 daltons. When the molecular weight of the pharmaceutically acceptable anionic stabilizer is greater than 1000 daltons, the charge density of the pharmaceutically acceptable anionic stabilizer is typically equal to or greater than 1 every 1000 daltons.

The pharmaceutically acceptable anionic stabilizer may not be a "pharmaceutically active ingredient".

In one embodiment, the pharmaceutically acceptable anionic stabilizer is an anionic polymer.

The anionic polymer is a C2-C5-diol ester of alginate or a C3-C5-triol ester of alginate. As used herein, an "esterified alginate" means an alginic acid in which some of the carboxyl groups of the alginic acid are esterified. The remainder of the carboxylic acid groups are optionally neutralized (partially or completely) as pharmaceutically acceptable salts. For example, propylene glycol alginate is an ester of alginic acid in which some of the carboxyl groups are esterified with propylene glycol, and the remainder of the carboxylic acid groups are optionally neutralized (partially or completely) as pharmaceutically acceptable salts. More preferably, the anionic polymer is ethylene glycol alginate, propylene glycol alginate or glycerol alginate. Propylene glycol alginate is even more preferred.

As noted above, the anionic polymer can be used in the form of a pharmaceutically acceptable salt (completely or partially neutralized). As used herein, a "pharmaceutically acceptable salt" refers to a salt prepared from pharmaceutically acceptable acids or bases. For example, the anionic polymers that possess a sufficiently acidic functional group can react with any of a number of pharmaceutically acceptable organic or inorganic bases to form a salt: Examples of salts include alkali metal and alkali earth metals, such as sodium, calcium, magnesium and potassium; zinc; and ammonium salts. Mixed salts are also included. "Ammonium" can be represented as NR'4 + where R' is -H or substituted or unsubstituted, linear or cyclic, or saturated or unsaturated alkyl, aryl or araryl. Examples of the ammonium include NH₄ ⁺ and N(R')H₃ ⁺, N(R')₂H₂ ⁺, N(R')₃H⁺ and N(R')₄ ⁺ R' is C1-C10 alkyl or phenyl.

In another embodiment, the pharmaceutically acceptable anionic stabilizer is an anionic polypeptide, including a protein. Examples of anionic polypeptides include gelatin, casein digest, whey protein, soy protein and polyglutamic acid.

One or more pharmaceutically acceptable anionic stabilizers can be used in the present invention.

The powder formulations of the invention typically include the pharmaceutically acceptable anionic stabilizer and aliphatic amine polymer in a ratio of 0.005-99.9:1 by weight, such as 0.005-50:1, 0.005-10:1; 0.005-3:1, 0.005-1:1, 0.005-0.05:1, and 0.008-0.05:1.

The aliphatic amine polymer is a carbonate salt of sevelamer; a mixed carbonate and bicarbonate salt of sevelamer; or a mixed carbonate and chloride salt of sevelamer.

In other embodiments, a monovalent anionic source is mixed with the carbonate salt of sevelamer. Various examples of carbonate salts of the aliphatic amine polymer and monovalent anionic sources are disclosed in U.S. Provisional Application No. 60/624,001 "Aliphatic Amine Polymer Salts For Tableting" filed November 1, 2004 and U.S. Provisional Application No. 60/628',752 "Aliphatic Amine Polymer Salts For Tableting" filed November 17,2004, the entire contents of which are incorporated herein by reference.

The monovalent anion comprises at least 0.01 %, preferably 0.05%, more preferably a range of 0.01 % to 2%, 0.05% to 1 %,0.08 % to 0.5%, or 0.1 % to 0.3% by I weight of the combined weights of the carbonate salt of aliphatic amine polymer and the monovalent anion source.

Examples of suitable monovalent anions include organic ions, inorganic ions, or a combination thereof, such as halides (Cl^-, I^-, F^-, Br^-), CH₃ OSO₃ ^-, HSO₄ ^-, acetate, lactate, butyrate, propionate, sulphate, citrate, tartrate, nitrate, sulfonate, oxalate, succinate or palmoate. Preferred monovalent anions are halides; most preferably chloride.

Also, the monovalent anion source can be a pharmaceutically acceptable acid, ammonium or metal salt of a monovalent anion. Preferably the monovalent anion source is sodium chloride or hydrochloric acid. In one preferred embodiment, the formulations of the invention comprise a carbonate salt of sevelamer and sodium chloride. In another preferred embodiment, the formulations of the invention comprise a carbonate salt of sevelamer and hydrochloric acid.

In yet another preferred embodiment, the monovalent anion source can be a monovalent anion salt of the aliphatic amine polymer. The formulations of the invention can comprise a "physically mixed polymer" or a "chemically mixed polymer". The combination of a carbonate salt of an aliphatic amine polymer and a monovalent anion salt of an aliphatic amine polymer is defined herein as a "physically mixed polymer". The monovalent anion salt of the aliphatic amine polymer can be the same or a different aliphatic amine polymer as the aliphatic amine polymer carbonate salt. Herein, a "chemically mixed polymer" means the combination of a carbonate salt and a monovalent anion salt on a single aliphatic amine polymer.

In some embodiments, the aliphatic amine polymer or pharmaceutically acceptable salt thereof is the only pharmaceutically active ingredient in the powder formulations.

The powder formulations of the invention for use in a subject comprise the aliphatic amine polymer and the pharmaceutically acceptable anionic stabilizer(s), optionally together with one or more acceptable excipients therefor. The excipients include carriers or diluents, such as lactose, starch, cellulose and dextrose; flavoring agents; sweeteners; and preservatives, such as methyl, ethyl, propyl and butyl parabens. Optionally, for a good appearance, excipients, such as microcrystalline cellulose, titanium dioxide, and/or coloring agents, such as FD&C Blue #1, FD&C Red #40, D&C Yellow #10, D&C Red #33, or yellow iron oxide, can also be included in the powder formulations of the invention. Examples of suitable sweeteners -include sucrose; glucose (com syrup); dextrose; invert sugar; fructose; saccharin and its various salts, such as sodium saccharinate; sodium, aspartame, xylose; maltitol; maltol; potassium acesulfame; neohesperidin dihydrochalcone; monoammonium glycyrrhizinate; maltodextrin and polydextrose saccharin and its various salts such as the sodium and calcium salts; cyclamic acid and its various salts; dipeptide sweeteners; sucralose; dihydrochalcone; glycyrrhin; Stevia rebaudiana (Stevioside); sorbitol; mannitol; xylitol; hexa-resorcinol; hydrogenated starch hydrolysate (Iycasin), and the potassium, calcium and sodium salts of 3,6-dihydro-6-methyl-1-1,2,3-oxathiazin-4-on3-2,2-dioxide, and a mixture of thereof. Of the foregoing, sucralose, sucrose, xylose, mannitol, maltitol, maltol, sorbitol or xylitol is particularly preferred, either alone or more desirably in combination. Suitable flavorings include grape, cherry, peppermint, menthol and vanilla flavors, such as orange vanilla flavor, lemon flavor, spearmint, wintergreen, cinnamon, menthone flavors, or a mixture thereof. The excipients must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

Typically, the average particle size of the powder of the invention is less than 500 microns, preferably less than 200 microns. In some embodiments, the powder contains less than 5 wt %, preferably less than 2 wt%, more preferably less than 1 wt%, of particles having a particle size more than 300 microns and less than 5 wt%, preferably less than 2 wt%, more preferably less than 1 wt%, of particles having a particle size less than 10 microns.

The disclosed powder formulation is typically dissolved and/or suspended in an ingestible liquid such as water. The resulting mixture has a pleasant mouth-feel and therefore can be conveniently administered to a patient as a drink. The drink can be a suspension or solution. The drink can be even more palatable with one or more sweeteners and/or flavorants. Alternatively, the disclosed powder formulation can be mixed with foods, such as mashed potatoes or oatmeal.

The powder formulations of the invention can be conveniently packaged in a container. Herein, a "container" is a non-ingestible containment device which can hold and preserve the stability of the powder formulation of the invention for a sufficient period of time, i.e., from the time of manufacture to the time of consumption by patients. As noted above, the powder formulation is uncapsulated and free-flowing. Containers suitable for the present invention include a sachet, such as a paper bag, powder bag of plastic films or metal foils; a bottle, such as a glass, plastic or metal bottle; a tub; and an ampule. Preferably, the container of the invention is a sachet. The container material is preferably impermeable to water and water vapor in order that the stability of the active agent contained in the container is ensured. Optionally, the container materials can contain substances which impart a particular type of protection, for example protection against light, to the contents. Examples of suitable container materials include plastics, such as MATT LACQUER/PET 23 µ/PX 12GR/AL 12 µ/SURLYN 23 GR (AMCOR Flexibles in Victoria, Australia), coated papers, such as Coated Paper 40GR/PX 12 GR/AL 12 µ/SURLYN 23 GR (AMCOR Flexibles in Victoria, Australia), foil pouches, such as TPC-2475 (TOLAS Health Care Packaging in Feasterville, PA), and a combination of these materials (e.g., laminates).

Preferably, the container is a multi-layer container having multiple layers of different container materials discussed above.

The container containing the powder formulation of the invention can be a unit-dose or a multi-dose container. For example, the container of the invention can contain a single dose of the aliphatic amine polymer mixed with the pharmaceutically acceptable anionic stabilizer, such as a single-dose sachet. Alternatively, the container of the invention can contain at least two doses of the aliphatic amine polymer mixed with the pharmaceutically acceptable anionic stabilizer, such as a bottle or tub with the powder formulation from which a unit dose is measured by, e.g., a spoon or cup, or an instrument capable of dispensing a pre-defined dosage amount. Herein, a "tub" means a container containing a bulk quantity of the powder formulation. A "bulk quantity" means an amount out of which a plurality of unit doses can be divided, e.g., 2,10, 50, 100 or more unit doses.

The powder formulations of the invention can be prepared by any of the methods known in the art of pharmacy. For example, standard pharmaceutical formulation techniques such as those described in Remington's Pharmaceutical Sciences, 18th ed. (1990), Mack Publishing Company, Easton, PA. can be used. Typically, the methods include the steps of mixing at least one aliphatic amine polymer with one or more pharmaceutically acceptable anionic stabilizers, and bringing into association the resulting mixture with any additional excipients. In general, the formulations are prepared by uniformly and intimately bringing the aliphatic amine polymer into association with the pharmaceutically acceptable anionic stabilizers and then, if necessary, dividing the product into unit dosages thereof. The powder formulation is then packaged within a suitable container, such as a sachet.

Typically, the container holds a unit dose which is generally about 5 mg to about 15 g (e.g., 600 mg-7.5g, 600 mg-5g, 800 mg-3.5 g and 800 mg-2.5 g) of the aliphatic amine polymer on an anhydrous basis if administered once a day. Typically, about 0.025 mg to about to about 14.9 g (e.g., 3 mg-7.5g; 3 mg-5g; 8 mg-3.5g; 8 mg-2.5 g; 6 mg-2.5 g, 6 mg-1.5 g, 6 mg-0.75g) of a pharmaceutically acceptable anionic stabilizer is included in the unit dose together with the aliphatic amine polymer. Alternatively, the container holds a unit dose which is generally the daily dosage divided by the number of administration per day if administered multiple times per day (e.g., 2, 3, 4, or 5 times/day). In one example, a sachet contains either 800 mg, 1.6g, 2.4 g, 3.2 g, 4.0g, 4.8g, 5.6g, 7.2 g or 9.6g of sevelamer on an anhydrous basis, and further contains propylene glycol alginate and optional excipients, such as sucrose, xylose, mannitol, maltitol, maltol, sodium chloride, yellow iron oxide, orange vanilla flavor and lemon flavor mixed with sevelamer.

The powder formulation may be introduced by a patient into a suitable amount of liquid, preferably water, to form a therapeutic formulation in situ, and the therapeutic formulation is then taken by the patient. The therapeutic formulation can be an aqueous-based therapeutic formulation or a non-aqueous formulation, preferably aqueous-based formulation, in which the aliphatic amine polymer and anionic stabilizer are each independently dissolved or suspended. Aqueous-based therapeutic formulations can be formed by adding the powder formulation within a container into a suitable aqueous vehicle, such as water, before administration. Non-aqueous therapeutic formulations can be obtained by dispersing in a suitable non-aqueous based vehicle, such as almond oil, arachis oil, soyabean oil, fractionated coconut oil, olive oil, poppy-seed oil or maize oil before administration. Alternatively, the powder formulations of the invention may be administered by a patient via direct ingestion. That is, a unit dose of the powder is administered directly into a mouth of the patient and then swallowed, preferably with the aid of water or any other ingestible liquid. Optionally, the powder formulations of the invention may be administered by a patient as a mixture with foods.

The powder formulations of the invention can be used for treating hyperphospatemia in a subject. Hyperphosphatemia is typically defined for humans as a serum phosphate level of greater than about 4.5 mg/dL. The condition, especially if present over extended periods of time, leads to severe abnormalities in calcium and phosphorus metabolism and can be manifested by aberrant calcification in joints, lungs and eyes. Elevated serum phosphate is commonly present in patients with renal insufficiency, hypoparathyroidism, pseudohypoparathyroidism, acute untreated acromegaly, overmedication with phosphate salts, and acute tissue destruction as occurs during rhabdomyolysis and treatment of malignancies.

As used herein a subject is a mammal, preferably a human, but can also be an animal in need of veterinary treatment, such as a companion animal (e.g., dogs, cats, and the like), a farm animal (e.g., cows, sheep, pigs, horses, and the like) or a laboratory animal (e.g., rats, mice, guinea pigs, and the like). A subject "in need of treatment" includes a subject with chronic renal failure. Other examples of subjects in need of treatment include patients with a disease associated with disorders of phosphate metabolism. Examples of diseases and/or disorders of this type include hyperparathyroidism, inadequate renal function, and hyperphosphatemia.

An "effective amount" of an aliphatic amine polymer is a quantity that results in a beneficial clinical outcome of or exerts an influence on, the condition being treated with the aliphatic amine polymer compared with the absence of treatment. The amount of an aliphatic amine polymer administered to the subject will depend on the degree, severity, and type of the disease or condition, the amount of therapy desired, and the release characteristics of the pharmaceutical formulation. It will also depend on the subject's health, size, weight, age, sex and tolerance to drugs. Typically, the composition of the invention is administered for a sufficient period of time to achieve the desired therapeutic effect. Typically between about 5 mg per day and about 15 g per day of an aliphatic amine polymer (alternatively between about 50 mg per day and about 10 g per day, alternatively between about 1 g per day and about 10 g per day, alternatively between about 1 g per day and about 8 g per day, alternatively between about 2 g per day and about 8 g per day, alternatively between about 4 g per day and about 8 g per day) is administered to the subject in need of treatment. These dosages can be administered several times/day (e.g., 2, 3,4 or 5 times/day) or once/day. The aliphatic amine polymer can be administered at least four times per day with meals, at least three times per day with meals, at least twice per day with meals, at least once per day with meals, (see US Provisional Application No. 60/623,985 , "Once a day formulation for phosphate binders" filed November 1,2004, the entire contents of which are incorporated herein by reference). In one specific example, about 0.8-7.2 g (e.g., 2.4 g or 3.2 g per dose for 2-3 times per day, or 4.0 or 4.8 g per dose for 2-3 times per day, or 7.2 g per dose for once per day) of the aliphatic amine polymer is administered per day.

Typically, the formulations of the invention can be administered before or after a meal, or with a meal. As used herein, "before" or "after" a meal is typically within two hours, preferably within one hour, more preferably within thirty minutes, most preferably within ten minutes of commencing or finishing a meal, respectively.

The method includes a mono-therapy where the powder formulations of the invention are used alone. The method also includes a co-therapy with other therapeutically active drugs. For example, the method can be used with other phosphate binders including pharmaceutically acceptable lanthanum, calcium, aluminum and iron salts, such as acetates, carbonates, oxides, hydroxides, citrates, alginates, and ketoacids. Calcium salts, including calcium carbonate, acetate (such as PhosLo® calcium acetate tablets), citrate, alginate, and ketoacids, have been utilized for phosphate binding. The ingested calcium combines with phosphate to form insoluble calcium phosphate salts such as Ca₃(PO₄)₂, CaHPO₄, or Ca(H₂PO₄)₂. Aluminium-based phosphate binders, such as Amphojel® aluminium hydroxide gel, have also been used for treating hyperphosphatemia. These compounds complex with intestinal phosphate to form highly insoluble aluminium phosphate; the bound phosphate is unavailable for absorption by the patient. More recently iron and lanthanide salts have been used. The most commonly used lanthanide salt, lanthanum carbonate (Fosrenol®) behaves similarly to calcium carbonate.

Those skilled in the art will be aware that the amounts of the various components of the formulations of the invention to be administered in accordance with the method of the invention to a subject will depend upon those factors noted above.

The invention is illustrated by the following examples.

EXEMPLIFICATION Example 1. Compositions of powder formulations of the invention

The powder formulations were prepared by standard pharmaceutical formulation techniques such as those described in Remington's Pharmaceutical Sciences, 18th ed. (1990), Mack Publishing Company, Easton, PA. Specific compositions of two exemplary powder formulations (Formulas A and B) of the invention are summarized in Table 1 below: Table 1. Compositions of the powder formulations

Ingredient
Anhydrous Sevelemer HCl		92.90
Anhydrous Sevelemer carbonate	94.97
PGA	1.00	3.00
Orange Vanilla PR90	2.00	2.00
WG55 Vanilla	0.50	0.50
Lemon Lime	0.11	0.12
NaCl	1.00	1.00
Sucralose	0.40	0.45
Yellow iron oxide	0.016	0.016

Claims (23)

1. A pharmaceutically active powder composition comprising:

   a) a pharmaceutically acceptable anionic polymer stabilizer comprising a C₂-C₅-diol ester of alginate or a C₃-C₅-triol ester of alginate; and

   b) a pharmaceutically active aliphatic polyallylamine polymer crosslinked with a difunctional cross-linking agent or a pharmaceutically acceptable salt thereof mixed with the anionic polymer stabilizer, characterised in that said crosslinked polymer is a carbonate salt of sevelamer.
2. The powder of claim 1, wherein the anionic polymer stabilizer is selected from the group consisting of ethylene glycol alginate, propylene glycol alginate and glycerol alginate.
3. The powder of claim 1 or 2, wherein the only pharmaceutically active ingredient in the powder is the sevelamercarbonate.
4. The powder of any preceding claim, wherein the anionic polymer stabilizer is propylene glycol alginate.
5. The powder of any preceding claim, further comprising a pharmaceutically acceptable sweetener comprising at least one member selected from the group consisting of sucralose, sucrose, xylose, mannitol, maltitol, maltol, sorbitol and xylitol.
6. The powder of any preceding claim, wherein the powder further comprises a pharmaceutically acceptable monovalent inorganic anion source comprising sodium chloride.
7. The powder of any preceding claim, wherein the powder further comprises yellow iron oxide.
8. The powder of any preceding claim, wherein the powder further comprises a pharmaceutically acceptable flavorant.
9. The powder of any preceding claim, wherein the powder further comprises a flavorant comprising a lemon flavor.
10. The powder of any preceding claim, wherein the powder is uncapsulated and free-flowing, and contains less than 5 wt% of particles having a particle size more than 300 micrometers (microns) and less than 5 wt% of particles having a particle size less than 10 micrometers (microns).
11. The powder of any preceding claim, wherein the powder is packaged in a container, comprising:

    a) a sachet, or

    b) a tub.
12. The powder of claim 11, wherein the container holds from 5 mg to 15 g of the sevelamer carbonate, the amount of the sevelamer carbonate being on an anhydrous basis.
13. The powder of claim 11, wherein the powder comprises:

    a) 800 mg or 2.4 g of sevelamer carbonate on an anhydrous basis; and

    b) the anionic polymer stabilizer is propylene glycol alginate;

    wherein the only pharmaceutically active ingredient in the powder is the sevelamer carbonate, and wherein the ratio of the propylene glycol alginate to the sevelamer carbonate is 0.005 - 1:1.
14. The powder of claim 11, wherein the container is a sachet.
15. The powder of claim 1, wherein the pharmaceutically acceptable anionic polymer stabilizer is propylene glycol alginate, the pharmaceutically active aliphatic ingredient is sevelamer carbonate and optionally the powder further comprises one or more ingredients selected from:

    a) monovalent anion source comprising sodium chloride;

    b) flavoring agents, comprising orange, vanilla and lemon flavors;

    c) sweeteners, comprising sucralose; and

    d) coloring agents, comprising yellow iron oxide.
16. A pharmaceutically active liquid or powder formulation that comprises the powder of any preceding claim for use in the treatment of a subject with hyperphosphatemia by orally administering to the subject an effective amount thereof.
17. The formulation for use of claim 16 wherein the formulation is a liquid formulation comprising the powder of any one of claims 1 to 15 being dissolved or suspended therein.
18. A container containing the powder of any one of claims 1-10 or 15.
19. A sachet containing the powder of any one of claims 1-10 or 15.
20. The sachet of claim 19, wherein the powder comprises 800 mg of sevelamer carbonate on an anhydrous basis.
21. The sachet of claim 19, wherein the pharmaceutically acceptable anionic polymer stabilizer is propylene glycol alginate.
22. The sachet of claim 21, wherein the ratio of the propylene glycol alginate to the sevelamer carbonate is 0.005-1:1.
23. The sachet of claim 21, wherein the powder further comprises one or more ingredients selected from:

    a) monovalent anion source comprising sodium chloride;

    b) flavoring agents, comprising orange, vanilla and lemon flavors;

    c) sweeteners, comprising sucralose; and

    d) coloring agents, comprising yellow iron oxide.