FR2566661A1 - Method for dissolving griseofulvin for the purpose of preparing a solution of this substance, which is chemically stable and possesses biological activity, for local applications. - Google Patents

Abstract

The invention relates to a method for dissolving griseofulvin and to the formulation of chemically stable solutions possessing biological activity, which solutions can be used for the treatment of superficial mycoses in man and animals. The method consists in dissolving solid griseofulvin, preferably in microcrystalline form, in a solvent chosen from eugenol, methyleugenol, acetyleugenol, isoeugenol and dihydrodieugenol. Another method consists in dissolving solid griseofulvin in a natural (essential) oil containing eugenol or an eugenol derivative chosen from off-set bulb, Japanese anise, laurel, asarum, calamus, camphor, champaca, cinnamon, patchouli, pepper and sassafras oils.

Description

 The present invention relates to a method for dissolving griseofulvin and to the formulation of chemically stable and biologically active solutions which can be used to treat superficial yeast infections in humans and animals.

Griseofulvin was first isolated in 1939 by Oxford and colleagues from
Penicillium griseofulvin, but it was ruled out because it did not offer the desired level of antibacterial activity that one would expect from the various penicillin derivatives that were being studied at that time.

In 1947, that is to say eight years later,
Brian points out in the literature a substance which he isolated from Penicillium janczewski, a substance which he calls "twisting factor" because it leads to an abnormal development of fungal hyphae, that is to say that the hyphae wrinkle and curl up under the effect of this substance. Subsequently, Grove and McGowan have shown that with regard to this "twist" factor and griseofulvin, it is the same substance.

Once identified, griseofulvin took a new interest, and in the following years it was very widely used against fungal infections of plants such as tomatoes, beans and fungi, as well as for the treatment of cattle infestations with ringworm (Goldman et al. "Current Status of Griseofulvin, Report on
One Hundred Seventy-five Cases "JAMA 11-4: 532 (1969).

 Griseofulvin has shown its effectiveness in the treatment of fungal infections, both of plants and animals, which led researchers like Gentles and his collaborators to study its use for the treatment in man of infections then practically intractable from the ringworm.

 Gentles was able to recover from the guise of the guinea pig hair from griseofulvin which had been given orally, which proves his thesis that this substance is taken from the gastrointestinal tract and is incorporated into new cells. This discovery opened the way for a very large human experiment (see Goldman above).

 After these first studies, a large number of scientific results have been gathered, concerning both the mode of action and the therapeutic efficacy of griseofulvin in the treatment of mycoses.

Griseofulvin, administered orally, was then the basis of the dominant therapy for many forms of fungal infections, and this although excellent results have been obtained and reported, in a very clear and well documented, regarding the efficacy of griseofulvin applied locally. We can consult on this subject Goîdman and aL "Topical Griseofulvin Therapy of that which is called Tinea Pedis", ACTA
DERMATO-VENEREOLOGICA, 39: 454-460 (1959); Arthur G. Knight, "The Activïty of Various Topical Griseofulvin Preparations and the Appearance of Oral Griseofulvin in the Stratum Corneum", British J. Dermatology 91/49 - 55 (1974); H. Abdel
Aal-et al, "Topically Applied Griseofulvin in the Treatment of Superficial Dermatomycosis in Egypt, J. Int'l. Med. Res.

5: 382 - 386 (1977; Wozniak et al, "Griselfulvin-salbenbehandlung superficieller trichophytien", Mykosen 13: (9) 427434 (1970; Epstein et al, "Topically applied Griseofulvin in Prevention and Treatment of Trichophyton Mentagarophytes",
Arch. Dermatology 111: 1293 - 1297 (1975); Zarowny et al, "Evaluation of the Effectiveness of Griseofulvin, Tolnaftate, and Placebo in the Topical Thearapy of Superficial Dermatophytoses", J. Invest. Dermatology 64: 268-272 (1975); Post and Saunders, "Topical Treatment of Experimental Ringworm in
Guinea Pigs with Griseoftlvin in Dimethylsulfoxide ", Can.

Vet. J. 20: 45-48 (1979).

 But the strange fact remains that after all the literature on topical griseofulvin, which practically proves that it is just as effective, and even in some cases more effective, than orally administered griseofulvin, the latter form of treatment remains pretty much the only shape available.

 It is sometimes claimed that this reluctance to apply griseofulvin locally results from indications in the literature such as those published by Cartwright in the "British Medical Journal" in 1978, in a report on antifungal agents which says: "griseofulvin is inactive when is applied locally ". (Cartwright, "Use of Antibiotics, Antifungals, British Med. J. 2: 108-111 (1978)).

 This conception and the results of contradictory tests seem to be due mainly to the difficulties which one encounters when one wants to prepare a solution of griseofulvin for local treatments topical treatments) which is chemically stable and endowed with biological activity.

 It is generally known that griseofulvin is only slightly soluble in alcohol, chloroform, dimethylsulfoxide, dimethylformamide and acetone, and that due to its strong hydrophobic nature, it is practically insoluble in polar solvents. While certain organic acids such as succinic acid can dissolve it better, most of these organic solvents irritate the tissues and are therefore not biocompatible.

 Although emulsions have been prepared with vegetable oils and emulsifiers, in many cases these known methods do not guarantee that the griseofulvin is in solution and it can be in suspension, weak traces of crystallized materials acting then as nucleating agents (that is to say crystallization) and thus causing rapid precipitation of this substance. As both the solid form and the microcrystalline form are inactive when applied locally, this can lead to preparations which can quickly lose their antifungal action as the griseofulvin precipitates.

 It is very likely that this resulted in contradictions in the experimental results, and a lack of confidence in the use of griseofulvin as a topical agent.

As mentioned earlier, griseofulvin is one of the most widely used antimycotic agents. It is almost exclusively given by the oral route, and the abundant literature on this subject will not be reviewed here because it can easily be found in current texts such as those of Goodman and Gilman (LS Goodman and A. Gilman, "The Pharamacological
Bases of Therapeutics ", 4th edition, The MacMillan Co. pp 1302 - 1304 (1970).

 Its side effects are numerous and its use is contraindicated for patients suffering from gastric disorders or whose liver is malfunctioning, as well as in pregnant women (Physician's Desk Reference, 35th Ed. Pp. 1600 - 1601 (1981)). The exact consequences of the antimitotic action of griseofulvin are not yet clear, and it has been suspected of being carcinogenic in animals and impairing the functions of the bone marrow.

a) Topical Griseofulvin
The indications of Grant-Peterkin (cited by Goldman, supra) that griseofulvin, despite its great efficacy when given orally, and of Pardo-Castello et al, Bilo. Soc. Cubana Dermatol. 16: 1 (1959), that griseofulvin is ineffective when applied locally, discouraged early work on the topical uses of this substance.

In 1969 Goldman et al, supra, prepared a griseofulvin lotion for local applications, a lotion containing about 1.5% of griseofulvin suspended in an oil with surfactants, stabilizer and urea. This topical application has been tried on 91 patients with ringworm of the head, body, thigh and feet by T. rubrum, T. mentagrophytes and
M. audonini, and most of these patients have been completely cleared of their infections.

These studies were followed by a work of
Wozinak et al, supra, who used an ointment containing 1.0 g of griseofulvin mixed with 0.6 g of castor oil and 0.6 g of salicylic acid in 20 g of a variable base material to qu '' It is tailored to the needs of patients.

Several common cases of trichophyton skin infections have been treated with this ointment, and all infections have been cured within 4 to 6 weeks.

 In 1975, Epstein et al. Dissolved griseofulvin in various solvents (DMSOf trichloroethanol, alcohol and a mixture of ether and acetone) and concluded that locally applied griseofulvin "may be useful for the prevention of superficial dark infections "(Pestein et al, supra).

 Also in 1975, Zarowny et al evaluated the effectiveness of a topical formula containing 2% of micronized grisofulvin, applied 3 times a day for 3 weeks to patients suffering from superficial dermatophytosis, and a parallel study in double blind was used to compare this formula with regular therapy (1% tolnaftate cream) and with a placebo ointment, one of the 3 preparations being given at random to a total of 52 people. Thirteen of the fifteen people treated with the placebo ointment were estimated not to respond to treatment. Nine of the eighteen people treated with griseofulvin, and nine of the nineteen treated with tolnaftate, responded to treatment. The clinical response appears to be related to the severity of the infection rather than the anatomical location of the lesions. The results obtained suggest that griseofulvin may be effective following local application, and they show the advantage of positive and negative controls when evaluating the action of topical antifungal agents.

In 1979, Abdel-Aal and his collaborators evaluated 155 patients suffering from T. Capitis, T. Corporis,
T. Cruris and T. Versicolor, in participation in studies on locally applied griseofulvin. They prepared ointments of the drug at various concentrations, in a solvent containing glycerol monostearate, sodium lauryl sulfate, dimethylacetamide and butylated hydroxy anisole, griseofulvin being added in the contents of 1.2 and 3%. Good results have been obtained with the 2% preparation in the cases of T. Corporis, T. Cruris and T.

Versicolor, but no results in the case of T. Capitis, and no side effects were observed with this 2% preparation. The authors' opinion is that griseofulvin applied locally in this new solvent is shown to be safe and very effective in the treatment of superficial dermatomycosis.

 Also in 1979, Post and Saunders reported that the topical application of 1.5 * griseofulvin in dimethyl sulfoxide for 5-7 days was a satisfactory treatment for experimental ringworm in coobail.

 With regard to the existing patents which relate to a method of dissolving griseofulvin for local applications, the following patents have been found.

 US Patent 3,450,718 (Kuljbakh et al) relates to a method for purifying crude griseofulvin, but an antibiotic griseofulvin is obtained when methylene chloride is used as a solvent to crystallize the crude product.

 US Patent 3,467,680 (Kuljbakh et al) relates to a method for isolating crude griseofulvin, again with the use of methylene chloride to extract griseofulvin.

 US Patent 3,109,849 (Walker et al) itself relates to a process for preparing analogs of griseofulvin and it indicates that the fundamental reaction is carried out in the presence of a solvent such as an aromatic hydrocarbon, the hydrocarbons indicated and claimed in this patent which may be benzene and toluene, ketones and halogenating agents.

 US Patent 3,147,282 (Slates et al) relates to the synthesis of griseofulvin and analogues thereof, and specifically indicates that griseofulvin and its analogs can be synthesized chemically.

 US patent 3,090,791 (Brossi et al) relates to the synthesis of griseofulvin and includes the use of solvents such as methynol, benzene or dioxin.

 US Patent 3,102,123 (Clark et al) relates to analogs of griseofulvin and indicates a number of solvents for their use with griseofulvin, which are hydrocarbons such as benzene and toluene, ketones such as acetone and methyl ethyl ketone, as well as esters such as ethyl acetate.

 US Patent 3,734,931 (Newman et al) relates to griseofulvin compounds, and it specifically mentions that these compounds are particularly soluble in organic solvents such as methylene chloride, chloroform, benzene and toluene.

 The other patents below all relate to other compounds and methods which have one or more of the elements or steps of the present invention in common, but none of them appear in any way to be better than the references than we just indicated. These other patents are US Pat. Nos. 3,557,151; 3,518,283 3,816,472; 3,152,150 t 3,029,185; 3,325,362, 3,313,827 3,467,678.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THIS INVENTION
As stated above, the present invention relates to a method for dissolving griseofulvin in order to prepare a griseofulvin solution for local applications which is chemically stable and has biological activity, a solution which can be used for the treatment of man and animal of superficial yeast infections.

 In a preferred embodiment of the present invention, the solid griseofulvin is dissolved in a solvent chosen from eugenol, methyl eugenol, acetyleugenol, isoeugenol and dihydrodieugenol.

 For the griseofulvin to be more soluble it is preferable that it be in a microcrystallized form.

 Dissolution should also be done at room temperature, and the solution should be gently stirred until the saturation point is reached, about 10% griseofulvin at room temperature.

 The solution is then filtered by any known method to remove the undissolved microcrystalline griseofulvin, because if it is not necessary to carry out this elimination, the literature indicates that the solid state griseofulvin is ineffective in applications. local.

 The filtered solution containing the dissolved griseofulvin can finally be stored until use, in containers which will preferably be opaque to light, for example in dark vial bottles.

 In another preferred embodiment of the invention, the microcrystallized griseofulvin can also be dissolved, to form a chemically stable and biologically active solution, in a natural oil (essence) containing eugenol, chosen from caleu essences , Japanese anise, bay leaf, asaret, calamus, camphor, champaca, cinnamon, patchouli, chilli and sassafras. Other essences of natural origin containing lteugenol can also be used in this process to dissolve microcrystallized griseofulvin.

 Another equally preferred embodiment of the present invention is the production of a cream containing griseofulvin, which cream is prepared with the above solution by the following additional operations.

 The above filtered solution is mixed with a base such as, for example, without limitation, petrolatum, lanolin, paraffin or a mineral oil, then mixed well to obtain a homogeneous cream.

 The particular example which follows illustrates the present invention without in any way limiting its scope.

EXAMPLE
Microcrystallized griseofulvin is dissolved in eugenol, as mentioned above, then a 10 ml sample is mixed with 10 g by volume of griseofulvin solution with 65 ml of a 3% solution. salicylic acid in 70% ethanol and 35 ml of glycerol. The solution thus obtained is shown to be both chemically stable and biologically active in the treatment of fungal infections.

Claims (9)

 1. A method for preparing a chemically stable solution of griseofulvin with biological activity, method according to which the solid griseofulvin is dissolved in a solvent chosen from eugenol, methyleugenol, acetyleugenol, isoeugenol and dihydrodieugenol.  2. Method according to claim 1 in which the griseofulvin is in a microcrystallized form.  3. Method according to claim 2 wherein the dissolution of griseofulvin is done at room temperature.  4. A method of preparing a chemically stable solution of griseofulvin with biological activity, a method by which the solid griseofulvin is dissolved in a natural oil (essence) containing eugenol.  5. Method according to claim 4 in which the solid griseofulvin is dissolved in a natural essence containing eugenol, chosen from essences of caleu, Japanese anise, laurel, asaret, calamus, camphor, champaca, cinnamon, patchouli, chilli and sassafras.  6. Method according to claim 5 in which the griseofulvin is in a microcrystallized form.  7. The method of claim 6 wherein the dissolution of griseofulvin is done at room temperature.  8. Method according to claim 1, in which the solution formed is then gently agitated and then filtered to remove the remaining microcrystalline griseofulvin (undissolved), and the filtered solution is stored in a light-opaque container.  9. The method of claim 8 wherein the filtered solution is then mixed with a base chosen from petrolatum, lanolin, paraffin, and a mineral oil to form an intermediate solution, solution which is heated and the mixing to obtain a homogeneous cream.