Compounds and methods for inhibiting nhe-mediated antiport in the treatment of disorders associated with fluid retention or salt overload and gastrointestinal tract disorders

Abstract

The present disclosure is directed to compounds and methods for the treatment of disorders associated with fluid retention or salt overload, such as heart failure (in particular, congestive heart failure), chronic kidney disease, end-stage renal disease, liver disease, and peroxisome proliferator-activated receptor (PPAR) gamma agonist-induced fluid retention. The present disclosure is also directed to compounds and methods for the treatment of hypertension. The present disclosure is also directed to compounds and methods for the treatment of gastrointestinal tract disorders, including the treatment or reduction of pain associated with gastrointestinal tract disorders.

Description

RELATED APPLICATIONS[0001]This application is a. National Stage application under 35 U.S.C. §371 of International Application No. PCT / GB2013 / 052193, filed Aug. 20, 2013, which claims the benefit of priority to U.S. Provisional Patent Application No. 61 / 691,637, filed Aug. 21, 2012. The contents of the foregoing applications are hereby incorporated by reference in their entirety.BACKGROUND[0002]1. Field[0003]The present disclosure is directed to compounds that are substantially active in the gastrointestinal tract to inhibit NHE-mediated antiport of sodium ions and hydrogen ions, and the use of such compounds in the treatment of disorders associated with fluid retention or salt overload and in the treatment of gastrointestinal tract disorders, including the treatment or reduction of pain associated with a gastrointestinal tract disorder.[0004]2. Description of the Related Art[0005]Disorders Associated with Fluid Retention and Salt Overload[0006]According to the American Heart Associa...

AI Technical Summary

Benefits of technology

This patent describes a compound or composition that can be used to treat various disorders or symptoms such as hypertension, hypertension associated with dietary salt intake, fluid overload, congestive heart failure, end stage renal disease, sodium overload, interdialytic weight gain in ESRD patients, edema, gastrointestinal tract disorder-related pain, visceral hypersensitivity, inflammation of the gastrointestinal tract, and gastrointestinal transit time. The compound or composition can be administered through various methods such as oral or injection.

Problems solved by technology

Long standing hypertension, particularly when it is poorly controlled, may lead to CHF.

Filling pressures may eventually increase to a level that causes transudation of fluid into the lungs and congestive symptoms (e.g., edema, shortness of breath).

Most people eat considerably more than this, so it is likely that a person with congestive heart failure will need to find ways to reduce dietary salt.

By counteracting the volume increase, diuretics reduce cardiac output; however, fatigue and dizziness may replace CHF symptoms.

However, these drugs are not effective when the glomerular filtration rate (GFR) is less than 30 ml / min.

Additionally, thiazides, as well as other diuretics, may cause hypokalemia.

Diuretic resistance may be caused by poor availability of the drug.

2008 April 10; 125(2): 246-253) it was shown that chronic diuretic use was associated with significantly increased mortality and hospitalization in ambulatory older adults with heart failure receiving angiotensin converting enzyme inhibitor and diuretics.

Angiotensin II also causes aldosterone to be released, causing reabsorption of Na and concomitant passive reabsorption of fluid, which in turn causes the blood volume to increase.

However, since ACE inhibitors lower aldosterone, the K-secreting hormone, one of the side-effects of their use is hyperkalemia.

In addition, ACE inhibitors have been show to lead to acute renal failure in certain categories of CHF patients.

The quasi-absence of renal function and ability to eliminate salt and fluid results in large fluctuations in body weight as fluid and salt build up in the body (sodium / volume overload).

High fluid overload is also worsened by heart dysfunction, specifically CHF.

However, symptomatic intradialytic hypotension (SIH) may occur when patients are over-dialyzed.

Like in hypertensive and CHF patients, dietary restrictions of salt and fluid are highly recommended but poorly followed because of the poor palatability of low-salt food

All these monogenic hypertensive syndromes are virtually confined to mutated genes involving gain of function of various components of the renin-angiotensin-aldosterone system, resulting in excessive renal sodium retention.

This complication significantly impairs the quality of life of cirrhotic patients and is also associated with poor prognosis.

This event, through a decrease in effective blood volume, leads to a drop in arterial pressure.

Splanchnic vasodilation increases splanchnic lymph production, exceeding the lymph transportation system capacity, and leads to lymph leakage into the peritoneal cavity.

Unfortunately, fluid retention has emerged as the most common and serious side-effect of TZD's and has become the most frequent cause of discontinuation of therapy.

However TZD-induced fluid retention is resistant to loop diuretics or thiazide diuretics, and combination of peroxisome proliferator-activated receptor (PPAR) alpha with PPAR gamma agonists, which were proposed to reduce such fluid overload, are associated with major adverse cardiovascular events.

Sorbitol and polyethyleneglycol triggers osmotic diarrhea with low levels of secreted electrolytes; thus, their utility in removing sodium salt from the GI tract is limited.

However, some laxatives, such as phenolphthalein, are not viable options for the chronic treatment of fluid overload, due to the potential risk of carcinogenicity in humans.

Furthermore, laxatives may not be used chronically, as they have been shown to be an irritant and cause mucosal damage.

However, for such polymers to effectively remove significant quantities of fluid, they must desirably resist the static and osmotic pressure range existing in the GI tract.

Such polymers may collapse in a normal colon where the salt absorption process is intact, hence removing a modest quantity of fluid and thereby salt.

However, with the exception of Kayexalate™ (or Kionex™), which is a polystyrene sulfonate salt approved for the treatment of hyperkalemia, cation exchange resins have very limited use as drugs, due at least in part to their limited capacity and poor cation binding selectivity.

Such resins may also cause constipation.

Calcium supplements have shown to be beneficial in ostoporotic patients to restore bone density but compliance is poor because of calcium-induced constipation effects.

Many of these treatment options are inadequate, as they may be habit forming, ineffective in some patients, may cause long term adverse effects, or otherwise are less than optimal.

However, such research failed to develop or recognize the value or importance of NHE inhibitors that are not absorbed (i.e., not systemic) and target the gastrointestinal tract, as disclosed recently in WO 2010 / 078449.

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