WO1994001422A1

WO1994001422A1 - Pharmaceutical compositions having antiaggregant and vasodilating activities

Info

Publication number: WO1994001422A1
Application number: PCT/EP1993/001559
Authority: WO
Inventors: Paolo Chiesi; Stefano Bongrani; Maurizio Civelli; Giancarlo Folco
Original assignee: Chiesi Farmaceutici S.P.A.
Priority date: 1992-07-03
Filing date: 1993-06-18
Publication date: 1994-01-20
Also published as: AU4419293A; ITMI921629A0; ITMI921629A1; IT1255207B

Abstract

Furoxan and furazan derivatives of formula (I) wherein R1, R and m have the meanings defined in the specification, are useful as cardiovascular agents.

Description

"PHARMACEUTICAL COMPOSITIONS HAVING ANTIAGGREGANT AND VASODILATING ACTIVITIES"

The present invention refers to pharmaceutical compositions having antiaggregant and vasodilating ac¬ tivities, containing as the active principle one or more furoxan or furazan derivatives of formula I

^(O) wherein R. is C.-C.-alkyl; C.-C.-alkoxy; phenyl; an S(O) R„ group wherein R_ is C,-C₄ alkyl or phenyl op- tionally substituted by C,-C.-alkyl, or by halogen atoms;

R is C,-C₄-alkyl or phenyl optionally substituted by C.-C.-alkyl or by halogen atoms; n = 0,1 or 2; m = 0 or 1. Compounds of formula I have been prepared and te¬ sted as antibacterial, antiprotozoal and antimycotic agents in Eur. J. Med. Chem. 12(2) 157-159, 1977 and in Eur. J. Med. Chem. 15(5) 485-487, 1980 in view of the fact that nitro and sulphonyl groups often impart anti- microbial properties to a molecule.

Other authors described their synthesis without recognizing any biological activity (Farrar WV, J. Chem. Soc. 1964, 904-6; Gasco et al, J. Heterocycl. Chem. 1973, 10, 587-90; Engbersen JFJ & Engberts JBFN, Syn. Commun. 1971, 1(2), 121-4; Jagt JC et al, Syn. Commun. 1974, 4(5), 311-16; Kelley JL et al, J. Hete- rocycl. Chem. 1977, 14(8), 1415-6). Notwithstanding that "in vitro" antiaggregant ac¬ tivity has already been described for one of the com¬ pounds of formula I, namely 4-methyl-3-phenyl- sulfonylfuroxan (Biochemical Pharmacology 1992, 43(6), 1281-1288), no pharmacodynamics effects have been up to now observed for the compounds of formula I so as to conceive their possible clinical use.

It has now been found that furoxan and furazan derivatives of formula I have a remarkable vasodilating activity and, therefore, they may be conveniently used as cardiovascular drugs, particularly as vasodilator, antihypertensive, antianginal, cerebral and coronary vasodilating and antithrombotic agents.

Preferred compounds I are those wherein R,, is C,-C₄-alkyl, C,-C.-alkoxy, phenyl or phenylsulphonyl and, R is phenyl.

The value of m is preferably 1.

The preparation of the compounds I has been di¬ sclosed in J. med. Chem. 1992, 35, p 3296, starting from easily available anti-l-chloro-2-methyl-glyossime which are reacted with suitable thiols in ether solu¬ tion and in the presence of triethylamine to give the corresponding l-arylthio-2-methylglyossime which are in turn oxidized by N₂0. yielding a furoxan mixture which can be separated into the single isomers or it can be reduced by trimethylphosphite to give the corresponding furazans. The preparation of the compounds 3-phenyl-4- phenylsulphonyl-furoxan (S77A) and 4-phenyl-3-phenyl- sulphonyl furoxan (S77B), having the following formulas

is disclosed in Eur. J. Med. Chem. 1980, 15(5), 485- 487.

The pharmacological properties of the compounds I are hereinafter reported. Methods

Platelet antiaggregant activity

Human blood from healthy volunteers who had not taken any drug during the past 2 weeks was collected in 1/10 volume of 3.8% trisodium citrate in plastic tubes. PRP (pH 7.6) was prepared by centrifugation at room temperature for 18 min at 160 g. Platelet poor plasma was prepared by subsequent centrifugation at 2000 g. Aggregation studies in PRP were performed according to the light transmission method of Born in a dual channel aggregometer (Elvi 840, Elvi Logos, Milan, Italy).

The tested compound dissolved in dimethyl sulfo- xide (DMSO) or the vehicle alone was added to PRP 1 min. prior to addition of one of the following aggrega¬ ting agents: collagen, ADP and PAF. For each PRP the employed concentration of the ag¬ gregating agent was corresponding to the minimal con- centration producing the maximal aggregating response in 5 minutes.

Such concentration was defined as "threshold ag¬ gregating concentration" . The induced aggregation was irreversible and was characterized by at least the 70-80% decrease in opti¬ cal density.

An IC₅₀ value was generated from regression analy¬ sis of the dose-response curve. Vasodilating activity

Transverse rings were obtained from the descending thoracic aorta of male New-Zealand white rabbits. Four rings were joined together with surgical silk (2.0) to form a chain and placed in a 10 ml glass organ bath containing Krebs¹ Henseleit bicarbonate solution at 37°C, aerated with a mixture of 95% 0-/5% C0₂. Basal tension (2 g) was applied, followed by an equilibration period of 1 hour and the changes in isometric contrac¬ tion were monitored with a force transducer (Basile, mod. 7004) connected to a "Gemini 7070" Basile pen re¬ corder.

Responses to various vasodilator agents were stu¬ died following enhancement of vascular tone with a sub- maximal concentration of Norepinephrine (NE,1 μM) added in the presence of 35 μM ascorbic acid.

Acetylcholine (Ach,l μM) was tested during the contraction evoked by NE, the bath rinsed and approx. 15 min. later the tone was again increased with NE. Glycerine trinitrate (NTG, 1.3 μM) was then added and left in contact with the aortic rings in order to allow full development of its vasodilation. After extensive rinsing of the preparations, a third NE-induced con¬ traction was evoked; different drugs under investiga¬ tion were then added in a cumulative fashion starting from 10 nM. Since all compounds investigated were dis- solved in dimethyl sulfoxide (DMSO) , a volume of DMSO equivalent to the total amount added with the drugs, was tested as control; the final concentration of DMSO in the organ bath did never exceed 0,05%, v/v. After attainment of maximal vasodilation, the aortic rings were extensively washed and another NE-induced contraction evoked, in order to verify full reversibility of the vasodilation. Ach and NTG were tested again in order to assess that the sensitivity of the preparations had remained constant. The composition (mM) of the Krebs¹ buffer was: NaCl 118.9, KC1 4.66, KH₂P0₄ 1.18, MgS0₄ 1.1, CaCl₂ 2.52, Glucosio 5.55, NaHC0₃ 25 (Merck; Darmstadt, Ger¬ many); pH was 7.4. The following drugs were used: acetylcholine HC1 (Sigma Chemical Company; St. Louis, Missouri, USA), glycerine trinitrate (Trinitrina (R ') ;

Carlo Erba; Milan, Italy), dimethyl sulfoxide (Sigma), norepinephrine (Sigma), ascorbic acid (Merck).

Drug solutions were prepared on the day of the ex¬ periment, stored on ice, and added to the tissue bath in a volume not exceeding 50 μl. Norepinephrine and ascorbic acid were added to the Krebs' reservoir. Acetylcholine was added tot the tissue bath in a volume of 25 μl, from a solution 0.4 mM. Glycerine trinitrate was added to the tissue bath, in a volume of 50 μl, from a solution 60 ✓/ml, obtained grinding a pill of Trinitrina (R) in a potter containing 5 ml of distilla- ted water.

Individual dose-response curves were linearized by plotting on semilog paper after probit transformation. The percentage of dilation was calculated, and the data from each tissue preparation were used for the calcula¬ tion of mean responses. EC_5Q values were obtained from regression lines fitted with log curves by the least square method.

Results Platelet antiaggregant activity

Besides compounds S77A and S77B (respectively 3- phenyl-4-phenylsulfonyl-furoxan and 4-phenyl-3-phenyl- sulfonyl-furoxan) , other two furoxan derivatives, alre¬ ady known from the literature but never tested for bio- logical activities, have been tested for antiaggregant activity: respectively,

3 ,4-bis(phenylsulfonyl)furoxan (Kelley J.L. et al., in J. Heteroσycl. Chem. 1977, 14, 1415, hereinaf¬ ter named SN010) and 4-ethoxy-3-phenylsulfonylfuroxan (Favar .V. in J. Chem. Soc. 1964, part I, pp. 904-906, hereinafter named SN011).

The activity of the compounds under examination was compared with that of a known nitrovasodilator, so¬ dium nitroprusside (NaNP). The results expressed as 1C_5Q are reported in Ta¬ ble 1.

4-phenyl-3-phenylsulfphonylfuroxan, S77B, turned out to be particularly effective, being 5-10 times more potent than nitroprusside. Table 1

Effect of S77A, S77B, 3 ,4-di(phenyl-sulfonyl)furoxan (SN010), 4-ethoxy-3-phenylsulfonylfu- roxan (SNOll) and NaNP on platelet aggregation in human PRP in vitro.

Results are expressed as the concentration required to inhibit by 50% the threshold aggre¬ gating concentration of various agents. The data are expressed as mean value ±S.E.M. , n=-5-8; NaNP n=2

Agent S77A S77B SNO10 SNOll NaNP

IC₅₀ ± S.E.M. (μM)

Collagen 3.41±0.564 0.378±0.010 0.306±0.023 0.566±0.0626 1.95±0.115

PAF 0.845±0.0545 0.132±0.013 0.177±0.0077 0.158±0.0141 0.748±0.260

ADP 2.62±0.502 0.115±0.018 0.34210.0574 0.386±0.0611 1.78±0.753

2) Vasodilating activity

The chemical structures of the tested compounds are reported in Table 2. The results of the vasodila¬ ting activity of the compounds under investigation are expressed as EC values against a fixed concentration of norepinephrine (1 μM). Their potency ranges between 0.027 and 247 μM and the most active compounds, S77B (4-phenyl-3-phenylsulfonyl-furoxan) , SNO10 (3,4- di(phenyl-sulfonyl)furoxan) , SNOll (4-ethoxy-3-phenyl- sulfonylfuroxan) , are approximately 4, 16 and 48 times more active than NTG, respectively.

Furazans are endowed with a potency distinctly lower than that found for furoxans.

The class of phenyl-sulfonyl substituted furoxans, in particular, did show a marked vasodilating efficacy. In a limited number of experiments the vasodila¬ ting effect of furazans and furoxans was tested in va¬ scular preparations in which the endothelium had been completely removed through rubbing of the intima and verified by complete suppression of acetylcholine indu¬ ced relaxation. The vasodilating capacity of the fura¬ zans and furoxans was fully independent of endothelial integrity.

In the same animal model the vasodilating effect of the compound S77B had been confirmed also against KCl and an agonist of tromboxane A~, the compound U46619, with an EC_5Q value of 9.7xl0^~8 and 3.0xl0~⁷ M respectively, so demonstrating that this new class of vasodilators can effectively inhibit the contraction induced by different contracturants.

Table 2: Results of the vasodilating activity of the compounds under investigation expres¬ sed as EC , against norepinephrine 1 μM. Reference Compound: glyceryl trinitrate (UTG)

R,

CH.

- continued

B

- continued -

R,

CH.

CH-

CH.

- continued -

EC = Efficacy Concentration

SE = Standard Error

Relative potency = potency ratio in comparison with glyceryl trinitrate (NTG)

The present invention also relates to pharmaceuti¬ cal compositions containing as the active principle the compounds of formula I or the salts thereof, in combi¬ nation with pharmaceutically acceptable excipients, for use in cardiovascular therapy as vasodilators, antihy- pertensive, antianginal, cerebral and coronary vasodi¬ lators, antiaggregants and antithrombotics.

The daily dosage of the active principle can vary from 1 to 1,000 mg, preferably it will range from 5 to 500 mg.

The administration will be carried out through any routes, preferable by the oral or parenteral routes.

For the oral administration, the compounds can be formulated in solid or liquid formulations and they can be in form of capsules, tablets, sugar-coated pills, coated tablets, granules, powders, solutions, suspen¬ sions or emulsions.

The oral solid forms can contain conventional ex¬ cipients, inert diluents, disgregation agents, binders and lubricants such as lactose, saccharose, sorbitol, mannitol; potato, cereal or maize starches, or amylo- pectin; cellulose and derivatives, gelatin, talc, ma¬ gnesium or calcium stearate, polyvinylpyrrolidone, cal¬ cium phosphate, calcium carbonate, polyethylene glycol or silica.

The tablets can variously be coated according to well-known pharmaceutical procedures. Hard gelatin cap¬ sules can contain granulates of the active principle, together with solid, powdered excipients, such as lac- tose, saccharose, sorbitol, mannitol, starches (of the above indicated types), cellulose derivatives, gelatin, and they can also contain stearic acid or magnesium stearate or talc.

Liquid formulations can be prepared by dissolving or dispersing the active principle in a pharmaceuti- cally acceptable aqueous or non-aqueous solvent, which can also contain suspending agents, sweeteners, fla¬ vours or preservatives.

For injectable formulations for the parenteral ad¬ ministration, the excipients can be a pharmaceutically acceptable sterile liquid such as water, saline solu¬ tion, dextrose or fructose solutions, alcohol solu¬ tions, polyvinylpyrrolidone aqueous solutions optio¬ nally containing a stabilizing agent and/or a buffer, or oily carriers. The active principle can either be dissolved in the liquid and sterilized before being distributed in vials, or it can suitably be freeze-dried, in which case vials containing injection liquid will be added to the package, to prepare the solution before use. Another particularly advantageous method for the administration of the compounds of the invention are the transdermal systems, consisting of adhesive matri¬ ces which can be applied to the skin, in which the ac¬ tive principle is incorporated in a suitable concentra- tion and from which it is gradually released to the skin, to enter the blood stream.

Claims

1. Compounds of formula I :

<©>» wherein R. is C,-C₄-alkyl; C,-C₄-alkoxy; phenyl; an S(0) R₂ group wherein R₂ is C,-C₄ alkyl or phenyl op¬ tionally substituted by C,-C₄-alkyl, or by halogen atoms;

R is C,-C₄-alkyl or phenyl optionally substituted by C,-C₄-alkyl or by halogen atoms; n = 0,l or 2; m = 0 or l, as cardiovascular agents.

2. Compounds of formula I as vasodilators, antihyper- tensives, antiangina agents, cerebral vasodilators, co¬ ronary vasodilators, antiaggregant, antithrombotic agents.

3. Compounds of formula I:

wherein R, is C,-C₄-alkyl, C,-C₄-alkoxy, phenyl or phenylsulphonyl and, R is phenyl of claims 1-3 as cardiovascular agents.

4. Compounds according to any claim wherein m is 1.

5. The use of compounds of formula I for the prepara¬ tion of medicaments useful for the treatment of cardio¬ vascular pathologies.

6. Pharmaceutical compositions containing as active principle a compound of formula I in admixture with a suitable carrier.