AU658979B2

AU658979B2 - The use of xanthine derivatives for the treatment of muscle damage after interruption of the blood circulation

Info

Publication number: AU658979B2
Application number: AU33761/93A
Authority: AU
Inventors: Michael Alfred Gregory; Maurice Mars; Ismahan Okyayuz-Baklouti
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1992-02-22
Filing date: 1993-02-19
Publication date: 1995-05-04
Anticipated expiration: 2013-02-19
Also published as: HUT64472A; ES2096115T3; GR3022183T3; ZA931184B; DE59304710D1; EP0557876B1; KR930017580A; HU9300476D0; JPH069634A; AU3376193A; TW288977B; CA2089959A1; DK0557876T3; JP3193800B2; EP0557876A1; ATE146078T1

Abstract

Xanthine derivatives of the formula I <IMAGE> where at least one of the radicals R<1> and R<3> is a radical of the formula Ia <IMAGE> R<4> is a (C1-C3)-alkyl radical, n is an integer from 2 to 5 and, if only one of the radicals R<1> and R<3> is such a tertiary hydroxyalkyl group of the formula Ia, the other radical is a hydrogen atom or an aliphatic hydrocarbon radical R<5> which has up to 6 C atoms and whose carbon chain can be interrupted by up to 2 oxygen atoms or be substituted by an oxo group or up to two hydroxyl groups, these oxo and hydroxyl groups being separated from the ring nitrogen by at least 2 C atoms, and R<2> is an alkyl group with 1-4 C atoms, are suitable for the preparation of pharmaceutical compositions for the prophylaxis and treatment of muscle damage which may occur after interruption of the blood circulation.

Description

IUI11 2W5/01 Regulat(on 3,2(2)

AUSTRALIA

Patents ,ct 1990 658979

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: THE USE OF XANTHINE DERIVATIVES FOR THE TREATMENT OF MUSCLE DAMAGE AFTER INTERRUPTION OF THE BLOOD

CIRCULATION

The following statement is a full description of this invention, including the best method of performing it known to :-US 1 HOECHST AKGIENGESELLSpHAFT HOE 92/F 049 Dr. Th/wo Description The use of xanthine derivatives for the treatment of muscle damage after interruption of the blood circulation A number of oxoalkyl- and hydroxyalkylxanthines promote blood flow and can also be employed for the treatment of disorders of muscular energy metabolism as are present, in particular, in cases of mitochondrial myopathy (EP 0 262 585).

Tourniquets are routinely used in surgery on the extremities in order to obtain an operation area free of blood.

Although there are reports that interruptions of blood S..flow are possible for up to three hours, surgeons generally restrict the interruption of blood flow to 90 120 minutes (Tountas and Bergman, J. Hand. Surg., 1977 15 2 31 37) because more prolonged ischemia with subsequent restoration of blood flow leads to a number of types of muscle damage, for example swelling of the muscle fibers, degeneration of the muscle cells, slight sensory and motor damage, destabilization of the membrane of muscle cells, in which case there is disturbance of the intracellular medium, or difficulties in rehabilitation. It is known that damage may occur after restoration of blood flow in ischemic tissue in the heart, kidney, intestine and skeletal muscles McCord, New England, 25 J. Med., 1985, 312 159 163). To date, no pharmaceuticals which allow the time of interruption of blood circulation to be prolonged or the disturbances of function caused by the interruption of the blood circulation to be significantly reduced are known.

It has now been found that certain xanthine derivatives are suitable for prolonging the time of interruption of blood flow, for improving the syndromes which occur after interruption of blood flow and subsequent restoration of blood flow, and for reducing the changes in the intracompartmental pressure.

2 Interruption of the blood circulation in tissues, organs or extremities occurs, for example, in operations after injuries to the large arteries or veins, after emergency operations in cases of severance of limbs, removal of thrombi or other occlusions in arteries or veins or in transplantations, for example of the kidney or heart.

Depending on the duration of the operation, there may then be more or less pronounced disturbances of function of the muscle tissue, which may range from slight disturbances to motor deficits, for example paralysis.

Partial or brief interruptions of the blood circulation lead as a rule only to reversible damage at the start of the interruption. Intact muscle tissue with a low extracellular potassium content and the possibility of com- 15 plete regeneration remains. Surprisingly, experimental animals with vascular occlusion in the rear extremities show a rapid recuperation of the muscle fibers on treatment with the xanthines of the formula I.

The invention therefore relates to the use of at least one xanthine derivative of the formula I 0

R

3 ,1 i /1 (I) R2 in which at least one of the radicals R 1 and R 3 is a tertiary hydroxyalkyl group of the formula Ia

RA

-(CH

2 ),-C-CH 3 I (Ia) 3 in which R 4 is an alkyl group with 1, 2 or 3 carbon atoms and n is an integer of 2 5 and if only one of the radicals R 1 or R 3 is such a tertiary hydroxyalkyl group of the formula la the other radical is a hydrogen atom or an aliphatic hydrocarbon radical R 5 which has 1 to 6 carbon atoms and whose carbon chain can be interrupted by 1 or 2 oxygen atoms or substituted by an oxo group or by 1 or 2 hydroxyl groups, these oxo and hydroxyl groups being separated by at least 2 carbon atoms from the ring nitrogen, and R 2 is an alkyl group with 1 4 carbon atoms, for the preparation of pharmaceuticals for the prophylaxis and treatment of muscle damage which may occur after interruption of the blood circulation.

:.Xanthine derivatives of the formula I which are preferab- 15 ly used are those in which R 2 is methyl or ethyl and/or only one of the two radicals R 1 or R 3 is the tertiary hydroxyalkyl group of the formula Ia.

Xanthine derivatives of the formula I which are furthermore preferably used are those in which R 1 or R 3 is 20 [(w-l)-hydroxy-(w-1)-methyl]-pentyl, -hexyl or -heptyl.

In addition, xanthine derivatives of the formula I which are preferably used are those in which R 1 is hydroxy-(w-l)-methyl]-pentyl, -hexyl or -heptyl, R 2 is methyl or ethyl and R 3 is hydrogen, alkyl or alkoxyalkyl 25 with, in each case, 1 4 carbon atoms or hydroxyalkyl with 2 5 carbon atoms.

7-Ethoxymethyl-l-(5-hydroxy-5-methylhexyl)-3-methylxanthine is particularly preferably used.

By muscle cells, muscle fibers or muscle tissues are meant all cells, tissues or organs which are capable of contraction, especially smooth or striated muscle tissues, as well as muscle fibers of the heart.

4 The xanthine derivatives of the formula I are prepared, for example, by the following process: 3-Alkylxanthines of the formula II 0 B A -N 0

N

R

2 in which R 2 is an alkyl group with 1 to 4 carbon atoms, A is a hydrogen atom, R 5 or the radical of the formula Ia and B is a hydrogen atom, R 5 benzyl or diphenylmethyl radical, but where at least one of these radicals A and B is a hydrogen atom, are alkylated in the presence of at least one basic condensing agent or in the form of their salts in position 1 and/or 7, in one step or stepwise, with appropriate alkylating agents of the formula III X-Q (III) in which X is a halogen atom or a sulfonic ester or phosphoric ester group and Q is a tertiary hydroxyalkyl group of the formula Ia,

R

5 benzyl or diphenylmethyl radical, with subsequent reductive elimination of the radical B when this is a benzyl or diphenylmethyl group, or, where appropriate, hydrolytic elimination of an alkoxymethyl or alkoxyalkoxymethyl radical from the position of the radical B and reduction of the keto group to the alcohol functionality when A or B is an oxoalkyl radical, at a 5 reaction temperature between 0°C and the boiling point of the particular reaction medium used.

The abovementioned reactions take place under standard conditions in a known manner (EP 0 268 585, US 4 833 146).

The starting materials for the reactions are known or can be easily prepared by methods known from the literature (EP 0 268 585).

The invention also relates to pharmaceuticals which contain at least an effective amount of a xanthine derivative of the formula I, in addition to pharmaceutically suitable and physiologically tolerated excipients, diluents and/or other active and ancillary substances The pharmaceuticals according to the invention are administered parenterally, orally, rectally or, where appropriate, also topically. The administration takes place before, during or after an interruption in the blood circulation.

The invention rlso relates to processes for the prepara- S 20 tion of a pharmaceutical wherein at least one xanthine derivative of the formula I is converted with a physio- :6 logically acceptable vehicle and other suitable active, additional or ancillary substances into a form suitable for administration.

Examples of suitable solid or liquid pharmaceutical formulations are granules, powders, coated tablets, tablets, (micro)capsules, suppositories, syrups, solutions, suspensions, emulsions, drops or injectable solutions as well as products with protracted release of active substance, in the preparaticn of which conventional aids such as excipients, disintegrants, binders, coating agents, swelling agents, glidants or lubricants, 6 flavorings, sweeteners or solubilizers are used. Fxamples of ancillary substances which are frequently used and which may be mentioned are magnesium carbonate, titanium dioxide, lactose, mannitol and other sugars, talc, lactalbumin, gelatin, starch, cellulose and its derivatives, animal and vegetable oils, polyethylene glycols and solvents such as, for example, sterile water and monohydric or polyhydric alcohols, for example glycerol.

Because of the pharmacological properties of the xanthine derivatives, these compounds can be used in all operations in hospital or outpatient procedures which are associated with use of a tourniquet and thus interruption of the blood circulation in the muscle tissue, for example for vascular injuries in which there is prolonged 15 bloodlessness in the extremities, such as clamping of the aorta, embolus removal by surgical means or delayed treatment of severed large blood vessels. They can furthermore be employed to reduce the damage which may occur after restoration of blood flow to muscle fibers of the heart, or ensure the survival of muscle or skin grafts permeated by blood vest3els.

The pharmaceutical products are preferably prepared and administered in dosage units, where each unit contains as active constituent a defined dose of at least one xanthine derivative of the formula I. In the case of solid dosage units such as tablets, capsules, coated tablets or suppositories, this dose is up to about 1000 mg, but preferably about 100 600 mg, and in the case of injection solutions in ampule form is up to 300 mg, preferably 20 200 mg.

Indicated for the treatment of a patient (70 kg) whose blood circulation has been interrupted is an intravenous infusion treatment of 100 2000 mg per day in early phases and an oral administration of 400 mg 3 times a day in the later rehabilitation phase, especially of 7 7-ethoxymethyl-l-(5-hydroxy-5-methylhexyl)-3-methylxanthine.

However, higher or lower doses are also appropriate in some circumstances. The administration of the dose can take place either by a single administration in the form of a single dosage unit or of several smaller dosage units, or by multiple administration of divided doses at particular intervals.

Finally, the xanthine derivatives of the formula I and/or their appropriate salts can also be formulated together with other suitable active substances, for example active substances which trap free oxygen radicals, for example, 1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one, superoxide dismutase, dimethyl sulfoxide or mannitol, heparin, 15 ascorbic acid or deferoxamine, to prepare the abovementioned pharmaceutical formulations.

9 Example 1: Preparation of 7-ethoxyimethyl-l-(5-hydroxy-5-methylhexyl)-3-methylxanthine (Compound 1) S: 20 a) 7-Ethoxymethyl-3-methvlxanthine 9* 0 CH,-0-CH 2

-CH

HN/i N 0 N

CH

3 83 g (0.5 mol) of 3-methylxanthine are dissolved in a hot solution of 20 g (0.5 mol) of sodium hydroxide in 400 ml of water. After filtration, the filtrate is concentrated under reduced pressure, methanol is distilled over 8 several times, and then the sodium salt is dried under high vacuum. The dried salt is suspended in 1.3 1 of dimethylformarnide and, while stirring, 47.3 g (0.5 mol) of ethoxymethyl chloride are added to the suspension, which is then stirred at 110°C for 18 hours. It is subsequently filtered hot, the filtrate is evaporated in vacuo, the residue is dissolved in 500 ml of 2 H sodium hydroxide solution, and extraction with chloroform is carried out to remove the 1,7-dialkylated 3-rethylxanthine which is formed as by-product. The aqueous alkaline solution is adjusted to pH 9 with 2 N hydrochloric acid while stirring, the crystals which form are separated off, and the crystals are washed initially with water until free of chloride and then with methanol and 15 dried in vacuo.

Yield: 77.6 g (69.2 of theory) Melting point: 263 264 0

C

9

H

12

N

4 0 3 (MW 224.2) b) 7-Ethoxymethyl-l-(5-hvdroxy-5-methvlhexyl)-3methylxanthine CH 0 CH 2

-O-CH

2

-CH

3

H

3

C-C-(CH

2

N

CH

N

0 N

CH

3 11.2 g (0.05 mo3) of 7-ethoxymethyl-3-methylxanthine in 300 ml of dimethylformamide are mixed with 7.5 g (0.054 mol) of potassium carbonate and 8.2 g (0.054 mol) of l-chloro-5-hydroxy-5-methylhexane and heated at 110°C while stirring for 5 hours. The mixture is filtered hot with suction, the filtrate is concentrated in vacuo, the residue is taken up in chloroform, the solution is washed first with 1 N sodium hydroxide solution and then with 9 water until neutral and is dried over sodium sulfate, the solvent is removed by distillation under reduced pressure, and the residue is recrystallized from diisopropyl ether with the addition of ethyl acetate and petroleum ether.

Yield: 14.1 g (83.3 of theory) Melting point: 102 103"C

C

16

H

2 6N 4 0 (MW 338.4) Analysis: Calculated: C 56.79 H 7.74 N 16.56 Found: C 56.76 H 7.82 N 16.59 Example 2: Preparation of a pharmaceutical S' An injectable pharmaceutical is prepared as follows: g of the compound from Example 1 are dissolved in 15 water by stirring and slowly heating, and the volume is finally made up to 1000 ml with water. The resulting solution is filtered through a 0.2 ym membrane filter and dispensed into ampules containing 5 or 10 ml which, after sealing, are sterilized at 120"C for 15 minutes.

S.

Tablets which contain 250 mg of the compound from ,Example 1 are prepared in a conventional way by mixing 200 g of the compound from Example 1, 150 g of lactose, 30 g of starch, 10 g of crospovidone, 10 g of talc, 2 g of colloidal silicon dioxide and 1.5 g of magnesium stearate. The tablets receive a coating of an aqueous suspension composed of 40 g of hydroxypr.opylmethylcellulose, 2 g of polyethylene glycol with an average molecular weight of 6000, 3.5 g of titanium dioxide, 3 g of talc and 451.5 g of water. About 5 to 10 mg of solids are applied as coating to each tablet.

Example 3: Two groups of eight adult male South African long-tailed monkeys (Cercopithecus pygerythrus) are investigated. The 10 anesthesia of the animals is induced with 15 mg/kg ketamine (Warner Lambert) intramuscularly and is maintained with thiopentone sodium (25 mg/kg, May of Baker) intravenously. One rear extremity is emptied of blood by a pneumatic tourniquet and an Esmarch bandage. The interruption of the blood circulation is maintained for three hours, and then the interruption is terminated and the animals are able to awake from the anesthesia. The removal of samples of muscle tissue takes place under anesthesia (15 mg/kg ketamine).

mg/kg compound 1 is administered intravenously to the animals over 30 minutes before the interruption of the blood circulation.

Muscle preparation: 15 T, 3 removed muscle tissue is immediately frozen in isopentane at -183 0 C. The muscle tissue is prepared as described by Dubowitz (Dubowitz et al. Muscle Biopsy A Practical Approach, London, Bailliere Tindall, 1985, pp. 82 128). Microscopic sections are stained with muscle fiber ATPase at pH 9.4 for 30 minutes, embedded and examined under a light microscope. The diameters of **at least 200 muscle fibers are evaluated with a computerized video image analyzer.

The average diameter of each type of muscle fiber is indicated in Table 1.

11 Table 1 Before inter- Interruption After After ruption of of the 3 hrs 6 hrs the blood blood circulation circulation Muscle Fiber Typel1 Control Compound 1 34,45 36.50 34.07 36.28 39.2* 39. 89* 38.8.5* 43.42* 99*999 .9 a 0$ 09 0 @9 9 9 *09* 9**R 9* S a. S 99 9.

a @909 Muscle 15 Fiber Type 2a Control 39.99 37.05 41.91 44.08* Compound 1 45.09 44.75 48.55* 53.37* Before interruption Interrupticn of After 12 After 18 After 24 of the blood the blood hours hours hours circulation circulation Muscle Fiber Type 1 Control 34.45 33.63 37.03* 37.99* 40.26* Compound 1 36.50 33.21 35.79 34.68 33.00 M4usc le Fiber Type 2a Control 39.99 45.86 49.98* 51.55' 54.62* Compound 1 45.09 38.69 42.28* 41.31 40.24 12 The values identified by differ significantly from the values before the interruption of the blood circulation; p 0.05.

The values in Table 1 show that the muscle tissues of the animals treated with compound 1 reveal a significantly reduced swelling of the muscle fibers of Type 1 and 2a after 18 24 hours restoration of blood flow.

b• •eg

Claims

1. A method of reduction of muscle fibre swelling which occurs after complete interruption of the blood circulation comprising administering to a patient requiring such treatment an effective amount of at least one xanthine derivative of the formula I 0 R 3 R 1 I I N N N I R 2 in which at least one of the radicals R1 and R3 is a tertiary hydroxyalkyl group of the formula la 4 R 4 -(CH 2 )n-C-CH (a) go•• I OH in which R4 is an alkyl group with 1, 2 or 3 carbon atoms and n is an integer of 2 5 and if only one of the radicals R1 or R3 is such a tertiary hydroxyalkyl' group of the formula la the other radical is ja hydrogen atom or an aliphatic hydrocarbon radical R5 which has 1 to 6 carbon atoms and whose carbon chain can be interrupted by 1 or 2 oxygen atoms or substituted by an oxo group or by 1 or 2 hydroxyl groups, these oxo and hydroxyl groups being separated by at least 2 carbon atoms from the ring nitrogen, and R2 is an alkyl group with 1 4 carbon atoms.

2. The method as claimed in claim 1, wherein at least one xanthine derivative of the formula I in which R2 is methyl or ethyl and/or only one of the two radicals R1 or R3 is the tertiary hydroxyalkyl group of the formula Ia defined in claim 1 is employed.

The method as claimed in claim 1 or 2, wherein at least one xanthine 14 derivative of the formula I in which R1 or R3 is [(c-1)-hydroxy-(o-1)-methyl]- pentyl, -hexyl or -hepty! is employed.

4. The method as claimed in one or more of claims 1 3, wherein at least one xanthine derivative of the formula I in which R1 is [(o-1)-hydroxy-(oi-1)- methyl]-pentyl, -hexyl or -heptyl, R2 is methyl or ethyl and R3 is hydrogen, alkyl or alkoxyalkyl with, in each case, 1 4 carbon atoms or hydroxyalkyl with 2 carbon atoms is employed.

A method of reduction of muscle fibre swelling which occurs after complete interruption of the blood circulation comprising administering to a patient requiring such treatment an effective amount of 7-ethoxymethyl-1-(5- hydroxy-5-methylhexyl)-3-methylxanthine.

6. A method of prolonging the operation time after complete interruption of the blood circulation comprising administering to a patient requiring such treatment an effective amount of 7-ethoxymethyl-1-(5-hydroxy-5-methylhexyl)-3- methylxanthine. S7. A method of stabilization of the membrane of muscle cells comprising administering to a patient requiring such treatment an effective amount of

7- S. ethoxymethyl-1 -(5-hydroxy-5-methylhexyl)-3-methylxanthine. S:

8. The method as claimed in any one or more of claims 1 7 before, after and during an operation in which there is a complete interruption of the blood circulation.

9. A pharmaceutical when used in the prophylaxis and treatment of muscle damage which may occur after complete interruption of the blood circulation, which has an effective content of at least one xanthine derivative of the formula I 1q 15 0 R 3 RI I N (I) R 2 in which at least one of the radicals R 1 and R 3 is a tertiary hydroxyalkyl group of the formula Ia R4 s:o -(CH 2 -C-CH3 (Ia) OH OH 5 in which R 4 is an alkyl group with 1, 2 or 3 carbon atoms and n is an integer of 2 5 and if only one of the radicals R 1 or R 3 is such a tertiary hydroxyalkyl group of the formula Ia the other radical is a hydrogen atom or an aliphatic hydrocarbon radical R 5 which has 1 to 6 car- bon aroms and whose carbon chain can be interrupted by 1 or 2 oxygen atoms or substituted by an oxo group or by 1 or 2 hydroxyl groups, these oxo and hydroxyl groups being separated by at least 2 carbon atoms from the ring nitrogen, and R 2 is an alkyl group with 1 4 carbon 15 atoms, besides pharmaceutically suitable and physiolcgic- ally tolerated excipients, diluents and/or other active and ancillary substances.

A pharmaceutical as claimed in claim 9, which con- tains at least one xanthine derivative of the formula I in which R 2 is methyl or ethyl and/or only one of the two radicals R 1 or R 3 is the tertiary bydroxyalkyl group of the formula la defined in Claim 1. 16

11. A pharmaceutical as claimed in claim 9 or 10, which contains at least one xanthine derivative of the formula I in which R1 or R 3 is [(w-l)-hydroxy-(w-1)- methyl]-pentyl, -hexyl or -heptyl.

12. A pharmaceutical as claimed in claim 9 or 10, which contains at least one xanthine derivative of the formula I in which R 1 is [(w-1)-hydroxy-(w-1)-methyl]- pentyl, -hexyl or -heptyl, R 2 is methyl or ethyl and R 3 is hydrogen, alkyl or alkoxyalkyl with, in each case, 1 4 carbon atoms or hydroxyalkyl with 2 5 carbon atoms.

13. A pharmaceutical as claimed in one or more of .0000 claims 9 12, which contains 7-ethoxymethyl-1-(5- s t hydroxy-5-methylhexyl)-3-methylxanthine. :9*0.9 Apr sfrteprp-io of a pha a 15 claimed in one or more of claims 9 13, which co es converting at least one xanthine ative of the formula I with a physiol y acceptable vehicle and other suitab ive, additional or ancillary substances form suitable adiistrat-EIo. *,DATED nis 18th day of February 1993. HOECHST APTIENGESELLSCHAFT 0* WATERMARK PATENT TRADEMARK ATTORNEYS "THE ATRIUM" 290 BURWCOD ROAD HAWTHORN. VIC. 3122. 1 HOE 92/F 049 Abstract of the disclosure The use of xanthine derivatives for the treatment of muscle damage after interruption of the blood circulation Xanthine derivatives of the formula I 0 R3 R 1 I (I) AN N 0 NS N R 2 where at least one of the radicals R 1 and R 3 is a radical of the formula Ia R -(CH 2 ),-C-CH 3 I (Ia) OH R 4 is a (C 1 -C 3 )--alkyl radical, n is an integer of 2 10 and if only one of the radicals R 1 and R 3 is such a tertiary hydroxyalkyl group of the formula la the other radical is a hydrogen atom or an aliphatic hydrocarbon radical R 5 which has up to 6 carbon atoms and whose carbon chain can be interrupted by up to 2 oxygen atoms or can 15 be substituted by an oxo group or up to two hydroxyl groups, where these oxo and hydroxyl groups are separated by at least 2 carbon atoms from the ring nitrogen, and R 2 is an alkyl group with 1 4 carbon atoms, are suitable for the preparation of pharmaceuticals for the prophyl- axis and treatment of muscle damage which may occur after interruption of the blood circulation.