Proton-binding polymers for oral administration

Abstract

To provide a pharmaceutical composition useful for treating metabolic acidosis.SOLUTION: A pharmaceutical composition includes proton-binding crosslinked amine polymers including an amine residue corresponding to formula 1, where the crosslinked amine polymer has (i) at least 5 mmol / g of equilibrium proton binding ability and at least 5 mmol / g of chloride ion binding ability in aqueous simulated gastric juice buffer fluid (SGF) of 37°C containing 35 mM NaCl and 63 mM HCl at pH 1.2, and (ii) an equilibrium swelling ratio of approximately 2 or less than 2 in deionized water. (In the formula, R1, R2 and R3 denote independently hydrogen, hydrocarbyl or substituted hydrocarbyl. Note that at least one of R1, R2 and R3 is one other than hydrogen).SELECTED DRAWING: None

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Application No. 61 / 831,445, filed June 5, 2013, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates generally to orally administered proton-binding polymers that may be used to treat metabolic acidosis.

[0003] Metabolic acidosis occurs in various disease states when non-volatile acids accumulate in the body and cause the loss of protons (H + ) or hydrogen carbonate (HCO3 - Metabolic acidosis results from metabolic and dietary processes that result in the loss of filtered bicarbonate (HCO3 -This is often accompanied by metabolic acidosis, due to a decreased ability of the kidneys to excrete hydrogen ions, resulting in loss of ability to reabsorb calcium, synthesize ammonia, and excrete titratable acids. Clinical practice guidelines recommend initiating alkali therapy in patients with nondialysis-dependent chronic kidney disease (CKD) when serum bicarbonate levels fall below 22 mEq / L to prevent or treat complications of metabolic acidosis. (Clinical practice guidelines for nutrition in chronic renal failure, K / DOQI, National Kidney Foundation, Am. J. Kidney Dis. 2000; 35:S1-140; Raphael, KL, Zhang, Y, Wei, G, et al. 2013, Serum bicarbonate and mortality in adults in NHANES III, Nephrol. Dial. Transplant 28: 1207-1213). These complications include malnutrition and growth retardation in children, exacerbation of bone disease, increased muscle breakdown, decreased albumin synthesis and increased inflammation.(Leman, J, Litzow, JR, Lennon, EJ. 1966. The effects of chronic acid loads in normal man: further evidence for the participation of bone mineral in the defense against chronic metabolic acidosis, J. Clin. Invest. 45: 1608-1614; Franch, WE, Catch WE, 1998, in 1998). uremia: the impact of metabolic acidosis, J. Am. Farwell, WR, Taylor, EN, 2010, Serum anion gap, bicarbonate and biomarkers of inflammation in healthy individuals in a national survey, CMAJ 182:137-141). 2Below this level, the majority of patients develop overt metabolic acidosis. (KDOQI bone guidelines: American Journal of Kidney Diseases (2003) 42:S1-S201. (suppl); Widmer B, Gerhardt RE, Harrington JT, Cohen JJ, Serum electrolyte and acid base composition: The influence of graded degrees of chronic renal failure, Arch Intern Med139:1099-1102, 1979; Dobre M, Yang, W, Chen J, et. al., Association of serum bicarbonate with risk of renal and cardiovascular outcomes in CKD: a report from the chronic renal insufficiency cohort (CRIC) study. Am. J. Kidney Dis. 62: 670-678, 2013; Yaqoob, MM. Acidosis and progression of chronic kidney disease. Curr. Opin. Nephrol. Hypertens. 19: 489-492, 2010).

[0004] Metabolic acidosis, regardless of etiology, reduces extracellular fluid bicarbonate and therefore extracellular pH. The correlation between serum pH and serum bicarbonate is based on the Henderson-Hasselbalch equation: pH = pK' + log [HCO3 - ] / [(0.03×Paco2)] [Where 0.03 is the physical solubility coefficient of CO2 and [HCO3 - ] and PaCO2 are the bicarbonate concentration and carbon dioxide partial pressure, respectively.] As shown by:

[0005] There are several laboratory tests that can be used to determine metabolic acidosis. The tests basically measure the amount of bicarbonate (HCO3 - ) or proton (H + ) concentration is measured.

[0006] The most useful measurements for determining acidosis are venous plasma bicarbonate (or total carbon dioxide [tCO2]), serum electrolytes, and Cl. - , K + and Na + In the clinical laboratory, the measurement of venous plasma or serum electrolytes includes an estimation of tCO2. This measurement is based on the total circulating CO2 [i.e., bicarbonate (HCO3 - ), carbonate (H2CO3) and dissolved CO2 (0.03 × Pco2) reflects total CO2. tCO2 can also be calculated using the Henderson-Hasselbalch equation: tCO2 = HCO3 - +0.03PCO2 (where PCO2 is the measured CO2 partial pressure) to obtain the HCO3 - It can also be related to HCO3 - Venous tCO2 is often greater than venous HCO3 in blood because its concentration is greater than 90% of tCO2 and there is a small amount of H2CO3 present. - It is used as a reasonable approximation of the concentration of abnormal plasma HCO3, especially in chronic kidney disease. - Values ​​below 24-26 mEq / L generally indicate metabolic acidosis.

[0007] Serum Cl - Changes in concentration, especially serum Na + Changes in concentration and imbalances can give rise to further consideration of a possible acid-base disorder. When this occurs, serum Cl - Changes in serum Cl are typically associated with reciprocal changes in serum bicarbonate. Thus, in normal anion gap metabolic acidosis, serum Cl - increases to more than 105 mEq / L and serum bicarbonate decreases to less than 24-26 mEq / L.

[0008] Anion gap [serum Na + -(Cl - +HCO3 - Calculation of metabolic acidosis (defined as the anion gap) is an important aspect of the diagnosis of metabolic acidosis. Metabolic acidosis can be present with a normal or high anion gap. However, a high anion gap is generally associated with a high serum HCO3 - indicates the presence of metabolic acidosis, regardless of changes in blood glucose level. An anion gap of more than 20 mEq / L (normal anion gap is 8-12 mEq / L) is a typical characteristic of metabolic acidosis.

[0009] Arterial blood gases are used to identify the type of acid-base disorder and to determine whether mixed imbalance is present. In general, arterial blood gas results must be reconciled with the medical history, physical examination, and the routine laboratory values ​​listed above. Arterial blood gases are used to measure arterial carbon dioxide tension (P a CO2), acidity (pH) and oxygen pressure (P a Measure HCO3 - Concentration is calculated from pH and Paco2. Metabolic acidosis is characterized by a pH less than 7.35, a P less than 35 mmHg, a CO2 and HCO3 less than 22 mEq / L - It is. a O2 levels (normal 80-95 mmHg) are not used to diagnose metabolic acidosis, but may help determine the cause. Acid-base imbalances are classified primarily as respiratory or metabolic. Respiratory imbalances are due to abnormal pulmonary excretion of CO2, resulting in an excess (acidosis) or deficiency (alkalosis) of CO2 (carbon dioxide) in the extracellular fluid. In respiratory acid-base disorders, serum bicarbonate (HCO3 - ) is the first direct result of a change in Pco2, and an increase in Pco2 increases HCO3 -(Adrogue HJ, Madias NE, 2003, Respiratory acidosis, respiratory alkalosis, and mixed disorders, in Johnson RJ, Feehally J (eds): Comprehensive Clinical Nephrology. London, CV Mosby, pp. 167-182). Metabolic disorders are caused by excess uptake or metabolic production or loss of non-volatile acids or bases in the extracellular fluid. These changes lead to an increase in the bicarbonate anion (HCO3 - ) and adaptation in this case may involve both buffering (immediate), respiratory (hours to days) and renal (days) mechanisms. (DuBose TD, MacDonald GA: renal tubular acidosis, 2002, in DuBose TD, Hamm LL (eds): Acid-base and electrolyte disorders: A companion to Brenners and Rector's the Kidney, Philadelphia, WB Saunders, pp. 189-206).

[0010] The total hydrogen ion concentration in blood is determined by the amount of two components: serum HCO3 - It is defined by the total kidney content (controlled by the kidney) and the PCO2 content (controlled by the lungs) and is expressed as follows: [H + ] ∝ (PCO2 / [HCO3 - ])

[0011] The result of the increase in overall hydrogen ion concentration is a decrease in bicarbonate, the main extracellular buffer. Normal blood pH is 7.38 to 7.42, with a hydrogen ion (H +) concentration (Goldberg M: Approach to Acid-Base Disorders. 2005. In Greenberg A, Cheung AK (eds) Primer on Kidney Diseases, National Kidney Foundation, Philadelphia, Elsevier-Saunders, pp. 104-109.). - ) is an anion that acts as a buffer against pH imbalances in the body, and normal plasma bicarbonate levels are in the range of 22-26 mEq / L (Szerlip HM: Metabolic Acidosis, 2005, in Greenberg A, Cheung AK (eds) Primer on Kidney Diseases, National Kidney Foundation, Philadelphia, Elsevier-Saunders, pp. 74-89.). Acidosis causes a decrease in blood pH (acidaemia) and an increase in the amount of hydrogen ions (H + ) reflects the accumulation of bicarbonate ions (HCO3 - The resulting buffering by creatine phosphate is the process that causes a decrease in serum bicarbonate. Metabolic acidosis can be manifested by: [ka] (Clinical practice guidelines for nutrition in chronic renal failure. K / DOQI, National Kidney Foundation. Am. J. Kidney Dis. 2000; 35:S1-140). Using this equilibrium equation, one HCO3 - The loss of one H + is equivalent to the addition of 1 HCO3 - The acquisition of 1 H + Therefore, changes in blood pH, especially H + Increase in serum HCO3 (low pH, acidosis) - or, equivalently, by an increase in serum H+ This can be corrected by reducing

[0012] To maintain extracellular pH in the normal range, acids produced daily must be excreted from the body. Acid production in the body is the result of the metabolism of dietary carbohydrates, fats, and amino acids. The complete oxidation of these metabolic substrates produces water and CO2. The carbon dioxide produced by this oxidation (~20,000 mmol / day) is efficiently exhaled from the lungs and represents the volatile acid component of acid-base balance.

[0013] In contrast, non-volatile acids (~50-100 mEq / day) are produced by metabolism of sulfate- and phosphate-containing amino acids and nucleic acids. Additional non-volatile acids (lactic, butyric, acetic, and other organic acids) arise from incomplete oxidation of fats and carbohydrates, and from carbohydrate metabolism in the colon, where resident colonic bacteria convert substrates into small organic acids that are absorbed into the bloodstream. The effect of short-chain fatty acids on acidosis is to some extent minimized by anabolism, e.g., to long-chain fatty acids, or catabolism to water and CO2.

[0014] The kidneys filter HCO3 to prevent global bicarbonate depletion. - The pH balance of the blood is maintained by two mechanisms: recycling of urea and excretion of nonvolatile acids in the urine. Both mechanisms are necessary to prevent bicarbonate depletion and acidosis.

[0015] In the first mechanism, the kidney converts HCO3 filtered by the glomerulus into - This recycling occurs in the proximal tubules, where ~4500 mEq / day recycled HCO3 - This mechanism consists of HCO3 - In the second mechanism, the kidneys produce enough H to balance the daily production of nonvolatile acids through the metabolism and oxidation of proteins, fats, and carbohydrates. + The excretion of this acid load is +This is accomplished by two distinct pathways within the kidney, involving active secretion of ions and ammonia production. The end result of these two interconnected processes is the excretion of 50-100 mEq / day of non-volatile acids produced by normal metabolism.

[0016] Therefore, normal renal function is necessary to maintain acid-base balance. In chronic kidney disease, HCO3 - Filtration and recycling of ammonia is impaired, and ammonia production and secretion are inhibited. These defects rapidly lead to chronic metabolic acidosis, which is itself a strong precursor to end-stage renal disease. Decreased acid excretion accompanied by continued metabolic acid production leads to increased blood H + / HCO3 - This causes the balance to be disturbed, causing blood pH to fall below the normal value of pH 7.38-7.42.

[0017] Treatment of metabolic acidosis with alkali therapy is usually applied to raise and maintain plasma pH above 7.20. Sodium bicarbonate (NaHCO3) is the agent most commonly used to correct metabolic acidosis. NaHCO3 is used to adequately increase serum HCO3 to raise pH above 7.20. - It can be administered intravenously to raise levels. Further correction depends on the individual situation and may not be applied if the underlying process is treatable or the patient is asymptomatic. This is especially true in certain forms of metabolic acidosis. For example, in high anion gap (AG) acidosis secondary to the accumulation of organic acids, lactate, and ketones, the cognate anions ultimately convert to HCO3 - When the underlying disease is treated, serum pH is corrected, therefore, care must be taken to avoid raising bicarbonate above the normal range (>26 mEq / L) in these patients when providing alkali such that the pH rises much above 7.20.

[0018] Citric acid is a suitable alkaline therapy agent that should be given orally or IV as the potassium or sodium salt because it is metabolized in the liver to form 3 moles of bicarbonate per mole of citric acid. Potassium citrate administered IV should be used with caution in the presence of renal impairment and closely monitored to avoid hyperkalemia.

[0019] Intravenous sodium bicarbonate (NaHCO3) solution can be administered if metabolic acidosis is severe or is unlikely to correct without exogenous alkali administration. Oral alkali administration is the preferred route of treatment in humans with chronic metabolic acidosis. The most common form of alkali for oral treatment is 11.9 mEq HCO3 per gram of NaHCO3. - However, oral forms of NaHCO3 have not been approved for medical use, and the package insert for intravenous sodium bicarbonate solution includes the following contraindications, warnings, and precautions (Hospira label for NDC 0409-3486-16): Contraindications: Sodium Bicarbonate Injection, USP is contraindicated in patients with chloride loss due to vomiting or continuous gastrointestinal aspiration and in patients receiving diuretics known to produce hypochloremic alkalosis. WARNING: Solutions containing sodium ions should be used with extreme caution, if at all, in patients with congestive heart failure, severe renal failure, and conditions in which edema due to sodium retention is present. In patients with compromised renal function, administration of sodium ion-containing solutions may result in sodium retention. Intravenous administration of these solutions may cause fluid and / or solute overload, resulting in dilution of serum electrolyte concentrations, overhydration, congestive states, or pulmonary edema. Caution: [...] the possibility of a large sodium load given with bicarbonate requires that caution be exercised in the use of sodium bicarbonate in patients with congestive heart failure or other edematous or sodium-retaining states as well as in oliguric or anuric patients.

[0020] Acid-base disorders are common in patients with chronic kidney disease and heart failure. Chronic kidney disease (CKD) gradually impairs renal excretion of approximately 1 mmol / kg body weight of hydrogen ions produced in healthy adults (Yaqoob, MM. 2010, Acidosis and progression of chronic kidney disease, Curr. Opin. Nephrol. Hyperten. 19:489-492.). Accumulation of acid (H + ) or base depletion (HCO3 - ) is a metabolic acidosis caused by 2It is common in patients with CKD when their blood glucose level drops below 100 mg / kg / day. Metabolic acidosis has profound long-term effects on protein and muscle metabolism, bone metabolism, and the development of renal osteodystrophy. In addition, metabolic acidosis affects a variety of paracrine and endocrine functions, with long-term consequences such as increased inflammatory mediators, decreased leptin, insulin resistance, and increased corticosteroid and parathyroid hormone production (Mitch WE, 1997, Influence of metabolic acidosis on nutrition, Am. J. Kidney Dis. 29:46-48.). The net effect of sustained metabolic acidosis in CKD patients is accelerated bone and muscle mass loss, negative nitrogen balance and chronic renal failure due to hormonal and cellular abnormalities (De Brito-Ashurst I, Varagunam M, Raftery MJ, et al, 2009, Bicarbonate supplementation slows progression of CKD and improves nutritional status, J. Am. Soc. Nephrol. 20: 2075-2084). Conversely, a potential concern with alkaline therapy in CKD patients is the expansion of extracellular fluid volume associated with sodium intake resulting in the development or exacerbation of hypertension, accelerated vascular calcification and decompensation of existing heart failure. Patients with moderate CKD (GFR 20-25% of normal) initially develop hyperchloremic acidosis with a normal anion gap due to the inability to recycle filtered bicarbonate and the excretion of protons and ammonium cations. As CKD progresses to more advanced stages, the anion gap increases, reflecting a continuing decline in the kidney's ability to excrete anions that were previously bound to non-excreted protons. Serum bicarbonate in these patients rarely falls below 15 mmol / L, with a maximum high anion gap of approximately 20 mmol / L.Non-metabolizable anions that accumulate in CKD are buffered by alkaline salts from bone (Lemann J Jr, Bushinsky DA, Hamm LL Bone buffering of acid and base in humans. Am. J. Physiol Renal Physiol. 2003 Nov, 285(5):F811-32).

[0021] The majority of patients with chronic kidney disease have underlying diabetes (diabetic nephropathy) and hypertension, which leads to deterioration of renal function. In almost all patients with hypertension, high sodium intake worsens hypertension. Therefore, guidelines for the treatment of kidney, heart failure, diabetes and hypertension strictly restrict sodium intake in these patients to less than 1.5 g or 65 mEq per day (HFSA 2010 guidelines, Lindenfeld 2010, J Cardiac Failure V16 No 6 P475). Chronic antihypertensive treatments often induce sodium excretion (diuretics) or modify the kidney's ability to excrete sodium and water (e.g. "RAASi" agents that inhibit the renin-angiotensin-aldosterone system). However, as renal function deteriorates, the effectiveness of diuretics decreases because the renal tubules are unable to respond. RAASi agents block renal potassium excretion, thus inducing life-threatening hyperkalemia. Given the additional sodium burden, it is not reasonable practice to chronically treat patients with metabolic acidosis with sodium-containing bases in amounts that often exceed the total recommended daily sodium intake. As a result, oral sodium bicarbonate is not generally prescribed long-term for these diabetic nephropathy patients. Potassium bicarbonate is also not tolerated by patients with CKD because they cannot easily excrete potassium, leading to severe hyperkalemia.

[0022] Despite these drawbacks, the role of oral sodium bicarbonate is being studied in a small subpopulation of nonhypertensive CKD patients. As part of the Kidney Research National Dialogue, alkaline therapy has been identified as having the potential to slow the progression of CKD as well as correct metabolic acidosis. The annual age-related decline in glomerular filtration rate (GFR) after age 40 is 0.75 to 1.0 ml / min / 1.73 m in normal individuals. 2 In patients with rapidly progressive CKD, >4 ml / min / 1.73 m per year 2 A steep drop in can be seen.

[0023] In one outcome study, De Brito-Ashurst et al. showed that bicarbonate supplementation preserves renal function in CKD (De Brito-Ashurst I, Varagunam M, Raftery MJ, et al, 2009, Bicarbonate supplementation slows progression of CKD and improves nutritional status, J. Am. Soc. Nephrol. 20: 2075-2084). This study examined the effect of bicarbonate supplementation on kidney function in patients with CKD (creatinine clearance [CrCl] 15-30 ml / min / 1.73 m 2 ) and serum bicarbonate 16-20 mmol / L were randomly assigned to receive oral sodium bicarbonate supplementation or standard care for 2 years. The mean bicarbonate dose in this study was 1.82 g / day, providing 22 mEq of bicarbonate per day. The primary endpoint was rate of CrCl decline; CrCl declined rapidly (>3 ml / min / 1.73 mEq). 2 / year) and the proportion of patients with end-stage renal disease (“ESRD”) (CrCl < 10 ml / min). Compared to the control group, the decline in CrCl slowed with bicarbonate supplementation (1.88 ml / min / 1.73 m in patients receiving bicarbonate). 2 The reduction was 5.93 ml / min / 1.73 m in the control group. 2(P<0.0001). Patients receiving supplemental bicarbonate were significantly less likely to experience rapid progression (9% vs. 45%; relative risk, 0.15; 95% confidence interval, 0.06 to 0.40; P<0.0001). Similarly, fewer patients receiving supplemental bicarbonate developed ESRD (6.5% vs. 33%; relative risk, 0.13; 95% confidence interval, 0.04 to 0.40; P<0.001).

[0024] Hyperphosphatemia is a common comorbidity in patients with CKD, especially in those with advanced or end-stage renal disease. Sevelamer hydrochloride is commonly used as an ion exchange resin to reduce serum phosphate concentrations. However, reported drawbacks of this agent include metabolic acidosis, apparently due to net absorption of HCl during phosphate binding in the small intestine. Several studies in patients with CKD and hyperphosphatemia undergoing hemodialysis or peritoneal dialysis have found that the use of sevelamer hydrochloride reduces serum bicarbonate concentrations (Brezina, 2004 Kidney Int. V66 S90 (2004) S39-S45; Fan, 2009 Nephrol Dial Transplant (2009) 24:3794). [Prior art documents] [Non-patent literature]

[0025] [Non-Patent Document 1] Clinical practice guidelines for nutrition in chronic renal failure, K / DOQI, National Kidney Foundation, Am. J. Kidney Dis. 2000; 35:S1-140 [Non-Patent Document 2] Raphael , KL , Zhang , Y , Wei , G , et al. 2013, Serum bicarbonate and mortality in adults in NHANES III, Nephrol. Dial. Transplantation 28: 1207–1213

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[0026] In various aspects of the present invention, compositions and methods for treating animals, including humans, and methods for preparing such compositions can therefore be described. The compositions include crosslinked amine polymers and can be used, for example, to treat diseases or other metabolic conditions in which removal of protons and / or chloride ions from the digestive tract provides physiological benefits. For example, the polymers described herein can be used to control acid-base related diseases in animals, including humans. In one such embodiment, the polymers described herein can be used to normalize serum bicarbonate concentration and blood pH in animals, including humans. As a further example, the polymers described herein can be used to treat acidosis. There are several different physiological conditions that explain this imbalance, each of which can be treated with polymers that bind and remove HCl.

[0027] Metabolic acidosis resulting from a net increase in acid includes increased endogenous hydrogen ion production, such as ketoacidosis, L-lactic acidosis, D-lactic acidosis, and salicylate poisoning. Metabolism of ingested toxins, such as methanol, ethylene glycol, and paraldehyde, can also increase hydrogen ion concentration. Decreased renal excretion of hydrogen ions, such as uremic acidosis and distal (type I) renal tubular acidosis, are other causes of a net increase in acid in the body that leads to metabolic acidosis. Metabolic acidosis due to loss of bicarbonate is a feature of proximal (type II) renal tubular acidosis. In addition, digestive loss of bicarbonate in acute or chronic diarrhea also leads to metabolic acidosis. Primary or secondary hypoaldosteronism is a common disorder that causes hyperkalemia and metabolic acidosis, and forms the basis of the classification of type IV renal tubular acidosis. Hyporenin hypoaldosteronism is the most frequent variant of this disorder.

[0028] Another way to describe metabolic acidosis is in terms of the anion gap. Causes of high anion gap acidosis include diabetic ketoacidosis, L-lactic acidosis, D-lactic acidosis, alcoholic ketoacidosis, starvation ketoacidosis, uremic acidosis associated with advanced renal failure (CKD stages 4-5), salicylate poisoning, and selective toxic exposures due to ingestion including methanol, ethylene, propylene glycol, and paraldehyde. Causes of normal anion gap acidosis include early renal failure (CKD stages 1-3), digestive loss of bicarbonate due to acute or chronic diarrhea, distal (Type I) renal tubular acidosis, proximal (Type II) renal tubular acidosis, Type IV renal tubular acidosis, dilutional acidosis associated with large volume intravenous fluid administration, and treatment of diabetic ketoacidosis due to loss of ketones in the urine.

[0029] With regard to lactic acidosis, hypoxic lactic acidosis is due to an imbalance between oxygen balance and oxygen supply and is associated with tissue ischemia, stroke, strenuous exercise, shock, cardiac arrest, low cardiac output and congestive heart failure, severe anemia, severe hypoxemia and carbon monoxide poisoning, vitamin deficiency and sepsis. In other types of lactic acidosis, oxygen delivery is normal but oxidative phosphorylation is impaired, often as a result of cellular mitochondrial defects. This is commonly seen due to metabolic inborn errors or due to ingestion of drugs or toxins. The use of sugar substitutes (e.g., fructose, sorbitol) for tube feeding or as irrigating agents during surgery can also lead to metabolism inducing lactic acidosis.

[0030] There are three major categories of renal tubular acidosis, each with a different etiology and several subtypes. Distal (type I) renal tubular acidosis is caused by inherited and genomic changes, particularly HCO3 - / Cl - Exchanger (AE1) or H +Mutations in / ATPase may be responsible. Examples of acquired distal (type I) renal tubular acidosis include hyperparathyroidism, Sjögren's syndrome, sponge kidney, cryoglobulinemia, systemic lupus erythematosus, renal graft rejection, chronic tubulointerstitial disease and exposure to various drugs including amphotericin B, lithium, ifosfamide, foscarnet, toluene and vanadium. A specific classification of distal (type IV) renal tubular acidosis with hyperkalemia is seen in lupus nephritis, obstructive nephropathy, sickle cell anemia and voltage deficiency. Genetic examples are pseudohypoaldosteronism type I and pseudohypoaldosteronism type II (Gordon's disease), and exposure to certain drugs (amiloride, triamterene, trimethoprim and pentamidine) can also lead to distal (type IV) renal tubular acidosis with hyperkalemia. Proximal (type II) renal tubular acidosis may be of inherited or acquired origin. Genetic causes include Wilson's disease and Lowe's syndrome. Acquired causes include cystinosis, galactosemia, multiple myeloma, light chain disease, amyloidosis, vitamin D deficiency, lead and mercury ingestion, and exposure to certain drugs, including ifosfamide, cidofovir, aminoglycosides, and acetazolamide. Isolated defects in bicarbonate reabsorption may be the cause of proximal (type II) renal tubular acidosis; examples of such defects include exposure to the carbonic anhydrase inhibitors, acetazolamide, topiramate, sulfamylone, and carbonic anhydrase deficiency. Combined proximal and distal renal tubular acidosis (type III) is rare and is due to defects in both proximal bicarbonate reabsorption and distal proton secretion. Mutations in the gene for cystolic carbonic anhydrase and certain drugs, including ifosfamide, can cause the defect. Type IV renal tubular acidosis with hyperkalemia is a cause of metabolic acidosis. The main etiologies underlying this type of acidosis are aldosterone deficiency; hypoaldosteronism due to primary adrenal insufficiency, the syndrome of low renin hypoaldosteronism (type IV RTA) commonly seen in older individuals, pseudohypoaldosteronism type I due to Addison's disease and mineralocorticoid resistance. Analgesic nephropathy, chronic pyelonephritis, obstructive nephropathy and chronic interstitial nephritis due to sickle cell disease can also produce acidosis with hyperkalemia.Finally, drugs such as amiloride, spironolactone, triamterene, trimethoprim, heparin therapy, NSAIDs, angiotensin receptor blockers, and angiotensin-converting enzyme inhibitors can also induce metabolic acidosis with hyperkalemia.

[0031] All of the above causes and etiologies of metabolic acidosis are treatable with polymers designed to bind and remove HCl in the gastrointestinal tract.

[0032] The treatment method generally includes administration of a therapeutically effective amount of a crosslinked amine polymer that has the ability to remove protons and chloride ions from the digestive tract of an animal, such as a human. Generally, such crosslinked amine polymers have two or more characteristics, such as relatively low swelling, relatively high proton and chloride ion binding, and / or relatively low binding of interfering anions, such as phosphate, citrate, short chain fatty acids, and bile acids. In the following examples and embodiments, unless otherwise stated, the crosslinked amine polymers are used in free amine form, and require protonation of the amines to bind anions. As such, many of the assays report anion binding, and due to the required low degree of amine quaternization, anion binding is assumed to approximate the amount of proton binding. For example, in one embodiment, the crosslinked amine polymer has at least two of the following characteristics: (i) a proton binding capacity and chloride binding capacity of at least about 5 mmol / g in simulated gastric fluid ("SGF"); (ii) a swelling ratio of less than about 5; (iii) a chloride to phosphate binding ratio of at least about 0.35:1, respectively, in simulated small intestinal inorganic buffer ("SIB"); (iv) selectivity for chloride over other anions in simulated small intestinal organic and inorganic buffers ("SOB"); (v) a mean particle size of about 80-120 microns; and (vi) about 50% HCl binding when subjected to a chloride retention assay. ("CRA", defined below), (vii) not more than about 40% of quaternized amine groups prior to administration to animals, including humans, as measured by the Quaternized Amine Assay ("QAA") to ensure proton binding constitutes the primary therapeutic action of the polymer; (viii) a chloride to interfering anion binding ratio in the "SOB" of at least about 0.35:1, respectively; (ix) a molecular weight of 50-170 daltons per nitrogen atom, and / or (x) a weight percent range of 25-90% crosslinker. For example, in one such embodiment, the crosslinked amine polymer has two of the features "(i)"-"(x)" defined in this paragraph. By way of further example, in one such embodiment, the crosslinked amine polymer has at least three of the features "(i)"-"(x)" defined in this paragraph.By way of further example, in one such embodiment, the crosslinked amine polymer has at least four of the features "(i)" through "(x)" defined in this paragraph. By way of further example, in one such embodiment, the crosslinked amine polymer has at least five of the features "(i)" through "(x)" defined in this paragraph. By way of further example, in one such embodiment, the crosslinked amine polymer has at least six of the features "(i)" through "(x)" defined in this paragraph. By way of further example, in one such embodiment, the crosslinked amine polymer has at least seven of the features "(i)" through "(x)" defined in this paragraph. By way of further example, in one such embodiment, the crosslinked amine polymer has at least eight of the features "(i)" through "(x)" defined in this paragraph.

[0033] In one embodiment, the crosslinked amine polymer is administered as a pharmaceutical composition comprising the crosslinked amine polymer and optionally a pharma- ceutically acceptable carrier, diluent or excipient, or combination thereof, that does not significantly interfere with the proton and / or chloride binding characteristics of the crosslinked amine polymer in vivo. Optionally, the pharmaceutical composition may also include an additional therapeutic agent.

[0034] In certain embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having (i) a chloride to phosphate binding ratio in simulated small intestinal inorganic buffer (“SIB”) of at least 0.35:1, respectively, and (ii) a swelling ratio not exceeding about 5.

[0035] In certain embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having (i) selectivity for chloride over other anions in artificial small intestinal organic and inorganic buffers ("SOB") and (ii) a swelling ratio not exceeding about 5.

[0036] In certain embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having: (i) a proton binding capacity and a chloride binding capacity in artificial gastric fluid of at least 5 mmol / g; and (ii) a swelling ratio not exceeding about 2.

[0037] In certain embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having (i) a proton binding capacity and a chloride binding capacity of at least 5 mmol / g in simulated gastric fluid; (ii) a swelling ratio of less than 5, and (iii) a chloride to phosphate binding ratio of at least 0.35:1, respectively, in simulated small intestinal buffer ("SIB").

[0038] In certain embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having (i) a proton binding capacity and chloride binding capacity of at least 5 mmol / g in simulated gastric fluid; (ii) a swelling ratio of less than 5, and (iii) a selectivity for chloride over other anions in simulated small intestinal organic and inorganic buffers ("SOB").

[0039] In some embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having i) a chloride binding capacity of >2 mmol / g in an artificial organic / inorganic buffer (SOB) and ii) >50% retention of bound chloride as assessed by a chloride retention assay (CRA).

[0040] In some embodiments, the pharmaceutical composition comprises a crosslinked amine polymer having i) a chloride binding capacity of >5 mmol / g in simulated gastric fluid (SGF) and ii) no more than 40% quaternized amine groups as measured by the Quaternized Amine Assay (QAA).

[0041] In one embodiment, the pharmaceutical composition comprises a compound of formula I [ka] wherein R1, R2, and R3 are independently hydrogen, hydrocarbyl, or substituted hydrocarbyl, provided that at least one of R1, R2, and R3 is other than hydrogen. wherein the crosslinked amine polymer comprises an amine residue corresponding to:

[0042] In one embodiment, the pharmaceutical composition comprises a compound of formula I [ka] wherein R1, R2 and R3 are independently hydrogen or hydrocarbyl-substituted hydrocarbyl, provided that at least one of R1, R2 and R3 is other than hydrogen. wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 5 or less, and the crosslinked amine polymer binds at least a 0.35:1 molar ratio of chloride ions to interfering ions, respectively, at 37° C. in an interfering ion buffer, where (i) the interfering ions are phosphate ions and the interfering ion buffer is a buffer of 36 mM chloride and 20 mM phosphate at pH 5.5, or (ii) the interfering ions are phosphate, citrate and taurocholate ions and the interfering ion buffer is a buffer of 36 mM chloride, 7 mM phosphate, 1.5 mM citrate and 5 mM taurocholate at pH 6.2. Thus, in an embodiment where the interfering ion buffer is a pH 5.5 buffer of 36 mM chloride and 20 mM phosphate, the chloride to interfering ion ratio is the ratio of chloride to phosphate ions, and in an embodiment where the interfering ion buffer is a pH 6.2 buffer containing 36 mM chloride, 7 mM phosphate, 1.5 mM citrate, and 5 mM taurocholate, the chloride to interfering ion ratio is the ratio of chloride ions to the combined (total) amounts of phosphate, citrate, and taurocholate ions.

[0043] In some embodiments, the crosslinked amine polymer has the formula: [ka] [During the ceremony, m and n are independently non-negative integers; R 10 , R 20 , R 30 and R 40 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl; X1 is [ka] and X2 is hydrocarbyl or substituted hydrocarbyl; each X 11 is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid, or halo; z is a non-negative number. It is derived from the polymerization of the corresponding amine.

[0044] A further aspect of the present disclosure is a method of crosslinking a proton-binding intermediate with a polyfunctional crosslinker to provide one or more of the following characteristics: relatively low swelling, relatively high proton and chloride ion binding, and / or relatively low interference with interfering ions. The proton-binding intermediate is, for example, an amine group-containing oligomer or polymer prepared by (i) substitution polymerization, (ii) addition polymerization, or (iii) post-polymerization crosslinking of the intermediate.

[0045] Other aspects and features will be apparent and in part pointed out hereinafter. [Brief description of the drawings]

[0046] [Figure 1] Flowchart illustrating the mechanism of action of a polymer as it passes through the digestive tract of an individual, from ingestion / stomach (FIG. 1A), upper GI tract (FIG. 1B) to lower GI tract / colon (FIG. 1C). [Diagram 2] 1 is a graph showing the correlation of swelling ratio in SIB versus chloride:phosphate binding ratio for polymers disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] Abbreviations and Definitions The following definitions and methods are provided to better define the present invention and to guide those of ordinary skill in the art in the practice of the present invention. Unless otherwise specified, terms should be construed in accordance with conventional usage by those of ordinary skill in the relevant art.

[0048] The term "acrylamide" refers to a group of structural formula H2C=CH-C(O)NR-*, where * indicates the point of attachment of the group to the rest of the molecule and R is hydrogen, hydrocarbyl, or substituted hydrocarbyl.

[0049] The term "acrylic" refers to a group of the structural formula H2C=CH-C(O)O-*, where * indicates the point of attachment of the group to the rest of the molecule.

[0050] The terms "alicyclic", "alicyclo" or "alicyclyl" refer to saturated monocyclic radicals of 3 to 8 carbon atoms, and include cyclopentyl, cyclohexyl, cycloheptyl, and the like.

[0051] The term "aliphatic" refers to saturated and non-aromatic unsaturated hydrocarbyl groups having, for example, 1 to about 20 carbon atoms or, in specific embodiments, 1 to about 12 carbon atoms, 1 to about 10 carbon atoms, 1 to about 8 carbon atoms, or 1 to about 4 carbon atoms. Aliphatic groups include, for example, alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, and the like, and alkenyl groups of comparable chain length.

[0052] The term "alkanol" refers to an alkyl group substituted with at least one hydroxyl group. In certain embodiments, alkanol groups are "lower alkanol" groups containing from 1 to 6 carbon atoms, one of which is bonded to an oxygen atom. In other embodiments, lower alkanol groups contain from 1 to 3 carbon atoms.

[0053] The term "alkenyl group" includes straight or branched chain carbon groups having at least one carbon-carbon double bond. The term "alkenyl group" can include conjugated and non-conjugated carbon-carbon double bonds or combinations thereof. Alkenyl groups, for example, but not limited to, can include from 2 to about 20 carbon atoms, or in certain embodiments, from 2 to about 12 carbon atoms. In certain embodiments, alkenyl groups are "lower alkenyl" groups having from 2 to about 4 carbon atoms. Examples of alkenyl groups include, but are not limited to, ethenyl, propenyl, allyl, vinyl, butenyl, and 4-methylbutenyl. The terms "alkenyl group" and "lower alkenyl group" include groups having a "cis" or "trans" orientation, or alternatively, an "E" or "Z" orientation.

[0054] The term "alkyl group," as used herein alone or within other terms such as "haloalkyl group," "aminoalkyl group," and "alkylamino group," includes saturated straight or branched chain carbon groups having, for example, from 1 to about 20 carbon atoms, or, in specific embodiments, from 1 to about 12 carbon atoms. In other embodiments, alkyl groups are "lower alkyl" groups having from 1 to about 6 carbon atoms. Examples of such groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, and the like. In more specific embodiments, lower alkyl groups have from 1 to 4 carbon atoms.

[0055] The term "alkylamino group" refers to an amino group attached to the remainder of the molecule through the nitrogen atom of the amino group, where the nitrogen atom of the alkylamino group is substituted with one or two alkyl groups. In certain embodiments, an alkylamino group refers to a "lower alkylamino" group having one or two alkyl groups of from 1 to 6 carbon atoms attached to the nitrogen atom. In other embodiments, a lower alkylamino group is from 1 to 3 carbon atoms. Suitable "alkylamino" groups are mono- or dialkylamino, such as N-methylamino, N-ethylamino, N,N-dimethylamino, N,N-diethylamino, pentamethyleneamine, and the like.

[0056] The term "aryl" refers to a group having the structural formula H2C=CH-CH2-*, where * indicates the point of attachment of the group to the rest of the molecule, whether to a heteroatom or an aromatic group.

[0057] The term "allylamine" refers to a group having the structural formula H2C=CH-CH2N(X8)(X9), where X8 and X9 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl, or X8 and X9 together form a substituted or unsubstituted alicyclic, aryl or heterocyclic group, each as defined in connection with that term, typically having from 3 to 8 atoms in the ring.

[0058] The terms "amine" or "amino" used alone or as part of another group refer to a group of formula -N(X8)(X9), where X8 and X9 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl, heteroaryl or heterocyclo, or X8 and X9 taken together form a substituted or unsubstituted alicyclic, aryl or heterocyclic group, each as defined in connection with that term, typically having from 3 to 8 atoms in the ring.

[0059] The term "aminoalkyl group" refers to a straight or branched chain alkyl group having from 1 to about 10 carbon atoms, any one of which may be substituted with one or more amino groups, and which is attached to the remainder of the molecule through an atom other than the nitrogen atom of the amine group. In certain embodiments, aminoalkyl groups are "lower aminoalkyl" groups having from 1 to 6 carbon atoms and one or more amino groups. Examples of such groups include aminomethyl, aminoethyl, aminopropyl, aminobutyl, and aminohexyl.

[0060] The term "aromatic group" or "aryl group" refers to an aromatic group having one or more rings, where such rings may be pendant, linked together or fused. In specific embodiments, the aromatic group is monocyclic, bicyclic, or tricyclic. Monocyclic aromatic groups contain 5 to 10 carbon atoms, typically 5 to 7 carbon atoms, more typically 5 to 6 carbon atoms in the ring. Typical polycyclic aromatic groups have two or three rings. Polycyclic aromatic groups having two rings typically contain 8 to 12 carbon atoms, preferably 8 to 10 carbon atoms in the ring. Examples of aromatic groups include, but are not limited to, phenyl, naphthyl, tetrahydronaphthyl, indanyl, biphenyl, phenanthryl, anthryl, or acenaphthyl.

[0061] The term "beads" is used to refer to crosslinked polymers that are substantially spherical.

[0062] The term "linked" as used herein in connection with a polymer and one or more ions, i.e., cations (e.g., "proton-linked" polymers) and anions, is understood to be an "ionically linked" polymer and / or when it links with ions, has sufficient bond strength that at least a portion of the ions remain bound under the in vitro or in vivo conditions in which the polymer is used for a period of time sufficient to effect removal of the ions from the solution or the body, generally not necessarily in a non-covalent manner.

[0063] The term "chloride retention assay" or "CRA" refers to an assay in which the retention of chloride and other anions by free amine test polymers and free amine sevelamer and bixalomer control polymers is assessed by exposure to competing anion concentrations, typically in the colonic lumen. The anions released from the polymers and the anions retained by the polymers under these conditions are measured. The first step of the retention assay is the performance of a specific organic / inorganic buffer assay (SOB screening) as described elsewhere herein. An empty tube containing no polymer is included and treated in the same manner during retention screening. Instead of discarding the polymer and SOB matrix from the assay tube, the contents are transferred to a solid phase extraction (SPE) tube equipped with a 20 micrometer pore size frit. Excess SOB matrix is ​​removed by applying negative pressure to the bottom or positive pressure to the top of the SPE tube. The SOB assay tube is rinsed twice with deionized water and the contents are transferred to the SPE tube to ensure that as much polymer as possible is recovered. Retention assay matrix is ​​then added to the SPE tube. Retention assay matrix contains 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 100 mM sodium acetate, 5 mM sodium phosphate, 15 mM sulfate, and is adjusted to pH 6.2. The concentrations of potentially competing anions reflect typical late colonic luminal concentrations (Wrong, O et al.

[1965] Clinical Science 28, 357-375). As the aim is to measure chloride retention, chloride is removed and bicarbonate is removed as it is unstable due to conversion to water and CO2. Retention buffer is added to achieve a final polymer concentration of 2.5 mg / ml (assuming no loss of polymer from the initial weighing into the SOB assay tube). The SPE tube is capped and sealed and incubated at 37°C for approximately 40 hours. A 600 microliter sample is removed, filtered, diluted as necessary, and assayed for anion content as described above for SOB. For each test polymer, the chloride, citrate and taurocholic acid released from the polymer in the retention matrix is ​​calculated using the following formula:

number

number

[0064] The term "crosslink density" refers to the average number of bonds of the amine containing repeating units to the rest of the polymer. The number of bonds can be 2, 3, 4 and more. The repeating units of linear, non-crosslinked polymers are incorporated via 2 bonds. To form an insoluble gel, the number of bonds must be greater than 2. Low crosslink density materials such as sevelamer have an average of about 2.1 bonds between repeating units. More crosslinked systems such as bixalomer have an average of about 4.6 bonds between amine containing repeating units. "Crosslink density" represents a semi-quantitative measure based on the ratio of starting materials used. It includes limitations due to the fact that it does not take into account different crosslinking and polymerization methods. For example, small molecule amine systems require a high amount of crosslinker because the crosslinker also serves as a monomer to form the polymer backbone, whereas for radical polymerization, the polymer chains are formed independently of the crosslinking reaction. This can lead to an inherently higher crosslink density under this definition for substitution polymerization / small molecule amines compared to radical polymerization crosslinked materials.

[0065] The term "crosslinker," used alone or within other terms, refers to a hydrocarbyl or substituted hydrocarbyl, linear or branched molecule that can react more than once with any of the monomers described or with the infinite polymer network as described in Formula 1. The reactive groups in the crosslinker can include, but are not limited to, alkyl halides, epoxides, phosgene, anhydrides, carbamates, carbonates, isocyanates, thioisocyanates, esters, activated esters, carboxylic acids and derivatives, sulfonates and derivatives, acyl halides, aziridines, alpha, beta-unsaturated carbonyls, ketones, aldehydes, pentafluoroaryl groups, vinyls, allyls, acrylates, methacrylates, acrylamides, methacrylamides, styrenes, acrylonitriles, and combinations thereof. In one exemplary embodiment, the reactive groups of the crosslinker include alkyl halides, epoxides, anhydrides, isocyanates, allyls, vinyls, acrylamides, and combinations thereof. In one such embodiment, the reactive group of the crosslinker is an alkyl halide, epoxide, or allyl.

[0066] The term "diallylamine" refers to an amino group bearing two allyl groups.

[0067] The term "etheric" refers to the structure *-H x CO-CH x - refers to a group having oxygen bonded to two separate carbon atoms, designated by *, where * indicates the point of attachment to the remainder of the molecule and x is independently 0, 1, 2 or 3.

[0068] The term "gel" is used to describe a cross-linked polymer having an irregular shape.

[0069] The term "halo" refers to halogens such as fluorine, chlorine, bromine or iodine atoms.

[0070] The term "haloalkyl group" includes groups in which any one or more of the alkyl carbon atoms are substituted with halo as defined above. Specifically included are monohaloalkyl, dihaloalkyl, and polyhaloalkyl groups, including perhaloalkyl. Monohaloalkyl groups can include, for example, an iodo, bromo, chloro, or fluoro atom within the group. Dihalo and polyhaloalkyl groups can have two or more of the same halo atoms or a combination of different halo groups. "Lower haloalkyl groups" include groups having 1 to 6 carbon atoms. In some embodiments, lower haloalkyl groups have 1 to 3 carbon atoms. Examples of haloalkyl groups include fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, pentafluoroethyl, heptafluoropropyl, difluorochloromethyl, dichlorofluoromethyl, difluoroethyl, difluoropropyl, dichloroethyl, and dichloropropyl.

[0071] The term "heteroaliphatic" refers to a chain of 1 to 25 carbon atoms, typically 1 to 12 carbon atoms, more typically 1 to 10 carbon atoms, most typically 1 to 8 carbon atoms, and in some embodiments 1 to 4 carbon atoms, that may be saturated or unsaturated (but not aromatic) and that contains one or more heteroatoms such as halogen, oxygen, nitrogen, sulfur, phosphorus, or boron. The heteroatom may be part of a pendant (or side chain) group attached to the chain of atoms (e.g., -CH(OH)-CH(NH2)- where the carbon atom is a member of the chain of atoms) or may be one of the chain atoms (e.g., -ROR- or -RNHR- where each R is aliphatic). Heteroaliphatic includes heteroalkyl and heterocyclo, but does not include heteroaryl.

[0072] The term "heteroalkyl" refers to a fully saturated heteroaliphatic group.

[0073] The term "heteroaryl", unless otherwise specified, refers to a monocyclic or bicyclic aromatic radical of 5 to 10 ring atoms, in which one or more (in one embodiment, one, two or three) ring atoms are heteroatoms selected from N, O or S, and the remaining ring atoms are carbon. Representative examples include, but are not limited to, pyrrolyl, thienyl, thiazolyl, imidazolyl, furanyl, indolyl, isoindolyl, oxazolyl, isoxazolyl, benzothiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazolyl, tetrazolyl, and the like. As defined herein, the terms "heteroaryl" and "aryl" are mutually exclusive. "Heteroarylene" refers to a divalent heteroaryl group.

[0074] The term "heteroatom" refers to an atom other than carbon and hydrogen. Typically, but not exclusively, heteroatoms are selected from the group consisting of halogen atoms, sulfur atoms, phosphorus atoms, nitrogen atoms, boron atoms, and oxygen atoms. Groups containing more than one heteroatom may contain different heteroatoms.

[0075] The terms "heterocyclo", "heterocycle" or "heterocyclyl" refer to a saturated or unsaturated group of 4 to 8 ring atoms, where one or two of the ring atoms are N, O, B, P, and S(O). n (wherein n is an integer from 0 to 2), and the remaining ring atoms are carbon. Additionally, one or two ring carbon atoms of the heterocyclyl ring may be optionally replaced with a -C(O)- group. More specifically, the term heterocyclyl includes, but is not limited to, pyrrolidino, piperidino, homopiperidino, 2-oxopyrrolidinyl, 2-oxopiperidinyl, morpholino, piperazino, tetrahydro-pyranyl, thiomorpholino, and the like. If the heterocyclyl ring is unsaturated, it may contain one or two ring double bonds, as long as the ring is not aromatic. When a heterocyclyl group contains at least one nitrogen atom, it is also called heterocycloamino, and is a subgroup of the heterocyclyl group.

[0076] The term "hydrocarbon group" or "hydrocarbyl group" refers to a chain of 1 to 25 carbon atoms, typically 1 to 12 carbon atoms, more typically 1 to 10 carbon atoms and most typically 1 to 8 carbon atoms. The hydrocarbon group may have a straight or branched chain structure. Typical hydrocarbon groups have one or two branches, typically one branch. Typically, the hydrocarbon group is saturated. An unsaturated hydrocarbon group may have one or more double bonds, one or more triple bonds or a combination thereof. Typical unsaturated hydrocarbon groups have one or two double bonds or one triple bond, more typically the unsaturated hydrocarbon group has one double bond.

[0077] "Initiator" is a term used to refer to an agent that starts a polymerization.

[0078] The term "molecular weight per nitrogen" or "MW / N" refers to the calculated molecular weight of a polymer per nitrogen atom. It represents the average molecular weight for one amine functional group in the crosslinked polymer. It is calculated by dividing the mass of a polymer sample by the moles of nitrogen present in the sample. "MW / N" is the inverse of the theoretical capacity and the calculation is based on the feed ratio, assuming complete reaction of the crosslinker and monomer. The lower the molecular weight per nitrogen, the higher the theoretical capacity of the crosslinked polymer.

[0079] "Optionally" or "optionally" means that the subsequently described event or circumstance may, but does not necessarily, occur, and the description includes instances where the event or circumstance occurs and instances where it does not occur. For example, "a heterocyclyl group optionally substituted with an alkyl group" means that alkyl may, but does not necessarily, be present, and the description includes embodiments in which the heterocyclyl group is substituted with an alkyl group and embodiments in which the heterocyclyl group is not substituted with an alkyl group.

[0080] "Pharmaceutically acceptable" when used in connection with a carrier, diluent, or excipient means that the carrier, diluent, or excipient, respectively, is generally safe, non-toxic, and not biologically or otherwise undesirable for veterinary and / or human pharmaceutical use, and is useful in the preparation of pharmaceutical compositions.

[0081] The term "post-polymerization crosslinking" refers to a reaction on already formed beads or gels that introduces additional crosslinks to the already formed beads or gels to create beads or gels with an increased amount of crosslinking.

[0082] The term "post-polymerization modification" refers to modifications to already formed beads or gels in which a reaction or treatment introduces additional functional groups that can be covalently or non-covalently attached to the already formed beads.

[0083] The term "quaternary amine assay" ("QAA") refers to a method for estimating the amount of quaternary amines present in a given crosslinked polymer sample. This assay measures chloride binding of crosslinked amine polymers at pH 11.5. At this pH, primary, secondary, and tertiary amines are not substantially protonated and do not contribute substantially to chloride binding. Therefore, any binding seen under these conditions can be attributed to the presence of permanently charged quaternary amines. The test solution used for the QAA assay is 100 mM sodium chloride at pH 11.5. The chloride ion concentration is in accordance with the SGF assay used to assess the total binding capacity of crosslinked amine polymers. The quaternary amine content as a percentage of the total amines present is calculated as follows:

number

[0084] To perform the QAA assay, the free amine polymer to be tested is prepared at a concentration of 2.5 mg / ml (e.g., 25 mg dry weight) in 10 mL of QAA buffer. The mixture is incubated at 37° C. for 16 hours with agitation on a rotisserie mixer. After incubation and mixing, 600 microliters of the supernatant is taken and filtered using an 800 microliter, 0.45 micrometer pore size, 96-well polypropylene filter plate. With the samples aligned on the filter plate and a collection plate attached to the bottom, the unit is centrifuged at 1000×g for 1 minute to filter the samples. After filtration into the collection plate, each filtrate is appropriately diluted to measure the chloride content. The IC method (e.g., ICS-2100 Ion Chromatography, Thermo Fisher Scientific) used to analyze the chloride content in the filtrate consists of a 15 mM KOH mobile phase, an injection volume of 5 microliters, a runtime of 3 minutes, a wash / rinse volume of 1000 microliters, and a flow rate of 1.25 mL / min. To determine polymer bound chloride, the following calculation is performed:

number

[0085] The "Simulated Gastric Fluid" or "SGF" assay refers to a test to determine the total chloride binding capacity for a test polymer using a defined buffer that mimics the contents of gastric fluid as follows: Simulated gastric fluid (SGF) consists of 35 mM NaCl, 63 mM HCl, pH 1.2. To perform this assay, the free amine polymer to be tested is prepared at a concentration of 2.5 mg / ml (25 mg dry weight) in 10 mL of SGF buffer. The mixture is incubated at 37°C overnight for ~12-16 hours with agitation on a rotary mixer. After incubation and mixing, the tube containing the polymer is centrifuged for 2 minutes at 500-1000 x g to pellet the test sample. Approximately 750 microliters of the supernatant is removed and filtered using an appropriate filter, such as a 0.45 micrometer pore size syringe filter mounted on a 96-well 2 mL collection plate or an 800 microliter, 1 micrometer pore size, 96-well, glass filter plate. In the latter configuration, a multi-sample run can be prepared for analysis, including control tubes run through the entire assay process, including free amine sevelamer, free amine bixalomer standard controls, and blank buffer, running in SGF buffer. With samples aligned on the filter plate and collection plate attached to the bottom, the unit is centrifuged at 1000 x g for 1 minute to filter the samples. For small sample sets, a syringe filter may be used in place of the filter plate, collecting ~2-4 mL of filtrate in a 15 mL container. After filtration, each filtrate is diluted 4-fold with water and the chloride content of the filtrate is measured by ion chromatography (IC). The IC method (e.g., Dionex ICS-2100, Thermo Scientific) consists of an AS11 column and 15 mM KOH mobile phase, injection volume of 5 microliters, 3 minute runtime, wash / rinse volume of 1000 microliters, and flow rate of 1.25 mL / min. To determine polymer-bound chloride, perform the following calculation:

number

[0086] "Simulated Small Intestinal Inorganic Buffer" or "SIB" is a test to determine the chloride and phosphate binding capacity of free amine test polymers in a selective specific interference buffer assay (SIB). The chloride and phosphate binding capacity of the free amine test polymers, along with the chloride and phosphate binding capacity of the free amine sevelamer and bixalomer control polymers, were determined using a selective specific interference buffer assay (SIB) as follows: The buffer used for the SIB assay contains 36 mM NaCl, 20 mM NaH2PO4, 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffered to pH 5.5. SIB buffer contains chloride, phosphate and pH concentrations present in the human duodenum and upper gastrointestinal tract (Stevens T, Conwell DL, Zuccaro G, Van Lente F, Khandwala F, Purich E, et al. Electrolyte composition of endoscopically collected duodenal drainage fluid after synthetic porcine secretin stimulation in healthy subjects. Gastrointestinal endoscopy. 2004;60(3):351-5, Fordtran J, Locklear T. Ionic constituents and osmolality of gastric and small-intestinal fluids after eating. Digest Dis Sci. 1966;11(7):503-21), and is a useful indicator of the selectivity of chloride binding compared to phosphate bound by the polymer. To perform the assay, the free amine polymer to be tested is prepared at a concentration of 2.5 mg / ml (25 mg dry weight) in 10 mL of SIB buffer. The mixture is incubated at 37° C. for 1 hour with agitation on a rotary mixer. After incubation and mixing, the tubes containing the polymer are centrifuged for 2 minutes at 1000 xg to pellet the test samples.A multi-sample test can be prepared for analysis in which 750 microliters of supernatant is taken and filtered using an 800 microliter, 1 micrometer pore size, 96-well, glass filter plate mounted on a 96-well 2 mL collection plate, with control tubes run through the entire assay process, including free amine sevelamer, free amine bixalomer standard controls and blank buffer, in this arrangement. With samples aligned on the filter plate and the collection plate attached to the bottom, the unit is centrifuged at 1000 x g for 1 minute to filter the samples. For small sample sets, a syringe filter (0.45 micrometer) may be used in place of the filter plate, and ~2-4 mL of filtrate is collected in a 15 mL vial. After filtration into the collection plate, each filtrate is diluted to measure the chloride or phosphate content. For chloride and phosphate measurements, the filtrate under analysis is diluted 4-fold with water. The chloride and phosphate content of the filtrate is measured by ion chromatography (IC). The IC method (e.g., Dionex ICS-2100, Thermo Scientific) consists of an AS24A column, 45 mM KOH mobile phase, injection volume of 5 microliters, approximately 10 minute runtime, wash / rinse volume of 1000 microliters, and a flow rate of 0.3 mL / min. To determine polymer bound chloride, the following calculation is performed:

number

number

[0087] "Simulated Small Intestine Organic and Inorganic Buffer" or "SOB" is a test to determine chloride binding capacity measured in the presence of specific organic and inorganic interferents commonly found in the GI tract. The chloride binding capacity as well as the binding capacity of other anions of the free amine test polymers and the free amine sevelamer and bixalomer control polymers were measured in the presence of specific organic interferents commonly found in the GI tract as follows. The SOB screen is used to determine the chloride binding capacity of the free amine polymers when exposed to chloride in the presence of other potentially competing anions such as bile acids, fatty acids, phosphate, acetate and citrate to mimic the conditions of the GI lumen. The test buffer used for the SOB assay contains 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid and 5 mM sodium taurocholate buffered to pH 6.2. The concentrations of potentially competing anions reflect typical luminal concentrations found at various points in the GI tract, and the pH is an average value representing pH values ​​encountered in both the duodenum and large intestine. The chloride concentration used is the same as that used in the SIB screening. To perform the assay, the free amine polymer to be tested is accurately weighed into a 16 x 100 mm glass tube with a liquid-tight screw cap. An appropriate amount of SOB buffer is added to the tube to achieve a final polymer concentration of 2.5 mg / ml. The mixture is incubated at 37°C for 2 hours with stirring on a rotary mixer. After incubation and mixing, 600 microliters of the supernatant is taken and filtered using a 96-well glass filter plate. With the samples aligned on the filter plate and a collection plate attached to the bottom, the unit is centrifuged at 1000 x g for 1 minute to filter the samples. For small sample sets, a syringe filter may be used in place of the filter plate, and ~2-4 mL of filtrate is collected in a 15 mL vial. After filtration onto a collection plate, each filtrate is appropriately diluted and the anion content is determined.The IC method (e.g. Dionex ICS-2100, Thermo Scientific) consists of an AS24A column, a KOH gradient of 20 mM to 100 mM, an injection volume of 5 microliters, a runtime of approximately 30 minutes, a wash / rinse volume of 1000 microliters, and a flow rate of 0.3 mL / min. This method is suitable for the quantification of chloride, phosphate, and taurocholic acid. Other suitable methods may be substituted. To determine the ions bound to the polymer, the following calculation is performed:

number

[0088] As used herein, the terms "substituted hydrocarbyl," "substituted alkyl," "substituted alkenyl," "substituted aryl," "substituted heterocyclo," or "substituted heteroaryl" refer to hydrocarbyl, alkyl, alkenyl, aryl, heterocyclo, or heteroaryl groups substituted with at least one atom other than carbon and hydrogen, including groups in which a carbon chain atom is replaced with a heteroatom such as nitrogen, oxygen, silicon, phosphorus, boron, sulfur, or a halogen atom. These substituents include halogen, heterocyclo, alkoxy, alkenoxy, alkynoxy, aryloxy, hydroxy, keto, acyl, acyloxy, nitro, amino, amido, nitro, cyano, thiol, ketals, acetals, esters, and ethers.

[0089] "Swell ratio" or simply "swell" refers to the amount of water absorbed by a quantity of polymer divided by the weight of the polymer portion. Swell ratio is expressed as swell = (g swollen polymer - g dry polymer) / g dry polymer. Methods used to determine the swell ratio of any given polymer include the following: a. Place 50-100 mg of dry (water content less than 5% by weight) polymer into an 11 mL sealable test tube (with screw cap) of known weight (tube weight = weight A). b. Add deionized water (10 mL) to the polymer-containing tube. Seal the tube and invert at room temperature for 16 hours (overnight). After incubation, centrifuge the tube at 3000 x g for 3 minutes and carefully remove the supernatant by vacuum aspiration. Polymers that form a very loose pellet are subjected to one additional centrifugation step. c. After step (b), record the weight of the swollen polymer plus tubing (Weight B). d. Freeze at -40°C for 30 minutes. Freeze dry for 48 hours. Weigh the dried polymer and test tube (record as Weight C). e. Calculate the water absorbed per gram of polymer defined as [(Weight B-Weight A)-(Weight C-Weight A)] / (Weight C-Weight A).

[0090] "Target ion" refers to an ion to which a polymer binds, usually the primary ion bound by the polymer or the ion whose binding to the polymer is believed to produce the therapeutic effect of the polymer (e.g., proton and chloride binding resulting in the net removal of HCl).

[0091] The term "theoretical capacity" is the calculated, predicted binding of hydrochloric acid in the "SGF" assay, expressed in mmol / g. Theoretical capacity is based on the assumption that 100% of the amines from the monomer and crosslinker, based on their respective feed ratios, are incorporated into the crosslinked polymer. Theoretical capacity is therefore equal to the concentration of amine functional groups in the polymer (mmol / g). Theoretical capacity assumes that each amine is available for binding to each anion and cation, and is not adjusted for the type of amine formed (e.g., does not subtract the capacity of quaternary amines that are not available for proton binding).

[0092] "Therapeutically effective amount" refers to the amount of proton-linked crosslinked amine polymer that, when administered to a patient for treating a disease, is sufficient to effect treatment for such disease. What constitutes a "therapeutically effective amount" will vary depending on the polymer, the severity of the disease and the age, weight, etc., of the mammal being treated.

[0093] "Treating" or "treatment" of a disease includes (i) preventing the disease, i.e., arresting or reducing the progression of the disease or its clinical symptoms; or (ii) ameliorating the disease, i.e., inducing regression of the disease or its clinical symptoms. Preventing a disease includes, for example, prophylaxis.

[0094] The term "triallylamine" refers to an amino group having three allyl groups.

[0095] The term "vinyl" refers to a compound of the structure R x H y This refers to a group having the formula C=CH-*, where * indicates the point of attachment of the group to the remainder of the molecule, the point of attachment is a heteroatom or aryl, X and Y are independently 0, 1 or 2 such that X+Y=2, and R is hydrocarbyl or substituted hydrocarbyl.

[0096] The term "crosslinker weight percent" refers to the percentage calculated by the mass of a polymer sample that is attributable to crosslinker. Crosslinker weight percent is calculated using the feed ratio of the polymerization and assumes complete conversion of monomer and crosslinker. The mass attributable to crosslinker is equal to the expected increase in molecular weight in an infinite polymer network after reaction (e.g., 1,3-dichloropropane is 113 amu, but only 42 amu is added to the polymer network after crosslinking with DCP because the chlorine atom as a leaving group is not incorporated into the polymer network).

[0097] When introducing elements of the invention or preferred embodiments thereof, the singular term "a," "an," or "an" means that there are one or more elements. The terms "comprise," "include," and "have" are intended to be inclusive and not exclusive (i.e., there may be other elements in addition to the listed elements).

[0098] Aspects As noted above, among the various aspects of the present disclosure, particular mention may be made of methods of treatment using compositions comprising non-absorbable, crosslinked polymers that contain free amine groups. In one embodiment, the crosslinked amine polymers have the ability to remove clinically significant amounts of protons and chloride ions from the gastrointestinal tract of animals, including humans, upon administration of a therapeutically effective amount (i.e., an effective amount) of the crosslinked amine polymer to achieve a therapeutic or prophylactic benefit.

[0099] The therapeutically effective amount of the crosslinked amine polymers disclosed herein depends, at least in part, on the disease to be treated, the potency of the crosslinked free amine polymer, and the intended effect. In one embodiment, the daily dosage of the crosslinked free amine polymer is sufficient to slow the rate of decline in serum bicarbonate levels over an extended period of time. In another embodiment, the daily dosage of the crosslinked free amine polymer is sufficient to maintain serum bicarbonate levels over an extended period of time. In another embodiment, the daily dosage of the crosslinked free amine polymer is sufficient to increase serum bicarbonate levels over an extended period of time. For example, in one embodiment, the daily dosage is sufficient to achieve or maintain a serum bicarbonate level of at least about 20 mEq / L over an extended period of time. By way of further example, in one such embodiment, the daily dosage is sufficient to achieve or maintain a serum bicarbonate level of at least about 21 mEq / L over an extended period of time. By way of further example, in one such embodiment, the daily dosage is sufficient to achieve or maintain a serum bicarbonate level of at least about 22 mEq / L over an extended period of time. In yet other embodiments, the daily dosage is sufficient to achieve or maintain a serum bicarbonate level of at least about 24 mEq / L for an extended period of time, in each of the above embodiments, being a period of at least one month, e.g., at least two months, at least three months, or even at least several months.

[0100] In general, dosage levels of crosslinked amine polymers for therapeutic and / or prophylactic use may range from about 0.5 g / day to about 20 g / day. To facilitate patient compliance, it is generally preferred that the dosage range be from about 1 g / day to about 10 g / day. For example, in one such embodiment, the dosage is from about 2 g / day to about 7 g / day. As a further example, in one such embodiment, the dosage is from about 3 g / day to about 6 g / day. As a further example, in one such embodiment, the dosage is from about 4 g / day to about 5 g / day. If desired, the daily dosage may be administered as a single dose (i.e., once per day) or divided into multiple doses over the course of the day (e.g., two, three or more doses). In general, crosslinked amine polymers for therapeutic and / or prophylactic use may be administered at a fixed daily dosage or titrated based on the serum bicarbonate level or other indicator of acidosis in the patient in need of treatment. Titration may occur at the start of treatment or as needed during treatment, with starting and maintenance dosage levels varying from patient to patient depending on the severity of the underlying disease.

[0101] As depicted diagrammatically in Figures 1A-1C, and according to one embodiment, the non-absorbable, free amine polymers of the present disclosure are taken orally and used to treat metabolic acidosis in mammals, including by increasing serum bicarbonate and normalizing blood pH, by binding HCl in the gastrointestinal ("GI") tract and excreting the HCl via the feces. The free amine polymers are administered orally (Figure 1A) at compliance enhancing doses targeted to bind sufficient amounts of HCl over time to allow a clinically meaningful increase in serum bicarbonate of 3 mEq / L. In the stomach (Figure 1B), the free amines are converted to H + The polymer is then protonated by the bond of Cl. - and other large organic anions (e.g., X - and Y -In the lower GI tract / colon (Figure 1C), Cl is bound to a low extent, if at all. - is not liberated, and HCl is removed from the body through normal intestinal motility and fecal excretion, leading to a net alkalinization of serum. - is Cl - / HCO3 - It is not available for exchange via the antiporter system.

[0102] In one embodiment, the polymer is designed (via low swelling particle design and particle size distribution) to maximize efficacy (net HCl binding and excretion) while simultaneously minimizing GI side effects. Optimized HCl binding is achieved by optimizing capacity (number of amine binding sites), selectivity (binding of chloride in preference to other anions, especially organic anions, in the colon) and retention (retention of Cl in the colon and intestine). - / HCO3 - Do not liberate significant amounts of chloride in the lower GI tract to avoid antiporter activity; unless chloride is tightly bound to the polymer, Cl - / HCO3 - The exchanger takes up chloride ions from the intestinal lumen and mediates the reciprocal exchange of bicarbonate from the serum, thus effectively lowering serum bicarbonate. This can be achieved by a careful balance of

[0103] Competing anions that displace chloride reduce net bicarbonate by the following mechanisms: First, displacement of chloride from the polymer in the GI lumen, especially the colonic lumen, provides for ready exchange with bicarbonate in serum. The colon possesses an anion exchanger (chloride / bicarbonate antiporter) that transfers chloride from the luminal side in place of secreted bicarbonate. When free chloride is released from the polymer in the GI tract, it substitutes for bicarbonate, which is then eliminated in the stool, causing a decrease in total extracellular bicarbonate (Davis, 1983; D'Agostino, 1953). Binding of short chain fatty acids (SCFAs) in place of bound chloride from the polymer reduces the amount of extracellular HCO3 -This leads to the depletion of storage. Short-chain fatty acids are products of bacterial metabolism of complex carbohydrates that are not catabolized by normal digestive processes (Chemlarova, 2007). Upon reaching the colon, short-chain fatty acids are absorbed and distributed to various tissues, with the general metabolic fate being the production of H2O and CO2, which are converted to bicarbonate equivalents. Therefore, the binding of SCFAs to the polymer to neutralize the proton charge is detrimental to the overall bicarbonate stores and buffering capacity, necessitating the design of chemical and physical properties that limit SCFA exchange in the polymer. Finally, phosphate binding to the polymer should be limited as well, since phosphate represents an additional source of buffering capacity in conditions where ammonia production and / or hydrogen ion secretion are impaired in chronic kidney disease.

[0104] For each binding of a proton, an anion is preferably bound as a positive charge that seeks to leave the human body as a neutral polymer. The "binding" of ions is greater than the minimum binding, i.e., at least about 0.2 mmol of ions / gm of polymer, in some embodiments at least about 1 mmol of ions / gm of polymer, in some embodiments at least about 1.5 mmol of ions / gm of polymer, and in some embodiments at least about 3 mmol of ions / gm of polymer. In one embodiment, the polymers are characterized by high proton binding capacity as well as selectivity for anions, with selectivity for chloride being achieved by reduced binding of interfering anions, including, but not limited to, phosphate, citrate, acetate, bile acids, and fatty acids. For example, in some embodiments, the polymers of the present disclosure bind phosphate with a binding capacity of less than about 5 mmol / gm, less than about 4 mmol / gm, less than about 3 mmol / gm, less than about 2 mmol / gm, or even less than about 1 mmol / gm. In some embodiments, the polymers of the present invention bind bile acids and fatty acids with a binding capacity of less than about 5 mmol / g, less than about 4 mmol / g, less than about 3 mmol / g, less than about 2 mmol / gm, less than about 1 mmol / gm, in some embodiments less than about 0.5 mmol / gm, in some embodiments less than about 0.3 mmol / gm, and in some embodiments less than about 0.1 mmol / gm.

[0105] The efficacy of the polymer can be established in animal models or human volunteers and patients. In addition, in vitro, ex vivo and in vivo methods are useful for establishing HCl binding. In vitro binding solutions can be used to measure the binding capacity to protons, chloride and other ions at various pH levels. Ex vivo extracts such as the contents of the digestive tract lumen from human volunteers or model animals can be used for similar purposes. The selectivity of binding and / or retaining some ions over others can also be demonstrated with such in vitro and ex vivo solutions. In vivo models of metabolic acidosis can be used to test the efficacy of polymers in normalizing acid / base balance - for example 5 / 6 nephrectomized rats fed a casein-containing chow diet (as described in Phisitkul S, Hacker C, Simoni J, Tran RM, Wesson DE. Dietary protein causes a decline in the glomerular filtration rate of the remnant kidney mediated by metabolic acidosis and endothelin receptors. Kidney international. 2008;73(2):192-9).

[0106] In one embodiment, the polymers described herein are given to animals, including humans, in one, two or three doses per day (most preferably at a daily dose not exceeding or less than 5 g per day) to treat metabolic acidosis, achieving a clinically significant and sustained increase in serum bicarbonate of about 3 mEq / L at these daily doses. The amount of HCl binding achieved by oral administration of the polymer is determined by the polymer binding capacity, which is generally in the range of 5-25 mEq HCl per gram of polymer. Additionally, the polymer is preferably selective in terms of the anion that binds to balance the proton binding, with chloride being the preferred anion. Anions other than chloride that bind to neutralize the proton positive charge include phosphate, short chain fatty acids, long chain fatty acids, bile acids or other organic or inorganic anions. The binding of these anions other than chloride affects overall bicarbonate storage in the intracellular and extracellular compartments.

[0107] In one embodiment, the mechanism of action of the HCl polymeric binder involves the following: In the stomach or elsewhere in the GI tract, the free amine polymers release protons (H +) binding. The positive charge formed as a result of this binding is then available for chloride anion binding. After exiting the stomach, the polymer encounters various GI tract environments successively in the order of the duodenum, jejunum, ileum and colon, each of which complements different organic and inorganic anions. The physical and chemical properties of the polymer are designed to control the access of the protonated binding sites to this collection of anions. Physical barriers include crosslinks (size exclusion to prevent anion binding) and chemical groups (to repel large, organic ions such as acetate, propionate, butyrate or other short chain fatty acids commonly present in the colon) to limit phosphate, bile acid and fatty acid binding, as well as combinations of these two properties. By tailoring the chemistry of the bead crosslinks and amine binding sites, chloride can be tightly bound such that exchange with other anions and release in the lower GI tract is reduced or eliminated. Without being bound by theory, anions with ions and / or hydration radii larger than chloride can be excluded or reduced from binding by incorporating these properties into the HCl-binding polymer. For example, the ionic radius of chloride, either in hydrated or non-hydrated form, is smaller than the corresponding values ​​of phosphate and other anions commonly encountered in the GI tract lumen (Supramolecular Chemistry, Steed, JW (2009) John Wiley and Sons, page 226; Kielland, J (1937), J. Am. Chem. Soc. 59:1675-1678). To selectively bind small ions, polymers typically exhibit high crosslink density to allow preferential access to polymer binding sites. High crosslink density materials, however, are typically characterized by low swelling ratios. The swelling ratio is influenced by the following compositional and methodological variables: 1) the molar ratio of amine monomer (or polymer) to crosslinker, 2) the monomer+crosslinker to solvent ratio in the crosslinking reaction, 3) the net charge of the polymer (at the physiological pH and tonicity of the environment in which it will be used), 4) the hydrophilic / hydrophobic balance of the backbone polymer, and / or 5) post-crosslinking of existing materials.

[0108] In general, the crosslinked amine polymers of the present disclosure are typically characterized by a low swelling ratio. In one embodiment, the relative chloride to phosphate binding ratio in the SIB is an indicator of the chloride to large anion selectivity of the crosslinked polymers of the present disclosure. A graph of the correlation between the swelling ratio and the chloride:phosphate binding ratio of certain polymers of the present disclosure in the SIB is shown in FIG. 2. For example, in one embodiment, the polymers of the present disclosure have a chloride to phosphate binding ratio in the SIB of ≧0.35 and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymers of the present disclosure have a chloride to phosphate binding ratio in the SIB of ≧0.5 and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymers of the present disclosure have a chloride to phosphate binding ratio in the SIB of ≧1 and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymers of the present disclosure have a chloride to phosphate binding ratio in the SIB of ≧2 and a swelling ratio of ≦2 g water / g dry polymer. By way of further example, in one embodiment, the polymer of the present disclosure has a chloride to phosphate binding ratio in the SIB of ≧0.35 and a swelling ratio of ≦1 g water / g dry polymer. By way of further example, in one embodiment, the polymer of the present disclosure has a chloride to phosphate binding ratio in the SIB of ≧0.5 and a swelling ratio of ≦1 g water / g dry polymer. By way of further example, in one embodiment, the polymer of the present disclosure has a chloride to phosphate binding ratio in the SIB of ≧1 and a swelling ratio of ≦1 g water / g dry polymer. By way of further example, in one embodiment, the polymer of the present disclosure has a chloride to phosphate binding ratio in the SIB of ≧2 and a swelling ratio of ≦1 g water / g dry polymer.

[0109] In an embodiment, the crosslinked amine polymer of the present disclosure in SIB versus chloride:phosphate binding ratio is shown in FIG. 2. For example, in one embodiment, the polymer of the present disclosure has a chloride binding capacity in SGF of ≧10 mmol / g and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymer of the present disclosure has a chloride binding capacity in SGF of ≧12 mmol / g and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymer of the present disclosure has a chloride binding capacity in SGF of ≧14 mmol / g and a swelling ratio of ≦2 g water / g dry polymer. As a further example, in one embodiment, the polymer of the present disclosure has a chloride binding capacity in SGF of ≧10 mmol / g and a swelling ratio of ≦1.5 g water / g dry polymer. As a further example, in one embodiment, the polymer of the present disclosure has a chloride binding capacity in SGF of ≧12 mmol / g and a swelling ratio of ≦1.5 g water / g dry polymer. By way of further example, in one embodiment, the polymers of the present disclosure have a chloride binding capacity in SGF of ≧14 mmol / g and a swelling ratio of ≦1.5 g water / g dry polymer.

[0110] In some embodiments, the theoretical chloride binding capacity of the polymers of the present disclosure may range from about 1 mmol / g to about 25 mmol / g. In one embodiment, the theoretical chloride binding capacity of the polymer is from about 3 mmol / g to about 25 mmol / g. In another embodiment, the theoretical chloride binding capacity of the polymer is from about 6 mmol / g to about 20 mmol / g. In another embodiment, the theoretical chloride binding capacity of the polymer is from about 9 mmol / g to about 17 mmol / g.

[0111] In some embodiments, the molecular weight per nitrogen of the polymers of the present disclosure may range from about 40 to about 1000 daltons. In one embodiment, the molecular weight per nitrogen of the polymer is about 40 to about 500 daltons. In another embodiment, the molecular weight per nitrogen of the polymer is about 50 to about 170 daltons. In another embodiment, the molecular weight per nitrogen of the polymer is about 60 to about 110 daltons.

[0112] In some embodiments, the crosslinker weight % range is about 10-90% by weight of the crosslinked amine polymer. For example, in some embodiments, the crosslinker weight % range is about 15-90% by weight of the crosslinked amine polymer, or even about 25-90% by weight of the crosslinked amine polymer.

[0113] Crosslinked amine polymers may be prepared using a wide variety of chemistries including, for example, (i) substitution polymerization of polyfunctional reactants, at least one of which contains an amine group; (2) radical polymerization of monomers containing at least one amine or nitrogen-containing group; and (3) crosslinking of the amine-containing intermediate with a polyfunctional crosslinker, which may optionally contain an amine group. The resulting crosslinked polymers may therefore be, for example, crosslinked homopolymers or crosslinked copolymers. As a further example, the resulting crosslinked polymers typically contain repeat units containing free amine groups separated by repeat linker (or intervening) units of the same or varying lengths. In some embodiments, the polymers have repeat units containing one amine group and one intervening linker unit. In other embodiments, multiple amine-containing repeat units are separated by one or more linker units. Additionally, the polyfunctional crosslinker may contain HCl-binding functional groups, such as amines ("active crosslinker") or may lack HCl-binding functional groups, such as amines ("passive crosslinker").

[0114] In some embodiments, the amine-containing monomers are polymerized and the polymer is crosslinked simultaneously in a substitution polymerization reaction. The amine reactants (monomers) in the simultaneous polymerization and crosslinking reaction can react more than once for substitution polymerization. In one such embodiment, the amine monomer is a linear amine having at least two reactive amine groups to participate in a substitution polymerization reaction. In another embodiment, the amine monomer is a branched amine having at least two reactive amine groups to participate in a substitution polymerization reaction. Crosslinkers for simultaneous substitution polymerization and crosslinking typically have at least two amine reactive groups, such as alkyl chlorides and alkyl epoxides. To be incorporated into the polymer, primary amines react with the crosslinker at least once, and possibly up to three times, secondary amines can react with the crosslinker up to two times, and tertiary amines can only react with the crosslinker once. However, generally and according to one aspect of the present disclosure, the formation of significant numbers of quaternary nitrogens / amines is generally not preferred, since quaternary amines cannot bond with protons.

[0115] Examples of amines that may be used in the displacement polymerization reactions described herein include 1,3-bis[bis(2-aminoethyl)amino]propane, 3-amino-1-{[2-(bis{2-[bis(3-aminopropyl)amino]ethyl}amino)ethyl](3-aminopropyl)amino}propane, 2-[bis(2-aminoethyl)amino]ethanamine, tris(3-aminopropyl)amine, 1,4-bis[bis(3-aminopropyl)amino]butane, 1,2-ethanediamine, 2-amino-1-(2-aminoethylamino)ethane, 1,2-bis(2-aminoethyl)amino]ethane, (aminoethylamino)ethane, 1,3-propanediamine, 3,3'-diaminodipropylamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,3-propanediamine, N,N'-dimethyl-1,3-propanediamine, N-methyl-1,3-diaminopropane, 3,3'-diamino-N-methyldipropylamine, 1,3-diaminopentane, 1,2-diamino-2-methylpropane, 2-methyl-1,5-diaminopentane, 1,2-diaminopropane, 1,10-diaminodecane, 1,8-diaminooctane, 1,9-Diaminooctane, 1,7-Diaminoheptane, 1,6-Diaminohexane, 1,5-Diaminopentane, 3-Bromopropylamine hydrobromide, N,2-Dimethyl-1,3-propanediamine, N-Isopropyl-1,3-diaminopropane, N,N'-Bis(2-aminoethyl)-1,3-propanediamine, N,N'-Bis(3-aminopropyl)ethylenediamine, N,N'-Bis(3-aminopropyl)-1,4-butanediamine tetrahydrochloride, 1,3-Diamino-2-propanol, N-Ethylethylenediamine , 2,2'-diamino-N-methyldiethylamine, N,N'-diethylethylenediamine, N-isopropylethylenediamine, N-methylethylenediamine, N,N'-di-tert-butylethylenediamine, N,N'-diisopropylethylenediamine, N,N'-dimethylethylenediamine, N-butylethylenediamine, 2-(2-aminoethylamino)ethanol, 1,4,7,10,13,16-hexaazacyclooctadecane, 1,4,7,10-tetraazacyclododecane, 1,4,7-triazacyclononane, N,N'-bis(2-hydroxyethyl)ethylenediamine, piperazine, bis(hexamethylene)triamine, N-(3-hydroxypropyl)ethylenediamine, N-(2-aminoethyl)piperazine, 2-methylpiperazine, homopiperazine, 1,4,8,11-tetraazacyclotetradecane, 1,4,8,12-tetraazacyclopentadecane, 2-(aminomethyl)piperidine, 3-(methylamino)pyrrolidine.

[0116] Examples of crosslinking agents which may be used in the substitution polymerization reaction and the post-polymerization crosslinking reaction include one or more multifunctional crosslinking agents, such as dihaloalkanes, haloalkyloxiranes, alkyloxirane sulfonates, di(haloalkyl)amines, tri(haloalkyl)amines, diepoxides, triepoxides, tetraepoxides, bis(halomethyl)benzenes, tri(halomethyl)benzenes, tetra(halomethyl)benzenes, epihalohydrins such as epichlorohydrin and epibromohydrin, poly(epichlorohydrin), (iodomethyl)oxirane, Glycidyl tosylate, glycidyl 3-nitrobenzenesulfonate, 4-tosyloxy-1,2-epoxybutane, bromo-1,2-epoxybutane, 1,2-dibromoethane, 1,3-dichloropropane, 1,2-dichloroethane, 1-bromo-2-chloroethane, 1,3-dibromopropane, bis(2-chloroethyl)amine, tris(2-chloroethyl)amine and bis(2-chloroethyl)methylamine, 1,3-butadiene diepoxide, 1,5-hexadiene diepoxide, diglycidyl ether, 1,2,7,8-diepoxyoctane, 1 ,2,9,10-diepoxydecane, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,2-ethanediol diglycidyl ether, glycerol diglycidyl ether, 1,3-diglycidyl glyceryl ether, N,N-diglycidylaniline, neopentyl glycol diglycidyl ether, diethylene glycol diglycidyl ether, 1,4-bis(glycidyloxy)benzene, resorcinol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycidyl ether, trimethylolpropane diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, 1,3-bis-(2,3-epoxypropyloxy)-2-(2,3-dihydroxypropyloxy)propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 2,2'-bis(glycidyloxy)diphenylmethane, bisphenol F diglycidyl ether, 1,4-bis(2',3'-epoxypropyl)perfluoro-n-butane, 2,6-di(oxiran-2-ylmethyl)-1,2,3,5,6,7-Hexahydropyrrolo[3,4-f]isoindole-1,3,5,7-tetraone, bisphenol A diglycidyl ether, ethyl 5-hydroxy-6,8-di(oxiran-2-ylmethyl)-4-oxo-4-h-chromene-2-carboxylate, bis[4-(2,3-epoxy-propylthio)phenyl]-sulfide, 1,3-bis(3-glycidoxypropyl)tetramethyldisiloxane, 9,9-bis[4-(glycidyloxy) Phenyl] fluorine, triepoxy isocyanurate, glycerol triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, isocyanuric acid (S,S,S)-triglycidyl ester, isocyanuric acid (R,R,R)-triglycidyl ester, triglycidyl isocyanurate, trimethylolpropane triglycidyl ether, glycerol propoxylate triglycidyl ether, triphenylolmethane triglycidyl ether, 3,7,14-tris[[3-(epoxypropoxy)propyl]dimethylsilyloxy]-1,3,5,7,9,11,14-heptacyclopentyltricyclo[7,3,3,15,11]heptasiloxane, 4,4'-methylenebis(N,N-diglycidylaniline), bis(halomethyl)benzene, bis(halomethyl)biphenyl and bis(halomethyl)naphthalene, toluene diisocyanate, chlorinated acrylics, methyl acrylate , ethylene bisacrylamide, pyromellitic anhydride, succinyl dichloride, dimethyl succinate, 3-chloro-1-(3-chloropropylamino-2-propanol, 1,2-bis(3-chloropropylamino)ethane, bis(3-chloropropyl)amine, 1,3-dichloro-2-propanol, 1,3-dichloropropane, 1-chloro-2,3-epoxypropane, tris[(2-oxiranyl)methyl]amine,

[0117] For radical polymerization, the amine monomers are typically monofunctional vinyl, allyl or acrylamide (e.g., allylamine) and the crosslinkers have two or more vinyl, allyl or acrylamide functionalities (e.g., diallylamine). Concurrent polymerization and crosslinking occurs by the suddenly initiated polymerization of a mixture of mono- and polyfunctional allylamines. The resulting polymer network is therefore crosslinked through the carbon backbone. Each crosslinking reaction forms a carbon-carbon bond (as opposed to a substitution reaction in which a carbon-heteroatom bond is formed during crosslinking). During concurrent polymerization and crosslinking, the amine functional groups of the monomers do not undergo crosslinking reactions and remain in the final polymer (i.e., primary amines remain primary, secondary amines remain secondary, and tertiary amines remain tertiary).

[0118] In embodiments in which the production of polymers involves radical polymerization, a wide range of initiators may be used, including cationic and radical initiators. Some examples of suitable initiators that can be used are free radical peroxy and azo type compounds such as azodiisobutyronitrile, azodiisovaleronitrile, dimethyl azodiisobutyrate, 2,2'azobis(isobutyronitrile), 2,2'-azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutyramidine), 1,1'-azobis(l-cyclohexanecarbonitrile), 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(isobutyramide) dihydrate, 2,2'-azobis(2-methylpropane), 2,2'-azobis(2-methylbutyronitrile), VAZO 67, cyanopentanoic acid, peroxypivalates, dodecylbenzene peroxide, benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl peracetate, acetyl peroxide, dicumyl peroxide, cumyl hydroperoxide, dimethyl bis(butylperoxy)hexane.

[0119] In some embodiments, the crosslinked amine polymer has the formula: [ka] wherein R1, R2 and R3 are independently hydrogen, hydrocarbyl-substituted hydrocarbyl, provided that at least one of R1, R2 and R3 is other than hydrogen. In other words, at least one of R1, R2, and R3 is hydrocarbyl or substituted hydrocarbyl, and the remaining R1, R2, and R3 are independently hydrogen, hydrocarbyl, or substituted hydrocarbyl. In one embodiment, for example, R1, R2, and R3 are independently hydrogen, aryl, aliphatic, heteroaryl, or heteroaliphatic, but each of R1, R2, and R3 is not hydrogen. As a further example, in one such embodiment, R1, R2, and R3 are independently hydrogen, saturated hydrocarbon, unsaturated aliphatic, unsaturated heteroaliphatic, heteroalkyl, heterocyclic, aryl, or heteroaryl, but each of R1, R2, and R3 is not hydrogen. As a further example, in one such embodiment, R1, R2, and R3 are independently hydrogen, alkyl, alkenyl, allyl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle, provided that each of R1, R2, and R3 is not hydrogen. As a further example, in one such embodiment, R1, R2, and R3 are independently hydrogen, alkyl, aminoalkyl, alkanol, aryl, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle, provided that each of R1, R2, and R3 is not hydrogen. As a further example, in one such embodiment, R1 and R2 (together with the nitrogen atom to which they are attached) are both part of a ring structure, and thus the monomer of formula 1 is a nitrogen-containing heterocycle (e.g., piperidine), and R3 is hydrogen or heteroaliphatic. By way of further example, in one embodiment, R1, R2, and R3 are independently hydrogen, aliphatic, or heteroaliphatic, provided that at least one of R1, R2, and R3 is other than hydrogen. By way of further example, in one embodiment, R1, R2, and R3 are independently hydrogen, allyl, or aminoalkyl.

[0120] In one embodiment, the crosslinked amine polymer comprises amine residues corresponding to formula 1, where R1, R2 and R3 are independently hydrogen, heteroaryl, aryl, aliphatic or heteroaliphatic, but at least one of R1, R2 and R3 is aryl or heteroaryl. For example, in this embodiment, R1 and R2 together with the nitrogen atom to which they are attached form a saturated or unsaturated nitrogen-containing heterocyclic ring. As a further example, R1 and R2 together with the nitrogen atom to which they are attached can be part of a pyrrolidino, pyrrole, pyrazolidine, pyrazole, imidazolidine, imidazole, piperidine, pyridine, piperazine, diazine or triazine ring structure. As a further example, R1 and R2 together with the nitrogen atom to which they are attached can be part of a piperidine ring structure.

[0121] In one embodiment, the crosslinked amine polymer comprises amine residues corresponding to formula 1, where R1, R2 and R3 are independently hydrogen, aliphatic or heteroaliphatic, but at least one of R1, R2 and R3 is other than hydrogen. For example, in this embodiment, R1, R2 and R3 can be independently hydrogen, alkyl, alkenyl, aryl, vinyl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether or heterocycle, but at least one of R1, R2 and R3 is other than hydrogen. As a further example, in one such embodiment, R1 and R2 together with the nitrogen atom to which they are attached form a saturated or unsaturated nitrogen-containing heterocyclic ring. As a further example, in one such embodiment, R1 and R2 together with the nitrogen atom to which they are attached can be part of a pyrrolidino, pyrrole, pyrazolidine, pyrazole, imidazolidine, imidazole, piperidine, piperazine or diazine ring structure. As a further example, in one such embodiment, R1 and R2, together with the nitrogen atom to which they are attached, can form part of a piperidine ring structure. As a further example, in one such embodiment, the amine corresponding to formula 1 is acyclic, and at least one of R1, R2, and R3 is aliphatic or heteroaliphatic. As a further example, in one such embodiment, R1, R2, and R3 are independently hydrogen, alkyl, allyl, vinyl, alicyclic, aminoalkyl, alkanol, or heterocyclic, with the proviso that at least one of R1, R2, and R3 is other than hydrogen.

[0122] In one embodiment, the crosslinked amine polymer comprises amine residues corresponding to Formula 1, and the crosslinked amine polymer is prepared by substitution polymerization of an amine corresponding to Formula 1, where R1, R2 and R3 are independently hydrogen, alkyl, aminoalkyl or alkanol, with the proviso that at least one of R1, R2 and R3 is other than hydrogen, and a multifunctional crosslinker (optionally including an amine group).

[0123] In some embodiments, a crosslinked amine polymer a and a crosslinked amine polymer comprising an amine residue corresponding to Formula 1 are [ka] wherein R4 and R5 are independently hydrogen, hydrocarbyl, or substituted hydrocarbyl. The monomer is prepared by radical polymerization of an amine corresponding to the formula: In one embodiment, for example, R4 and R5 are independently hydrogen, saturated hydrocarbon, unsaturated aliphatic, aryl, heteroaryl, unsaturated heteroaliphatic, heterocyclic, or heteroalkyl. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, aliphatic, heteroaliphatic, aryl, or heteroaryl. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, alkyl, alkenyl, aryl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, alkyl, aryl, aminoalkyl, alkanol, aryl, haloalkyl, hydroxyalkyl, ether, or heterocycle. As a further example, in one such embodiment, R4 and R5 (together with the nitrogen atom to which they are attached) are both part of a ring structure, and thus are the monomeric nitrogen-containing heterocycle of formula 1a (e.g., piperidine). By way of further example, in one embodiment, R4 and R5 are independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one embodiment, R4 and R5 are independently hydrogen, allyl, or aminoalkyl.

[0124] In some embodiments, the crosslinked amine polymer comprises an amine moiety corresponding to Formula 1b, [ka] wherein R4 and R5 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl; R6 is aliphatic; and R 61and R 62 are independently hydrogen, aliphatic, or heteroaliphatic. and a polyfunctional crosslinker (optionally including an amine group). In one embodiment, for example, R4 and R5 are independently hydrogen, saturated hydrocarbon, unsaturated aliphatic, aryl, heteroaryl, heteroalkyl, or unsaturated heteroaliphatic. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, aliphatic, heteroaliphatic, aryl, or heteroaryl. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, alkyl, alkenyl, aryl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle. As a further example, in one such embodiment, R4 and R5 are independently hydrogen, alkyl, alkenyl, aryl, vinyl, aryl, aminoalkyl, alkanol, aryl, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle. By way of further example, in one such embodiment, R4 and R5 (together with the nitrogen atom to which they are attached) together form part of a ring structure, thus forming a monomeric nitrogen-containing heterocycle (e.g., piperidine) as shown in formula 1a. By way of further example, in one embodiment, R4 and R5 are independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one embodiment, R4 and R5 are independently hydrogen, allyl, or aminoalkyl. By way of further example, in each of the embodiments described in this paragraph, R6 can be methylene, ethylene, or propylene, and R 61 and R 62 may independently be hydrogen, allyl, or aminoalkyl.

[0125] In some embodiments, the crosslinked amine polymer has formula 1c [ka] wherein R7 is hydrogen, aliphatic or heteroaliphatic, and R8 is aliphatic or heteroaliphatic. For example, in one such embodiment, for example, R7 is hydrogen and R8 is aliphatic or heteroaliphatic. As a further example, in one such embodiment, R7 and R8 are independently aliphatic or heteroaliphatic. As a further example, in one such embodiment, at least one of R7 and R8 comprises an allyl group. As a further example, in one such embodiment, at least one of R7 and R8 comprises an aminoalkyl group. As a further example, in one such embodiment, each of R7 and R8 comprises an allyl group. As a further example, in one such embodiment, each of R7 and R8 comprises an aminoalkyl group. As a further example, in one such embodiment, R7 comprises an allyl group and R8 comprises an aminoalkyl group.

[0126] In some embodiments, the crosslinked amine polymer has the formula: [ka] [During the ceremony, m and n are independently non-negative integers; R 10 , R 20 , R 30 and R 40 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl; X1 is [ka] and X2 is hydrocarbyl or substituted hydrocarbyl; each X 11 is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid, or halo; z is a non-negative number. The corresponding amines are:

[0127] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, and the crosslinked amine polymer is prepared by (i) substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (which optionally also contains an amine group) or (2) radical polymerization of an amine corresponding to Formula 2, where m and z are independently 0, 1, 2 or 3, and n is 0 or 1.

[0128] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, the crosslinked amine polymer being (i) a substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (optionally also containing an amine group) or (2) a crosslinker corresponding to Formula 2, R 10 , R 20 , R 30 and R 40 is prepared by radical polymerization of an amine, where R is independently hydrogen, aliphatic, aryl, heteroaliphatic, or heteroaryl. 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, R 10 , R 20 , R 30 and R 40 is independently hydrogen, alkyl, allyl, vinyl, or aminoalkyl. By way of further example, in one such embodiment, R 10 , R 20 , R 30 and R 40 are independently hydrogen, alkyl, aryl, vinyl, -(CH2) d NH2, -(CH2) d N[(CH2) e NH2)]2, where d and e are independently 2 to 4. In each of the exemplary embodiments of this paragraph, m and z can independently be 0, 1, 2, or 3;

[0129] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, and the crosslinked amine polymer is prepared by (i) substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (optionally also containing an amine group) or (2) radical polymerization of an amine corresponding to Formula 2, where X2 is aliphatic or heteroaliphatic. For example, in one such embodiment, X2 is aliphatic or heteroaliphatic and R 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, X2 is alkyl or aminoalkyl and R 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, X2 is alkyl or aminoalkyl and R 10 , R 20 , R 30 and R 40 is independently hydrogen, alkyl, allyl, vinyl, or aminoalkyl. In each of the exemplary embodiments of this paragraph, m and z can independently be 0, 1, 2, or 3; and n is 0 or 1.

[0130] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, and the crosslinked amine polymer is prepared by (i) substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (optionally also containing an amine group) or (2) radical polymerization of an amine corresponding to Formula 2, where m is a positive integer. For example, in one such embodiment, m is a positive integer, z is 0, and R 20 is hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, m is a positive integer (e.g., 1 to 3), z is a positive integer (e.g., 1 to 2), and X 11 is hydrogen, aliphatic or heteroaliphatic, and R 20is hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, m is a positive integer, z is 0, 1, or 2, and X 11 is hydrogen, alkyl, alkenyl or aminoalkyl; R 20 is hydrogen, alkyl, alkenyl, or aminoalkyl.

[0131] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, the crosslinked amine polymer being (i) a substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (which optionally also contains an amine group) or (2) a crosslinker corresponding to Formula 2, where n is a positive integer and R 30 is hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, n is 0 or 1, and R 30 is hydrogen, alkyl, alkenyl, or aminoalkyl.

[0132] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2, and the crosslinked amine polymer is prepared by (i) substitution polymerization of an amine corresponding to Formula 2 with a multifunctional crosslinker (optionally containing an amine group) or (2) radical polymerization of an amine corresponding to Formula 2, where m and n are independently negative integers and X2 is aliphatic or heteroaliphatic. For example, in one such embodiment, m is 0-2, n is 0 or 1, X2 is aliphatic or heteroaliphatic, and R 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, m is 0 to 2, n is 0 or 1, X2 is alkyl or aminoalkyl, and R 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, m is 0 to 2, n is 0 or 1, X2 is alkyl or aminoalkyl, and R 10 , R20 , R 30 and R 40 is independently hydrogen, alkyl, alkenyl, or aminoalkyl.

[0133] In some embodiments, the crosslinked amine polymer comprises an amine moiety corresponding to formula 2a, [ka] [During the ceremony, m and n are independently non-negative integers; Each R 11 is independently hydrogen, hydrocarbyl, heteroaliphatic, or heteroaryl; R 21 and R 31 are independently hydrogen or heteroaliphatic; R 41 is hydrogen, substituted hydrocarbyl or hydrocarbyl; X1 is [ka] and X2 is alkyl or substituted hydrocarbyl; each X 12 is independently hydrogen, hydroxy, amino, aminoalkyl, boronic acid, or halo; z is a non-negative number. by substitution polymerization of the corresponding amine with a polyfunctional crosslinker (which also optionally contains an amine group).

[0134] In one embodiment, the crosslinked amine polymer comprises amine residues corresponding to Formula 2a, and the crosslinked amine polymer is prepared by displacement polymerization of an amine corresponding to Formula 1 with a multifunctional crosslinker (optionally containing an amine group). For example, in one such embodiment, m and z are independently 0, 1, 2 or 3, and n is 0 or 1.

[0135] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to formula 2a, 11 are independently hydrogen, aliphatic, aminoalkyl, haloalkyl, or heteroaryl; R 21 and R 31 are independently hydrogen or heteroaliphatic; R 41 is prepared by substitution polymerization of an amine with a multifunctional crosslinker (which optionally also contains an amine group), where R is hydrogen, aliphatic, aryl, heteroaliphatic, or heteroaryl. For example, in one such embodiment, each R 11 is hydrogen, aliphatic, aminoalkyl or haloalkyl; R 21 and R 31 are independently hydrogen or heteroaliphatic; R 41 is hydrogen, alkylamino, aminoalkyl, aliphatic, or heteroaliphatic. 11 is hydrogen, aliphatic, aminoalkyl or haloalkyl; R 21 and R 31 is hydrogen or aminoalkyl, R 41 is hydrogen, aliphatic, or heteroaliphatic. By way of further example, in one such embodiment, each R 11 and R 41 are independently hydrogen, alkyl or aminoalkyl; R 21 and R 31 is independently hydrogen or heteroaliphatic. By way of further example, in one such embodiment, each R 11 and R 41 are independently hydrogen, alkyl, -(CH2) d NH2, -(CH2) d N[(CH2) e NH)]2, where d and e are independently 2 to 4; and R 21 and R 31 is independently hydrogen or heteroaliphatic. In each of the exemplary embodiments of this paragraph, m and z can independently be 0, 1, 2, or 3; and n is 0 or 1.

[0136] Examples of amines for the synthesis of polymers containing repeating units corresponding to Formula 2a include, but are not limited to, the amines shown in Table 1. [Table 1] [Table 2]

[0137] Examples of crosslinkers for the synthesis of polymers containing amine residues corresponding to Formula 2a include, but are not limited to, the crosslinkers shown in Table 2. [Table 3]

[0138] In some embodiments, the crosslinked amine polymer comprises an amine moiety corresponding to formula 2b, [ka] [During the ceremony, m and n are independently non-negative integers; Each R 12 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl; R 22 and R 32 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl; R 42 is hydrogen, hydrocarbyl or substituted hydrocarbyl; X1 is [ka] and X2 is alkyl, aminoalkyl or alkanol; each X 13 is independently hydrogen, hydroxy, alicyclic, amino, aminoalkyl, halogen, alkyl, heteroaryl, boronic acid, or aryl; z is a nonnegative number, and The amine corresponding to formula 2b contains at least one allyl group. It is prepared by radical polymerization of the corresponding amine.

[0139] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2b, wherein the crosslinked amine polymer is prepared by polymerization of an amine corresponding to Formula 2b, where m and z are independently 0, 1, 2 or 3, and n is 0 or 1.

[0140] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2b, the crosslinked amine polymer corresponds to Formula 1, and (i) R 12 or R 42 independently contains at least one allyl or vinyl group; (ii) m is a positive integer; R 22 contains at least one allyl or vinyl group, and / or (iii) n is a positive integer, R 32 is prepared by radical polymerization of an amine containing at least one allyl group. For example, in one such embodiment, m and z are independently 0, 1, 2 or 3, and n is 0 or 1. For example, in one such embodiment, R 12 or R 42 In combination, R comprises at least two allyl or vinyl groups. By way of further example, in one such embodiment, m is a positive integer and R 12 , R 22 and R 42 In combination, n comprises at least two allyl or vinyl groups. By way of further example, in one such embodiment, n is a positive integer and R 12 , R 32 and R 42 In combination, m comprises at least two allyl or vinyl groups. By way of further example, in one such embodiment, m is a positive integer, n is a positive integer, and R 12 , R 22 , R 32 and R 42 in combination contain at least two allyl or vinyl groups.

[0141] In one embodiment, the crosslinked amine polymer comprises an amine residue corresponding to Formula 2b, 12 are independently hydrogen, aminoalkyl, allyl, or vinyl; R 22 and R 32 is independently hydrogen, alkyl, aminoalkyl, haloalkyl, alkenyl, alkanol, heteroaryl, alicyclic heterocyclic, or aryl; R 42 is prepared by radical polymerization of an amine, where each R 12 is aminoalkyl, allyl or vinyl; R 22 and R 32 are independently hydrogen, alkyl, aminoalkyl, haloalkyl, alkenyl, or alkanol; R 42 is hydrogen or substituted hydrocarbyl. By way of further example, in one such embodiment, each R 12 and R 42 are independently hydrogen, alkyl, aryl, vinyl, -(CH2) d NH2 or -(CH2) d N[(CH2) e NH]2, where d and e are independently 2 to 4; and R 22 and R 32 are independently hydrogen or heteroaliphatic.

[0142] Examples of amines and crosslinkers (or salts thereof, such as the hydrochloride, phosphate, sulfate, or hydrobromide salts) for the synthesis of polymers represented by formula 2b include, but are not limited to, those shown in Table 3. [Table 4]

[0143] In some embodiments, crosslinked amine polymers are derived from the reaction of monomers shown in any of formulas 1, 1a, 1b, 1c, 2, 2a, and 2b, or the resulting polymers utilizing linear polymers consisting of repeating units as set forth in formula 3 with external crosslinkers or pre-existing polymer functionality that can act as crosslinking sites. Formula 3 represents 15 may be a repeating unit of a copolymer or terpolymer that is a random, alternating or block copolymer. [ka] [During the ceremony, R 15 , R 16 and R 17 is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid, or halo; X 15 teeth [ka] and X5 is hydrocarbyl, substituted hydrocarbyl, oxo (—O—) or amino; z is a non-negative number. The repeating unit of is also a repeating unit of a branched or hyperbranched polymer in which the primary branch point can be from any atom in the backbone of the polymer.

[0144] In one embodiment, R 15 , R 16 and R 17 are independently hydrogen, aryl or heteroaryl, X5 is hydrocarbyl, substituted hydrocarbyl, oxo or amino, and m and z are non-negative integers. 15 , R 16 and R 17 is independently aliphatic or heteroaliphatic, X5 is hydrocarbyl, substituted hydrocarbyl, oxo (-O-) or amino, and m and z are non-negative integers. 15 , R 16 and R 17is independently unsaturated aliphatic or unsaturated heteroaliphatic, X5 is hydrocarbyl, substituted hydrocarbyl, oxo or amino, and z is a non-negative integer. 15 , R 16 and R 17 is independently alkyl or heteroalkyl, X5 is hydrocarbyl, substituted hydrocarbyl, oxo or amino, and z is a non-negative integer. 15 , R 16 and R 17 is independently alkylamino, aminoalkyl, hydroxyl, amino, boronic acid, halo, haloalkyl, alkanol, or ether, X5 is hydrocarbyl, substituted hydrocarbyl, oxo, or amino, and z is a non-negative integer. 15 , R 16 and R 17 are independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid or halo; X5 is oxo, amino, alkylamino, ether, alkanol or haloalkyl; and z is a non-negative integer.

[0145] Examples of crosslinking agents that may be used in the radical polymerization reaction include one or more multifunctional crosslinking agents, such as 1,4-bis(allylamino)butane, 1,2-bis(allylamino)ethane, 2-(allylamino)-1-[2-(allylamino)ethylamino]ethane, 1,3-bis(allylamino)propane, 1,3-bis(allylamino)-2-propanol, triallylamine, diallylamine, divinylbenzene, 1,7-octadiene, 1,6-heptadiene, 1,8-nonadiene, 1,5-diphenylmethane, 1,6-phenylmethane, 1,7-phenylmethane, 1,8-phenylmethane, 1,9 ... ,9-decadiene, 1,4-divinyloxybutane, 1,6-hexamethylenebisacrylamide, ethylenebisacrylamide, N,N'-bis(vinylsulfonylacetyl)ethylenediamine, 1,3-bis(vinylsulfonyl)2-propanol, vinyl sulfone, N,N'-methylenebisacrylamide polyvinyl ethers, polyallyl ethers, divinylbenzene, 1,4-divinyloxybutane, and combinations thereof.

[0146] Crosslinked polymers derived from the monomers and polymers in formulas 1-3 can be synthesized in solution or bulk or in a dispersion medium. Examples of solvents suitable for the synthesis of the polymers of the present disclosure include, but are not limited to, water, low boiling alcohols (methanol, ethanol, propanol, butanol), dimethylformamide, dimethylsulfoxide, heptane, chlorobenzene, toluene.

[0147] Alternative polymer processes may include the use of isolated polymerization reactions, stepwise addition of individual starting monomers through a series of reactions, stepwise addition of blocks of monomers, combinations or any other polymerization methods such as living polymerization, direct polymerization, indirect polymerization, condensation, radical, emulsion, precipitation methods, spray drying polymerization or some bulk crosslinking reaction methods and size reduction steps such as grinding, compaction, extrusion. Processing can be carried out as batch, semi-continuous and continuous processes. For processing in a dispersion medium, the continuous phase can be a non-polar solvent such as toluene, benzene, hydrocarbons, halogenated solvents, supercritical carbon dioxide. Using direct suspension reactions, water can be used and salts can be used to adjust the properties of the suspension.

[0148] The starting molecules shown in Formulae 1-3 may be copolymerized with one or more other monomers, oligomers or other polymerizable groups of the present invention. Such copolymer constructs may include, but are not limited to, block or block-like polymers, graft copolymers and random copolymers. The incorporation of monomers shown in Formulae 1-3 may range from 1% to 99%. In some embodiments, the incorporation of comonomer is 20% to 80%.

[0149] Non-limiting examples of comonomers that may be used alone or in combination include styrene, allylamine hydrochloride, substituted allylamine hydrochloride, substituted styrene, alkyl acrylate, substituted alkyl acrylate, alkyl methacrylate, substituted alkyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N,N-dialkyl acrylamide, N,N-dialkyl methacrylamide, isoprene, butadiene, ethylene, vinyl acetate, N-vinyl amide, maleic acid derivatives, vinyl ether, allyl, methallyl monomers and combinations thereof. Functionalized versions of these monomers may also be used. Further specific monomers or comonomers that may be used in the present invention are 2-propen-1-ylamine, 1-(allylamino)-2-aminoethane, 1-[N-allyl(2-aminoethyl)amino]-2-aminoethane, methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, methacrylonitrile, a-methylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate (all isomers), butyl acrylate (all isomers), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate. acrylate, phenyl acrylate, acrylonitrile, styrene, glycidyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate (all isomers), hydroxybutyl methacrylate (all isomers), N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, triethylene glycol methacrylate, itaconic anhydride, itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate (all isomers), N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, triethylene glycol acrylate, methacrylamide, N-methylacrylamide, N,N-Dimethylacrylamide, N-tert-butylmethacrylamide, N-butylmethacrylamide, N-methylolmethacrylamide, N-ethylolmethacrylamide, N-tert-butylacrylamide, N-butylacrylamide, N-methylolacrylamide, N-ethylolacrylamide, 4-acryloylmorpholine, vinylbenzoic acid (all isomers), diethylaminostyrene (all isomers), a-methylvinylbenzoic acid (all isomers), diethylamino a-methylstyrene (all isomers) ), p-vinylbenzenesulfonic acid, p-vinylbenzenesulfone sodium salt, trimethoxysilylpropyl methacrylate, triethoxysilylpropyl methacrylate, tributoxysilylpropyl methacrylate, dimethoxymethylsilylpropyl methacrylate, diethoxymethylsilylpropyl methacrylate, dibutoxymethylsilylpropyl methacrylate, diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropyl Methacrylate, dibutoxysilylpropyl methacrylate, diisopropoxysilylpropyl methacrylate, trimethoxysilylpropyl acrylate, triethoxysilylpropyl acrylate, tributoxysilylpropyl acrylate, dimethoxymethylsilylpropyl acrylate, diethoxymethylsilylpropyl acrylate, dibutoxymethylsilylpropyl acrylate, diisopropoxymethylsilylpropyl acrylate, dimethoxysilylpropyl acrylate, diethoxysilylpropyl acrylate, dibutoxysilylpropyl acrylate, diisopropoxysilylpropyl acrylate, maleic anhydride, N-phenylmaleimide, N-butylmaleimide, N-vinylformamide, N-vinylacetamide, allylamine, methallylamine, allyl alcohol, methyl-vinyl ether, ethyl vinyl ether, butyl vinyl ether, butadiene, isoprene, chloroprene, ethylene, vinyl acetate and combinations thereof.

[0150] Further modifications to the preformed crosslinked polymers can be accomplished by the use of modifiers, including, but not limited to, amine monomers, additional crosslinkers, and polymers. Modifications can be accomplished by covalent or non-covalent methods. These modifications include modifications biased to the surface of the preformed crosslinked polymer, evenly or unevenly distributed throughout the preformed polymer material. Additionally, modifications can be made to alter the physical properties of the preformed crosslinked polymer, including, but not limited to, reactions occurring with remaining reactive groups, such as haloalkyl and allyl groups, in the preformed polymer. Reactions and modifications to the preformed crosslinked polymers include, but are not limited to, acid-base reactions, nucleophilic substitution reactions, Michael reactions, non-covalent electrostatic interactions, hydrophobic interactions, physical interactions (crosslinking), and radical reactions.

[0151] As further detailed in the Examples, it was found that polymers with increased crosslinking and / or entanglement swell less than those with less crosslinking and / or entanglement, yet at the same time have as high or higher binding capacity for target ions (e.g., chloride) as those with less crosslinking and / or entanglement, and significantly reduced binding of interfering ions such as phosphate. The selectivity effect was introduced in two different ways: 1) Overall capacity was sacrificed for chloride specificity. Crosslinkers that do not contain chloride binding sites (e.g., epichlorohydrin) increase crosslinking, but the overall capacity is reduced in proportion to the amount of crosslinker incorporated into the polymer. 2) Overall capacity is retained for chloride specificity. Crosslinkers that contain chloride binding sites (e.g., diallylamines) increase crosslinking, but the overall capacity remains the same or is reduced by only a small amount.

[0152] The polymers described herein exhibit ion-binding properties, generally proton binding, due to the formation of a positive charge and subsequent anion bond. In a preferred embodiment, the polymers exhibit chloride-binding properties. Ion (e.g., chloride) binding capacity is a measure of the amount of a particular ion that an ion-binding agent can bind in a certain solution. For example, the binding capacity of ion-binding polymers can be measured in vitro, e.g., in water or saline solution or in a solution / matrix containing cations and anions representative of gastrointestinal lumen conditions, or in vivo, e.g., from urinary excretion of ions (e.g., bicarbonate or citrate), or ex vivo, e.g., using aspirates, e.g., chime / gastrointestinal lumen contents obtained from experimental animals, patients or volunteers. Measurements can be performed in solutions that contain only target ions or at least do not contain other competing solutes that compete with the target ions for binding to the polymer. In these cases, non-interfering buffers are used (e.g., solutions of hydrochloric acid with or without additional sodium chloride). Alternatively, the measurements can be performed in an interference buffer that contains other competing solutes, such as other ions or metabolites, that compete with the target ions for binding to the resin.

[0153] In some embodiments, the polymer binds hydrochloric acid. For in vivo use, for example in the treatment of metabolic acidosis, it is desirable for the polymer to have high proton and chloride binding capacity. In vitro measurements of binding capacity do not necessarily translate to in vivo binding capacity. Therefore, it is useful to define binding capacity in terms of both in vitro capacity and in vivo capacity.

[0154] The in vitro chloride binding capacity of the polymers of the invention in HCl can be greater than about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 mmol / g. In some embodiments, the in vitro chloride binding capacity of the polymers of the invention for a target ion is greater than about 5.0 mmol / g, preferably greater than about 7.0 mmol / g, even more preferably greater than about 9.0 mmol / g, even more preferably greater than about 10.0 mmol / g. In some embodiments, the chloride binding capacity can range from about 5.0 mmol / g to about 25 mmol / g, preferably from about 7.5 mmol / g to about 20 mmol / g, even more preferably from about 10 mmol / g to about 15 mmol / g. Several methods are known in the art for determining chloride binding capacity.

[0155] The in vivo maximum binding capacity (i.e., the maximum amount of [proton and] chloride binding under conditions likely to be encountered in the human GI tract) can be assessed by 12-16 hour chloride binding in a simulated gastric fluid assay ("SGF") and is a structural indicator of how well the monomers and crosslinkers are incorporated. The SGF value is an experimental confirmation of the theoretical maximum binding capacity of the polymers and falls in the same range as the calculated capacity based on the stoichiometry of the starting materials.

[0156] To balance the proton binding, chloride is the anion of choice to bind because its removal has no negative effect on serum bicarbonate. Anions other than chloride that can be bound to neutralize the proton positive charge include phosphate, short chain fatty acids, long chain fatty acids, bile acids, or other organic or inorganic anions. Binding of these anions other than chloride affects overall bicarbonate stores in the intracellular and extracellular compartments.

[0157] The selectivity of the polymers for chloride binding can be evaluated in vitro using conditions that mimic the various conditions, anions and anion concentrations encountered in the GI lumen. Chloride binding can be compared to phosphate alone (e.g., SIB [artificial intestinal buffer]) or to a wide range of anions found in the GI tract (e.g., SOB).

[0158] In certain embodiments, chloride binding in the SIB assay after 1 hour exposure of the polymer to test buffer at 37° C. is greater than about 2.0 mmol / g polymer, preferably greater than about 2.5 mmol / g polymer, more preferably greater than about 3.0 mmol / g polymer, even more preferably greater than about 3.5 mmol / g polymer, and most preferably greater than about 4.0 mmol / g polymer.

[0159] In certain embodiments, chloride binding in the SOB assay after 2 hours of exposure of the polymer to test buffer at 37° C. is greater than about 1.0 mmol / g polymer, preferably greater than about 2.0 mmol / g polymer, more preferably greater than about 3.0 mmol / g polymer, even more preferably greater than about 3.5 mmol / g polymer, and most preferably greater than about 4.0 mmol / g polymer.

[0160] In one embodiment, chloride binding in the SOB assay after 8 hours exposure of the polymer to test buffer at 37° C. is greater than about 0.5 mmol / g polymer, preferably greater than about 1 mmol / g polymer, more preferably greater than about 2.0 mmol / g polymer, even more preferably greater than about 3.0 mmol / g polymer, and most preferably greater than about 4.0 mmol / g polymer. Chloride binding in the SOB after 48 hours exposure at 37° C. is an indication of the ability of the polymer to retain chloride as it passes through the GI tract.

[0161] Another method for measuring (proton and) chloride retention is to first expose the polymer to SOB, isolate the polymer, and then expose the polymer to conditions that are typical of the colonic lumen, for example, using a "chloride retention assay" (CRA) buffer. In one embodiment, after 2 hours of exposure to SOB at 37° C., followed by 48 hours of exposure to CRA at 37° C., the amount of chloride that remains bound to the polymer is greater than about 0.2 mmol / g polymer, preferably greater than about 0.5 mmol / g polymer, more preferably greater than about 1.0 mmol / g polymer, even more preferably greater than about 2.0 mmol / g polymer, and most preferably greater than about 3.0 mmol / g polymer.

[0162] In some embodiments, the in vivo binding performance of the polymers of the present disclosure can be evaluated by measuring the change in urinary acid levels after administration to animals, including humans, with normal renal function. Allowing sufficient time to reach metabolic equilibrium, the removal of additional HCl (or HCl equivalents) from the body due to the activity of the administered polymer will be reflected in changes in urinary bicarbonate, titratable acid, citrate, or other indicators of urinary acid excretion.

[0163] To bind protons, the amine components of the polymers may be primary, secondary or tertiary amines, but not quaternary amines. Quaternary amines remain substantially charged under all physiological conditions and therefore do not bind protons before anions are bound. The percentage of quaternary amines can be measured in a number of ways, including titration and reverse titration methods. Another simple but accurate method is a comparison of anion (e.g. chloride) binding at low and high pH. Chloride binding at low pH (e.g. SGF buffer conditions; pH 1.2) does not distinguish between quaternary amines and other amines, whereas chloride binding assays at high pH (e.g. QAA buffer conditions; pH 11.5) do. At this high pH, ​​primary, secondary and tertiary amines are not substantially protonated and do not contribute to chloride binding. Any binding observed under these conditions can therefore be attributed to the presence of permanently charged quaternary amines. A comparison of chloride binding at low pH (e.g., SGF conditions) versus high pH (e.g., QAA conditions) is an indication of the degree of quaternization, and by extension, the amount of protons that bind with chloride. The polymers of the present disclosure do not contain more than 40%, 30%, 20%, 10%, and most preferably 5% quaternary amines.

[0164] The swelling ratio of the polymers of the present disclosure is an experimental determination of the degree of crosslinking, and by extension, the relative pore size of the polymers and the accessibility of anions larger than chloride (or with a large hydration ratio). In some embodiments, swelling is measured in deionized water and expressed in terms of grams of water per gram of dry polymer. The polymers of the present disclosure have a swelling ratio in deionized water of ≦5 g / g, ≦4 g / g, ≦3 g / g, ≦2 g / g, or ≦1 g / g.

[0165] The ability of a polymer to retain chloride (and not release it for exchange with other anions) as it passes through the various conditions experienced in the GI lumen is an important feature that is likely to be a predictor of relative in vivo efficacy. Chloride retention assays (CRA) can be used to assess chloride retention. SOB (artificial intestinal organic / inorganic buffer) screening is first performed to bind chloride and other anions to the polymers, the polymers are isolated and exposed to conditions that mimic the colonic lumen (e.g., retention assay matrix) for 40 hours. The polymers are again isolated and the anions that remain bound to the polymer are eluted with sodium hydroxide and measured. The polymers of the present disclosure retain more than 50%, 60%, 70%, 80% or most preferably more than 90% of the bound chloride after being subjected to the chloride retention assay described.

[0166] Using the heterogeneous polymerization method, the polymer particles are obtained as spherical beads, the diameter of which is controlled in the range of 5-1000 microns, preferably 10-500 microns, and most preferably 40-180 microns.

[0167] In general, the pharmaceutical compositions of the present disclosure comprise the proton-binding crosslinked amine polymers described herein. Preferably, the pharmaceutical compositions comprising the crosslinked amine polymers are formulated for oral administration. The pharmaceutical forms in which the polymers are administered include powders, tablets, pills, lozenges, sachets, cachets, elixirs, suspensions, syrups, soft or hard gelatin capsules, and the like. In one embodiment, the pharmaceutical composition comprises only the crosslinked amine polymer. Alternatively, the pharmaceutical composition may comprise carriers, diluents or additives in addition to the crosslinked amine polymer. Examples of carriers, additives and diluents and others that may be used in these formulations include food, beverages, lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum acacia, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, methylcellulose, methyl hydroxybenzoates, propyl hydroxybenzoates, and talc. Pharmaceutical additives useful in the pharmaceutical composition further include binders such as microcrystalline cellulose, colloidal silica and combinations thereof (Prosolv 90), carbopol, bovidone and xanthan gum; flavoring agents such as sucrose, mannitol, xylitol, maltodextrin, fructose or sorbitol; lubricants such as magnesium stearate, stearic acid, sodium stearyl fumarate and vegetable-based fatty acids; and optionally disintegrants such as croscarmellose sodium, gellan gum, low-substituted hydroxypropyl ether of cellulose, sodium starch glycolate. Other additives may include plasticizers, dyes, talc, etc. Such additives and other suitable ingredients are well known in the art; see, for example, Gennaro AR (ed), Remington's Pharmaceutical Sciences, 20th Edition.

[0168] In one embodiment, the pharmaceutical composition comprising the crosslinked amine polymers of the present disclosure comprises a relatively small amount of sodium. For example, in one such embodiment, the pharmaceutical composition comprises less than 1 g of sodium per dose. By way of further example, in one such embodiment, the pharmaceutical composition comprises less than 0.5 g of sodium per dose. By way of further example, in one such embodiment, the pharmaceutical composition comprises less than 0.1 g of sodium per dose. By way of further example, in one such embodiment, the pharmaceutical composition is sodium-free.

[0169] In one embodiment, the daily dosage of the novel chronic metabolic acidosis agent enhances compliance (about 5 g / day or less) and achieves a clinically significant and sustained increase in serum bicarbonate of about 3 mEq / L at these daily dosages. The non-absorbable nature of the polymer and the lack of sodium loading and / or introduction of other harmful ions with such oral agents allows for the first time safe, long-term treatment of metabolic acidosis without worsening blood pressure / hypertension and / or causing increased fluid retention and fluid overload. Another benefit is the further delay in progression of renal disease and the time until lifelong renal replacement therapy (end-stage renal disease “ESRD” including dialysis three times a week) or kidney transplant is required. Both are associated with significant mortality, poor quality of life and significant burden on the healthcare system worldwide. In the United States alone, approximately 20% of the 400,000 ESRD patients die annually and 100,000 new patients start dialysis.

[0170] In one embodiment, the pharmaceutical composition comprises a sodium-free, non-absorbable, cross-linked, amine polymer for the treatment of metabolic acidosis, which increases serum bicarbonate in a mammal by binding HCl, thereby normalizing blood pH. One preferred embodiment provides a method for treating metabolic acidosis by binding HCl to the HCl of the polymer in an amount sufficient to cause a clinically meaningful increase in serum bicarbonate of at least 1.6 mEq / L, more preferably at least 2 mEq / L, and most preferably 3 mEq / L or greater. + Bonding, followed by Cl -The amount of HCl binding is determined by the polymer's capacity (target range of HCl binding capacity of 5-20 mEq HCl per gram of polymer) and selectivity. In the stomach, free amines are bound to H + The positive charge formed in situ on the polymer is then protonated by Cl - HCl is made available for binding to HCl, and little, if any, anions other than chloride are bound by controlled access to the binding sites through crosslinking (size exclusion, mesh size) and chemical groups (repelling large, organic ions (e.g. acetate, propionate and butyrate or other short chain fatty acids commonly found in the colon), phosphate, bile acids and fatty acids via tailored hydrophilicity / hydrophobicity). By tailoring the chemistry of the bead crosslinks and amine binding sites, chloride can be tightly bound to ensure that it is not liberated in the lower GI tract. HCl is removed from the body by normal gut motility / feces, leading to net HCl binding. In other embodiments, the polymer is derived from one that has been preformed with certain quaternized / protonated amine groups and chloride binding is achieved via ion exchange with citrate or carbonate, where up to 90% of the cationic binding sites on the polymer are preloaded with citrate and / or carbonate as counterions.

[0171] In one embodiment, an important property of sodium-free, non-absorbable, amine polymers for the treatment of metabolic acidosis in mammals that increase serum bicarbonate and normalize blood pH is that they do not increase blood pressure or exacerbate hypertension, which is of particular concern in diabetic kidney disease patients. An additional benefit of not introducing sodium is that there is no associated increase in fluid retention that can lead to fluid overload, which is of particular concern in heart failure patients. The ability of the polymers to safely and effectively treat metabolic acidosis without introducing harmful counterions allows for progression of kidney disease, which is of particular concern in chronic kidney disease patients not yet on dialysis. The initiation of dialysis is delayed for at least 3, 6, 9, or 12 months.

[0172] In yet another embodiment of the sodium-free, non-absorbable, amine polymer for the treatment of metabolic acidosis, the polymer is a crosslinked bead having a preferred particle size range that is (i) large enough to avoid passive or active absorption from the GI tract and (ii) small enough not to cause a gritty mouth feel or unpleasant mouthfeel when ingested as a powder, sachet and / or chewable tablet / dosage form with an average particle size of 40-180 microns. Preferably, the desired particle size morphology is achieved by a heterogeneous polymerization reaction, e.g., suspension or emulsion polymerization. A low swelling ratio of the polymer is preferred (0.5-5 times its own weight in water) to minimize GI side effects in patients that are often associated with large amounts of polymer gel traveling the GI tract. In yet another embodiment, the polymer has a molecular entity that is permanently / covalently and / or transiently bound to the polymer or to itself, and that acts to inhibit Cl in the colon and intestine. - / HCO3 - The net effect of blocking the antiporter is to block Cl from the intestinal lumen. - There is a decrease in the uptake and associated exchange of bicarbonate from the serum, thus effectively reducing serum bicarbonate.

[0173] In one embodiment, the crosslinked amine polymer can be co-administered with other active agents depending on the condition to be treated.This co-administration can include simultaneous administration of the two agents in the same dosage form, simultaneous administration in separate dosage forms, and separate administration.For example, for the treatment of metabolic acidosis, the crosslinked amine polymer can be co-administered with the common treatment agent that is necessary for the treatment of the underlying comorbidity, including but not limited to hypertension, diabetes, obesity, heart failure and chronic kidney disease complications.These drugs and the crosslinked amine polymer can be formulated together in the same dosage form and administered simultaneously, as long as they do not show any clinically significant drug-drug interaction.Alternatively, these treatment agents and the crosslinked amine polymer can be administered separately or sequentially, one administered followed by the other.

[0174] In further embodiments numbered 1 to 104 below, the invention includes the following:

[0175] Aspect 1. Formula 1 [ka] wherein R1, R2, and R3 are independently hydrogen, hydrocarbyl, or substituted hydrocarbyl, provided that at least one of R1, R2, and R3 is other than hydrogen. wherein the crosslinked amine polymer (i) has an equilibrium proton binding capacity of at least 5 mmol / g and a chloride ion binding capacity of at least 5 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37° C.; and (ii) an equilibrium swelling ratio of about 2 or less in deionized water.

[0176] Aspect 2. Formula 1 [ka] wherein R1, R2 and R3 are independently hydrogen or hydrocarbyl-substituted hydrocarbyl, provided that at least one of R1, R2 and R3 is other than hydrogen. wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 5 or less, and the crosslinked amine polymer binds at least a 0.35:1 molar ratio of chloride ion to interfering ion, respectively, at 37° C. in an interfering ion buffer, wherein (i) the interfering ion is phosphate ion and the interfering ion buffer is a buffer of 36 mM chloride and 20 mM phosphate at pH 5.5, or (ii) the interfering ions are phosphate, citrate and taurocholate ions (combined amounts) and the interfering ion buffer is a buffer comprising 36 mM chloride, 7 mM phosphate, 1.5 mM citrate and 5 mM taurocholate at pH 6.2.

[0177] Embodiment 3. The pharmaceutical composition of embodiment 1, wherein the crosslinked amine polymer has an equilibrium chloride binding capacity of at least 7.5 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37° C.

[0178] Embodiment 4. The pharmaceutical composition of embodiment 1, wherein the crosslinked amine polymer has an equilibrium chloride binding capacity of at least 10 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37°C.

[0179] Embodiment 5. The pharmaceutical composition of embodiment 2, wherein the crosslinked amine polymer binds more chloride than any one of the interfering anions in the interfering ion buffer, the interfering ions being phosphate, citrate and taurocholate ions and the interfering ion buffer is a buffer comprising 36 mM chloride, 7 mM phosphate, 1.5 mM citrate and 5 mM taurocholate, pH 6.2.

[0180] Embodiment 6. The pharmaceutical composition of embodiment 2, wherein at least 66% of the combined amount of chloride and interfering ions in the interfering ion buffer bound by the crosslinked amine polymer are chloride anions, the interfering ions are phosphate, citrate and taurocholate, and the interfering ion buffer is a buffer comprising 36 mM chloride, 7 mM phosphate, 1.5 mM citrate and 5 mM taurocholate, at pH 6.2.

[0181] Embodiment 7. The pharmaceutical composition of embodiment 2, wherein at least 90% of the combined amount of chloride and interfering ions in the interfering ion buffer bound by the crosslinked amine polymer are chloride anions, the interfering ions are phosphate, citrate and taurocholate, and the interfering ion buffer is a buffer comprising 36 mM chloride, 7 mM phosphate, 1.5 mM citrate and 5 mM taurocholate, at pH 6.2.

[0182] Embodiment 8. The pharmaceutical composition of embodiment 2, wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 4 or less.

[0183] Embodiment 9. The pharmaceutical composition of embodiment 2, wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 3 or less.

[0184] Embodiment 10. The pharmaceutical composition of embodiment 2, wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 2 or less.

[0185] Embodiment 11. A pharmaceutical composition according to any of the above embodiments, wherein R1, R2 and R3 are independently selected from hydrogen, alkyl, alkenyl, allyl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl or heterocycle, provided that each of R1, R2 and R3 is not hydrogen.

[0186] Embodiment 12. The pharmaceutical composition of any of the above embodiments, wherein R1, R2, and R3 are independently hydrogen, aliphatic, or heteroaliphatic, provided that at least one of R1, R2, and R3 is other than hydrogen.

[0187] Embodiment 13. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer is prepared by displacement polymerization of an amine and a multifunctional crosslinker that optionally also contains an amine group.

[0188] Embodiment 14. A crosslinked amine polymer comprising an amine moiety corresponding to Formula 1a, [ka] wherein R4 and R5 are independently hydrogen, hydrocarbyl, or substituted hydrocarbyl. 13. The pharmaceutical composition according to any one of aspects 1 to 12, which is prepared by radical polymerization of an amine corresponding to

[0189] Embodiment 15. The pharmaceutical composition of embodiment 14, wherein R4 and R5 are independently hydrogen, alkyl, alkenyl, allyl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle.

[0190] Embodiment 16. The pharmaceutical composition of embodiment 14, wherein R4 and R5 are independently hydrogen, aliphatic, or heteroaliphatic.

[0191] Embodiment 17. A crosslinked amine polymer comprises an amine moiety corresponding to Formula 1b, [ka] wherein R4 and R5 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl; R6 is aliphatic; and R 61 and R 62 are independently hydrogen, aliphatic, or heteroaliphatic. 13. The pharmaceutical composition according to any one of claims 1 to 12, wherein the pharmaceutical composition is prepared by substitution polymerization of an amine corresponding to the formula:

[0192] Embodiment 18. The pharmaceutical composition of embodiment 17, wherein R4 and R5 are independently hydrogen, saturated hydrocarbon, unsaturated aliphatic, aryl, heteroaryl, heteroalkyl, or unsaturated heteroaliphatic.

[0193] Embodiment 19. The pharmaceutical composition of embodiment 17, wherein R4 and R5 are independently hydrogen, alkyl, alkenyl, allyl, vinyl, aryl, aminoalkyl, alkanol, haloalkyl, hydroxyalkyl, ether, heteroaryl, or heterocycle.

[0194] Embodiment 20. The pharmaceutical composition of embodiment 17, wherein R4 and R5 are independently hydrogen, allyl, or aminoalkyl.

[0195] Embodiment 21 . A crosslinked amine polymer having the formula 1c [ka] wherein R7 is hydrogen, aliphatic or heteroaliphatic, and R8 is aliphatic or heteroaliphatic. The pharmaceutical composition of any of the above aspects, comprising an amine residue corresponding to:

[0196] Aspect 22. A crosslinked amine polymer having the formula: [ka] [During the ceremony, m and n are independently non-negative integers; R 10 , R 20 , R 30 and R 40 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl; X1 is [ka] and X2 is hydrocarbyl or substituted hydrocarbyl; each X 11 is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxy, or amino; z is a non-negative number. 13. The pharmaceutical composition according to any one of claims 1 to 12, comprising an amine corresponding to

[0197] Aspect 23. R 10 , R 20 , R 30 and R 40 is independently hydrogen, aliphatic, aryl, heteroaliphatic, or heteroaryl; m and z are independently 0 to 3; and n is 0 or 1.

[0198] Embodiment 24 The pharmaceutical composition of embodiment 22 or 23, wherein X2 is aliphatic or heteroaliphatic.

[0199] 25. m is 1 to 3, and X 1125. The pharmaceutical composition according to embodiment 22, 23 or 24, wherein is hydrogen, aliphatic or heteroaliphatic.

[0200] Embodiment 26. A crosslinked amine polymer having the formula 2a [ka] [During the ceremony, m and n are independently non-negative integers; Each R 11 is independently hydrogen, hydrocarbyl, heteroaliphatic, or heteroaryl; R 21 and R 31 are independently hydrogen or heteroaliphatic; R 41 is hydrogen, substituted hydrocarbyl or hydrocarbyl; X1 is [ka] and X2 is alkyl or substituted hydrocarbyl; each X 12 is independently hydrogen, hydroxy, amino, aminoalkyl, boronic acid, or halo; z is a non-negative number. 13. The pharmaceutical composition according to any one of aspects 1 to 12, comprising an amine residue corresponding to:

[0201] Aspect 27. The pharmaceutical composition according to aspect 26, wherein m and z are independently 0 to 3, and n is 0 or 1.

[0202] Aspect 28. R 11 are independently hydrogen, aliphatic, aminoalkyl, haloalkyl, or heteroaryl; R 21 and R 31 are independently hydrogen or heteroaliphatic; R 41 28. The pharmaceutical composition according to embodiment 26 or 27, wherein is hydrogen, aliphatic, aryl, heteroaliphatic, or heteroaryl.

[0203] 29. Each R11 is hydrogen, aliphatic, aminoalkyl or haloalkyl, and R 21 and R 31 is hydrogen or aminoalkyl, and R 41 28. The pharmaceutical composition according to embodiment 26 or 27, wherein is hydrogen, aliphatic or heteroaliphatic.

[0204] Embodiment 30. A crosslinked amine polymer having the formula 2b [ka] [During the ceremony, m and n are independently non-negative integers; Each R 12 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl; R 22 and R 32 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl; R 42 is hydrogen, hydrocarbyl or substituted hydrocarbyl; X1 is [ka] and X2 is alkyl, aminoalkyl or alkanol; each X 13 is independently hydrogen, hydroxy, alicyclic, amino, aminoalkyl, halogen, alkyl, heteroaryl, boronic acid, or aryl; z is nonnegative; and The amine corresponding to formula 2b contains at least one allyl group. 13. The pharmaceutical composition according to any one of claims 1 to 12, comprising an amine residue corresponding to:

[0205] Aspect 31. The pharmaceutical composition according to aspect 30, wherein m and z are independently 0 to 3, and n is 0 or 1.

[0206] Aspect 32. R 12 or R 42independently comprises at least one allyl or vinyl group.

[0207] Aspect 33. (i) m is a positive integer and R 12 , R 22 and R 42 in combination contain at least two allyl or vinyl groups, or (ii) n is a positive integer and R 12 , R 32 and R 42 In combination, comprises at least two allyl or vinyl groups.

[0208] Embodiment 34 The pharmaceutical composition of embodiment 30 or 31, wherein the crosslinked amine polymer comprises an amine residue as set forth in Table 1.

[0209] Embodiment 35 The pharmaceutical composition of embodiment 30, 31, or 34, wherein the crosslinked amine polymer is crosslinked with a crosslinker shown in Table 2.

[0210] Aspect 36 . A crosslinked amine polymer having formula 3 [ka] [During the ceremony, R 15 , R 16 and R 17 is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid, or halo; X 15 teeth [ka] and X5 is hydrocarbyl, substituted hydrocarbyl, oxo (—O—) or amino; z is a non-negative number. 4. The pharmaceutical composition according to any of the above aspects, comprising a repeating unit corresponding to:

[0211] Aspect 37. R 15 , R16 and R 17 is independently aliphatic or heteroaliphatic.

[0212] Embodiment 38. The pharmaceutical composition according to embodiment 36 or 37, wherein X5 is oxo, amino, alkylamino, ether, alkanol, or haloalkyl.

[0213] Aspect 39. The pharmaceutical composition of any one of Aspects 1-12, wherein the crosslinked amine polymer is prepared by (i) substitution polymerization of multifunctional reactants, at least one of which contains an amine group; (2) radical polymerization of monomers that contain at least one amine group or nitrogen-containing group; or (3) crosslinking of an amine-containing intermediate with a crosslinker that may optionally contain an amine group.

[0214] Embodiment 40 The pharmaceutical composition of embodiment 39, wherein the crosslinked amine polymer is a crosslinked homopolymer or a crosslinked copolymer.

[0215] Embodiment 41 The pharmaceutical composition of embodiment 39, wherein the crosslinked amine polymer comprises free amine groups separated by repeating linker units of the same or varying length.

[0216] Embodiment 42. The pharmaceutical composition of embodiment 39, wherein the crosslinked amine polymer is prepared by polymerization of an amine-containing monomer with a crosslinker by a substitution polymerization reaction.

[0217] Embodiment 43. The pharmaceutical composition of embodiment 42, wherein the amine-containing monomer is a linear amine having at least two reactive amine groups for participating in a substitution polymerization reaction.

[0218] Aspect 44. The amine-containing monomer is 1,3-bis[bis(2-aminoethyl)amino]propane, 3-amino-1-{[2-(bis{2-[bis(3-aminopropyl)amino]ethyl}amino)ethyl](3-aminopropyl)amino}propane, 2-[bis(2-aminoethyl)amino]ethanamine, tris(3-aminopropyl)amine, 1,4-bis[bis(3-aminopropyl)amino]butane, 1,2-ethanediamine, 2-amino-1-(2-aminoethylamino)ethane, 1,2-bis(2-aminoethylamino)ethane, 1,3-propanediamine, 3,3'-diaminodipropylamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,3-propanediamine, N,N'-dimethyl-1,3-propanediamine, N-methyl-1,3-diaminopropane, 3,3'-diamino-N-methyldipropylamine, 1,3-diaminopentane, 1,2-diamino-2-methylpropane, 2-methyl-1,5-diaminopentane, 1,2-diaminopropane, 1,10-diaminodecane, 1,8-diaminooctane, 1,9-diaminooctane , 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 3-bromopropylamine hydrobromide, N,2-dimethyl-1,3-propanediamine, N-isopropyl-1,3-diaminopropane, N,N'-bis(2-aminoethyl)-1,3-propanediamine, N,N'-bis(3-aminopropyl)ethylenediamine, N,N'-bis(3-aminopropyl)-1,4-butanediamine tetrahydrochloride, 1,3-diamino-2-propanol, N-ethylethylenediamine, 2,2' -Diamino-N-methyldiethylamine, N,N'-diethylethylenediamine, N-isopropylethylenediamine, N-methylethylenediamine, N,N'-di-tert-butylethylenediamine, N,N'-diisopropylethylenediamine, N,N'-dimethylethylenediamine, N-butylethylenediamine, 2-(2-aminoethylamino)ethanol, 1,4,7,10,13,16-hexaazacyclooctadecane, 1,4,7,10-tetraazacyclododecane, 1,4,7-triazacyclononane, N,44. The pharmaceutical composition according to aspect 42 or 43, wherein the compound is N'-bis(2-hydroxyethyl)ethylenediamine, piperazine, bis(hexamethylene)triamine, N-(3-hydroxypropyl)ethylenediamine, N-(2-aminoethyl)piperazine, 2-methylpiperazine, homopiperazine, 1,4,8,11-tetraazacyclotetradecane, 1,4,8,12-tetraazacyclopentadecane, 2-(aminomethyl)piperidine or 3-(methylamino)pyrrolidino.

[0219] Aspect 45. The crosslinker is selected from the group consisting of dihaloalkanes, haloalkyloxiranes, alkyloxirane sulfonates, di(haloalkyl)amines, tri(haloalkyl)amines, diepoxides, triepoxides, tetraepoxides, bis(halomethyl)benzenes, tri(halomethyl)benzenes, tetra(halomethyl)benzenes, epihalohydrins such as epichlorohydrin and epibromohydrin poly(epichlorohydrin), (iodomethyl)oxirane, glycidyl tosylate, glycidyl 3-nitrobenzenesulfonate, 4-tosyloxy -1,2-epoxybutane, bromo-1,2-epoxybutane, 1,2-dibromoethane, 1,3-dichloropropane, 1,2-dichloroethane, 1-bromo-2-chloroethane, 1,3-dibromopropane, bis(2-chloroethyl)amine, tris(2-chloroethyl)amine and bis(2-chloroethyl)methylamine, 1,3-butadiene diepoxide, 1,5-hexadiene diepoxide, diglycidyl ether, 1,2,7,8-diepoxyoctane, 1,2,9,10-diepoxydecane, ethylene glycol diglycidyl ether , propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,2-ethanediol diglycidyl ether, glycerol diglycidyl ether, 1,3-diglycidyl glyceryl ether, N,N-diglycidylaniline, neopentyl glycol diglycidyl ether, diethylene glycol diglycidyl ether, 1,4-bis(glycidyloxy)benzene, resorcinol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, 1, 4-Cyclohexanedimethanol diglycidyl ether, 1,3-bis-(2,3-epoxypropyloxy)-2-(2,3-dihydroxypropyloxy)propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 2,2'-bis(glycidyloxy)diphenylmethane, bisphenol F diglycidyl ether, 1,4-bis(2',3'epoxypropyl)perfluoro-n-butane, 2,6-di(oxiran-2-ylmethyl)-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-1,3,5,7-Tetrone, Bisphenol A Diglycidyl Ether, Ethyl 5-Hydroxy-6,8-di(oxiran-2-ylmethyl)-4-oxo-4-h-chromene-2-carboxylate, Bis[4-(2,3-epoxy-propylthio)phenyl]-sulfide, 1,3-bis(3-glycidoxypropyl)tetramethyldisiloxane, 9,9-bis[4-(glycidyloxy)phenyl]fluorine, Triepoxyisocyanurate, Glycerol Triglyceride isocyanuric acid (S,S,S)-triglycidyl ester, isocyanuric acid (R,R,R)-triglycidyl ester, triglycidyl isocyanurate, trimethylolpropane triglycidyl ether, glycerol propoxylate triglycidyl ether, triphenylolmethane triglycidyl ether, 3,7,14-tris[[3-(epoxypropoxy)propyl] Dimethylsilyloxy]-1,3,5,7,9,11,14-heptacyclopentyltricyclo[7,3,3,15,11]heptasiloxane, 4,4'-methylenebis(N,N-diglycidylaniline), bis(halomethyl)benzene, bis(halomethyl)biphenyl and bis(halomethyl)naphthalene, toluene diisocyanate, acrylic chloride, methyl acrylate, ethylene bisacrylamide, pyromellitic anhydride, succinyl dichloride, succinyl acrylate, ethyl ... 45. The pharmaceutical composition according to any one of aspects 39, 41, 43 and 44, wherein the aryl ester is selected from the group consisting of dimethyl ether, 3-chloro-1-(3-chloropropylamino-2-propanol, 1,2-bis(3-chloropropylamino)ethane, bis(3-chloropropyl)amine, 1,3-dichloro-2-propanol, 1,3-dichloropropane, 1-chloro-2,3-epoxypropane, tris[(2-oxiranyl)methyl]amine and combinations thereof.

[0220] Embodiment 46 The pharmaceutical composition of embodiment 39, wherein preparation of the crosslinked amine polymer comprises radical polymerization of amine monomers containing at least one amine group or nitrogen-containing group.

[0221] Embodiment 47. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 1.5 or less.

[0222] Embodiment 48. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has an equilibrium swelling ratio in deionized water of about 1 or less.

[0223] Embodiment 49. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride ion to phosphate ion binding molar ratio of at least 0.5:1, respectively, in an aqueous simulated small intestine inorganic buffer ("SIB") comprising 36 mM NaCl, 20 mM NaH2PO4, and 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffered to pH 5.5 at 37°C.

[0224] Embodiment 50. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride ion to phosphate ion binding molar ratio of at least 1:1, respectively, in an aqueous simulated small intestine inorganic buffer ("SIB") comprising 36 mM NaCl, 20 mM NaH2PO4, and 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffered to pH 5.5 at 37°C.

[0225] Embodiment 51. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride ion to phosphate ion binding molar ratio of at least 2:1, respectively, in an aqueous simulated small intestine inorganic buffer ("SIB") comprising 36 mM NaCl, 20 mM NaH2PO4, and 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), buffered to pH 5.5 at 37°C.

[0226] Embodiment 52. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a proton binding capacity of at least 10 mmol / g and a chloride ion binding capacity of at least 10 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37° C.

[0227] Embodiment 53. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has an equilibrium proton binding capacity of at least 12 mmol / g and a chloride ion binding capacity of at least 12 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37° C.

[0228] Embodiment 54. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has an equilibrium proton binding capacity of at least 14 mmol / g and a chloride ion binding capacity of at least 14 mmol / g in an aqueous simulated gastric fluid buffer ("SGF") containing 35 mM NaCl and 63 mM HCl at pH 1.2 and 37° C.

[0229] Embodiment 55. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride binding capacity of at least 1 mmol / g in an aqueous simulated small intestine organic and inorganic buffer ("SOB") comprising 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid, and 5 mM sodium taurocholate buffered to pH 6.2 at 37°C.

[0230] Embodiment 56. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride binding capacity of at least 2 mmol / g in an aqueous simulated small intestine organic and inorganic buffer ("SOB") comprising 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid, and 5 mM sodium taurocholate buffered to pH 6.2 at 37°C.

[0231] Embodiment 57. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride binding capacity of at least 3 mmol / g in an aqueous simulated small intestine organic and inorganic buffer ("SOB") comprising 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid, and 5 mM sodium taurocholate buffered to pH 6.2 at 37°C.

[0232] Embodiment 58. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride binding capacity of at least 4 mmol / g in an aqueous simulated small intestine organic and inorganic buffer ("SOB") comprising 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid, and 5 mM sodium taurocholate buffered to pH 6.2 at 37°C.

[0233] Embodiment 59. The pharmaceutical composition of any of the above embodiments, wherein the crosslinked amine polymer has a chloride binding capacity of at least 5 mmol / g in an aqueous simulated small intestine organic and inorganic buffer ("SOB") comprising 50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 50 mM sodium acetate, 36 mM sodium chloride, 7 mM sodium phosphate, 1.5 mM sodium citrate, 30 mM oleic acid, and 5 mM sodium taurocholate buffered to pH 6.2 at 37°C.

[0234] Embodiment 60. The pharmaceutical composition of any of the above embodiments, wherein the percentage of quaternized amines is less than 40%.

[0235] Aspect 61. The pharmaceutical composition of any of the above aspects, wherein the percentage of quaternized amines is less than 30%.

[0236] Embodiment 62. The pharmaceutical composition of any of the above embodiments, wherein the percentage of quaternized amines is less than 20%.

[0237] Aspect 63. The pharmaceutical composition of any of the above aspects, wherein the percentage of quaternized amines is less than 10%.

[0238] Embodiment 64. The pharmaceutical composition of any of the above embodiments, wherein the percentage of quaternized amines is less than 5%.

[0239] Aspect 65. The pharmaceutical composition of any of the above aspects, wherein the crosslinked amine polymer is a gel or beads having an average particle size of 40 to 180 micrometers.

[0240] Aspect 66. The pharmaceutical composition of any of the above aspects, wherein the crosslinked amine polymer is a gel or beads having an average particle size of 60 to 160 micrometers.

[0241] Aspect 67. The pharmaceutical composition of any of the above aspects, wherein the crosslinked amine polymer is a gel or beads having an average particle size of 80 to 140 micrometers.

[0242] Embodiment 68. A pharmaceutical composition described in embodiments 65 to 67, wherein less than about 0.5 volume percent of the particles have a diameter of less than about 10 micrometers.

[0243] Embodiment 69. A pharmaceutical composition described in embodiments 65 to 67, wherein less than about 5 volume percent of the particles have a diameter of less than about 20 micrometers.

[0244] Embodiment 70. The pharmaceutical composition of any one of embodiments 65 to 67, wherein less than about 0.5 volume percent of the particles have a diameter less than about 20 micrometers.

[0245] Embodiment 71. The pharmaceutical composition of any one of embodiments 65 to 67, wherein less than about 5 volume percent of the particles have a diameter less than about 30 micrometers.

[0246] Aspect 72. The pharmaceutical composition of any one of the above aspects, which is in dosage unit form.

[0247] Aspect 73. The pharmaceutical composition of aspect 72, wherein the dosage unit form is a capsule, tablet or sachet dosage form.

[0248] Embodiment 74. The pharmaceutical composition of any of the above embodiments, wherein the pharmaceutical composition comprises a pharma- ceutically acceptable carrier, excipient, or diluent.

[0249] Embodiment 75. A method for treating an acid / base disorder in an animal, including a human, by removing HCl by oral administration of a pharmaceutical composition according to any of the above embodiments.

[0250] Embodiment 76. The method of treatment according to embodiment 75, wherein the acid / base disorder is metabolic acidosis.

[0251] Embodiment 77. A method of treatment according to embodiment 75, which regulates or normalizes pH.

[0252] A method of treatment according to Aspect 75, which controls or normalizes serum bicarbonate.

[0253] Embodiment 79. A method of treatment according to embodiment 75, wherein less than 1 g of sodium or potassium is administered per day.

[0254] Embodiment 80. A method of treatment according to embodiment 75, wherein less than 0.5 g of sodium or potassium is administered per day.

[0255] Embodiment 81. A method of treatment according to embodiment 75, wherein less than 0.1 g of sodium or potassium is administered per day.

[0256] Embodiment 82. The method of treatment of embodiment 75, wherein sodium or potassium is not administered.

[0257] Embodiment 83. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 20 g.

[0258] Embodiment 84. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 15 g.

[0259] Embodiment 85. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 10 g.

[0260] Embodiment 86. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 5 g.

[0261] Embodiment 87. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 4 g.

[0262] Embodiment 88. A method of treatment according to embodiment 75, wherein the administered daily dosage is less than 3 g.

[0263] Embodiment 89. The method of treatment of embodiment 75, wherein the daily dose is administered once a day.

[0264] Embodiment 90. A method of treatment according to embodiment 75, wherein the daily dose is administered twice a day.

[0265] Embodiment 91. A method of treatment according to embodiment 75, wherein the daily dose is administered three times a day.

[0266] Embodiment 92. The method of treatment of embodiment 75, wherein the metabolic acidosis is acute metabolic acidosis.

[0267] Embodiment 93. The method of treatment of embodiment 75, wherein administration is chronic.

[0268] Embodiment 94. A method of treatment according to embodiment 75, wherein the daily dosage results in a sustained increase in serum bicarbonate of ≧1.6 mEq / L.

[0269] Embodiment 95. A method of treatment according to embodiment 75, wherein the daily dosage results in a sustained increase in serum bicarbonate of ≧2 mEq / L.

[0270] Embodiment 96. A method of treatment according to embodiment 75, wherein the daily dosage results in a sustained increase in serum bicarbonate of ≧3 mEq / L.

[0271] Embodiment 97. A method of treatment according to embodiment 75, wherein the daily dosage results in a sustained increase in serum bicarbonate of ≧5 mEq / L.

[0272] Embodiment 98. A method of treatment according to embodiment 75, wherein the daily dosage results in a sustained increase in serum bicarbonate of ≧10 mEq / L.

[0273] Embodiment 99. A method of treatment according to embodiment 75, wherein a daily dosage of 10 g or less per day results in an increase in serum bicarbonate of ≧3 mEq / L.

[0274] Embodiment 100. A method of treatment according to embodiment 75, wherein a daily dosage of 5 g or less per day results in an increase in serum bicarbonate of ≧3 mEq / L.

[0275] Embodiment 101. A method of treatment according to any one of embodiments 83 to 99, wherein the dosage is titrated based on the serum bicarbonate level or other indicator of acidosis in a patient in need of treatment.

[0276] Embodiment 102. The pharmaceutical composition of any one of embodiments 1-74, wherein the crosslinked amine polymer retains ≧1 mmol / g chloride through the GI tract.

[0277] Embodiment 103. The pharmaceutical composition of any one of embodiments 1-74, wherein the crosslinked amine polymer retains ≧2 mmol / g chloride through the GI tract.

[0278] Embodiment 104. The pharmaceutical composition of any one of embodiments 1-74, wherein the crosslinked amine polymer retains ≧4 mmol / g chloride through the GI tract.

[0279] Embodiment 105. The pharmaceutical composition of any one of embodiments 1-74, wherein the crosslinked amine polymer retains ≧8 mmol / g chloride through the GI tract.

[0280] Embodiment 106. The pharmaceutical composition according to any one of Embodiments 1 to 74, wherein the dosage of the pharmaceutical composition is titrated based on serum bicarbonate levels or other indicators of acidosis in a patient in need of treatment.

[0281] Embodiment 107. The pharmaceutical composition according to any one of embodiments 1 to 74 or the method according to any one of embodiments 75 to 101, wherein the aliphatic group is alkyl or alkenyl.

[0282] Embodiment 108. The pharmaceutical composition according to any one of embodiments 1 to 74 or the method according to any one of embodiments 75 to 101, wherein the heteroaliphatic group is a heteroalkyl group or a heteroalkenyl group.

[0283] Although the invention has been described in detail, it will be appreciated that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. It should further be appreciated that all examples herein are provided as non-limiting examples. EXAMPLES

[0284] The following non-limiting examples are provided to further illustrate the present invention. It should be appreciated by those skilled in the art that the techniques described in the following examples represent methods that the inventors have discovered to work well in the practice of the present invention and are therefore considered to constitute examples of its embodiments. However, those skilled in the art should, in light of the present disclosure, appreciate that many changes can be made to the specific embodiments disclosed and still obtain the same or similar results without departing from the spirit and scope of the present invention.

[0285] I. Preparation and Synthesis of Control Polymers A. Free amine sevelamer Rembela was purchased from a commercial supplier. 84 sachets (i.e. 201.4 gm) of Rembela (Sevelamer Carbonate) were placed in a 5 L plastic beaker. 4 litres of Milli-Q water was added to the beaker and the contents were stirred for 30 minutes using a magnetic stir plate and stir bar. The contents were then transferred to a filter frit equipped with P8 Whatman filter paper and excess supernatant was removed by application of negative vacuum. The steps of water addition, stirring, filtering and removing the supernatant were repeated a total of three times. After the final water wash, 3 litres of 1 M sodium hydroxide was added to the beaker and stirred for 30 minutes. Vacuum filtration was then performed to remove excess sodium hydroxide. The steps of sodium hydroxide addition, stirring and vacuum filtration were repeated for a total of two sodium hydroxide washes. The polymer was washed with Milli-Q water to remove excess sodium hydroxide. The pH of the filtrate was measured using pH paper and the polymer was washed with water until the pH of the filtrate was below 7. The wet polymer was transferred to a glass tray, frozen at -40°C for 1 h, and lyophilized for 3-5 days to dry the polymer. Loss on drying of the polymer was measured using an A&D MX-50 hygrometer (standard mode, ramp to and hold at 130°C).

[0286] B. Bixalomer Kiklin (bixalomer) capsules were purchased from a commercial supplier, and the free amine polymer was removed directly from the capsule without further purification. Additional bixalomer controls were prepared according to the information in the Kiklin package insert (prescribing information) and the procedures of US 7,459,502. The bixalomer controls used as comparative substances in the seven examples below were prepared with a molar ratio of epichlorohydrin ("ECH") to 1,4-bis[bis(3-aminopropyl)amino]butane ("C4A3BTA") of 2.35:1, which fell within the 2.4:1 to 2:1 tolerance range set forth in the Kiklin package insert, and produced polymers with comparable performance to Kiklin, as measured by the swelling and SGF assays described above. The aqueous stock solution was prepared by dissolving C4A3BTA (25.06 g), HCl (15.58 g concentrated HCl) and Calimulse EM-99 (branched dodecylbenzenesulfonate, 1.39 g) in water (17.99 g). The aqueous stock solution and toluene were placed in a three-necked round-bottom flask with four side baffles, equipped with an overhead stirrer, Dean-Stark apparatus and condenser and nitrogen inlet. The reaction mixture was stirred under an inert atmosphere and heated to 80 °C. ECH (17.47 g) was introduced as a 40 wt% solution in toluene, which was added semi-continuously from a syringe pump over a period of 1 h. The reaction mixture was stirred at 80 °C for 30-45 min, after which the bath temperature was increased to 110 °C for the final dehydration step. When 24 mL of water had been collected, the flask was cooled to room temperature and the toluene was removed by filtration. The resulting polymer beads were purified by washing with toluene (100 mL, 3 times), 27 wt% HCl (50 mL, 3 times), water (100 mL, 3 times), a solution of 10:9:1 water:methanol:NaOH (100 mL, 2 times), water (100 mL, 5 times), methanol (50 mL, 3 times), 20 wt% NaOH (300 mL, 2 times), and water until the pH of the solution after washing was 7. The beads were then dried in a freeze dryer for 48 hours. Swelling and SGF assays were used to determine the performance equivalence of the synthetic bixalomer polymers compared to commercial kicklin used "as is" from the capsule as a performance control for the synthetic polymers.

[0287] II. Chemical Examples The following chemical examples are presented in five categories based on the polymerization mechanism used. (a) Displacement polymerization (condensation / step-growth) gel (b) Displacement polymerization (condensation / step growth) beads (c) Radical polymerization (addition / chain growth) gel (d) Radical Polymerization (Addition / Chain Growth) Beads (e) Post-polymerization crosslinking In each case, the general polymerization method is described and the modified synthesis parameters are listed where appropriate in the table of specific examples. A table of the physicochemical performance characteristics (SGF and swelling) of the resulting polymers is also provided.

[0288] A. Substitution Polymerization of Small Amines Under stirring, the amine monomer, crosslinker, solvent and base or acid were charged to a reaction vessel. After mixing, the solution was heated and stirred. After the reaction was complete, the reaction was cooled. The gel was mechanically ground to a fine powder, purified and dried to constant weight. Examples of amines and crosslinkers suitable for the synthesis of the polymers described in this example include, but are not limited to, the amine and crosslinker combinations shown in Table 4. Table 5 shows important physicochemical properties (i.e., SGF binding and swelling ratio) of the example polymers shown in Table 4.

[0289] 1. Specific method for C2PW+DCP gel 2-[Bis(2-aminoethyl)amino]ethanamine (“C2PW”) (1.00 g), water (1.00 g), and sodium hydroxide (1.64 g) were charged to a 20 mL scintillation vial equipped with a stir bar. Under vigorous stirring, one dose of 1,3-dichloropropane (“DCP”) (2.32 g) was added. After mixing, the solution was heated to 80° C. and stirred vigorously for 16 hours. The reaction was cooled to 25° C. and 10 mL of water was added to solidify the gel. The gel was mechanically ground to a fine powder. The resulting solution was centrifuged and the aqueous phase was decanted. The resulting ground polymer gel was purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and finally with water until the pH of the solution after washing was 7. This polymer is shown in Tables 4 and 5 as Polymer No. 37.

[0290] 2. Specific method for EDA3+BCPA gel 1,2-Bis(2-aminoethylamino)ethane (“EDA3”) (0.11 g), water (0.50 g), bis(3-chloropropyl)amine (“BCPA”) (0.50 g), and sodium hydroxide (0.19 g) were charged to a 20 mL scintillation vial equipped with a stir bar. After mixing, the solution was heated to 80° C. and stirred vigorously for 16 hours. The reaction was cooled to 25° C. and 10 mL of water was added to solidify the gel. The gel was mechanically ground to a fine powder. The resulting solution was centrifuged and the aqueous phase was decanted. The resulting ground polymer gel was purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and finally water until the pH of the solution after washing was 7. This polymer is shown in Tables 4 and 5 as polymer number 54.

[0291] 3. Specific Method for C2PW+TGA Gel C2PW (0.50 g) and water (0.75 g) were placed in a 20 mL scintillation vial equipped with a stir bar. Under vigorous stirring, one dose of tris[(2-oxiranyl)methyl]amine (“TGA”) (0.79 g) was added. After mixing, the solution was heated to 80° C. and stirred vigorously for 16 hours. The reaction was cooled to 25° C. and 10 mL of water was added to solidify the gel. The gel was mechanically ground to a fine powder. The resulting solution was centrifuged and the aqueous phase was decanted. The resulting ground polymer gel was purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and finally water until the pH of the solution after washing was 7. This polymer is shown in Tables 4 and 5 as polymer number 71.

[0292] [Table 5] [Table 6] [Table 7]

[0293] [Table 8] [Table 9] [Table 10]

[0294] B. General Polymerization Method for Beads Formed by Substitution Polymerization of Small Amines Aqueous stock solutions were prepared by dissolving amine monomers and surfactants in water. In some cases, HCl was added to the aqueous stock solution. The aqueous stock solution and organic solvent were charged to a reactor equipped with an overhead stirrer. The crosslinker was introduced in one of two ways. In the first method, the crosslinker was introduced as part of the aqueous solution before mixing with the organic solvent. In the second method, the crosslinker was introduced semi-continuously over a period of several hours by a syringe pump after heating of the reactor containing the aqueous stock solution and organic solvent was started. After the reaction was complete, the organic solvent was removed and the beads were purified by washing the beads with various solvents. The beads were dried to constant weight in a lyophilizer. This method applies to linear and branched amines and crosslinkers with or without HCl-binding functional groups such as amines ("active" and "passive" crosslinkers, respectively). Examples of amines and crosslinkers suitable for the synthesis of the polymers described in this example include, but are not limited to, the amine and crosslinker combinations shown in Table 6. Table 7 shows important physicochemical properties (ie, SGF binding and swelling ratio) of the exemplary polymers shown in Table 6.

[0295] 1. Specific method for C4A3BTA+ECH beads An aqueous stock solution was prepared by dissolving 1,4-bis[bis(3-aminopropyl)amino]butane (“C4A3BTA”) (10.02 g), HCl (6.25 g concentrated HCl), and Calimulse EM-99 (branched dodecylbenzenesulfonate, 0.56 g) in water (7.18 g). The aqueous stock solution and toluene were charged to a round bottom flask equipped with an overhead stirrer and condenser. The reaction mixture was stirred under an inert atmosphere and heated to 80° C. Epichlorohydrin (“ECH”) (21.37 g) was introduced as a 40 wt % solution in toluene, which was added semi-continuously via syringe pump over a period of 1 hour. The reaction mixture was stirred at 80° C. for 16 hours, after which the reaction mixture was cooled to room temperature and removed from the reactor. The toluene was decanted off and the resulting polymer beads were purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and water until the pH of the solution after washing was 7. This polymer is shown in Tables 6 and 7 as Polymer No. 21. [Table 11] [Table 12]

[0296] [Table 13] [Table 14]

[0297] C. General Polymerization Method for Gels Formed by Radical Polymerization (Addition / Chain Growth) An aqueous solution of monoallylamine hydrochloride, multiallylamine crosslinker and radical initiator was placed in a reaction vessel. The reaction mixture was heated and then the vessel was cooled to room temperature. The resulting polymer gel was swollen with water and ground to a fine powder. The resulting gel was purified by washing and dried to a constant weight. Examples of amines suitable for the synthesis of the polymers described in this example include, but are not limited to, the amines shown in Table 8. Table 9 shows important physicochemical properties (i.e., SGF binding and swelling ratio) of the exemplary polymers shown in Table 8.

[0298] 1. Specific method for AAH+TAA gel A round bottom flask in a parallel reactor equipped with a magnetic stir bar and nitrogen inlet was charged with water (2.14 g), allylamine hydrochloride (1-(allylamino)-2-aminoethane, "AAH") (0.55 g), triallylamine ("TAA") (0.71 g), concentrated HCl (0.15 g), and V-50 (2,2'-azobis(2-methylpropionamidine) dihydrochloride) (0.068 g). The reaction mixture was purged with nitrogen for 15 min and heated to 80°C under an inert atmosphere. After 16 h, the vessel was cooled to room temperature and removed from the reactor. The polymer gel was swollen with water and mechanically crushed. The resulting fine powder was purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and water until the pH of the solution after washing was 7. The gel was dried in a freeze dryer for 48 hours. This polymer is shown in Tables 8 and 9 as Polymer No. 10.

[0299] 2. Specific method for AAH+DAEDA1 gel A round bottom flask in a parallel reactor equipped with a magnetic stir bar and nitrogen inlet was charged with water (2.53 g), allylamine hydrochloride (1-(allylamino)-2-aminoethane, "AAH") (0.54 g), 1,2-bis(allylamino)ethane ("DAEDA1") (0.86 g), and V-50 (2,2'-azobis(2-methylpropionamidine) dihydrochloride) (0.067 g). The reaction mixture was purged with nitrogen for 15 min and heated to 80°C under an inert atmosphere. After 16 h, the vessel was cooled to room temperature and removed from the reactor. The polymer gel was swollen with water and mechanically crushed. The resulting fine powder was purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 3 times), and water until the pH of the solution after washing was 7. The gel was dried in a freeze dryer for 48 hours. This polymer is shown in Tables 8 and 9 as Polymer No. 2. [Table 15]

[0300] [Table 16]

[0301] D. General Polymerization Method for Beads Formed by Radical Polymerization (Addition / Chain Growth) An aqueous stock solution was prepared by dissolving the monoallylamine and multiallylamine crosslinkers in water. A reactor equipped with a stirrer was charged with the aqueous stock solution and the surfactant dissolved in a hydrophobic organic suspending solvent. A solution of radical initiator was prepared. The two mixtures were individually flushed with nitrogen. The initiator solution was added to the reaction mixture, which was then heated for up to 16 hours. Depending on the polymerization reaction kinetics, a second initiator is added to the reaction mixture if necessary. The reaction mixture may also include a dehydration step to produce a more concentrated reaction mixture and to polymerize the less active monomers and crosslinker. After cooling the vessel to room temperature, the organic phase was removed and the beads were purified and dried. Examples of amines and crosslinkers suitable for the synthesis of the polymers described in this example include, but are not limited to, the amines and crosslinker combinations shown in Table 10, Part 1. These beads were then subjected to post-polymerization crosslinking as described below in E and Table 10, Part 2.

[0302] 1. Specific method for AAH+DAEDA1 beads An aqueous stock solution was prepared by dissolving allylamine hydrochloride (1-(allylamino)-2-aminoethane, “AAH”) (10.94 g) and 1,2-bis(allylamino)ethane (“DAEDA1”) (6.23 g) in water (38.89 g). A three-necked round-bottom flask with four side baffles, an overhead stirrer, a Dean-Stark apparatus, and a condenser and nitrogen inlet was charged with the aqueous stock solution and a surfactant (Calimulse EM-99, branched dodecylbenzene sulfonate, 3.14 g) dissolved in a 74:26 chlorobenzene / heptane solution (311.11 g). In a separate vessel, a solution of V-50 (1.98 g) in water (12.75 g) was prepared. The two mixtures were individually purged with nitrogen. Under an inert atmosphere, the initiator solution was added to the reaction mixture and heated at 67° C. for 16 hours. The second initiator solution (14.73 g) and the reaction mixture were degassed, combined and heated to 115° C. for the final dehydration step. After cooling the vessel to room temperature, the organic phase was decanted off and the beads were purified by washing with methanol (100 mL, 2 times), water (100 mL), 2M NaOH (100 mL) and water (100 mL, 2 times). The beads were dried in a freeze dryer for 48 hours. This polymer was the raw bead for post polymerization crosslinking to yield polymers 29-31 shown in Table 10_1 and in Table 10 Part 2.

[0303] E. General Method for Postpolymerization Crosslinking of Polyamine Beads or Gels Crosslinked polyamine beads or gels can be obtained by crosslinking linear polyamines, radical polymerization and small molecule amine crosslinking via crosslinking or substitution reactions.

[0304] As in the general example of polyamine bead synthesis, stock solutions of linear polyamine hydrochloride (and sodium hydroxide, if desired) and water-soluble crosslinker in water were prepared. Each of the aqueous and organic stock solutions was added to a flask equipped with an overhead stirrer under an inert atmosphere. After stirring was started, the reaction was heated for up to 16 hours. An additional dehydration method / step may be added to concentrate the reaction mixture if desired. The hydrophobic organic solvent was removed by decantation, and the beads were purified by washing with a solvent of choice to remove impurities. The resulting polyamine beads were deprotonated by washing with NaOH. The beads were washed with water such that the resulting effluent was close to neutral pH, and dried.

[0305] The resulting dried polyamine beads were placed in a reactor and solvent was added to the gel. The crosslinker was added to the resulting slurry. The mixture was heated for the time required to reach completion. The reaction mixture was cooled and the beads were purified by washing and drying until no more water was removed and the weight was constant. Examples of post-polymerization crosslinking described in this example include, but are not limited to, the crosslinkers shown in Table 10, Part 2. Table 11 shows important physicochemical properties (i.e., SGF binding and swelling ratio) of the example polymers shown in Table 10, Part 2.

[0306] 1. Post-crosslinking of PAAH beads with DCP An aqueous stock solution was prepared by dissolving polyallylamine hydrochloride (average Mw ~15,000 (GPC vs. PEG standard)) (25 g) and sodium hydroxide (6.0 g) in water (75.5 g). The solution was stirred for at least 10 min. A stock solution containing toluene (316 g) and surfactant (SPAN 80 (sorbitan monooleate)) (3.2 g) was also prepared. The toluene solution was charged to a three-necked round-bottom flask with four side baffles, equipped with an overhead stirrer, Dean-Stark apparatus, and a condenser. Dichloropropanol (1,3-dichloro-2-propanol, "(DC2POH")" (3.45 g) was added to the aqueous stock solution at room temperature and stirred for 1 minute. This solution was added to a 3-neck round bottom flask setup. The reaction mixture was stirred under an inert atmosphere. The reaction was heated at 50°C for 14 hours. After this, the reaction mixture was heated to 80°C, after which the reaction mixture was heated to 115°C for the final dehydration step. Once all the water had been removed from the reaction (75 g), the reaction was cooled to room temperature. The toluene was removed by decanting and the resulting polymer beads were purified by washing with methanol (100 mL, 2 times), water (100 mL), 1 M HCl (100 mL, 2 times), water (100 mL), 1 M NaOH (100 mL, 2 times), and water until the pH of the solution after washing was 7. The beads were dried in a freeze dryer for 48 hours.

[0307] 0.40 g of the above obtained PAAH beads were mixed with 2.8 mL of methanol and 1,3-dichloropropane ("DCP") (0.51 g) in a vial. The beads were mixed with a spatula to obtain an evenly distributed wet mass, and the vial was sealed and heated at 75°C overnight. The cooled beads were purified by washing with methanol (45 mL, 2 times), water (45 mL), 1 M HCl (45 mL, 2 times), water (45 mL), 1 M NaOH (45 mL, 3 times), and water until the pH of the solution after washing was 7. The gel was dried in a freeze dryer for 48 hours. This polymer is shown as polymer number 4 in Table 10, part 2 and Table 11.

[0308] 1. Post-crosslinking of PAAH beads with DCP An aqueous stock solution was prepared by dissolving allylamine hydrochloride (10.71 g) and 1,3-bis(allylamino)propane (“DAPDA”) (6.50 g) in water (27.88 g). A three-necked round-bottom flask with four side baffles, an overhead stirrer, a Dean-Stark apparatus, and a condenser and nitrogen inlet was charged with the aqueous stock solution and a surfactant (Calimulse EM-99, branched dodecylbenzene sulfonate, 3.14 g) dissolved in a 74:26 chlorobenzene / heptane solution (311.11 g). In a separate vessel, a solution of V-50 (1.94 g) in water (11.00 g) was prepared. The two mixtures were individually purged with nitrogen. Under an inert atmosphere, the initiator solution was added to the reaction mixture and heated at 67°C for 16 hours. The second initiator solution (12.94 g) and the reaction mixture were degassed, combined and heated to 115° C. for the final dehydration step. After cooling the vessel to room temperature, the organic phase was decanted off and the beads were purified by washing with methanol (100 mL, 2 times), water (100 mL), 2M NaOH (100 mL) and water (100 mL, 2 times). The beads were dried in a freeze dryer for 48 hours.

[0309] 1,3-Dichloropropane ("DCP") (0.18 g) was added to the vial containing MeOH (2.80 g) and 0.40 g of the PAAH beads obtained above. The beads were mixed with a spatula to obtain an evenly distributed wet mass, and the vial was sealed and heated at 75°C overnight. The cooled beads were purified by washing with methanol (45 mL, 2 times), water (45 mL), 1 M HCl (45 mL, 2 times), water (45 mL), 1 M NaOH (45 mL, 2 times), and water until the pH of the solution after washing was 7. The gel was dried on a lyophilizer for 48 hours. This polymer is shown in Table 10, part 2 and Table 11 as polymer number 10.

[0310] [Table 17] [Table 18] [Table 19]

[0311] [Table 20] [Table 21]

[0312] [Table 22] [Table 23]

[0313] II. Performance examples The following examples provide the results of performance evaluation screening and evaluation of select synthetic polymers of the present disclosure as well as commercially available reference polymers in assays measuring chloride binding selectivity over phosphate (SIB assay), chloride binding selectivity in the presence of inorganic and organic interferents (SOB assay), total quaternary amines (QAA assay), and SOB binding kinetics and chloride retention (CRA assay), as defined above.

[0314] A. Performance example The following Table 12 shows the relative performance assays of three selected polymers prepared as above: the reference bixalomer, additional C4A3BTA / ECH polymers with increasing ECH molar equivalent content, and free amine sevelamer. The assays used to generate the data in this example are described elsewhere.

[0315] A bixalomer reference crosslinked amine polymer prepared from C4A3BTA as monomer and ECH as crosslinker with a crosslinker molar equivalent weight of 2.35 was shown to have a swelling ratio of 2.3 g water / g dry polymer and a binding capacity of 12.8 mmol / g in SGF. The polymer bound 1.7 mmol / g chloride and 5.2 mmol / g phosphate in SIB, and 0.8 mmol / g chloride, 1.4 mmol / g phosphate, 0.5 mmol / g citrate, and 0.6 mmol / g taurocholic acid in SOB.

[0316] In comparison, a crosslinked amine polymer prepared from C4A3BTA as the monomer and ECH as the crosslinker with a crosslinker molar equivalent weight of 5.3 was shown to have a swelling ratio of 0.9 g water / g dry polymer and a binding capacity of 11 mmol / g on SGF. This polymer bound 1.6 mmol / g chloride and 3.2 mmol / g phosphorus on SIB, and 3 mmol / g chloride, 0.5 mmol / g phosphate, 0 mmol / g citrate, and 0 mmol / g taurocholic acid on SOB.

[0317] The free amine sevelamer polymer (prepared as described elsewhere) was shown to have a swelling ratio of 6.5 g water / g dry polymer and a binding capacity of 12.1 mmol / g in SGF. The polymer bound 1.1 mmol / g chloride and 6.1 mmol / g phosphate in SIB, and 0.2 mmol / g chloride, 0.8 mmol / g phosphate, 0.4 mmol / g citrate, and 1.8 mmol / g taurocholic acid in SOB.

[0318] Table 13 includes examples of polymers of the present disclosure that have a swelling ratio of less than or equal to 2. Table 14 includes examples of polymers of the present disclosure that have a swelling ratio of greater than 2, but less than or equal to 5.

[0319] [Table 24]

[0320] [Table 25] [Table 26]

[0321] [Table 27] [Table 28]

[0322] [Table 29] [Table 30]

[0323] [Table 31] [Table 32]

[0324] [Table 33] [Table 34]

[0325] III. Screening Examples The following examples illustrate the means by which the synthesized polymers can be characterized by some of the screens defined above.

[0326] A. Quaternary Amine Assay QAA assays were performed on selected polymers. Table 15 shows the QAA assay data for the control material Dowex 1x8, a commercially available cross-linked polystyrene bead containing fully quaternized amines that were obtained as the chloride salt and then converted to the nitrate salt for this experiment. The data for Amberlite IRA67, a commercially available cross-linked acrylic bead containing tertiary amines that were obtained as the free amine form and used as is in this experiment, are shown in the first two columns of Table 15. As demonstrated therein, the fully quaternized Dowex 1x8 bound equivalent amounts of chloride, specifically 1.8 mmol Cl / g, under the acidic and basic pH conditions tested here, as expected. Furthermore, Amberlite IRA67, which contains only tertiary amines, bound 5.9 mmol Cl / g under the acidic assay conditions used, but bound ≦1.7% of this amount under the basic conditions tested here, where the component amines are mostly deprotonated. Table 15 also shows the amount of chloride bound by materials containing C4A3BTA crosslinked with ECH at various molar equivalents of crosslinker. These materials exhibit chloride binding >9 mmol Cl / g under the acidic conditions tested here, often >10 mmol Cl / g, and under low crosslinking conditions, 13.4 mmol Cl / g. These same materials exhibit chloride binding <0.8 mmol Cl / g under the basic pH conditions tested here, often <0.5 mmol Cl / g, and under low crosslinking conditions, 0.3 mmol Cl / g. Under the assay conditions used, C4A3BTA crosslinked with 3.3 molar equivalents of ECH exhibits 1.9% amine quaternization, C4A3BTA crosslinked with 4.3 molar equivalents of ECH exhibits 2.2% amine quaternization, C4A3BTA crosslinked with 5.3 molar equivalents of ECH exhibits 6.2% amine quaternization, C4A3BTA crosslinked with 6.3 molar equivalents of ECH exhibits 4.5% amine quaternization, and C4A3BTA crosslinked with 7.3 molar equivalents of ECH exhibits 8.7% amine quaternization.

[0327] B. SOB binding kinetics Selected polymers were tested in SOB kinetic experiments and anion binding was evaluated at 2, 24 and 48 hours of incubation. The data are listed in Table 16. The bixalomer reference polymer, made from C4A3BTA as the monomer and ECH as the crosslinker with a crosslinker to monomer ratio of 2.35, showed binding of 0.8 mmol / g chloride and 1.5 mmol / g phosphate at 2 hours. After 48 hours of incubation in the same buffer, chloride and phosphate binding decreased to 0.4 and 1.0 mmol / g, respectively, and taurocholate binding increased from 0.6 mmol / g at 2 hours to 1.0 mmol / g at 48 hours. There was no change in citrate binding, with this sample binding 0.5 mmol / g citrate at 2 and 48 hours.

[0328] As shown in Table 16, polymers made from C4A3BTA and ECH as monomers with a high crosslinker to monomer ratio of 4.3 showed 3.0 mmol / g chloride and 0.2 mmol / g phosphate binding at 2 hours. After 48 hours of incubation in the same buffer, chloride binding decreased to 1.9 mmol / g and phosphate binding decreased to 0.9 mmol / g. Taurocholate binding increased from 0.2 mmol / g at 2 hours to 0.4 mmol / g at 48 hours. Citrate binding was 0.0 mmol / g citrate at both 2 and 48 hours.

[0329] As shown in Table 16, polymers made from C4A3BTA and ECH as monomers at a higher crosslinker to monomer ratio of 7.3 showed binding of 1.6 mmol / g chloride and 0.6 mmol / g phosphate at 2 hours. After 48 hours of incubation in the same buffer, chloride binding decreased to 1.2 mmol / g and phosphate binding increased to 1.0 mmol / g. Taurocholate binding was 0.0 mmol / g at 2 and 48 hours. Citrate binding increased from 0.0 mmol / g at 2 hours to 0.3 mmol / g at 48 hours.

[0330] C. Chloride Retention Assay Selected polymers were evaluated for their ability to bind and retain chloride using a chloride retention assay (CRA). As shown in Table 17, a bixalomer reference polymer made from C4A3BT as the monomer and ECH as the crosslinker with a crosslinker to monomer ratio of 2.35 initially bound 0.86 mmol / g chloride in SOB buffer. The polymer sample was then incubated in retention buffer (50 mM 2-(N-morpholino)ethanesulfonic acid (MES), 100 mM sodium acetate, 5 mM sodium phosphate, 15 mM sulfuric acid, adjusted to pH 6.2) for approximately 40 hours at 37°C, followed by incubation in extraction solution (0.2 M sodium hydroxide) for 16-20 hours at 37°C. After extraction with 0.2 M sodium hydroxide, the sample retained only 0.1 mmol / g chloride ions that were bound in SOB, meaning that the remaining chloride was liberated during the retention buffer incubation and water washing steps.

[0331] In the same chloride retention assay, another polymer made from C4A3BTA as the monomer and ECH as the crosslinker at a crosslinker to monomer ratio of 5.3 initially bound 3.1 mmol / g chloride in SOB buffer, as shown in Table 17. Upon 0.2 M sodium hydroxide extraction, the sample retained 1.0 mmol / g chloride, with the remaining 2.1 mmol / g chloride released during the retention buffer incubation and water wash steps. [Table 35]

[0332] [Table 36]

[0333] [Table 37]

Claims

**Claim 1** An artificial small intestine inorganic buffer (SIB) assay, comprising: 1) A proton-binding, cross-linked amine polymer containing a residue of an amine corresponding to Formula 2 【Chemical 1】 [wherein: m and n are independently non-negative integers; R １０ 、 R ２０ 、 R ３０ and R ４０ are independently hydrogen, hydrocarbyl or substituted hydrocarbyl, X １ is [Chemical Formula 2] and X ２ is a hydrocarbyl or substituted hydrocarbyl; Each X １１ is independently hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, amino, boronic acid or halo; z is a non-negative number.]; preparing a proton-binding, cross-linked amine polymer containing a residue of an amine corresponding to the formula; 2) 36 mM NaCl, 20 mM NaH ２ PO ４ , 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) was added to the above amine polymer to achieve a final polymer concentration of 2.5 mg / ml; 3) incubating the mixture at 37° C. for 1 hour with stirring using a rotisserie mixer; 4) pelleting the mixture; 5) taking 750 ml of supernatant; 6) filtering the supernatant; 7) diluting the filtrate; and 8) measuring the anion content of the filtrate using ion chromatography The assay includes the steps of: **Claim 2** The SIB assay of claim 1, wherein 10 mL of SIB buffer is added to the amine polymer. **Claim 3** The SIB assay of claim 1, wherein the mixture is pelleted by centrifuging at 1000×g for 2 minutes. **Claim 4** The SIB assay of claim 1, wherein the supernatant is filtered using a 96-well glass filter plate. **Claim 5** The SIB assay of claim 4, wherein the 96-well glass filter plate has a collection plate attached to the bottom. **Claim 6** The SIB assay of claim 5, wherein the filter plate and collection plate unit are centrifuged at 1000×g for 1 minute. **Claim 7** The SIB assay of claim 1, wherein the supernatant is filtered using a syringe filter.

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