ITMI952475A1 - AMMONIUM SALTS OF URS-12 ENOIC ACIDS AND PHARMACEUTICAL COMPOSITIONS THAT CONTAIN THEM - Google Patents

Abstract

URS-12-ENOIC ACID AMMONIUM SALTS FOR PHARMACEUTICAL USE, IN PARTICULAR FOR TOPICAL USE IN THE PROMOTION AND ACCELERATION OF CICATRIZATION PROCESSES IN SKIN LESIONS OF VARIOUS ORIGIN.

Description

DESCRIPTION OF INDUSTRIAL INVENTION

having as title:

AMMONIUM SALTS OF URS-12-ENOIC ACIDS AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM

Abstract: Ammonium salts of urs-12-enoic acids for pharmaceutical use, in particular for

topical use in the promotion and acceleration of wound healing processes

skin of various origins.

Description·.

The promotion and acceleration of healing processes has always been a therapeutic objective of paramount interest in the treatment of various types of skin lesions such as varicose and arterial ulcers, pressure sores, burns, traumatic and surgical wounds. Serious and multifaceted are the problems that must be faced in the therapy of these pathologies and of the complications following surgical interventions that involve necrosis of the cellular tissue and / or reparative processes of secondary intention.

The use of Centella Asiatica, or of Centella Asiatica extracts, has long been known to favor the healing processes. It originates from popular tradition, but more recently a series of studies have confirmed its usefulness and therapeutic efficacy, shedding light on the structure of the active principles and their mechanism of action.

For a long time, the Asiatic, Madecassic acids and the Asiaticoside glycoside have been indicated as the main components and active principles of the extract.

Common mechanism of action of these Centella asiatica terpenoids would be the stimulation of fibroblasts to promote collagen synthesis [Maquart et al., Connect. Tissue Res., 24, 107, (1990), Del Vecchio et al., Farmaco Ed. Prat., 39, 355 (1984)] and fibronectin [Tenni et al., Ita !. J. Biochem., 37, 69 (1988)]. More recent insights [Boote et al, Plant Med., 60, 133 (1994)] and studies of biokinetics in animals [(Chasseaud et al., Arzneim.-Forsch. (Drug Res.), 21, 1380, (1971 )] and in humans [Grimaldi et al., J. Etnopharmacol., 2 £. 235, (1990); Rush et al., Eur. J. Drug Metabol. Ph arma coki net., 18, 323 (1993) ] made it possible to find precise correlations between the extent of the therapeutic effect of an extract and its composition in active principles.The active fraction of the extract would be constituted only by Asian and Madecassic acids.

The glucosidic component, asiaticoside, would be ineffective in itself or, alternatively, would be so poorly assorted as to be ineffective in practice. In fact, the systemic absorption of the glucoside would require a preventive hydrolysis to free the Asian acid aglycone from the glucosidic bond; a process that does not occur at the skin level or, when the environmental conditions of pH make it possible, only in an inadequate way to achieve therapeutic significance.

Centella asiatica extracts are generally titrated for their content in Asiatic and Madecassic acids and in Asiaticoside.

The extracts of Centella Asiatica from Madagascar may also contain a fourth component, madecassoside [see P. Boiteau et al, C. R. Acad. Se., 264 D, 407, (1967)], which is extremely soluble in water contrary to the more well-known asiaticosides, practically insoluble Asiatic and madecassic acids. Its presence and relative concentration in the extracts is therefore quite variable and depends on the methods used during the extraction process. Thus, for example, the hydrolysis of madecassoside in an acidic medium can favor the appearance of relevant quantities of a fifth component, anhydro-madecassic acid, while that in an alkaline medium can contribute to enriching the madecassic acid extract. Centella asiatica extracts are used for the preparation of pharmaceutical compositions for oral and topical use.

The compositions for topical use, in the form of aspersory powders or ointments, may contain the extracts of Centella Asiatica as the only active ingredient or in simple association with antibiotics [preferably neomycin] or in a more articulated combination including antibiotics and anti-inflammatory steroids [such as eg. hydrocortisone].

A completely extemporaneous application is also that which involves its use, during bandaging operations, in the form of sterile gaize previously medicated with Centella asiatica extracts. Due to the poor hydrophilicity and solubility of the active ingredients of the extract in mainly aqueous solvent phases, it was necessary to disperse it in mainly lipidic media such as mixtures of lanolin, propylene glycol oleostearate and stringy vaseline.

Finally, compositions of Centella asiatica extracts for ophthalmic use are also known, in the form of eye drops for the treatment of ulcerative lesions of the cornea and other types of corneal erosions.

Notoriously, the cause of the non-optimal success of these types of pharmacological treatment, which represents the limiting element, is placed in the inadequate bioavailability of the set of active ingredients constituting the extract. A problem so real and of general warning that, even recently, attempts have been made to remedy it with the use of mixtures of synthetic and natural phospholipids to develop new pharmaceutical compositions based on seracosides [E. Bombardelti et al., E.P. Appi. 283,713 (09.28.1988)].

The therapeutic relevance of Centella asiatica extracts and its individual components is also underlined by recent teachings that propose its use in the treatment of cognitive and CNS disorders and in cerebral diseases of vascular origin [N. J. De Souza et al., E.P. Appi. 383171 (22.08.1990)] or as an adjuvant in that of gastric ulcers [Chatterjee et al., Indian J. Exp. Biol., 30,889, (1992)]. Finally, the use of asiaticoside as a pharmacological tool has recently been proposed, since it is a selective and dose-dependent inhibitor of serotonin-induced contractions of guinea pig ileus but not bradikinin-induced contractions of guinea pig ileus.

Although, better than in the past, the most modern analytical techniques allow the qualitative and quantitative evaluation of the components of plant extracts, their variable composition (depending on the plant subspecies, the harvest time, the different climatic conditions, storage and of the various manipulations and purifications to which an extract can be subjected) is generally recognized as one of the main aspects that limit the reproducibility of precise pharmacological effects. A not always positive aspect is the use of heterogeneous mixtures of active ingredients in particular when some of the main components are not active in themselves (such as the glycosides asiaticoside and madecassoside in the case of Centella Asiatica) but can become such only after metabolic conversion in the their aglycones (Rush and Grimaldi, cited above). This is an aspect that is limiting and not very predictive from a therapeutic point of view for the individuality of the clinical responses to be expected, not only a function of the bio-availability of the individual components and of the state of health, age and sex of the patient but also and above all of the aptitude metabolic rate of the latter, i.e. of the individual metabolic processing capacity of the individual glucosides.

Cases of adverse events, mostly contact dermatitis, have been reported in the literature following the use of composite extracts of Centella Asiatica [H. C. Eun and A. Y. Lee, Contact Dermatitis, 13, 310 (1985); R. Izu et al., Ibidem, 26, 192 (1992)]. They do not seem attributable to the use of the crude extract as such but, more likely, to the association with different excipients and vehicles used in the preparation of the pharmaceutical formulations available so far. This is supported by the low risk of contact sensitivity subsequently documented for the extract as a whole and for its main components [B. M. Hausen, ibid., 29, 175 (1993)].

Many of these limitations are overcome by the present invention. It relates to water-soluble ammonium and alkylammonium salts of urs-12-enoic acids and more particularly the ammonium and alkylammonium salts of Asiatic and madecassic acids, a process suitable for their preparation and pharmaceutical compositions containing them.

More particularly, the salts of urs-12-enoic acids of formula (1) are the object of the present invention:

(1)

in which:

R and R 'are H 0 they form a 2,2-dimethyl-1,3-dioxane ring, when they are taken together with the oxygen atoms to which they are bonded;

Y, R3 and R4 are hydrogen;

one of R1 and R2 is hydrogen, the other being selected from the group of H and OH and R ·) and R2

they form a carbonyl group when they are taken together with the C atom to which they are bound; X * is the cation of a pharmaceutically acceptable ammonium, alkyl and aralkylammonium base.

Cations X +, pharmaceutically acceptable, particularly preferred are those of ammonium, of C1-C24 alkyl and optionally mono- and polysubstituted aralkylammonium, of polyoxyethn-C- | -C24-alkyl and aralkylammonium, optionally mono- and polysubstituted, which more they are suitable for giving the salts of said urs-12-enoic acids the desired solubility in water and in isotonic solutions. Examples of said cations are those that derive from primary, secondary and tertiary amines such as: tris (hydroxymethyl) aminomethane (tromethamine), D-glucosamine, L-lysine, L-arginine, L-omithine, morpholine, piperidine, N-methylpiperazine, 3- (morpholin-4-yl) -propan-1,2-diol, 3- {4-methyl-piperazin-1-yl) -propan-1,2-dioIo, 3- {piperidin-1-yl) - propan-1,2-diol; of tertiary amines of formula (2):

(2)

In which A is selected from the group of H, CH2OH, C- | 1C3-alkyl or when each of A joined to the C atoms to which they are bound form a nitrogenous heterocycle of 5 or 6 members such as pinrolidine, piperidine, morpholine, N -methyl-piperazine, Ra is selected from the group of H, HO, methoxy and ethoxy and n is an integer from 1 to 6; and the quaternary cations of benzyltrimethylammonium, benzyl-triethylammonium and those of benzyltrialconio of formula (3):

where Ra, A, and n are as above defined.

Particularly preferred compounds of the invention are the salts of Asiatic, madecassl, isopropifidenmadecassic and isopropylidenasiatic acids with: tromethamine, L-lysine, L-arginine, D-glucosamine, morpholine, (S) 3- (morpholin-4-yl) -propan -1.2-diol, benzyltrimethylammonium, N-3,6-dioxa-octylmorpholine.

The salification process is a completely conventional process which consists in the reaction of equimolecular quantities of an add of formula (1a):

in which R, R ', R-1, R2, R3, R4 and Y have the meanings described above, in a solvent, inert and suitable for crystallization, with equimolecular quantities of a base chosen from the ammonia group, of both a primary amine that secondary 0 tertiary and a quaternary ammonium hydrate.

Particularly preferred primary, secondary and tertiary amines are:

- C1-C24 alkylamines and polyoxyethyl-C-1-C24-alkylamines, optionally mono- and polysubstituted, such as: tromethamine 0 tris (hydroxymethyl) aminomethane, D-glucosamine, L-lysine, L-arginine, L-omithine, morpholine, piperidine, N-methylpiperazine, 3- (morpholin-4-yl) -propan-1.2-diol, 3- (4-methyl-piperazin-1-yl) -propan-1, 2-diol, 3- (piperidin-1 -yl) -propan-1,2-diol;

- an amine of formula (2a):

(2a)

where Ra is selected from the group of H, HO, methoxy and ethoxy, n is an integer from 1 to 6, A is H when m is zero and m being the integer 1, A is chosen from the group of H, CH2OH, C- 1 -C3-alkyl and each of A joined to the C atoms to which they are bound together, if desired, can form a nitrogenous heterocycle of 506 members such as pyrrolidine, piperidine, morpholine, N-methyl-piperazine; - a quaternary ammonium hydrate selected from the group of benzyltrimethylammonium, benzyltrimethylammonium and benzyltrialconio of formula (3):

where Ra, A, and n are as above defined.

Particularly preferred compound of formula 2a and 3, is that in which, being m zero, and Ra ethoxy (C2H5O), n is the integer 1. Particularly preferred compounds of formula 2a and 3 are those in which, being m and n l Integer 1, Ra is preferably ethoxy.

The reaction is usually carried out in a temperature range that goes from room temperature to that of the boiling of the solvent to obtain the complete solution of at least one of the two reagents; which is followed first by the total solution of the reactants and then by the start of the crystallization process which can be, depending on the case, as is well known in the art, favored by a convenient stirring of the reaction mixture, by its subsequent cooling up to temperatures a few tens of degrees below 0 <°> C, provided they are compatible with the freezing temperature of the solvent.

Particularly preferred solvents during the crystallization processes are C1-C4 alcohol and preferably methanol, ethanol, isopropyl alcohol; ethers such as diethyl ether, dimethoxyethane, dioxane, tetrahydrofuran; esters such as ethyl and methyl acetate, ethyl and methyl formates, C5-C6 hydrocarbons such as pentane and hexane; acetone, dimethylformamide, water and their mixtures.

Thus, for example, a solution of 0.5 g of Asian acid in ethyl acetate (30 mL) is added with 0.125 g of 2-amino-2-hydroxymethyl-1,3-propanediol to allow 0.48 g of the corresponding salt to precipitate. : Asiatic trometammonium.

Alternatively, the alkaline hydrolyzate of an ester of Asian acid or madecassic acid or e.g. the ethanolic solution obtained from the cleavage of madecassoside (as described by H. Pinhas et al., Bull. Soc. Chim. France, 1890, 1967) by heating for 1 hour in a water bath with KOH N, if desired, can be percolated through an ion exchange resin in a form suitable for selectively retaining the anion of the Asian acid and / or of the madecassic acid and thus allowing its subsequent elution in the form of the corresponding ammonium salt after percolation of suitable solutions of the desired amine. The eluate, containing the salt, is then evaporated to dryness and crystallized from the desired solvent.

The salts with amino acids, in particular those with L-lysine and L-arginine, are obtained by adding concentrated aqueous solutions of these animins to solutions of the acids of formula (1a) preferably in ethanol, propanol and isopropanol. Alternatively, for example, in an inert gas environment, a solution of L-arginine (2.7 g) in 50 mL is added, under stirring, to a finely divided suspension of 7.2 g of Asian acid in 25 mL of deionized water. of deionized water, it is kept under stirring for 2 hours at 60 ° C, then it is cooled to room temperature and filtered, the filtered is brought to the volume of 100 mL to obtain a 10% solution of the L-arginine salt of Asian acid which, if desired, can be used as such in the preparation of the pharmaceutical formulations indicated below. The subsequent concentration of the solution to a quarter of its volume, followed by dilution with at least 4 volumes of ethanol, allows the separation of 8.9 g of the salt.

The quaternary ammonium amines and hydrates as defined above, which are used in the salification of the acids of formula (1a) are compounds well known in the art, available commercially or otherwise are prepared by methods well known in the art.

The acids of formula (1a) are compounds known in literature, obtained with known methods from the crude extracts of Centella Asiatica and prepared from Asiatic and madecassic acids using methods well known in the art, such as e.g. those described by H. Pinhas et al., and by Chasseaud et al., cited above and by J. Polonsky (Bull. Soc. Chim. France, 649, 1952) and references cited here, which describe among other things the sodium asiaticate as a salt soluble in alcohol and only partially soluble in water (1%) from which the free acid is easily precipitated by simple carbonation (CO2).

The ammonium salts of the invention of formula (1) are characterized by a good solubility in water and stability of the aqueous solutions, the pH ranges of which are close to physiological pH either by themselves or after adjustment by adding buffer solutions. Therefore said ammonium salts of the invention of formula (1) are particularly useful and suitable for the preparation of pharmaceutical formulations, suitable for the uses of Centella asiatica extracts, as they are currently proposed in clinical practice.

Particularly preferred pharmaceutical compositions for topical use are those which contain the ammonium salts of the invention of formula (1) as individual components. Also within the scope of the invention are compositions which contain mixtures having a composition ranging from 1 to 9 parts of a salt for example of Asian acid for part of the corresponding madecassic acid salt and / or vice versa. The present invention also includes solutions of the salts of the invention of formula (1) which are prepared or prepared extemporaneously after reaction or mixing of an acid of formula (1a) with at least one molar equivalent of the ammonium counterbase, as specified above, in fact, these extemporaneous preparations of the salts of the invention are equally suitable for the preparation of the compositions of the invention and for the purposes specifically set forth by the invention.

the active principle content, referred to or expressed in weight equivalents of Asian acid as a single molecular unit, is between 0.01 and 10% by weight of the total formulation and preferably between 0.1 and 2%, depending on the type of formulation chosen.

For the preparation of said formulations, it can be useful to refer to classical technical texts of pharmaceutical formulations, eg. in the "Remington's Pharmacaceutical Sciences" Handbook, Mack Publishing Company U.S.A.

Alongside solutions essentially in an aqueous isotonic medium for use as eye drops and 0 of lotions for irrigation, the particularly preferred compositions are those which provide for the use of the compounds of the invention of formula (1) as a healing agent in the form of a gel. water-soluble and / or mainly water-soluble foams to be applied locally. The use of foams, to the formation of which the use of a propellant can contribute, if desired, is among other things advantageous and particularly useful because in addition to being avoided manual contact, with a reduction in pain from contact and any risks infectious, can help both to standardize the recommended dosage and above all to reduce the inconvenience for the patient, since administration as a foam allows the user to achieve an adequate sprinkling of the drug even in those anatomical areas of poor accessibility. Examples of excipients used in these foams, also mixed together, are polysorbates, propylene glycol, polyvinylpyrrolidone, polyethylene glycolestearates, sorbitan monolaurate, lauryl ether sulfate as sodium or monoethanolamine salt, in the presence or not of C-JQ- C- | g triglycerides of alcohols such as benzyl and ethanol and, if desired, of perfuming compositions.

Preferred propellant is a mixture of C3-C4 hydrocarbons consisting of propane (0.1-0.2g) isobutane (0.37-0.75g) and butane (0.02-0.05g). In this case, the foam is contained in a suitable pressurized canister suitable for topical administration, in which the number of applications will vary according to the pathology in progress, the area of exposure and the state of the patient.

It is also known that the extracts of Centella Asiatica are useful, when administered orally, in the treatment of various venous diseases, such as eg. varicose veins, phlebitis, varìcoflebit! and more (Beicaro G. et al. Phlebology, 1987; 2: 189-195-Belcaro G. et al. Cunr. Ther Res 1989; 46: 6).

The water-soluble salts of the present invention of formula (1) are particularly suitable for the preparation of pharmaceutical formulations containing extracts of Centella Asiatica, intended for oral administration in the treatment of said venous diseases. In fact, better than the extracts, the single active principles and their mixtures, the use of these salts allows the preparation of pharmaceutical formulations which are dispersible in water and which in any case contain the active principles or allow their administration in a highly dispersed form. Among the salts of the invention of formula (1), particularly preferred and most suitable compounds for the preparation of said pharmaceutical compositions, useful for oral administration, are the salts of L-lysine and L-arginine of formula 1, to be administer to the adult in a dose interval between 10 and 150 mg / day. The use of L-lysine and L-arginine salts, even in the case of water-dispersible formulations for oral use, is particularly advantageous due to the peculiarities of these salts such as high tolerability accompanied, moreover, by a more adequate and better bioavailability.

Claims (12)

CLAIMS 1. Compounds of formula (1) in which: R and R 'are H or form a 2,2-dimethyl-1,3-dioxane ring, when taken together with the oxygen atoms to which they are bonded; Y, R3 and R4 are hydrogen; one of R1 and R2 is hydrogen, the other being selected from the group of H and OH and R1 and R2 form a carbonyl group when taken together with the C atom to which they are bonded; X <+> is the cation of a pharmaceutically acceptable base of ammonium, of C1-C24 alkyl and aralkylammonium, of poloxyethyl-C1-C24-alkyl and aralkylammonium, mono- and polysubstituted. 2. A compound of formula 1 wherein said pharmaceutically acceptable ammonium cation, X <+>, of claim 1, derives from the salification with a nitrogenous base selected from the ammonia group, of a primary, secondary and / or aliphatic and arylaliphatic amine tertiary and a quaternary hydrate of aliphatic and arylaliphatic ammonium. 3. A compound of formula 1 wherein, according to claims 1 and 2, said cation of di C1 -C24 alkyl and polyoxyethyl-Cf-C24-alkyl ammonium, mono- and polysoslituited, pharmaceutically acceptable, X <+>, which is derived by salification with a primary, secondary and tertiary amine, is selected from the group of tris (hydroxymethy) aminomethane (0 tromethamine), D-glucosamine, L-lysine, L-arginine, L- omithine, morpholine, piperidine, N-methylpiperazine, 3- (morpholin-4-yl) -propan-1, 2-diol, 3- (4-methyl-piperazin-1-yl) -propan-1, 2-diol, 3- (piperidin-1-yl) propan 1 2 diol; of an amine of formula (2a): where Ra is selected from the group of H, HO, methoxy and ethoxy, n is an integer from 1 to 6, A is H when m is zero and m being the integer 1, A is chosen from the group of H, CH2OH, C-1-C3-alkyl and when each of A is joined to the C atoms to which it is bound it forms a nitrogenous heterocycle of 5 or Θ members chosen from the group of pyrrolidine, piperidine, morpholine, N-methyl-piperazine and a quaternary hydrate of ammonium selected from the group of benzyltrimethylammonium, benzyltriethylammonium and benzyltrialconio of formula (3): (3) in which Ra, A, and n are as above defined. 4. According to each of claims 1 to 3. a salt of formula (1) in which the cation X <+> derives from a nitrogenous base selected from the group of ammonia, tromethamine, L-lysine, L-arginine, D-glucosamine , morpholine, (S) 3- (morpholin-4-yl) -propan-1,2-diol, benzyltrimethylammonium, N-3,6-dioxa-octylmorpholine of Asian, madecassic, isopropylidenemadecassic and isopropylidenasian acids. 5. Pharmaceutical compositions containing the compounds of formula (1), according to each of claims 1 to 4, as a water-soluble active principle. 6. Use of the compounds of formula (1), according to each of claims 1 to 5, for the preparation of a medicament for human and / or veterinary use with a healing action. 7. Use of the compounds of formula (1), according to each of claims 1 to 6, for the preparation of a medicament for human and / or veterinary use with a healing action of topical application in the form of a water-soluble gel. 8. Use of the compounds of formula (1), according to each of claims 1 to 6, for the preparation of a medicament for human and / or veterinary use with a healing action of topical application in the form of mainly water-soluble foam. 9. Use of the compounds of formula (1), according to each of claims 1 to 5, for the preparation of a medicament useful for the systemic treatment of venous diseases. 10. Use of the compounds of formula (1), according to each of claims 1 to 5 and 9, for the preparation of a medicament useful for the systemic treatment of venous diseases, to be administered by mouth. 11. Use of the L-lysine and L-arginine salts of the compounds of formula (1), according to each of claims 1 to 6 and 9-10, for the preparation of a medicament useful for the systemic treatment of venous diseases, to be administered orally. Pharmaceutical compositions, according to each of claims 1 to 5 and 9 - 12, dispersible in water useful for the systemic treatment of venous diseases, to be administered orally, containing a compound of the invention of formula (1).