JP7763436B2 - Alkalizing blood purification - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies. Date of website publication: March 13, 2017. Website address: https://endai.umin.ac.jp/cgi-open-bin/hanyou/lookup/detail.cgi?cond=%27A00018-00058-20341%27&&&parm=a00018-00058

The present invention relates to blood purification using alkalinizing agents.

The number of patients with end-stage kidney disease (ESKD), who require dialysis or transplants, is increasing worldwide. This trend is also evident in Japan, where the number of dialysis patients reached 320,000 at the end of 2014.
Chronic kidney disease (CKD) is recognized as a precursor to ESKD. CKD is a comprehensive concept encompassing all chronic kidney diseases, regardless of underlying cause, including all pathological conditions in which there is a decline in renal function, as measured by glomerular filtration rate (GFR), or signs suggesting kidney damage persist chronically (for more than three months). CKD not only poses a risk for progression to ESKD, but also a strong risk for the development of cardiovascular disease (CVD), making early detection and appropriate treatment of CKD extremely important. While numerous CKD treatments have been established to date, they are still insufficient, and further development of renal protective agents is needed.

In CKD, various uremic toxins accumulate in the body due to decreased renal clearance. In particular, the blood concentration of indoxyl sulfate, a terminal metabolite of tryptophan, increases as CKD progresses, resulting in high concentrations (100 μM to 1 mM) of indoxyl sulfate accumulating in the blood. Indoxyl sulfate is known to be deeply involved in CKD complications, such as the progression of renal damage due to renal fibrosis and CVD due to vascular calcification. It has been reported that serum indoxyl sulfate concentrations correlate with the mortality rate and incidence of cardiovascular events in dialysis patients (Non-Patent Document 1). It is believed that reducing the blood indoxyl sulfate concentration in CKD patients can slow the progression to ESKD and the onset of CVD associated with renal failure. In fact, a spherical adsorbent charcoal preparation (Kremezin®), which adsorbs indole, a precursor of indoxyl sulfate, in the intestinal tract and reduces blood indoxyl sulfate concentrations, delays the initiation of dialysis and improves arteriosclerosis in CKD patients (Non-Patent Document 2).

On the other hand, in patients with advanced CKD, the blood bicarbonate ion (HCO ₃ ^- ) concentration decreases, leading to metabolic acidosis, and alkalinizing agents such as sodium bicarbonate and citric acid preparations are administered. It has been reported that the administration of sodium bicarbonate, an alkalinizing agent, inhibits the progression of CKD (Non-Patent Document 3). It has also been reported that oral administration of sodium bicarbonate inhibits renal tubular cell injury caused by acidic urine in an animal model of nephrosis (Non-Patent Document 4).
However, there have been no reports on the suppression of the progression of kidney damage by administering alkalinizing agents to early stage CKD patients, nor on the reduction of blood concentrations of uremic substances.

Barreto, F.C., et al.: Serum indoxyl sulfate is associated with vascular disease and mortality in chronic kidney disease patients. Clin. J. Am. Soc. Nephrol., 4: 1551-1558, 2009. Nakamura T., et al.: Oral ADSORBENT AST-120 decreases carotid intima-media thickness and arterial stiffness in patients with chronic renal failure. Kidney Blood Press Res, 27: 121-6, 2004. Brito-Ashurst, I.D., et al.: Bicarbonate supplementation slows progression of CKD and improves nutritional status. J. Am. Soc. Nephrol., 20: 2075-2084, 2009. Souma T., et al.: Luminal alkalinization attenuates proteinuria-induced oxidative damage in proximal tubular cells. J. Am. Soc. Nephrol., 22: 635-648, 2011.

One object of the present invention is to provide a pharmaceutical useful for blood purification in patients with kidney disease. Another object of the present invention is to provide a pharmaceutical useful for inhibiting the progression of chronic kidney disease (aggravation of chronic kidney disease), treating and preventing uremic symptoms, and delaying the initiation of dialysis. Another object of the present invention is to provide a pharmaceutical useful for inhibiting the progression of acute kidney disease to chronic kidney disease. Another object of the present invention is to provide a food product for promoting the excretion of uremic substances from the body. Another object of the present invention is to provide a method for determining inhibition of the progression of chronic kidney disease, and a method for determining a decrease in the concentration of uremic substances in the blood and/or promotion of excretion of uremic substances in the urine.

The inventors conducted extensive research to achieve the above-mentioned objectives and discovered that agents that alkalize body fluids are useful for promoting the excretion of uremic substances from the bodies of patients with kidney disease (e.g., promoting the excretion of uremic substances into the urine), leading to the completion of the present invention.

In one aspect, the present invention provides a pharmaceutical composition for promoting the excretion of uremic substances from the body, which comprises an alkalizing agent.

In one aspect, the present invention provides a pharmaceutical composition for reducing the blood concentration of a uremic substance, comprising an alkalizing agent.

In one aspect, the present invention provides a pharmaceutical composition for promoting urinary excretion of uremic substances, comprising an alkalizing agent.

In one aspect, the present invention provides a pharmaceutical composition for improving uremic symptoms in chronic kidney disease, comprising an alkalinizing agent.

In one aspect, the present invention provides a pharmaceutical composition for delaying the initiation of dialysis in chronic kidney disease, comprising an alkalinizing agent.

In one aspect, the present invention provides a pharmaceutical composition for treating or preventing cardiovascular disease associated with chronic kidney disease, comprising an alkalinizing agent.

In one aspect, the present invention provides a pharmaceutical composition for inhibiting the progression of acute kidney disease to chronic kidney disease, comprising an alkalinizing agent.

In one aspect, the present invention provides a food composition for promoting the excretion of uremic substances from the body, which contains an alkalizing agent.

In one aspect, the present invention provides a method for determining whether progression of chronic kidney disease has been inhibited.

In one aspect, the present invention provides a method for determining whether a uremic toxin concentration in human blood is reduced and/or whether excretion of a uremic toxin into urine is promoted.

The pharmaceutical compositions and other products provided by the present invention enable uremic substances to be excreted from the body in mammals. The methods provided by the present invention allow for a preliminary determination of whether uremic substances are being excreted from the body and/or whether the progression of chronic kidney disease has been suppressed.

1. Pharmaceutical Compositions In one embodiment, the pharmaceutical compositions provided herein include an alkalizing agent.
An alkalizing agent is a drug capable of increasing the HCO ₃ ^{-concentration} or pH of mammalian (especially human) body fluids, such as blood or urine. Examples of alkalizing agents include pharmaceutically acceptable salts of citric acid, their hydrates, or mixtures thereof, and sodium bicarbonate (baking soda). Examples of pharmaceutically acceptable salts of citric acid include alkali metal citrates. Examples of alkali metal citrates include potassium citrate and sodium citrate, which may be hydrated, such as stable potassium citrate monohydrate (C ₆ H ₅ K ₃ O ₇ ·H ₂ O) and sodium citrate dihydrate (C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O), respectively.
Examples of preferred alkalinizing agents include sodium citrate, potassium citrate, or hydrates thereof, or mixtures thereof, such as a mixture of potassium _citrate monohydrate ( _C6H5K3O7 · _H2O ) and sodium _citrate dihydrate ( _C6H5Na3O7 · _{2H2O )} . _The mixing ratio of potassium _citrate monohydrate ( _C6H5K3O7 · _H2O ) and sodium citrate dihydrate ( _C6H5Na3O7 · _{2H2O )} can be appropriately determined by those skilled in the art _. For example _, the molar ratio of potassium citrate monohydrate to sodium _citrate dihydrate can be ₁ part potassium citrate monohydrate to 0.01 to ₁₀₀ parts sodium citrate dihydrate. _The mixing ratio may be approximately 1:1 molar ratio.
Another example of a preferred alkalizing agent is sodium citrate or a hydrate thereof, such as sodium citrate dihydrate (C ₆ H ₅ Na ₃ O _{7.2H 2} O).
Another example of a preferred alkalizing agent is potassium citrate or a hydrate thereof, such as potassium citrate monohydrate (C ₆ H ₅ K ₃ O ₇ ·H ₂ O).

As used herein, "uremic substances" refers to substances (such as waste products and toxins) excreted by normal kidneys that increase (accumulate) in the blood and cause the symptoms or disease of uremic disease when excretory function declines due to some cause such as impaired renal function. Examples of uremic substances include indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and argininosuccinic acid.
Of these, indoxyl sulfate is produced in the liver by oxidation and sulfate conjugation of indole produced by intestinal bacteria from tryptophan derived from dietary protein. Most indoxyl sulfate exists in the blood bound to albumin, is not metabolized, and is excreted in the urine by the kidneys in healthy people, but in patients with kidney disease, high concentrations of indoxyl sulfate remain in the blood due to impaired kidney function.
Indoxyl sulfate, a uremic substance, not only induces uremia in patients with kidney disease, but also accumulates in renal tubular cells, causing renal tubular cell damage and leading to the initiation of dialysis in patients with chronic kidney disease.
Therefore, by reducing the blood indoxyl sulfate concentration, uremic symptoms in kidney disease patients are improved, and uremia can be treated and/or prevented. Furthermore, by reducing the blood indoxyl sulfate concentration, renal tubular cell damage can be suppressed, renal tubular function (e.g., reabsorption of glucose, amino acids, etc.) can be maintained, and the initiation of dialysis in chronic kidney disease patients can be delayed. In one embodiment, the chronic kidney disease patient has progressive chronic kidney disease.

In addition, indoxyl sulfate, a uremic substance, induces myocardial fibrosis, arteriosclerosis, proliferation of vascular smooth muscle cells, vascular endothelial cell damage, thickening of arterial walls, calcification of the aorta, and other cardiovascular diseases (e.g., heart failure, myocardial infarction, stroke, etc.), which are complications of chronic kidney disease.
Therefore, by lowering the concentration of indoxyl sulfate in the blood, myocardial fibrosis, arteriosclerosis, proliferation of vascular smooth muscle cells, vascular endothelial cell damage, thickening of the arterial wall, calcification of the aorta, etc. can be suppressed, making it possible to treat and/or prevent cardiovascular diseases, which are one of the complications of chronic kidney disease patients.

The pharmaceutical composition provided by the present invention is capable of reducing the concentration of uremic substances in the blood (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid, preferably indoxyl sulfate and phenylacetyl-L-glutamine, more preferably indoxyl sulfate).
Furthermore, the pharmaceutical composition provided by the present invention is capable of promoting the excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl L glutamine, hippuric acid and/or argininosuccinic acid, preferably indoxyl sulfate, p-cresyl sulfate and/or phenylacetyl L glutamine, more preferably indoxyl sulfate and phenylacetyl L glutamine, and even more preferably indoxyl sulfate) into urine.
Due to these characteristics of the pharmaceutical composition provided by the present invention, the pharmaceutical composition provided by the present invention can be used not only as a pharmaceutical composition for reducing the blood concentration of uremic substances and/or a pharmaceutical composition for promoting urinary excretion of uremic substances, but also as any of a pharmaceutical composition for improving uremic symptoms in patients with kidney disease, a pharmaceutical composition for treating and/or preventing uremia in patients with kidney disease, a pharmaceutical composition for inhibiting renal tubular (e.g., proximal tubule) cell damage in patients with kidney disease, a pharmaceutical composition for maintaining renal tubular function (e.g., proximal tubule) in patients with kidney disease, a pharmaceutical composition for inhibiting the progression of chronic kidney disease, and a pharmaceutical composition for delaying the initiation of dialysis in patients with chronic kidney disease.
Furthermore, due to the above-mentioned characteristics of the pharmaceutical composition provided by the present invention, the pharmaceutical composition provided by the present invention can also be used as any of a pharmaceutical composition for suppressing myocardial fibrosis in patients with kidney disease, a pharmaceutical composition for suppressing arteriosclerosis in patients with kidney disease, a pharmaceutical composition for suppressing the proliferation of vascular smooth muscle cells in patients with kidney disease, a pharmaceutical composition for suppressing vascular endothelial cell damage in patients with kidney disease, a pharmaceutical composition for suppressing arterial wall thickening in patients with kidney disease, a pharmaceutical composition for suppressing aortic calcification in patients with kidney disease, and a pharmaceutical composition for treating and/or preventing cardiovascular diseases associated with chronic kidney disease.

Furthermore, it has been reported that when non-diabetic chronic kidney disease patients were administered a drug that reduces blood levels of indoxyl sulfate, pulse wave velocity and carotid intima-media thickness, indicators of arteriosclerosis, significantly improved compared to pre-administration levels (Nakamura T., et al.: Oral ADSORBENT AST-120 decreases carotid intima-media thickness and arterial stiffness in patients with chronic renal failure. Kidney Blood Press Res, 27: 121-6, 2004.). Therefore, the pharmaceutical composition provided by the present invention that reduces blood levels of indoxyl sulfate can be used as a pharmaceutical composition for improving arteriosclerosis or thickening of the arterial (e.g., carotid) wall in kidney disease patients (preferably, chronic kidney disease patients, more preferably, non-diabetic chronic kidney disease patients).

In addition, it has been reported that drugs that reduce blood concentrations of indoxyl sulfate suppress acute kidney injury induced by cisplatin (Morisaki T., et. Al.,: Regulation of renal organic ion transporters in cisplatin-induced acute kidney injury and uremia in rats. Pharm. Res., 25(11): 2526-33, 2008). Therefore, the pharmaceutical composition provided by the present invention that reduces blood concentrations of indoxyl sulfate can be used as a pharmaceutical composition for treating acute kidney disease or a pharmaceutical composition for inhibiting the progression of acute kidney disease to chronic kidney disease.

Furthermore, p-cresyl sulfate, a uremic substance, has been reported to be a causative agent of vascular endothelial damage (Meijers BK, et. Al.,: The uremic retention solute p-cresyl sulfate and markers of endothelial damage., Am. J. Kidney Dis., 54: 891-901, 2009).
Therefore, the pharmaceutical composition of the present invention, which promotes urinary excretion of p-cresyl sulfate, can be used as a pharmaceutical composition for suppressing vascular endothelial damage in patients with kidney disease (preferably, patients with chronic kidney disease).
Furthermore, it has been reported that phenylacetyl-L-glutamine, a uremic substance, increases the risk of developing cardiovascular disease in patients with chronic kidney disease.
Therefore, the pharmaceutical composition of the present invention, which promotes urinary excretion of phenylacetyl-L-glutamine, can be used as a pharmaceutical composition for treating and/or preventing cardiovascular diseases in patients with chronic kidney disease.
The pharmaceutical composition provided by the present invention promotes the urinary excretion of uremic substances such as indoxyl sulfate, p-cresyl sulfate, hippuric acid, argininosuccinic acid, and phenylacetyl L-glutamine, and therefore can be used as a pharmaceutical composition for promoting the urinary excretion of indoxyl sulfate, p-cresyl sulfate, hippuric acid, argininosuccinic acid, and/or phenylacetyl L-glutamine in patients with kidney disease (preferably patients with chronic kidney disease) (e.g., a composition for promoting the urinary excretion of indoxyl sulfate and phenylacetyl L-glutamine, a composition for promoting the urinary excretion of indoxyl sulfate, or a composition for promoting the urinary excretion of phenylacetyl L-glutamine).

The pharmaceutical compositions provided by the present invention may be administered to humans or other mammals orally or parenterally. Examples of parenteral administration include intravenous administration, subcutaneous administration, intramuscular administration, intraarticular administration, transmucosal administration, transdermal administration, nasal administration, rectal administration, intrathecal administration, intraperitoneal administration, and topical administration.
The pharmaceutical compositions provided by the present invention may be prepared by mixing the alkalinizing agent directly or with a pharmaceutically acceptable carrier, for example, an excipient (e.g., lactose, D-mannitol, crystalline cellulose, glucose), a binder (e.g., hydroxypropyl cellulose (HPC), gelatin, polyvinylpyrrolidone (PVP)), a lubricant (e.g., magnesium stearate, talc), a disintegrant (e.g., starch, carboxymethylcellulose calcium (CMC-Ca)), a diluent (e.g., water for injection, physiological saline), and, if necessary, other additives (e.g., pH adjusters, surfactants, solubilizing agents, preservatives, emulsifiers, isotonicity agents, stabilizers), and may be in the form of tablets, capsules, suspensions, injections, suppositories, and the like. For example, to prepare a tablet, the alkalinizing agent may be mixed with an excipient (e.g., lactose, D-mannitol, crystalline cellulose, glucose), a disintegrant (e.g., starch, carboxymethylcellulose calcium (CMC-Ca)), a binder (e.g., hydroxypropyl cellulose (HPC), gelatin, polyvinylpyrrolidone (PVP)), a lubricant (e.g., magnesium stearate, talc), etc.

The amount of alkalinizing agent in the pharmaceutical composition provided by the present invention can be appropriately determined. For example, the dosage of the alkalinizing agent may be determined so that administration to a human improves acidic urine associated with gout or hyperuricemia, or so that acidosis is improved. The dosage of the alkalinizing agent that improves acidic urine associated with gout or hyperuricemia when administered to a human may be, for example, such that the pH of the human's urine (e.g., early morning urine) becomes 6.2 to 6.8 or 6.5 to 6.8.
In one embodiment, the pharmaceutical composition provided by the present invention is in the form of a tablet, and each tablet may contain 10 mg to 1 g, preferably 100 mg to 500 mg, and more preferably 400 mg to 500 mg of potassium citrate monohydrate or sodium citrate dihydrate as an alkalinizing agent.
In one embodiment, the pharmaceutical composition provided by the present invention is in the form of a tablet, and each tablet may contain 10 mg to 300 mg of potassium citrate monohydrate and 20 mg to 600 mg of sodium citrate dihydrate in total, preferably 150 to 250 mg of each and 400 to 500 mg of total, more preferably 190 to 240 mg of each and 400 to 450 mg of total.
In another embodiment, the pharmaceutical composition of the present invention is in the form of a tablet, and each tablet may contain 10 mg to 1 g, preferably 100 mg to 500 mg, of sodium bicarbonate as an alkalizing agent.
Furthermore, in one embodiment, the pharmaceutical composition provided by the present invention is a tablet, which contains 231.5 mg of potassium citrate monohydrate and 195.0 mg of sodium citrate dihydrate as alkalizing agents, and may contain anhydrous citric acid, crystalline cellulose, partially pregelatinized starch, hydroxypropyl cellulose, magnesium stearate, hypromellose, macrogol 6000, titanium oxide, and carnauba wax as excipients.

The dosage of the alkalizing agent is determined appropriately depending on the type of alkalizing agent, the method of administration, the age, weight, sex, symptoms, sensitivity to the drug, etc. of the subject, but the dosage may be adjusted depending on the degree of improvement in symptoms.
In one embodiment, when a mixture of potassium citrate monohydrate and sodium citrate dihydrate is orally administered to a human as an alkalinizing agent, potassium citrate monohydrate and sodium citrate dihydrate may be administered at 0.1 to 5 g/day each for a total of 0.2 to 10 g/day, 0.1 to 3 g/day each for a total of 0.2 to 6 g/day, 0.5 to 3 g/day each for a total of 1 to 6 g/day, preferably 0.5 to 1.5 g/day each for a total of 1 to 3 g/day, 1 to 1.5 g/day each for a total of 2 to 3 g/day, or 0.5 to 1 g/day each for a total of 1 to 2 g/day, and may be administered 1 to 5 times a day, preferably 3 times a day.
In one embodiment, when potassium citrate monohydrate or sodium citrate dihydrate is orally administered to a human as an alkalinizing agent, the dose may be 1 to 10 g/day, 1 to 6 g/day, 2 to 5.5 g/day, 1 to 3 g/day, 2 to 3 g/day, or 1 to 1.5 g/day, and may be administered 1 to 5 times a day, preferably 3 times a day.
In one embodiment, when sodium bicarbonate is orally administered to a human as an alkalinizing agent, it may be administered at a dose of 1 to 6 g/day, preferably 3 to 5 g/day, in divided doses 1 to 5 times a day, preferably 3 times a day.

In one embodiment, the alkalinizing agent may be administered chronically, for example, for 1 week or more, 2 weeks or more, 3 weeks or more, 6 weeks or more, 8 weeks or more, 10 weeks or more, 12 weeks or more, 24 weeks or more, 6 weeks to 24 weeks, 12 weeks to 24 weeks, or 12 weeks to 30 weeks.
In one embodiment, when a mixture of potassium citrate monohydrate and sodium citrate dihydrate is orally administered to a human as an alkalinizing agent, the blood concentration of indoxyl sulfate begins to decrease between 6 and 12 weeks after the start of administration compared to before administration, and its urinary excretion begins to increase between 6 and 12 weeks after the start of administration compared to before administration. Also in this embodiment, the urinary excretion of p-cresyl sulfate begins to increase between 6 and 12 weeks after the start of administration compared to before administration, the blood concentration of hippuric acid begins to decrease between 12 and 24 weeks after the start of administration compared to before administration, and the urinary excretion of hippuric acid begins to increase between 0 and 6 weeks after the start of administration compared to before administration. Furthermore, in this embodiment, the urinary excretion of argininosuccinic acid begins to increase between 6 and 12 weeks after the start of administration compared to before administration, and the urinary excretion of phenylacetyl-L-glutamine begins to increase between 6 and 12 weeks after the start of administration compared to before administration. Considering the above embodiment, when the mixture of potassium citrate monohydrate and sodium citrate dihydrate is orally administered to a human, it may be administered for, for example, 6 weeks or more, preferably 12 weeks or more, and more preferably 24 weeks or more.

In one embodiment, the pharmaceutical compositions provided herein are administered to a human suffering from kidney disease, which includes acute kidney disease and chronic kidney disease unless otherwise specified.
Examples of acute kidney disease include acute kidney disease caused by drugs (e.g., nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, aminoglycoside antibiotics, new quinolone antibacterial drugs, iodine contrast agents, platinum preparations such as cisplatin), and acute kidney disease caused by renal ischemia.
Chronic kidney disease (CKD) is a concept that encompasses all chronic kidney diseases, regardless of the underlying disease, and includes all pathological conditions in which there is a decline in renal function, as measured by glomerular filtration rate (GFR), or findings suggesting kidney damage persist chronically (for three months or more).

According to the CKD Clinical Practice Guide 2012 (Journal of the Japanese Society of Nephrology 2012), the severity of chronic kidney disease is assessed by classification based on the cause (Cause: C), renal function (GFR: G), and proteinuria (albuminuria: A).
The GFR classification is as follows:
G1: Normal or high GFR (≥ 90 mL/min/1.73 ^m2 )
G2: Normal or mildly decreased GFR (60-89 mL/min/1.73 ^m2 )
G3a: Mild to moderate decrease in GFR (45-59 mL/min/1.73 ^m2 )
G3b: Moderate to severely decreased GFR (30-44 mL/min/1.73 ^m2 )
G4: Severely decreased GFR (15-29 mL/min/1.73 ^m2 )
G5: End-stage renal disease (ESKD) (<15 mL/min/1.73 m ² )
When the primary disease is diabetes, proteinuria (albuminuria: A) is classified as follows using the urinary albumin/creatinine (Cr) ratio:
A1: Normal (less than 30 mg/gCr)
A2: Microalbuminuria (30-299 mg/gCr)
A3: Overt albuminuria (300 mg/gCr or more)
In addition, classification based on proteinuria (albuminuria: A) is performed using the urinary protein/creatinine (Cr) ratio as follows when the primary disease is hypertension, nephritis, polycystic kidney disease, transplanted kidney, or other conditions other than diabetes.
A1: Normal (less than 0.15 g/gCr)
A2: Mild proteinuria (0.15-0.49 g/gCr)
A3: Severe proteinuria (0.50 g/gCr or more)
According to the CKD Treatment Guide 2012 (Journal of the Japanese Society of Nephrology 2012), the severity of chronic kidney disease (CKD) is classified using the above C, G, and A, and is expressed as, for example, diabetes G2A3, chronic nephritis G3bA1, etc.
However, taking into consideration that the severity of chronic kidney disease has traditionally been expressed only in stages classified by GFR, it is now possible to express the severity of chronic kidney disease in stages G1, G2, G3a, G3b, G4, and G5 as before.

In one embodiment, the pharmaceutical compositions provided herein are administered to patients with less severe, early stage chronic kidney disease.
In one embodiment, the pharmaceutical composition provided by the present invention is administered to a patient with chronic kidney disease at stage G3b or below, preferably at stage G2 or below.
In one embodiment, the pharmaceutical composition provided by the present invention is administered to a patient with chronic kidney disease at stage G3b or below and with urinary protein excretion of less than 3.5 g/gCr, preferably to a patient with chronic kidney disease at stage G2 and with urinary protein excretion of less than 3.5 g/gCr.
In one embodiment, the pharmaceutical compositions provided herein are administered to patients with advanced chronic kidney disease.

In one embodiment, the pharmaceutical composition provided by the present invention is administered to a patient undergoing treatment in accordance with the CKD Clinical Practice Guide. For example, the pharmaceutical composition is administered to a patient undergoing blood pressure control (e.g., administration of RA system inhibitors such as ARBs and ACE inhibitors, diuretics, and calcium channel blockers), proteinuria control (e.g., administration of RA system inhibitors), blood glucose control (e.g., administration of α-glucosidase inhibitors), lipid control (e.g., administration of statins and fibrates), anemia control (e.g., administration of erythropoietin), and/or bone and mineral control (e.g., administration of bisphosphonates) in accordance with the CKD Clinical Practice Guide.

In one embodiment, the pharmaceutical composition provided by the present invention is administered to a patient with less severe, early stage chronic kidney disease (e.g., a patient with chronic kidney disease at stage G3b or below, preferably stage G2) to reduce the concentration of uremic substances (e.g., indoxyl sulfate and/or phenylacetyl-L-glutamine) in the patient's blood and promote the excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, hippuric acid, argininosuccinic acid and/or phenylacetyl-L-glutamine) from the body (e.g., into the urine). In this embodiment, the pharmaceutical composition provided by the present invention may be a pharmaceutical composition for improving uremic symptoms, a pharmaceutical composition for treating or preventing uremia, a pharmaceutical composition for inhibiting damage to renal tubule (e.g., proximal tubule) cells, a pharmaceutical composition for maintaining the function of renal tubule (e.g., proximal tubule) cells, a pharmaceutical composition for inhibiting the progression of chronic kidney disease, a pharmaceutical composition for delaying the initiation of dialysis, a pharmaceutical composition for inhibiting myocardial fibrosis, a pharmaceutical composition for inhibiting arteriosclerosis, a pharmaceutical composition for improving arteriosclerosis, a pharmaceutical composition for inhibiting the proliferation of vascular smooth muscle cells, a pharmaceutical composition for inhibiting vascular endothelial cell damage, a pharmaceutical composition for inhibiting arterial wall thickening, a pharmaceutical composition for improving arterial wall thickening, a pharmaceutical composition for inhibiting aortic calcification, or a pharmaceutical composition for treating or preventing a complication of cardiovascular disease (e.g., heart failure, myocardial infarction, stroke, etc.).
In one embodiment, the pharmaceutical composition provided by the present invention is administered to a patient with chronic kidney disease of moderate or greater severity (e.g., a patient with chronic kidney disease at stage G3b or greater, preferably at stage G4 or greater), to reduce the concentration of uremic substances (e.g., indoxyl sulfate and/or phenylacetyl-L-glutamine) in the patient's blood and promote the excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, hippuric acid, argininosuccinic acid and/or phenylacetyl-L-glutamine) from the body (e.g., into the urine). In this embodiment, the pharmaceutical composition provided by the present invention may be a pharmaceutical composition for improving uremic symptoms, a pharmaceutical composition for treating or preventing uremia, a pharmaceutical composition for inhibiting renal tubular (e.g., proximal tubule) cell damage, a pharmaceutical composition for maintaining renal tubular (e.g., proximal tubule) cell function, a pharmaceutical composition for inhibiting the progression of chronic kidney disease, a pharmaceutical composition for delaying the initiation of dialysis, a pharmaceutical composition for inhibiting myocardial fibrosis, a pharmaceutical composition for inhibiting arteriosclerosis, a pharmaceutical composition for improving arteriosclerosis, a pharmaceutical composition for inhibiting the proliferation of vascular smooth muscle cells, a pharmaceutical composition for inhibiting vascular endothelial cell damage, a pharmaceutical composition for inhibiting arterial wall thickening, a pharmaceutical composition for improving arterial wall thickening, a pharmaceutical composition for inhibiting aortic calcification, or a pharmaceutical composition for treating or preventing a complication of cardiovascular disease (e.g., heart failure, myocardial infarction, stroke, etc.).

Examples of other embodiments of the present invention include the following.
a) a method for reducing the blood level of a uremic substance in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent;
b) a method for enhancing the excretion of uremic substances from the body (e.g., into the urine) in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent;
c) a method for ameliorating uremic symptoms in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
d) A method for treating or preventing uremia in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
e) a method for inhibiting renal tubular (e.g., proximal tubule) cell damage in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, the subject suffering from a kidney disease;
f) a method of maintaining renal tubular (e.g., proximal tubule) cell function in a mammalian subject (e.g., a human), comprising administering an effective amount of an alkalinizing agent to a subject in need of maintaining renal tubular (e.g., proximal tubule) cell function, wherein the subject is suffering from a kidney disease;
g) a method for inhibiting the progression of chronic kidney disease in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent;
h) a method for delaying the onset of dialysis in a mammalian subject (e.g., a human), comprising administering to a subject in need of delayed onset of dialysis an effective amount of an alkalinizing agent, wherein the subject is suffering from chronic kidney disease;
i) a method for inhibiting myocardial fibrosis in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, the subject suffering from kidney disease;
j) a method for inhibiting arteriosclerosis in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
k) a method for inhibiting vascular smooth muscle cell proliferation in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
l) A method for inhibiting vascular endothelial cell damage in a mammalian subject (e.g., human), comprising administering an effective amount of an alkalinizing agent to a subject in need of inhibiting vascular endothelial cell damage, wherein the subject is suffering from kidney disease;
m) a method for inhibiting arterial wall thickening in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
n) a method for inhibiting aortic calcification in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, the subject suffering from kidney disease;
o) a method for treating or preventing cardiovascular disease in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
p) a method for ameliorating arteriosclerosis in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
q) a method for improving arterial wall thickening in a mammalian subject (e.g., a human), comprising administering to a subject in need thereof an effective amount of an alkalinizing agent, wherein the subject is suffering from kidney disease;
r) a method for treating acute kidney disease in a mammalian subject (e.g., a human), comprising administering to a subject in need of treatment for acute kidney disease an effective amount of an alkalinizing agent;
s) a method for inhibiting the progression of acute kidney disease to chronic kidney disease in a mammalian subject (e.g., a human), the method comprising administering to a subject in need thereof an effective amount of an alkalinizing agent;
aa) an alkalizing agent for use as an agent for reducing the blood concentration of uremic substances;
bb) alkalinizing agents for use as agents promoting the excretion of uremic substances from the body (e.g., into the urine);
cc) an alkalinizing agent for use as an agent for improving uremic symptoms in patients with kidney disease;
dd) an alkalinizing agent for use as an agent for the treatment or prevention of uremia in patients with kidney disease;
ee) an alkalinizing agent for use as an inhibitor of renal tubular (e.g. proximal tubule) cell damage in patients with kidney disease;
ff) an alkalinizing agent for use as an agent for maintaining renal tubular (e.g. proximal tubule) cell function in patients with kidney disease;
gg) an alkalizing agent for use as an agent for inhibiting the progression of chronic kidney disease;
hh) an alkalinizing agent for use as an agent for delaying the initiation of dialysis in patients with chronic kidney disease;
ii) an alkalizing agent for use as an agent for suppressing myocardial fibrosis in patients with kidney disease;
jj) an alkalinizing agent for use as an anti-arteriosclerosis agent in patients with kidney disease;
kk) an alkalizing agent for use as an inhibitor of vascular smooth muscle cell proliferation in patients with kidney disease;
ll) An alkalizing agent for use as an inhibitor of vascular endothelial cell damage in patients with kidney disease;
mm) an alkalizing agent for use as an inhibitor of arterial wall thickening in patients with kidney disease;
nn) an alkalinizing agent for use as an inhibitor of aortic calcification in patients with kidney disease;
oo) an alkalinizing agent for use as an agent for the treatment or prevention of cardiovascular diseases in patients with kidney disease;
pp) an alkalizing agent for use as an agent for improving arteriosclerosis in patients with kidney disease;
qq) An alkalizing agent for use as an agent for improving arterial wall thickening in patients with kidney disease;
rr) an alkalinizing agent for use as a treatment for acute kidney disease;
ss) an alkalinizing agent for use as an agent for inhibiting the progression of acute kidney disease to chronic kidney disease;
aaa) alkalinizing agents for use in reducing blood levels of uremic substances;
bbb) alkalinizing agents for use in promoting the excretion of uremic substances into the urine;
ccc) an alkalinizing agent for use in improving uremic symptoms in patients with kidney disease;
ddd) alkalinizing agents for use in the treatment or prevention of uremia in patients with kidney disease;
eee) an alkalinizing agent for use in inhibiting renal tubular (e.g., proximal tubule) cell damage in patients with kidney disease;
fff) an alkalinizing agent for use in maintaining renal tubular (e.g. proximal tubule) cell function in patients with kidney disease;
ggg) an alkalizing agent for use in inhibiting the progression of chronic kidney disease;
hhh) an alkalinizing agent for use in delaying the initiation of dialysis in patients with chronic kidney disease;
iii) an alkalinizing agent for use in inhibiting myocardial fibrosis in patients with kidney disease;
jjj) an alkalizing agent for use in inhibiting arteriosclerosis in patients with kidney disease;
kkk) an alkalizing agent for use in inhibiting the proliferation of vascular smooth muscle cells in patients with kidney disease;
lll) an alkalizing agent for use in inhibiting vascular endothelial cell damage in patients with kidney disease;
mmm) an alkalinizing agent for use in inhibiting arterial wall thickening in patients with kidney disease;
nnn) an alkalizing agent for use in inhibiting aortic calcification in patients with kidney disease;
ooo) alkalinizing agents for use in the treatment or prevention of cardiovascular disease in patients with kidney disease;
ppp) an alkalizing agent for use in improving arteriosclerosis in patients with kidney disease;
qqq) An alkalizing agent for use in improving arterial wall thickening in patients with kidney disease;
rrr) an alkalinizing agent for use in the treatment of acute kidney disease;
sss) an alkalinizing agent for use in inhibiting the progression of acute kidney disease to chronic kidney disease;
aaaa) Use of an alkalizing agent for producing a pharmaceutical composition for reducing the blood concentration of a uremic substance;
bbbb) Use of an alkalizing agent for producing a pharmaceutical composition for promoting the excretion of uremic substances from the body (e.g., into the urine);
cccc) Use of an alkalinizing agent for the manufacture of a pharmaceutical composition for improving uremic symptoms in patients with kidney disease;
dddd) Use of an alkalizing agent for the manufacture of a pharmaceutical composition for the treatment or prevention of uremia in patients with kidney disease;
eeee) Use of an alkalinizing agent for producing a pharmaceutical composition for suppressing renal tubular (e.g., proximal tubular) cell damage in patients with kidney disease;
ffff) Use of an alkalinizing agent for the manufacture of a pharmaceutical composition for maintaining renal tubule (e.g., proximal tubule) cell function in patients with kidney disease;
gggg) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting the progression of chronic kidney disease;
hhhh) Use of an alkalizing agent for producing a pharmaceutical composition for delaying the initiation of dialysis in patients with chronic kidney disease;
iii) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting myocardial fibrosis in patients with kidney disease;
jjjj) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting arteriosclerosis in patients with kidney disease;
kkkk) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting the proliferation of vascular smooth muscle cells in patients with kidney disease;
llll) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting vascular endothelial cell damage in patients with kidney disease;
mmmm) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting arterial wall thickening in patients with kidney disease;
nnnn) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting aortic calcification in patients with kidney disease;
oooo) Use of an alkalizing agent for the manufacture of a pharmaceutical composition for the treatment or prevention of cardiovascular diseases in patients with kidney disease;
pppp) Use of an alkalizing agent for producing a pharmaceutical composition for improving arteriosclerosis in patients with kidney disease;
qqqq) Use of an alkalizing agent for producing a pharmaceutical composition for improving arterial wall thickening in patients with kidney disease;
rrrr) Use of an alkalizing agent for producing a pharmaceutical composition for treating acute kidney disease; and ssss) Use of an alkalizing agent for producing a pharmaceutical composition for inhibiting the progression of acute kidney disease to chronic kidney disease.
In the above embodiments a) to ssss), the alkalinizing agent may be a pharmaceutically acceptable salt of citric acid, a hydrate thereof, or a mixture thereof, or sodium bicarbonate. Examples of the pharmaceutically acceptable salt of citric acid include alkali metal citrates, such as _potassium citrate and sodium citrate, which may be in the form of stable hydrates such _as potassium _citrate monohydrate ( _C6H5K3O7.H2O ) _{and sodium} citrate dihydrate _{( C6H5Na3O7.2H2O} ) _{, respectively} .
Examples of preferred alkalinizing agents include sodium citrate, potassium citrate, or hydrates thereof, or mixtures thereof, such as a mixture of potassium _citrate monohydrate ( _C6H5K3O7 · _H2O ) and sodium _citrate dihydrate ( _C6H5Na3O7 · _{2H2O )} . _The mixing ratio of potassium _citrate monohydrate ( _C6H5K3O7 · _H2O ) and sodium citrate dihydrate ( _C6H5Na3O7 · _{2H2O )} can be appropriately determined by those skilled in the art _. For example _, the molar ratio of potassium citrate monohydrate to sodium _citrate dihydrate can be ₁ part potassium citrate monohydrate to 0.01 to ₁₀₀ parts sodium citrate dihydrate. _The mixing ratio may be approximately 1:1 molar ratio.
Another example of a preferred alkalizing agent is sodium citrate or a hydrate thereof, such as sodium citrate dihydrate (C ₆ H ₅ Na ₃ O _{7.2H 2} O).
Another example of a preferred alkalizing agent is potassium citrate or a hydrate thereof, such as potassium citrate monohydrate (C ₆ H ₅ K ₃ O ₇ ·H ₂ O).
The amount of the alkalizing agent can be set appropriately, and for example, when the alkalizing agent is selected from the group consisting of potassium citrate monohydrate, sodium citrate dihydrate, a mixture of potassium citrate monohydrate and sodium citrate dihydrate, and sodium bicarbonate, the amount may be 10 mg to 1 g, preferably 100 mg to 500 mg, and more preferably 400 mg to 500 mg.
The dosage of the alkalinizing agent may be an amount that, when administered to a human, improves acidic urine associated with gout or hyperuricemia, or an amount that improves acidosis. For example, the amount of alkalinizing agent in the pharmaceutical composition provided by the present invention may be set so that the pH of human urine (e.g., early morning urine) becomes 6.2 to 6.8 or 6.5 to 6.8 when the alkalinizing agent is administered.
In one embodiment, when a mixture of potassium citrate monohydrate and sodium citrate dihydrate is orally administered to a human as an alkalinizing agent, potassium citrate monohydrate and sodium citrate dihydrate may be administered at 0.1 to 5 g/day each for a total of 0.2 to 10 g/day, 0.1 to 3 g/day each for a total of 0.2 to 6 g/day, 0.5 to 3 g/day each for a total of 1 to 6 g/day, preferably 0.5 to 1.5 g/day each for a total of 1 to 3 g/day, 1 to 1.5 g/day each for a total of 2 to 3 g/day, or 0.5 to 1 g/day each for a total of 1 to 2 g/day, and may be administered 1 to 5 times a day, preferably 3 times a day.
In one embodiment, when potassium citrate monohydrate or sodium citrate dihydrate is orally administered to a human as an alkalinizing agent, the dose may be 1 to 10 g/day, 1 to 6 g/day, 2 to 5.5 g/day, 1 to 3 g/day, 2 to 3 g/day, or 1 to 1.5 g/day, and may be administered 1 to 5 times a day, preferably 3 times a day.
In one embodiment, when sodium bicarbonate is orally administered to a human as an alkalinizing agent, it may be administered at a dose of 1 to 6 g/day, preferably 3 to 5 g/day, in divided doses 1 to 5 times a day, preferably 3 times a day.
In one embodiment, the alkalinizing agent may be administered chronically, for example, for 1 week or more, 2 weeks or more, 3 weeks or more, 6 weeks or more, 8 weeks or more, 10 weeks or more, 12 weeks or more, 24 weeks or more, 6 weeks to 24 weeks, 12 weeks to 24 weeks, or 12 weeks to 30 weeks.
In the above embodiments of a) to ssss), examples of kidney disease include acute kidney disease and chronic kidney disease. Examples of chronic kidney disease include chronic kidney disease of stage 3b or lower (e.g., stage 2), chronic kidney disease of stage 3b or lower (e.g., stage 2) in which the patient's urinary protein excretion is less than 3.5 g/gCr, and chronic kidney disease of stage 3b or higher (e.g., stage 4 or higher). In one embodiment, the kidney disease patient may be a patient receiving treatment in accordance with the CKD Clinical Practice Guide. For example, the patient may be a patient receiving blood pressure management (e.g., administration of RA system inhibitors such as ARBs and ACE inhibitors, diuretics, and calcium channel blockers), proteinuria control (e.g., administration of RA system inhibitors), blood glucose level management (e.g., administration of α-glucosidase inhibitors), lipid management (e.g., administration of statins and fibrates), anemia management (e.g., administration of erythropoietin), and/or bone and mineral management (e.g., administration of bisphosphonates) in accordance with the CKD Clinical Practice Guide.

2. Food Composition In one embodiment, the food composition provided by the present invention contains an alkalizing agent and has the effect of promoting the excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and/or argininosuccinic acid) from the body.
The alkalinizing agent is as described above in "1. Pharmaceutical Compositions." Examples of the alkalinizing agent include a pharmaceutically acceptable salt of citric acid (e.g., an alkali metal citrate or its hydrate, or a mixture thereof), sodium _bicarbonate , and _preferably a _mixture of _{potassium citrate monohydrate ( C6H5K3O7.H2O} ) and sodium citrate dihydrate ( _{C6H5Na3O7.2H2O} ), or sodium citrate dihydrate _.
The uremic substances are also as described above in "1. Pharmaceutical Compositions." Examples of uremic substances include indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and argininosuccinic acid.
The content of the alkalizing agent in the food composition of the present invention can be appropriately determined depending on the type of food. Examples of food compositions include foods for specified health uses, nutritional supplements, functional foods, foods for hospital patients, and supplements.
The food compositions provided by the present invention can be prepared by those skilled in the art depending on the type of food, for example, by blending an alkalizing agent (e.g., potassium citrate and/or sodium citrate) into a food ingredient.

3. Method for Determining a Decreased Concentration of a Uremic Substance in the Blood, etc. In one embodiment, the present invention provides a method for determining a decrease in the concentration of a uremic substance (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) in the blood of a patient with chronic kidney disease, the method comprising measuring the pH of urine.
In one embodiment, the present invention provides a method for determining the promotion of excretion of uremic substances (indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and/or argininosuccinic acid) into the urine of a patient with chronic kidney disease, the method comprising measuring the pH of the urine.
The content of uremic substances (e.g., indoxyl sulfate) in body fluids can be measured by HPLC or enzymatic methods, but these methods require specialized and expensive reagents.
As described herein, administration of an alkalinizing agent reduces uremic substances (e.g., indoxyl sulfate concentration, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and/or argininosuccinic acid) in the blood and promotes excretion of these uremic substances into the urine. Therefore, by measuring the pH of their urine, patients with chronic kidney disease can very simply and inexpensively determine whether or not they have reduced uremic substances (e.g., indoxyl sulfate concentration, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and/or argininosuccinic acid) in the blood and/or promoted excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and/or argininosuccinic acid) into the urine. pH can be measured using well-known techniques, such as pH test paper, a pH test solution, or a simple pH meter.
In one embodiment, a patient with chronic kidney disease measures the pH of their early morning urine (the first urine they urinate after waking up) over time from the start of taking an alkalinizing agent (e.g., a mixture of potassium citrate monohydrate and sodium citrate dihydrate, or sodium citrate dihydrate), and if the urine pH increases, it can be simply determined that a decrease in the concentration of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) in the blood and/or promotion of excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) into the urine has been achieved.
In one embodiment, a patient with chronic kidney disease takes an alkalinizing agent (e.g., a mixture of potassium citrate monohydrate and sodium citrate dihydrate, or sodium citrate dihydrate) and then measures the pH of their early morning urine (the first urine they urinate upon waking up). If the urine pH is in the range of 6.2 to 6.8 (e.g., the urine pH is in the range of 6.5 to 6.8), it can be simply determined that a decrease in the concentration of uremic substances in the blood (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) and/or promotion of excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) into the urine has been achieved.
The determination of whether or not a reduction in the concentration of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) in the blood and/or promotion of excretion of uremic substances (e.g., indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid and/or argininosuccinic acid) into the urine has been achieved can aid in the diagnosis of whether or not the progression of chronic kidney disease has been inhibited.
Thus, in one embodiment, the present invention provides a method for determining whether progression of chronic kidney disease has been inhibited, the method comprising measuring the pH of urine (e.g., early morning urine) from a patient to whom an alkalinizing agent (e.g., a mixture of potassium citrate monohydrate and sodium citrate dihydrate, or sodium citrate dihydrate) has been administered. If an increase in urine pH over time or a urine pH in the range of 6.2 to 6.8 (e.g., a urine pH in the range of 6.5 to 6.8) is observed, this can aid in the diagnosis that progression of chronic kidney disease has been inhibited.

The present invention will be further explained below with reference to examples, but the present invention is not limited to these examples.

A human clinical trial was conducted to investigate whether oral administration of oral alkalinizing agents, potassium citrate/sodium citrate hydrate combination preparations and sodium bicarbonate preparations, promotes urinary excretion of uremic substances.

1. Methods: Forty-seven patients with stage G2-G3b chronic kidney disease (eGFR: 30-89 ml/min/ ^1.73m2 , urinary protein excretion less than 3.5 g/gCr) were randomly divided into a potassium citrate and sodium citrate hydrate compound group (Group A: 16 patients), a sodium bicarbonate (sodium bicarbonate) compound group (Group B: 16 patients), and a control group (Group C: 15 patients). Each group received treatment based on the "CKD Clinical Practice Guide - Treatment Summary" (hereinafter referred to as standard treatment).
The control group received no alkalinizing agents. Group _A received three tablets containing 231.5 mg of potassium citrate _{( C6H5K3O7} · _H2O ) and 195.0 mg of sodium citrate hydrate ( _C6H5Na3O7 · _2H2O ) orally three times _daily (morning, noon, and evening) for 24 weeks. For patients with _early morning urine pH below 6.5, the dose was increased to _six tablets three times _daily (morning, noon, and evening) at the physician's discretion. Group B received three tablets containing 500 mg of sodium bicarbonate orally three times daily (morning, noon, and evening) for 24 weeks. For patients with early morning urine pH below 6.5, the dose was increased to six tablets three times daily (morning, noon, and evening) at the physician's discretion.
Early morning urine and blood samples were collected at the start of treatment and at 6, 12, and 24 weeks after the start of treatment, and each sample was stored at -80°C. Urine and plasma indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and argininosuccinic acid were quantitatively analyzed using a liquid chromatography triple quadrupole mass spectrometer (LC-MS/MS) according to methods used in the field (e.g., Sato, E., et. al., Metabolic alteration by indoxyl sulfate in skeletal muscle induce uremic sarcopenia in chronic kidney disease., Sci Rep. 2016 Nov 10;6:36618. doi: 10.1038/srep36618).
LC was performed using NANOSPACE SI-2 (Shiseido) and CAPCELLPAK MGIII was selected as the analytical column.
MS was performed using a TSQ Quantiva (Thermo Fisher Scientific) with five compounds ionized in negative in-mode and detected using selected reaction monitoring. Quantitative values were calculated using a calibration curve prepared using standard solutions of each compound.
Statistical analysis was performed using the Mann-Whitney test.

2. result
From the measurement results using LC-MS/MS, the following was calculated for each patient in Group A (group administered a potassium citrate/sodium citrate hydrate formulation), Group B (group administered a sodium bicarbonate formulation), and Group C (control group):
(i) the concentration of each uremic substance in plasma at the start of administration; (ii) the concentration of each uremic substance in early morning urine at the start of administration; and (iii) the ratio of the uremic substance concentration in early morning urine to the uremic substance concentration in plasma at the start of administration (amount of uremic substance in urine/amount of uremic substance in plasma).
(iv) Concentration of each uremic substance in plasma at 6, 12, and 24 weeks after the start of administration. (v) Concentration of each uremic substance in early morning urine at 6, 12, and 24 weeks after the start of administration. (vi) Ratio of uremic substance concentration in early morning urine to uremic substance concentration in plasma at 6, 12, and 24 weeks after the start of administration (amount of uremic substance in urine/amount of uremic substance in plasma).
(vii) Changes from the start of administration in the concentration of each uremic substance in plasma at 6, 12, and 24 weeks after the start of administration; (viii) Changes from the start of administration in the concentration of each uremic substance in early morning urine at 6, 12, and 24 weeks after the start of administration; (ix) Changes from the start of administration in the ratio of the uremic substance concentration in early morning urine to the uremic substance concentration in plasma (amount of uremic substance in urine/amount of uremic substance in plasma) at 6, 12, and 24 weeks after the start of administration. The mean and SD of each group were calculated for (i) to (ix) above. For each of (iv) to (ix) above, the mean and SD of each group were calculated using all data from 6, 12, and 24 weeks after the start of administration.
The results are shown in the table below. In the table, Group A (the group administered the potassium citrate-sodium citrate hydrate formulation) is referred to as "Citrate," and Group B (the group administered the sodium bicarbonate formulation) is referred to as "Bicarbonate." The numbers in parentheses in the table indicate the number of cases.
Table 1-1-1: Amount of indoxyl sulfate in plasma (μg/mL)
Table 1-1-2: Changes in plasma indoxyl sulfate from the start of administration (μg/mL)
Table 1-2-1: Amount of indoxyl sulfate in early morning urine (μg/mL)
Table 1-2-2: Changes in indoxyl sulfate in early morning urine from the start of administration (μg/mL)
Table 1-3-1: Ratio of indoxyl sulfate in urine to indoxyl sulfate in plasma
Table 1-3-2: Changes in the ratio of indoxyl sulfate in urine to indoxyl sulfate in plasma from the start of administration
Table 2-1-1: Amount of p-cresyl sulfate in plasma (μg/mL)
Table 2-1-2: Changes in plasma p-cresyl sulfate from the start of administration (μg/mL)
Table 2-2-1: Amount of p-cresyl sulfate in early morning urine (μg/mL)
Table 2-2-2: Changes in p-cresyl sulfate in early morning urine from the start of administration (μg/mL)
Table 2-3-1: Ratio of p-cresyl sulfate in urine to p-cresyl sulfate in plasma
Table 2-3-2: Changes from the start of administration in the ratio of p-cresyl sulfate in urine to p-cresyl sulfate in plasma
Table 3-1-1: Hippuric acid amount in plasma (μg/mL),
Table 3-1-2: Change in plasma hippuric acid from the start of administration (μg/mL)
Table 3-2-1: Amount of hippuric acid in early morning urine (μg/mL)
Table 3-2-2: Change in hippuric acid in early morning urine from the start of administration (μg/mL)
Table 3-3-1: Ratio of hippuric acid in urine to hippuric acid in plasma
Table 3-3-2: Changes in the ratio of hippuric acid in urine to hippuric acid in plasma from the start of administration
Table 4-1-1: Plasma argininosuccinic acid content (μg/mL)
Table 4-1-2: Changes in plasma argininosuccinic acid from the start of administration (μg/mL)
Table 4-2-1: Amount of argininosuccinic acid in early morning urine (μg/mL)
Table 4-2-2: Changes in argininosuccinic acid in early morning urine from the start of administration (μg/mL)
Table 4-3-1: Ratio of argininosuccinic acid in urine to argininosuccinic acid in plasma
Table 4-3-2: Change from the start of administration in the ratio of argininosuccinic acid in urine to argininosuccinic acid in plasma
Table 5-1-1: Plasma phenylacetyl-L-glutamine (PAG) levels (μg/mL)
Table 5-1-2: Changes in plasma phenylacetyl-L-glutamine (PAG) from the start of administration (μg/mL)
Table 5-2-1: Amount of phenylacetyl-L-glutamine (PAG) in early morning urine (μg/mL)
Table 5-2-2: Changes in phenylacetyl-L-glutamine (PAG) in early morning urine from the start of administration (μg/mL)
Table 5-3-1: Ratio of phenylacetyl-L-glutamine (PAG) amount in urine to phenylacetyl-L-glutamine (PAG) amount in plasma
Table 5-3-2: Changes from the start of administration in the ratio of phenylacetyl-L-glutamine (PAG) amount in urine to phenylacetyl-L-glutamine (PAG) amount in plasma.

In Group A (administered a citrate (potassium citrate/sodium citrate hydrate) formulation), indoxyl sulfate (IS) concentrations were higher in early morning urine compared to Group B (administered a bicarbonate (sodium bicarbonate) formulation) and Group C (control) (see Tables 1-2-1 and 1-2-2). Furthermore, plasma indoxyl sulfate concentrations were lower in Group A compared to Groups B and C (see Tables 1-1-1 and 1-1-2). Plasma indoxyl sulfate concentrations from 6 to 24 weeks were significantly lower in Group A compared to Groups B and C, and the increase in indoxyl sulfate concentrations in early morning urine from 6 to 24 weeks was significantly greater in Group A compared to Groups B and C.
Furthermore, when a potassium citrate/sodium citrate hydrate formulation was administered to patients with chronic kidney disease, the urinary concentration of indoxyl sulfate, a uremic substance, increased compared to before administration, and the blood concentration of indoxyl sulfate decreased compared to before administration. Even though both are alkalinizing agents, the potassium citrate/sodium citrate hydrate formulation exhibited a greater effect of lowering blood indoxyl sulfate concentrations and increasing urinary indoxyl sulfate concentrations than sodium bicarbonate formulations. The effects of the potassium citrate/sodium citrate hydrate formulation on lowering blood indoxyl sulfate concentrations and increasing urinary indoxyl sulfate concentrations were observed from 12 weeks after administration.
The ratio of indoxyl sulfate concentration in urine to indoxyl sulfate concentration in plasma suggests that administration of potassium citrate-sodium citrate hydrate formulation promotes excretion of indoxyl sulfate from the blood into urine, thereby promoting excretion from the body. Furthermore, it was suggested that the excretion effect of indoxyl sulfate from the blood into urine was stronger with administration of potassium citrate-sodium citrate hydrate formulation compared to administration of sodium bicarbonate formulation (see Tables 1-3-1 and 1-3-2).

Regarding p-cresyl sulfate (PCS), the concentration of p-cresyl sulfate in early morning urine was higher in Group A (the group administered a citrate (potassium citrate and sodium citrate hydrate preparation) compared to Group C (control group), and the concentration of p-cresyl sulfate in early morning urine was also higher in Group A (the group administered a potassium citrate and sodium citrate hydrate preparation) compared to Group B (the group administered a bicarbonate (sodium bicarbonate) preparation) (see Tables 2-2-1 and 2-2-2). The increase in p-cresyl sulfate concentration in early morning urine from 6 to 24 weeks was significantly greater in Group A compared to Groups B and C.
Furthermore, when a potassium citrate/sodium citrate hydrate formulation was administered to patients with chronic kidney disease, the urinary concentration of p-cresyl sulfate, a uremic substance, increased compared to before administration (see Tables 2-2-1 and 2-2-2). Even though both are alkalinizing agents, the potassium citrate/sodium citrate hydrate formulation was more effective at increasing urinary p-cresyl sulfate concentrations than a sodium bicarbonate formulation. The effect of the potassium citrate/sodium citrate hydrate formulation in increasing urinary p-cresyl sulfate concentrations was observed from 12 weeks after administration.
The ratio of urinary p-cresyl sulfate concentration to plasma p-cresyl sulfate concentration suggests that administration of a potassium citrate-sodium citrate hydrate formulation promotes the excretion of p-cresyl sulfate from the blood into urine, thereby promoting its excretion from the body. Furthermore, it was suggested that the excretion effect of p-cresyl sulfate from the blood into urine was stronger with administration of a potassium citrate-sodium citrate hydrate formulation than with administration of a sodium bicarbonate formulation (see Tables 2-3-1 and 2-3-2).

Regarding hippuric acid (HA), the concentration of hippuric acid in early morning urine was increased in Group A (the group administered a citrate: potassium citrate and sodium citrate hydrate compound preparation) compared to Group C (control group) (see Tables 3-2-1 and 3-2-2).
Furthermore, administration of a potassium citrate-sodium citrate hydrate formulation to patients with chronic kidney disease increased the urinary concentration of hippuric acid, a uremic substance, compared to before administration (see Tables 3-2-1 and 3-2-2). Even though both are alkalinizing agents, the potassium citrate-sodium citrate hydrate formulation exhibited a greater effect of increasing urinary hippuric acid concentrations than sodium bicarbonate formulations. The effect of the potassium citrate-sodium citrate hydrate formulation in increasing urinary hippuric acid concentrations was observed from 6 weeks after administration. Administration of a potassium citrate-sodium citrate hydrate formulation to patients with chronic kidney disease reduced plasma hippuric acid concentrations from 24 weeks after administration compared to before administration. This effect was not observed with sodium bicarbonate formulations.

Regarding argininosuccinic acid (ASA), the concentration of argininosuccinic acid in early morning urine was increased in Group A (Citrate: potassium citrate/sodium citrate hydrate compounded preparation administration group) compared to Group C (Control: control group) (see Tables 4-2-1 and 4-2-2).
Furthermore, administration of a potassium citrate-sodium citrate hydrate formulation to patients with chronic kidney disease increased the urinary concentration of argininosuccinic acid, a uremic substance, compared to before administration (see Tables 4-2-1 and 4-2-2). The effect of the potassium citrate-sodium citrate hydrate formulation in increasing urinary argininosuccinic acid concentrations was observed from 12 weeks after administration.

With regard to phenylacetyl-L-glutamine (PAG), Group A (administered a citrate: potassium citrate and sodium citrate hydrate preparation group) had lower plasma phenylacetyl-L-glutamine concentrations and higher phenylacetyl-L-glutamine concentrations in early morning urine compared to Group C (control group). Group A (administered a potassium citrate and sodium citrate hydrate preparation group) also had higher early morning urine phenylacetyl-L-glutamine concentrations compared to Group B (administered a bicarbonate: sodium bicarbonate preparation group) (see Tables 5-1-1 and 5-2-2).
Furthermore, administration of a potassium citrate-sodium citrate hydrate formulation to patients with chronic kidney disease increased the urinary concentration of phenylacetyl-L-glutamine, a uremic toxin, compared to before administration (see Tables 5-2-1 and 5-2-2). Even though both alkalinizing agents are the same, the potassium citrate-sodium citrate hydrate formulation exhibited a greater effect in increasing urinary phenylacetyl-L-glutamine concentrations than sodium bicarbonate formulations. The effect of the potassium citrate-sodium citrate hydrate formulation in increasing urinary phenylacetyl-L-glutamine concentrations was observed from 12 weeks after administration. Administration of a potassium citrate-sodium citrate hydrate formulation to patients with chronic kidney disease decreased the plasma concentration of phenylacetyl-L-glutamine, a uremic toxin, compared to before administration (see Tables 5-1-1 and 5-2-2).
The ratio of phenylacetyl-L-glutamine concentration in urine to that in plasma suggests that administration of potassium citrate-sodium citrate hydrate preparations promotes the excretion of phenylacetyl-L-glutamine from the blood into urine, thereby promoting its excretion from the body.Furthermore, it was suggested that the excretion effect of phenylacetyl-L-glutamine from the blood into urine was stronger with administration of potassium citrate-sodium citrate hydrate preparations than with administration of sodium bicarbonate preparations (see Tables 5-3-1 and 5-3-2).

The effects of potassium citrate-sodium citrate hydrate (Citrate) and sodium bicarbonate (Bicarbonate) on plasma concentrations, early morning urine concentrations, and ratios of early morning urine concentrations to plasma concentrations of each uremic substance are summarized in the table below. In the table below, the comparator refers to sodium bicarbonate (Citrate) in the case of potassium citrate-sodium citrate hydrate (Citrate), and potassium citrate-sodium citrate hydrate (Citrate) in the case of sodium bicarbonate (Bicarbonate). A circle indicates a significantly superior effect compared to the control group or comparator group; an × indicates a significantly inferior effect compared to the control group or comparator group; and a - indicates no significant difference. The effect of the sodium bicarbonate (Bicarbonate) group on early morning urine indoxyl sulfate concentrations compared to the control group is indicated by a circle in the table below. This is because the sodium bicarbonate (bicarbonate) administration group significantly increased indoxyl sulfate concentrations in early morning urine compared to the control group, but because the indoxyl sulfate concentrations in early morning urine after administration of the sodium bicarbonate (bicarbonate) preparation decreased compared to when administration began, it is not possible to determine whether or not there is an effect of promoting the excretion of indoxyl sulfate into the urine.

From the table above, it can be seen that potassium citrate/sodium citrate hydrate preparations generally exhibit a higher excretion effect on uremic substances than sodium bicarbonate preparations. It also suggests that administering alkalinizing agents to patients with chronic kidney disease in stage G2, as well as stage G3b, can slow the progression of chronic kidney disease, and that potassium citrate/sodium citrate hydrate preparations slow the progression of chronic kidney disease more effectively than sodium bicarbonate preparations.

Claims (15)

A pharmaceutical composition containing an alkalizing agent for reducing uremic substance concentrations in the blood and for inhibiting renal tubular cell damage in patients with kidney disease, wherein the alkalizing agent is a mixture of sodium citrate or its hydrate and potassium citrate or its hydrate. A pharmaceutical composition containing an alkalizing agent for increasing the concentration of uremic substances in urine and for suppressing renal tubular cell damage in patients with kidney disease, wherein the alkalizing agent is a mixture of sodium citrate or its hydrate and potassium citrate or its hydrate. A pharmaceutical composition containing an alkalizing agent for reducing uremic substance concentrations in the blood and maintaining renal tubular cell function in patients with kidney disease, wherein the alkalizing agent is a mixture of sodium citrate or its hydrate and potassium citrate or its hydrate. A pharmaceutical composition for increasing the concentration of uremic substances in urine and maintaining renal tubular cell function in patients with kidney disease, comprising an alkalinizing agent, wherein the alkalinizing agent is a mixture of sodium citrate or its hydrate and potassium citrate or its hydrate. The pharmaceutical composition according to any one of claims 1 to 4, which is administered to a patient with chronic kidney disease or acute kidney disease. The pharmaceutical composition according to any one of claims 1 to 5, wherein the uremic substance is selected from the group consisting of indoxyl sulfate, p-cresyl sulfate, phenylacetyl-L-glutamine, hippuric acid, and argininosuccinic acid. The pharmaceutical composition according to any one of claims 1 to 6, wherein the uremic substances are indoxyl sulfate and phenylacetyl-L-glutamine. The pharmaceutical composition according to any one of claims 1 to 7, wherein the uremic substance is indoxyl sulfate. The pharmaceutical composition according to any one of claims 1 to 8, which is administered to patients with early-stage chronic kidney disease. The pharmaceutical composition according to any one of claims 1 to 9, which is administered to patients with chronic renal failure at stage G3b or below. The pharmaceutical composition according to any one of claims 1 to 10, which is administered to patients with stage G2 chronic renal failure. The pharmaceutical composition according to any one of claims 1 to 11, wherein the alkalinizing agent is designed to be administered in an amount that improves acidic urine in gout or hyperuricemia. The pharmaceutical composition according to any one of claims 1 to 12, wherein the alkalinizing agent is administered chronically. The pharmaceutical composition according to any one of claims 1 to 13, wherein the alkalinizing agent is administered for a period of 6 weeks or more. The pharmaceutical composition according to any one of claims 1 to 14, wherein the pharmaceutical composition is a tablet.