In vivo use of water absorbent polymers

Abstract

The subject invention is a method and material for removing fluid from the intestinal tract of a host and may be useful in treating animals or human patients suffering from fluid overload states. In one embodiment, the subject method involves ingesting an enterically coated non-systemic, non-toxic, non-digestible, water absorbing polymer which absorbs fluid while passing through the intestinal tract. The polymer is excreted in the feces wherein the polymer and absorbed fluid is removed from the body. Preferred polymers include super absorbent acrylic acid polymers, preferably provided in bead form. The polymers may include functional groups for selectively removing blood borne waste products, e.g. urea, from the G.I. tract.

Description

BACKGROUND OF THE INVENTION Fluid overload states are associated with a number of serious medical conditions. Many cardiac diseases can lead to compromise in the heart's ability to pump blood. Myocardial infarction frequently causes the replacement of heart muscle by fibrotic tissue. This fibrotic tissue is not capable of pumping blood and results in a decrease in the cardiac output. Cardiomyopathy causes the heart muscle to have less strength resulting in reduced cardiac output. These and other cardiac diseases result in blood pooling in the pulmonary vasculature and even in peripheral tissues such as the feet and legs. This congestive heart failure can cause fluid to leak from the vascular space into the extravascular space to cause edema of the tissue involved, e.g. pulmonary edema, edema of the legs, etc. The reduced cardiac output causes lowered blood flow to the kidneys which decreases the urinary output. Diseases of the kidney can also lead to fluid overload states. For exam...

AI Technical Summary

Benefits of technology

The present invention can reduce the number of dialysis treatments, amount of dialysis treatment time required and / or completely alleviate the need for conventional dialysis. The present invention can remove fluid from animals or patients with congestive heart failure, ascites, and other fluid overload conditions. The present invention can also remove waste products from animals or patients.

The enteric coatings used to encapsulate or coat the subject polymers ensure that fluid removal occurs substantially in the intestine rather than the stomach. By preventing the polymers from becoming active in the stomach, the present invention also allows the polymers to absorb more fluid secreted into the intestinal tract which contains metabolic waste products rather than recently ingested dietary fluids. In contrast to previous art cited above, the present invention protects the polymers from exposure to gastric acid, thereby improving the fluid absorbing performance. By preventing the polymers from absorbing fluid in the proximal small intestine, the present invention has less interference with normal absorption of nutrients and medications than the absorbents mentioned in prior art.

Problems solved by technology

Many cardiac diseases can lead to compromise in the heart's ability to pump blood.

This fibrotic tissue is not capable of pumping blood and results in a decrease in the cardiac output.

Cardiomyopathy causes the heart muscle to have less strength resulting in reduced cardiac output.

This congestive heart failure can cause fluid to leak from the vascular space into the extravascular space to cause edema of the tissue involved, e.g. pulmonary edema, edema of the legs, etc.

Diseases of the kidney can also lead to fluid overload states.

For example, nephrosis and nephritis cause decreases in the ability of the kidney to excrete urine with resultant fluid retention in the body and formation of edema.

Acute and chronic renal failure compromise or eliminate the production of urine, resulting in fluid overload of the body.

Intestinal or nutritional disorders can result in decreased serum protein levels.

Particularly when the serum albumin levels are decreased, the colloidal pressure in the vascular space is inadequate to retain fluid in the blood vessels and tissue edema forms.

Hepatic disease can also lead to fluid overload states.

Cirrhosis of the liver results in decreased synthesis of serum proteins such as albumin.

It also causes obstruction to blood flow from the body below the diaphragm to the heart.

This obstruction causes increased pressure the vasculature with resultant edema formation below the diaphragm, ascites formation, and decreased blood flow to the kidneys.

Hormonal alterations, such as the syndrome of inappropriate antidiuretic syndrome and states with high progesterone levels, can result in fluid retention and overload.

Pulmonary diseases, such as pulmonary fibrosis and chronic obstructive pulmonary diseases, also result in fluid overload states.

In addition to the fluid overload, many of these conditions cause buildup of other substances.

Any condition that compromises urinary output can result in increases in urea, creatinine, other nitrogenous waste products, and electrolytes or minerals such as sodium, phosphate, and potassium.

If untreated, the build up of water (i.e. fluid overload) and other blood borne waste products can lead to unpleasant symptoms and serious medical complications.

Peripheral edema can be painful and cause clothing to be too tight.

The swelling from the edema can compromise the blood flow to or from the tissues resulting in infections or ulcers.

Pulmonary edema causes difficulty in absorbing enough oxygen to properly oxygenate tissues.

Ascites can be quite painful.

Edema of the intestine secondary to liver disease causes malabsorption of nutrients leading to malnutrition.

Ammonia retention can result in neurological damage.

Any organic acid in excess can cause metabolic acidosis with resultant dysfunction of pH dependent processes such as enzymatic metabolic reactions.

Ischemic tissues with increased lactic acid can be compromised in function or even necrose.

This method of treatment is not usually adequate for fluid removal and is not designed to remove other metabolic wastes.

As such, it is not usually the sole treatment of a fluid overload state.

These agents usually interfere with the normal renal handling of electrolytes.

For instance, furosemide interferes with normal sodium reabsorption from the tubules and results in excessive wasting of sodium and potassium.

Increasing the dietary sodium usually worsens the fluid overload state, but not increasing the dietary sodium frequently results in decreased total body sodium and decreased serum sodium concentrations.

However, hemodialysis and peritoneal dialysis involve significant patient discomfort and / or inconvenience.

In addition, removal of water and wastes through dialysis is not uniform for all substances.

However, the object of this invention is to prevent the absorption of dietary phosphate and oxalate and does not address fluid overload.

However, the fluid capacity of these polymers is limited and not clinically practical as a fluid overload agent.

Again these polymers are limited in their ability to absorb fluids and are not practical for treatment of fluid overload.

Unfortunately, the described polysaccharides can be difficult to synthesize and relatively expensive.

Moreover, their ability to absorb water or saline on a per-weight basis is limited; thus leading to very high doses to the patient in order to obtain an effective treatment.

Such direct exposure to stomach acid can lead to significant polymer degradation due to the low pH environment.

Thus, although the disclosed polymers absorb significantly more water or saline than polysaccharides on a per weight basis, direct exposure to stomach acid can result in undesired polymer degradation, absorption of nutrients, and polymer saturation with ingested fluid rather than the absorption of excess fluid and waste from the intestinal tract.

Thus, there was no suggestion that this polymer could be used to treat fluid overload states or remove metabolic waste products or fluid from the intestinal tract.

Removal of metabolic wastes was not anticipated or desired.

Although these literature references evidence attempts to provide orally administered substances, such as polysaccharides, polystarches, polyaldehydes, activated charcoal, and polyacrylic acid compounds, none evidence a successful approach to removing fluid from the GI tract.

Most of the agents have had inadequate fluid absorbing capacity.

The current investigators have found that orally administered polyacrylates exposed to acidic conditions common in the stomach do not absorb fluid as well after exposure to acid, begin their absorption of fluid in the stomach where most fluid is recently ingested fluid, and interfere with normal absorption of nutrients and medications.