EP0248046A1

EP0248046A1 - Medicament for use against circulatory disorders

Info

Publication number: EP0248046A1
Application number: EP86906828A
Authority: EP
Inventors: Elfriede Leniger-Follert
Original assignee: LENIGER-FOLLERT Elfriede; Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
Current assignee: LENIGER-FOLLERT Elfriede
Priority date: 1985-12-12
Filing date: 1986-12-02
Publication date: 1987-12-09
Also published as: WO1987003479A2; US5008269A; JPH01500175A; WO1987003479A3; JPH0223162B2; DE3543974A1

Abstract

Le médicament ci-décrit contient comme substance active au moins une substance captant des ions de potassium à des valeurs pH physiologiques, comme par ex. un composé de formule générale (I) dans laquelle R1, R2 et R3 représentent chacun un groupe alkyle comprenant de 1 à 4 atomes de carbone, et n, p et q représentent indépendamment les uns des autres un nombre entier de 1 à 5, ou un éther en couronne, éventuellement avec des additifs, solvants et/ou diluants physiologiques usuels.The described medicament contains as active substance at least one substance which scavenges potassium ions at physiological pH values, such as e.g. a compound of general formula (I) in which R1, R2 and R3 each represent an alkyl group comprising from 1 to 4 carbon atoms, and n, p and q independently of each other represent an integer from 1 to 5, or a crown ether, optionally with customary physiological additives, solvents and / or diluents.

Description

Medicines to control circulatory disorders

The invention relates to a medicament for combating circulatory disorders.

Circulatory disorders are caused by various causes. You can, for example, purely mechanically by z. B. thrombus or embolus or by a vascular stenosis in changes in the vascular wall or by cardiovascular-related drop in blood pressure below a critical lower perfusion pressure. Furthermore, disorders of the blood composition can lead to circulatory disorders. The blood circulation in an organ or in the whole organism can only be reduced or completely abolished compared to the normal state. As a result of the circulatory disorder, there is a lack of oxygen and a lack of substrate, a reduced removal of the metabolic end products and damage to the cell membranes in the affected organ or in the entire organism.

Depending on the extent of the reduction in blood flow, this leads to serious consequences in the areas concerned and therefore to serious clinical pictures which can even lead to death.

From a pathophysiological point of view, in the event of a disorder, calcium ions first flow into the cell from the extracellular space and, in return, potassium ions flow out of the cells into the extracellular space. Furthermore, intracellular and extra-cellular acidosis results from increased lactate formation. The increase in potassium concentration in the extracellular space initially causes an expansion of the arterial blood vessels in the range of 3 to 20 mmol per liter through hyperpolarization of the smooth vascular muscle cell membrane. Above 20 mmol per liter, a further increase in the K concentration in the extracellular space leads to a narrowing of the blood vessels, caused by a K depolarization of the smooth vascular muscle cell membrane. The K concentration can rise up to a maximum of 100 mmol per liter and lead to a complete occlusion of the arterial blood vessels. An increase in the extracellular K concentration, which has a narrowing effect on the vessels, can also take place by releasing potassium ions from erythrocytes after bleeding into the tissue, for example after subarachnoid hemorrhage in the case of aneurysms of the brain arteries.

The narrowing of the vessels due to the increased potassium concentration in the extracellular space has very serious consequences for the organs or tissues affected. It is the actual reason why the blood flow can no longer be started after a primary disorder. This then leads to a final destruction of cells and parts of the tissue, so that, particularly in the cerebral and coronary areas, clinical pictures arise which can even lead to death.

Cerebral and coronary circulatory disorders are common in the population. There is therefore a need to provide a drug for the treatment of these diseases. The aim of the invention was therefore to provide a medicament which is suitable for the treatment of circulatory disorders, in particular in the cerebral and coronary area.

This aim is achieved by a medicament for combating circulatory disorders, which is characterized in that it contains at least one substance which intercepts potassium ions at physiological pH values, optionally together with conventional physiological additives, solvents and / or diluents contains.

Surprisingly, it has been shown that circulatory disorders can be treated with an agent which can trap potassium ions in the extracellular region. With the help of this new drug, the narrowing of the arterial blood vessels in the organs, which is due to a K concentration increase between 20 and 100 mmol, is eliminated and the vessels are enlarged so that blood can flow again.

To combat circulatory disorders, the medicament contains a substance that intercepts potassium ions. This active ingredient exhibits the K-ion trapping properties at both normal and pathophysiological pH values. For this purpose, a compound is used which can selectively complex potassium ions, whereby Na, Ca and Mg are not complexed. The compound should preferably be water-soluble since it is supplied to the blood. It should also not be too fat-soluble so that it cannot penetrate the cell membrane. Of course, this substance must not be toxic to humans. Furthermore, it must not be mutagenic or teratogenic. The substance trapping potassium ions is preferably used together with conventional physiological additives, solvents and / or diluents. These means are known to the person skilled in the art.

A compound of the general formula:

where R_. , R ₂ and R ^ independently of one another denote an alkyl group with 1 to 4 C atoms and n, p and q independently denote an integer from 1 to 5.

These compounds, referred to as cryptates, are excellently suitable for the selective complexation of potassium ions. They are water soluble and non-toxic. Compounds in which R ₁ , R ₂ and R _{3 represent} a C ₂ alkyl group and n, p and q 2 are particularly preferably used.

It is preferred to make the cryptates even more water-soluble by introducing hydrophilic substituents.

The advantage of this compound, which is used with preference, is that the pH is increased somewhat when complexing potassium. In the case of the deficiency supply caused by the circulatory disorder, the pH is shifted into the acidic range. Therefore, it is It is particularly advantageous that this acidotic shift, which can lead to cell death, is prevented by the agent according to the invention.

Another preferred substance trapping potassium ions is a crown ether. A compound of the general formula:

wherein the C atoms 1,2 and 7,8 can be part of a cyclohexyl or benzyl group.

The compounds referred to as crown ethers are also very well suited for selectively complexing potassium ions. Crown ethers in which the two rings are substituted with hydrophilic groups are preferably used. The compound designated as Zl87-Krone-6, which shows no rings, is particularly preferably used.

Customary additives can also be added to the drug. In particular, physiologically suitable buffer substances come into consideration. Tris buffer, bicarbonate or phosphate buffer are used in particular as buffer substances. In a preferred embodiment, the drug is still a thrombolytic additive is added. This is particularly useful if the circulatory disorder to be treated due to a vascular blockage z. B. was triggered by a thrombus in an infarction. Anti-dehydrating agents can also be added to the drug.

In particular in the case of coronary circulatory disorders, it is further preferred to add a compound to the medicament which acts as a calcium antagonist.

The medicament according to the invention is suitable for treating all types of circulatory disorders. It can be used to treat circulatory disorders in all organs and in the whole organism. The agent is suitable for generalized and local circulatory disorders. It is particularly preferably used in the treatment of cerebral and coronary circulatory disorders. A preferred application is also the treatment of cerebral circulatory disorders in the newborn infant.

The agent can be applied systemically. Due to its good water solubility, the agent can be administered in the form of injections and infusions. The injection is preferably carried out intra-arterially. However, it is also possible to administer the agent intravenously. As an infusion, the drug is preferably contained in a rheologically effective infusion for hemodilution of the blood. In addition, the agent can also be administered orally in the form of drops or tablets. In a further preferred embodiment, the agent is used to treat circulatory disorders in individual organs injected directly into the affected organ. For example, in the case of a cerebral infarction, the agent is injected directly into a cerebral artery, and in the case of a heart attack, the agent is injected directly into the heart. In particular if the heart is affected, it is also preferred to place a catheter and to introduce the agent through this catheter.

Furthermore, the agent can also be applied locally from the outside to the affected organ. So z. B. after bleeding in the area of the pial brain arteries, the agent is applied to the brain through a borehole or during the neurosurgical operation in order to eliminate the localized or generalized spasms due to the K release after bleeding.

The dose of the drug depends on the type and location of the circulatory disorder. The agent can be dosed precisely depending on the potassium concentration at the site of the circulatory disorder. The drug is preferably used in a concentration such that the potassium ion concentration is set in a range from 3 to 20 mmol, particularly preferably 3 to 10 mmol.

Circulatory disorders and vascular occlusions can be treated with the medicament according to the invention. With the remedy, the vascular constriction is removed and the ischemia is eliminated. Surprisingly, it is thus possible to prevent or at least reduce damage caused by ischemia.

The invention will be illustrated by examples: Example 1

The effect of (2,2,2) cryptate on the K -

Concentration in the rat brain examined. The

K + activity of the cerebral cortex was measured with a K + sensitive valinomycin surface electrode on an anesthetized rat. The physiological parameters were in the normal range. The K starting concentration on the brain cortex was 4.5 mmol / l and was constant. About 100 μl of a 100 mmol KC1 solution were then dripped onto the entire exposed surface of the brain. The K activity of the brain rose to 34 mmol / 1. Drop of 100 mmol (2.2.2) -

Let cryptate dissolved in physiological saline

_ the K activity drops immediately. After about 2 minutes all of the applied potassium was bound away and the

K -value of 4.5 mmol / 1 reached again.

After 4 1/2 minutes the K value was 4.2 mmol. Another local supply of KC1 from the outside to the cortex in the same amount and concentration as before left the

K value only increase to 5.6 mmol / 1. A further addition of cryptate led to a decrease in the K + activity in the tissue to 4.4 mmol / l.

The K electrode was removed from the tissue and rinsed the surface of the brain several times with warm physiological NaCl Lδsung and NaCl ^"aspirated. Then, the K electrode was set up again and a K value of 4.5 mmol / 1 was measured. Renewed application of 100 mmol KCl solution now led to an increase in K in the tissue to 20 mmol / l. By adding (2,2,2) cryptate, the K concentration dropped to 4.5 mmol / l within 2 1 /2 minutes. Example 2

The effect of (2,2,2) cryptate on the blood flow to the brain of the anesthetized rat was examined. The changes in cerebral blood flow in the microcirculation area were measured continuously and qualitatively by means of the local hydrogen clearance using the Stosseck and Lübbers method, modified according to Leniger-Follert and Lübbers, with an H ₂ / pH ₂ surface element according to Leniger-Follert and Lübbers and Lübbers Bathelt and Leniger-Follert.

First, the blood flow was registered continuously over approximately 10 minutes with normal physiological control parameters and a normal K value in the brain and steady state conditions. During this time the blood flow remained completely constant and was in the normal range. Then 30 μl of a 100 mmol KC1 solution was applied to the brain surface directly at the measuring point. The blood flow showed a two-phase course. At first it rose immediately and decreased again after about 10 seconds and fell well below the initial value. There was insufficient blood flow (ischemia). After a further 40 seconds, approximately 40 μl (2,2,2) cryptate was added to the brain tissue from the outside. The blood flow increased rapidly within a few seconds and was above the starting area after about 1 minute. ^" - Example 3

The effect of (2,2,2) cryptate on the K concentration was tested in an unbuffered and buffered solution. The K + concentration in the solution was measured using a K-sensitive valinomycin.

Surface electrode.

a) The effect of (2,2,2) cryptate on the potassium activity or potassium concentration was investigated in the unbuffered system at different starting pH.

The K ions were present as dissolved KCl in physiological (0.9%) NaCl. The pH of the solution was adjusted with concentrated NaOH. As a starting solution

4 ml of a 100 mM KCl related, dissolved in 0> 9% NaCl. 1 ml of 500 mM (2.2.2) cryptate, which was dissolved in 100 M KCl and 0.9% NaCl, was added to this solution in order to eliminate a dilution effect. After the solutions were put together

Receive 5 ml of a solution with the following concentration: 100 mM KCl, 100 mM (2,2,2) cryptate, 0.9% NaCl. With a theoretical 100% complexation of the potassium ions, the entire free potassium can be complexed.

Solutions with the following pH values were used: pH 7, 8, 10. In all three solutions "the potassium was complexed to over 80%. However, after the cryptate had been added, the pH in the alkaline range was pH 9. Only in the starting solution with pH 10 did the pH change only slightly (see Table 1). Table

pH value of the K conc. the K -conc. according to the pH value of the starting solution. Starting solution Cryptate addition mixture

10 100 π 19 9.8

8 100 πM 16 8.9

7 100 mM 16 8.9

As is clear from the table, the initial concentration of 100 mM drops after addition of an equivalent amount of cryptate to values below 20 mM at all 3 pH levels.

b) Because of the pH shift described above, a second attempt was made in which the system was buffered and a lower concentration of starting substances was used.

The solutions (both the KCl starting solution and the cryptate solution were buffered to pH 7.0 with 0.1 M phosphate buffer (Na-HPO. + NaH-PO.).

The following mixtures were used as the starting solution: 4 ml of 50 mM KCl; 0.9% NaCl; 0.1 phosphate buffer pH 7.0 1 ml 250 mM (2.2.2) cryptate; 50 M KCl; 0.9% NaCl; 0.1 M phosphate buffer.

The addition of the complexing agent led to a reduction in the K activity by more than 50%. Only a slight shift in pH in the alkaline range occurred. The pH shifted by 0.4 units to pH 7.4. Table

+ + pH value of the K conc. the K -conc. according to the pH of the

Starting solution Starting solution Cryptate addition mixture

7.0 50mM 22 7.4

Claims

P a t e n t a n s r u c h e

1. Medicament for combating circulatory disorders, that is, that it contains at least one potassium ion-trapping substance as active ingredient at physiological pH values, if appropriate together with conventional physiological additives, solvents and / or diluents.

2. Medicament according to claim 1, d a d u r c h g e k e n n z e i c h n e t that it is a compound of the general formula:

wherein R, R ₂ and R_ each represent an alkyl group with 1 to 4 carbon atoms and n, p and q independently of one another are an integer from 1 to 5.

Medicament according to claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that it as the potassium-intercepting substance the compound

_{/ C} H ₂ -CH ₂ 0-CH ₂ CH ₂ 0-CH ₂ -CH ₂

N \ - CH2-CH 2--0-CH 2CH20-CH 2CH-2, ^ N

CH ₂ -CH ₂ 0-CH ₂ CH ₂ 00-CH ₂ CH ₂

contains. 4. Medicament according to claim 1, characterized in that it as

Potassium ^* trapping substance is a compound of the general formula:

where the C atoms 1, 2 and 7, 8 can be part of a cyclohexyl or benzyl group, which is optionally substituted with hydrophilic groups.

5. Medicament according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that it contains the potassium ion-trapping substance in such a concentration that the potassium ion concentration is adjusted to 3 to 20 mmol.

6. Medicament according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that it contains as an additive buffer substances and / or thrombolytic additives and / or anti-edematous additives.

7. Medicament according to one of the preceding claims, which also means that it additionally contains calcium antagonists.

8. Medicament according to one of the preceding claims, characterized in that it is rheologically effective Infusion for blood hemodilution is included.

9. Use of the medicament according to one of the preceding claims for combating peripheral circulatory disorders.

10. Use of the medicament according to one of claims 1 to 8 for combating cerebral circulatory disorders.

11. Use of the medicament according to one of claims 1 to 8 for combating coronary circulatory disorders.