ITRM960851A1 - PHARMACEUTICAL COMPOSITIONS FOR THE TREATMENT OF VIRAL INFECTIONS INCLUDING A 4 ARILCUMARIN - Google Patents

Description

DESCRIPTION

attached to a patent application for INDUSTRIAL INVENTION entitled:

"PHARMACEUTICAL COMPOSITIONS FOR THE TREATMENT OF VIRAL INFECTIONS INCLUDING A 4-ARILCUMARIN."

SUMMARY

The use of 4-arylcoumarins is described for the preparation of pharmaceutical compositions suitable in particular for topical application for the prophylaxis and treatment of infections caused by DNA viruses, particularly by herpesviruses, such as cold sores and genital herpes and herpes zoster.

DESCRIPTION

The present invention relates to the use of 4-arylcoumarins for the preparation of pharmaceutical compositions suitable for the prophylaxis and treatment of viral infections caused by DNA viruses. These viruses include poxviruses, herpesviruses, adenoviruses, hepadnaviruses and papillomaviruses which are the causative agents of smallpox, herpes simplex and herpes zoster, conjunctivitis, pharyngitis, hepatitis B and warts, respectively.

The present invention preferably relates to the use of the aforementioned 4-arylcoumarins for the preparation of compositions with antiviral activity towards herpesviruses, i.e. herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), of the varicellazoster virus ( VSV) and cytomegalovirus (CMV).

The present invention also relates to pharmaceutical compositions that can be administered orally, parenterally and for topical application suitable for the prophylaxis and treatment of infections caused by the viruses mentioned above, comprising a 4-arylcoumarin as active ingredient and a pharmacologically acceptable excipient.

Herpes simplex is an infection characterized by the appearance on the epidermis and mucous membranes of small vesicles that occur in single or multiple groups, filled with a clear liquid, on an erythematous basis. LHSV-1 causes cold sores and keratitis; HSV-2 genital herpes. The lesions can appear in any skin or mucous area, but are more frequent around the mouth, lips, conjunctiva and cornea for those caused by HSV-1; on the genital or perirectal areas for those caused by HSV-2.

Herpes zoster is an acute infection of the central nervous system involving the dorsal root ganglia and is characterized by neuralgic pain of the skin areas controlled by the peripheral sensory nerves that branch off from the root ganglia affected by the infection.

In recent years, considerable progress has been made in the development of drugs with antiviral and in particular antiherpetic activity and in the understanding of their mechanisms of action, for example on viral replication. Nonetheless, there is currently no drug on the market that is sufficiently free of toxic and / or unwanted effects that is truly effective in infections sustained by both herpes simplex and varicella-zoster viruses.

In non-serious superficial infections, drugs for local use such as hydroxyuridine (IDU) and trifluridine have shown some efficacy.

Vidarabine, the first proven effective anti-herpesvirus drug, approved in 1977, was used - due to its high toxicity - only for particularly severe, life-threatening HSV and VZV infections.

Vidarabine has been largely supplanted by aciclovir, approved in 1982, which is more effective and less toxic than vidarabine. Acyclovir, which is today the antiviral of choice for the treatment of cold sores and genital herpes and zoster is the prototype of a group of antiviral drugs that are intracellularly phosphorylated by a viral kinase, thus being converted into inhibitors of synthesis of viral DNA.

Although acyclovir is the most widespread antiviral in the world and the seventh best-selling drug in the world (see Pharma Business July / August 1996, No. 10), while generally well tolerated, it has several undesirable effects. Topically it can cause irritation of the mucous membranes and a transient burning when applied to lesions of the genitals. Orally it can cause nausea, diarrhea and skin rashes.

A further limitation of the antiviral drugs currently on the market consists in the scarcity of forms suitable for topical application, and, when these are also available, in their poor efficacy.

In fact, among the antiviral drugs particularly aimed at the treatment of herpetic infections currently on the market (aciclovir, famciclovir, foscamet, ganciclovir, sorivudine, valaciclovir and vidarabine), only aciclovir is also available in compositions suitable for topical application (see Goodman & Gilman's The pharmacological basis of thérapeutics, ninth edition, 1996, p. 1193).

However, in herpes simplex virus infections the topical application of acyclovir is much less effective than the systemic one; in fact, it does not offer significant clinical benefits in recurrent genital herpes (see Goodman & Gilman, loc. cit. p. 1197).

It is therefore evident the need to have other powerful antiherpetic agents and the like, which are substantially free of toxic and / or undesirable effects and which are highly effective even when formulated in the aforesaid compositions for topical use.

It has now been found that the 4-arylcoumarins which will be identified and described in detail below constitute powerful antiviral agents towards DNA viruses and in particular herpesviruses.

For some time the 4-arylcoumarins (or neoflavonoids) have aroused the interest of pharmacologists and biochemists as various compounds presenting the variously substituted 4-phenylcoumarin nucleus have been isolated from the bark of trees native to Central and South America (particularly Brazil. and Mexico), the extracts of which are credited in folk medicine with various therapeutic effects.

Thus, for example Reher G. and Kraus L. J. in Journal of Naturai Products, Vol. 47, n.

1, pp. 172-4, 1984 described the isolation of 5,2 ', 5'-trihydroxy-7-methoxy-4-phenylcoumarin from a species of the genus Coutarea (Rubiaceae family). According to popular belief, the bark extracts of this species show antimalarial and antidiabetic activity.

Delle Monache et al. (Phytochemistry, Vol. 22, n. 7, pp. 1657-8, 1983) described the isolation of 5,7,4'-trimethoxy-4-phenylcoumarin, 4'-hydroxy-5,7-dimethoxy-4 -phenylcoumarin, 3'-hydroxy-5,7-4, -trimethoxy-4-phenylcoumarin and 3 ', 4'-dihydroxy-5,7-dimethoxy-4-phenylcoumarin from the caule of Coutarea hexandra used in folk medicine as a substitute for Cinchona as an antimalarial. Subsequently, Delle Monache et al. (Phytochemistry, Vol. 29, n. 12, pp. 3984-6, 1990) have isolated from the same plant two other neoflavonoids, 3'-hydroxy-5,7,8,4'-tetramethoxy-4-phenylcoumarin and 8.3'-dihydroxy-5,7,4'-trimethoxy-4-femlcumarin.

The interest in the possible therapeutic properties of these 4-arylcoumarins has also promoted the interest in the synthesis of these compounds starting from various substrates, as an alternative to the purely extractive methods originally used. This also for the purpose of comparing, confirming the hypothesized structures, natural products with synthetic compounds.

Thus, for example, Delle Monache et al. (Phytochemistry, Vol. 24, n. 6, pp. 1355-7) reported the synthesis of a series of 5,7-dimethoxy-4-arylcoumarins and the corresponding 5,7-dihydroxy analogues in order to confirm the structure of some neoflavonoids isolated by the same Author by extraction from Coutarea hexandra (the teachings of this publication are fully incorporated by reference in the present description).

As described in this article, the preparation of 4-arylcoumarins can be carried out according to two distinct synthesis ways: the Perkin coumarin synthesis or the Pechman-Duisberg one, both of which are well known to organic synthesis experts. According to the first, an orthohydros siayl aldehyde or ketone is reacted hot with acetic anhydride in the presence of an alkaline acetate, preferably sodium or potassium. In the second, particularly suitable when it is desired to obtain a coumarin substituted in position 4 of the pyronic ring (for example a 4-phenylcoumarin), a phenol is condensed with an aryl-β-ketoester in the presence of a strong acid or aluminum chloride .

It is essential to note that neither on the basis of the alleged therapeutic properties known from folk medicine, nor from the studies conducted subsequently, was the therapeutic application of the 4-arylcumarins which is the object of the present invention.

It has now been found, in accordance with the present invention, that the use of 4-arylcoumarins of general formula (I):

with at least one R1 on ring A and at least one R2 on ring B, in which R1 and R2, equal 0 different, represent:

hydrogen;

halogen;

linear or branched alkyl, with 1-10 carbon atoms, optionally substituted with one or more halogen atoms;

alkoxy with 1-10 carbon atoms; And

1-10 carbon acyloxy,

it allows the preparation of pharmaceutical compositions that can be administered orally, parenteral or for topical application suitable for the prophylaxis and treatment of viral infections from DNA viruses.

Preferably, such compositions are suitable for the prophylaxis and treatment of infections caused by herpesviruses such as herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella zoster virus (VZV) or cytomegalovirus (CMV) . Therefore, such compositions are particularly suitable for the prophylaxis or treatment of cold sores, genital herpes and herpes zoster.

In the compounds of formula (I), when R1 and / or R2 are halogen this is preferably fluorine or chlorine;

when R1 and / or R2 are alkyl, this is preferably methyl, ethyl, propyl, isopropyl, bufyl, isobutyl, sec-butyl or tert-butyl;

when R1 and / or R2 are halogen-substituted alkyl, this is preferably chloromethyl, dichloromethyl, trichoromethyl, 2-chloroethyl, 3-chloroethyl. 2,3-dichloroethyl, fluoromethyl, difluoromethyl, trifluoromethyl:

when R1 and / or R2 are alkoxy, this is preferably methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy or benzyloxy;

when R1 and / or R2 are acyloxy, this is preferably acetoxy, propionyloxy or benzoyloxy.

It has also been found that a particularly preferred subclass of 4-arylcoumarins of formula (I) for use and the compositions of the present invention consists of the compounds of general formula (I '):

(THE)

wherein R1 and R2, the same or different, represent hydrogen, hydroxyl or acetoxy. Among these, 5,7-diacetoxy-4-phenylcoumarin is particularly preferred.

Some non-limiting examples of preparation of 4-phenylcoumarins suitable for use according to the invention are given below.

EXAMPLE 1:

Preparation of 5,7-dihydroxy-4-phenylcumarma.

A mixture of phloroglucin (1,3,5-benzentriol) (0.1 mol) and ethyl benzoyl acetate (0.1 mol) in 25 mL of trifluoroacetic acid and 10 mL of anhydrous ethanol was refluxed for 2-3 hours, until complete disappearance of the β-ketosester. Upon completion of the reaction, 300 mL of cold distilled water was added to the reaction mixture, and the resulting mixture was filtered. The residue was washed and purified by crystallization with dry ethyl acetate.

The title product was obtained (yield about 85%).

P.F. = 245-247 ° C

UV Lmax (EtOH) (nm) 225.5; 259.5; 330 (without fluorescence).

EXAMPLE 2:

Preparation of various 4-phenylcoumarins

A mixture of 0.1 moles of the phenol indicated in Table 1 and 0.1 moles of ethyl benzoylacetate in 25 mL of trifluoroacetic acid was refluxed for the time indicated in Table 1.

At the end of the reaction, the resulting mixture was poured into about 300 mL of cold water to obtain a precipitate. This was filtered under vacuum and the solid dried in air, giving the yield in crude product indicated in Table 1. The dried compounds were purified by taking them up with ethyl acetate, filtering them and precipitating them with heptane. This purification step was repeated until a constant melting point compound was obtained.

EXAMPLE 3:

Preparation of 3,7-diacetoxy-4-phenylcoumarin (celodynine diacetylate).

A mixture of the compound of Example 1 was prepared with acetic anhydride and pyridine. The mixture, after being allowed to react overnight, was poured into cold water and filtered. The solid was purified by recrystallizing it twice from boiling heptane. The title compound was obtained, having a melting point of 183 ° C. Physico-chemical characteristics of the compound: insoluble in water; soluble in chloroform, ethyl ether, acetone and ethanol; soluble in vegetable oils and tween.

Thin layer chromatography using silica gel as absorbent (230 mesh)

EXAMPLE 4:

Preparation of SJ ^ -trndrossM-phenylcoumarin.

A cooled solution of ethyl p-benzyloxybenzoyl acetate (0.6 g) and phloroglucine (0.28 g) in ethanol (24 mL) was saturated with dry gaseous HCl. After three days, water was added to the reaction mixture and the resulting mixture was concentrated in vacuo. Filtration of the concentrate yielded a red solid which by silica gel chromatography with CHC13 -MeOH mixtures yielded the title compound (320 mg, 60% yield), M.P. 294-295 ° C with decomposition. (j);

EXAMPLE 5:

Preparation of 5,7,4'-triacetoxy-4-phenylcoumarin.

The compound of Example 4 (60 mg) treated with pyridine and acetic anhydride for

EXAMPLE 6:

Methyl derivatives of 5,7,4'-trihydroxy4-phenylheimarine.

A saturated solution of diazomethane in ethyl ether (20 mL) was added under stirring to 5,7,4, -triohydroxy-4-phenylcoumarin (270 mg) in chloroform (18 mL) and methanol (2 mL). After 45 minutes the reaction mixture was evaporated in vacuo and the residue passed over the silica gel with benzene-ethyl acetate (4: 1) giving 5,7,4'-trimethoxy-4-phenylcoumarin (135 mg, yield of the 43%) and 5,7-dimethoxy-4'-hydroxy-4-phenylcoumarin (150 mg, 50% yield).

Although the 4-arylcoumarins of formula (I) and (I ') lend themselves to being formulated also in compositions which can be administered orally or parenterally, according to a preferred aspect of the invention they are formulated in compositions suitable for topical application. Such compositions are therefore particularly suitable for the treatment of infections of the skin, mouth, eyes and genitals caused by herpesviruses.

For such infections the formulations are in fact preferably applied in the form of creams or ointments containing the active principle in quantities of 0.1-20% by weight, preferably 1-10% by weight. When formulated as an ointment, the active ingredient can be used with a paraffinic or water-miscible ointment base. Alternatively, the active ingredient can be formulated in the form of a cream with an oil-in-water base for creams. Furthermore, topical applications can be carried out transdeimically by means of an iontophoresis device.

If desired, the aqueous phase of the base of the cream can comprise at least 30% by weight of a polyhydric alcohol, i.e. an alcohol having two or more hydroxyl groups, such as for example propylene glycol, butan-1,3-diol, mannitol, sorbitol, glycerol or polyethylene glycol or their mixtures. Topical formulations may suitably comprise a compound that improves the absorption or penetration of the active ingredient through the skin or other skin areas affected by the infection. Examples of such skin penetration enhancing agents include dimethyl sulfoxide and similar compounds.

Formulations suitable for topical administration in the eyes include eye drops in which the active ingredient is dissolved or suspended in a suitable vehicle.

The formulations for rectal administration can consist of suppositories the base of which includes, for example, cocoa butter or a salicylate.

The formulations suitable for vaginal administration can be in the form of vaginal candles, tampons, creams, gels, foams or sprays containing, in addition to the active principle, carrier means well known to those skilled in pharmaceutical technology.

By way of example, some data relating to pharmacological tests and clinical studies carried out with 5,7-diacetoxy4-phenylcoumarin are reported below.

A PHARMACOLOGICAL TESTS

The pharmacological evaluation of the compound was carried out in vitro and in vivo for the following activities:

(a) Toxicity:

The results of acute toxicity tests in oral guinea pigs have shown that the compound does not exhibit toxic effects up to 5.0 g / kg.

(b) Cytotoxicity:

The minimum non-toxic concentration (CMNT) of the compound is 125 μΜ. (c) Antiviral activity:

In in vitro tests against the Herpes simplex virus, the compound exhibited 85% inhibition at the concentration of 65μΜ and 95% inhibition at the concentration of 125μΜ. Tested in vitro against cytomegalovirus, the compound exhibited 78% inhibitory activity at a concentration of 65μΜ.

B. CLINICAL STUDIES.

B.1 Clinical study on Herpes simplex patients.

The clinical study was conducted for 4 years on 80 volunteer patients, 40 men and 40 women aged between 22 and 48, who had already suffered various relapses and used other antiviral drugs.

The product in the form of a cream at a concentration of 1.5% by weight was applied locally three times a day by gently massaging the infected area.

A 10% placebo was used in the study. The results showed that in the entire patient population 38% of them began clinical treatment at the onset of herpetic manifestation when they felt burning or itching in the relapsed region or soon after the appearance of small blisters. In these patients the product completely inhibited pain and infection: in the other patients the product was shown to reduce the infection at different times. In those patients who had more than one relapse during the clinical evaluation, inhibition of the infectious process occurred when they used the product at the onset of herpetic infection.

In patients who used placebo the clinical picture was typical of absence of activity.

During the study, 15% of the population discontinued treatment. B .2 Clinical study in patients with herpes zoster.

The clinical study was conducted for a period of three months on 5 volunteer patients, 1 man of 48 years and 4 women aged between 55 and 65 years, affected by herpes zoster. The product in the form of a cream at a concentration of 2% by weight was applied locally three times a day with a gentle massage of the infected area.

In this study, due to the severity of the disease, no placebo was used.

Three of the patients began clinical treatment at the onset of the herpetic infection as soon as they felt burning or itching in the affected region or soon after the formation of small blisters. In these patients, the product partially inhibited pain and the infection was stopped. For the patient who showed a large part of the lumbar region infected, the result was not fully evaluated, while in the fifth patient the product favored the improvement of the clinical picture.

Claims (12)

CLAIMS 1. Use of 4-arylcoumarins of general formula (I): (i) with at least one R1 on ring A and at least one R2 on ring B, in which Rj and R2, equal 0 different, represent: hydrogen; halogen; branched linear O alkyl, with HO carbon atoms, optionally substituted with one or more halogen atoms; alkoxy with 1-10 carbon atoms; And 1-10 carbon acyloxy, for the preparation of pharmaceutical compositions that can be administered orally, parenteral or for topical application suitable for the prophylaxis and treatment of viral infections from DNA viruses. Use according to claim 1, wherein the DNA virus is a herpesvirus. Use according to claim 2, wherein the terpesvirus is herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella zoster virus (VZV) or cytomegalovirus (CMV). Use according to claim 3, wherein the composition is suitable for the prophylaxis or treatment of cold sores, genital herpes and herpes zoster. 5. Composition that can be administered orally, parenteral or for topical application suitable for prophylaxis or treatment of viral infections caused by DNA viruses comprising a 4-arylcoumarin of general formula (I) with at least one R1 on ring A and at least one R2 on ring B, in which R1 and R2, equal 0 different, represent: hydrogen; halogen; branched linear O alkyl, with 1-10 carbon atoms, optionally substituted with one or more halogen atoms; alkoxy with 1-10 carbon atoms; And acyloxy with 1-10 carbon atoms. and a pharmacologically acceptable excipient. 6. Composition according to claim 5, for the prophylaxis and treatment of herpesvirus-borne infections. 7. Composition according to claim 5, for the prophylaxis and treatment of infections caused by herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella zoster virus (ZVZ) and cytomegalovims (CMV ). 8. Composition according to claim 5, for the prophylaxis and treatment of cold sores, genital herpes and herpes zoster. 9. Composition according to any one of claims 5-8, comprising a 4-arylcoumarin of general formula (Γ): wherein R1 and R2, the same or different, represent hydrogen, hydroxyl or acetoxy. 10. Composition according to claim 9, wherein the 4-arylcoumarin is 5,7-diacetoxy4-phenylcoumarin. 11. Composition according to any one of claims 5-10, suitable for topical application comprising from 0.1 to 20% by weight, preferably from 1 to 10% by weight, of the 4-arylcoumarin of formula (I) or (I ). 12. Composition according to claim 11 in the form of a cream, ointment. lotion, foam, spray, eye drops, suppository or gel.