NL2016203B1 - Composition and device for the treatment of fungal nails. - Google Patents

Abstract

The invention relates to a topical composition based on a nail nutrient and a lipid for the treatment of toe and fingernails damaged by fungal infection (onychomycosis). The invention relates to a composition which is applied by means of an applicator pen, type of marker, directly to the nails. The invention relates to a method for producing said topical composition.

Description

COMPOSITION AND DEVICE FOR TREATMENT OF

MOLD NAILS

TECHNICAL DOMAIN

The present invention relates to a composition comprising nail nutrients and lipids which is topically applicable. These are useful for repairing the nail during the treatment of fungal diseases of the nail (onychomycosis). The composition according to the invention has superior treatment properties and speeds up the recovery of the nails. Moreover, this composition has an improved penetration capacity to allow the active substances to penetrate the nail.

BACKGROUND ART

Nail fungus is caused by the damage to the nail by mold spores. The nail can be considered as a wall made of bricks and grout cement. Here, onychocytes, the flattened dead corneocytes, the role of bricks and the interstitial space of 25-35 nm thickness between these bricks play normally is filled with lipids such as triglycerides and fatty acids, ceramides, squalene, (cholesterol) sterols, esters and waxes. also to a lesser extent with hydrophilic proteins such as mucopolysaccharides. These interstitial substances take on the role of joint cement. As people get older, the amount of joint cement decreases and more interstitial space is created between the onychocytes. These interstitial spaces can be used by fungal spores to penetrate the nail, exposing the onychocytes to keratinase and allowing the fungal infection to spread.

To recover the damaged nail, the affected part of the nail plate must be replaced with new nail growth. It is known that biotin, keratin derivatives and some amino acids are needed for nail growth. High intakes of biotin improve nail thickness and reduce brittle nails. Although oral biotin preparations are known, they have not been very successful in treating a nail locally. This is attributed to the low bioavailability in topical delivery systems. The rate of absorption of topically applied known compositions is generally much lower than the rate of absorption through the gastrointestinal tract. This is even more the case when a known composition is applied topically to a nail. Since the nail creates an even greater barrier against penetration relative to the skin, it is a well-known problem that for this reason, antifungal products are difficult to fulfill their function in the treatment of fungal nails. Most known biotin preparations are therefore oral preparations with high doses of biotin. They should therefore be taken in tablet form to make the biotin available in the nail to a sufficient extent after admission into the gastrointestinal tract and after the first liver passage.

In order to provide a solution for the low bioavailability with topical application, an improved release is desired. An important challenge in the development of topical delivery systems is to achieve absorption in a reproducible manner and in sufficient quantities to exert a therapeutic and / or cosmetic effect. The release should be done in a safe and effective manner, meaning that a preparation is conceived to provide the desired systemic and / or local effect, without toxicity, irritation, allergic reaction and the like. In addition, such a topical product, in addition to an adequate amount of lipids, would have to contain a much lower amount of biotin because, unlike an oral product, it delivers concentrated, local biotin where it is needed. Given the very high cost price of biotin, this is a strong economic benefit.

SUMMARY OF THE INVENTION

The invention provides a solution to at least some of the above problems by providing a composition that is easy to use, treats fungal diseases of nails (onychomycosis) and does this by placing nail lipids (fatty acids) and nail nutrients in the nail plate with the help of an penetration enhancing agent bring. Furthermore, the added lipids in the composition ensure that the nail becomes saturated with lipids, thus enhancing the natural barrier against the penetration of fungal spores.

In particular, the invention relates in a first aspect to a topical composition which is suitable for transporting nail nutrients through a finger or toenail and for saturating the nail with lipids comprising: - 0.001-10% by weight nail nutrients selected from the list of biotin, keratin derivatives, amino acids such as cysteine, cystine or a mixture thereof; - 0.1-20% by weight of lipids selected from the list of triglycerides, fatty acids, ceramides, squalane, squalene, sterols, waxes and fatty alcohols or a mixture thereof; 1-10 weight percent of an penetration-promoting agent; supplemented with other components from the list of solvents, film former, carboxylic acid, preservative or moisturizing agent; wherein the sum of nail nutrient, the penetration-promoting agent, lipids and other constituents is equal to 100% by weight of the total composition.

In a preferred form, the composition is used to treat fungal diseases of the nails.

Preferably, the composition comprises an penetration enhancing agent selected from the group of glycols, monoethers of glycols, diethers of glycols, dimethyl sulfoxide, caprolactam, dimethylisosorbitol, isopropylidene glycerol, glycerol, dimethylimidazolidinone, pentylene glycol, N-methylpyrrolidone, ethylidene pyrrolidone, glycerol, glycerol C9 -C10 polyoxyethylenes, polyethylene glycol glyceryl laurate and dimethylacetamide. More preferably, the composition comprises dimethyl sulfoxide.

Preferably, the composition also comprises a moisturizing agent: water or an emollient. The emollient is preferably selected from the non-exhaustive list of propylene glycol, hexylene glycol, butylene glycol, glyceryl triacetate, aloe vera gel, urea, vinyl alcohol, glycerol, sugar alcohols and polyols, sorbitol, xylitol, maltitol, polydextrose, quillaia or mixtures thereof. Water and emollients, especially if they are hygroscopic, have the effect of causing the nail to swell, which additionally promotes penetration of the composition.

Preferably, the composition comprises a solvent consisting of a C 1 -C 6 alkyl ester of an organic acid or of a hydroxy acid, which satisfies the following structural formula: F 4 -O-R 2, wherein R 1 is a straight or branched alkyl group of one to six and for example one to three carbon atoms, and R 2 is a group derived from an organic acid or from acetic acid, lactic acid, or formic acid; more preferably ethyl lactate.

Preferably, the aforementioned composition comprises a carboxylic acid or alpha-hydroxy acid, preferably selected from the non-exhaustive list of acetic acid, lactic acid, citric acid, tartaric acid, fumaric acid, and mixtures thereof; more preferably acetic acid or lactic acid. This acid helps to acidify the nail and makes it so inhospitable for dermatophytes.

Preferably, the composition also comprises a preservative.

In order to express the degree of lipophilicity (fat-lovingness) of a chemical, the known octanol-water partition coefficient, also known as the Log P, is used in the prior art. In a preferred form, said solvent has a Log P comprised between 0 and 1.

In another preferred embodiment, the invention provides a topical composition wherein said solvent has a vapor pressure at 20 ° C that is lower than 5 mm Hg.

In another aspect, the invention provides an applicator pen, such as a marker pen or marker pen, for use in the treatment of nail diseases, wherein said pen comprises the topical composition according to an embodiment of the invention and means for applying said composition to and / or around a nail.

In a third aspect, the invention provides a method for manufacturing a composition according to the invention. In particular, the invention provides a method for producing a topical composition for treating onychomycosis applied to a toe or finger nail by means of an applicator pen, wherein the following constituents are mixed together: - 0.001-10% by weight of nail nutrients selected from the list of biotin, keratin derivatives, amino acids such as cysteine, cystine or a mixture thereof; - 0.1-20% by weight of lipids selected from the list of triglycerides, fatty acids, ceramides, squalane, squalene, sterols, waxes and fatty alcohols or a mixture thereof; 1-10 weight percent of an penetration-promoting agent; supplemented with other components from the list of solvents, film former, carboxylic acid, preservative or moisturizing agent; - wherein the sum of nail nutrient, penetration-promoting agent, lipids and other constituents is equal to 100% by weight of the total composition.

The above-mentioned physical properties confer on the composition according to the invention the optimum properties in terms of application, penetration and effectiveness.

DESCRIPTION OF THE FIGURES

Figure 1 shows a perspective drawing of a device according to the present invention.

Figure 2 shows a perspective drawing of a user who applies the device according to Figure 1 to a nail surface.

DETAILED DESCRIPTION

The present invention relates to a biotin and lipid composition that offers better protection and treatment against onychomycosis.

The term "composition" is used herein as a synonym for "product" or "agent". The term "nails" as used herein refers not only to human finger and / or toenails, but also includes similar structures that are present in animals, such as animal nails, hooves, claws, etc. The present composition relies essentially on the following aspects .

A preferred embodiment of a composition according to an embodiment of the invention is biotin-containing. Biotin (CAS 58-85-5) is an organic compound with a structure as shown in formula (I):

(I)

Biotin is also referred to as vitamin H or vitamin B8.

Biotin is present in the compositions of the present invention in an amount of 0.001-10% by weight, preferably 0.01-1% by weight, most preferably 0.05-0.1% by weight, expressed relative to the total composition. Being able to dose biotin in lower amounts than is the case with oral composition is economically advantageous since biotin is an expensive ingredient.

The biotin in the composition can also be replaced by other nail nutrients. These can be selected from, among others, the list of keratin derivatives, amino acids such as cysteine, cystine, vitamin B12 or a mixture thereof. The amount of nail nutrients present in the composition is preferably between 0.001-10% by weight, preferably 0.01-1% by weight, most preferably 0.05-0.1% by weight, expressed relative to the total composition.

Analytical methods for determining biotin are known to those skilled in the art. Methods that can be used to determine biotin in pharmaceutical preparations include gas chromatography, a radiometric-microbiological assay, liquid chromatography with fluorimetric detection, chemiluminescence energy transfer methods, polarographic methods, HPLC, avidin-binding assays, fluorimetric methods, enzymatic methods and colorimetric procedures . The most standard method is a microbiological method according to FDA LST AB 266.1, 1995.

The present composition comprises an agent suitable to promote penetration of biotin or other nail nutrients, also referred to herein as penetration-promoting agent, which promotes the penetrating power of the composition. The term "penetration enhancer" or "penetration enhancer" or "penetration enhancer" are used herein as synonyms and refer to a molecule that promotes the extent of biotin delivery through the nail without damaging the nail.

The penetration enhancing agent is preferably selected from the group including, but not limited to, glycols, glycol monoethers, glycol diethers, dimethyl sulfoxide, caprolactam, dimethylisosorbitol, isopropylidene glycerol, pentylene glycol, dimethylimidazolidinone, N-methylpyrrolidone-pyrrolidone-pyrrolidone 2, ethyl lactate, glycerides of C 8 -C 10 polyoxyethylenes, polyethylene glycol glyceryl laurate and dimethylacetamide. More preferably, the penetration-promoting agent is dimethyl sulfoxide.

In another preferred form, ethyl lactate or ethyl acetate is present in the composition.

The penetration-promoting agent is present in a composition according to the present invention in an amount of 0.1-10% by weight, preferably 0.5-5% by weight, more preferably 1-3% by weight, expressed relative to the weight of the total composition.

Adding lipids to the composition has the effect that the damaged nail again becomes saturated with lipids and thus closes the pores in the nail for the penetration of the fungal spores. The lipids added to the composition can be selected from the list of triglycerides, fatty acids, ceramides, squalane and squalene, sterols, waxes and fatty alcohols or a mixture thereof. Preferably the lipid is a fatty alcohol. The lipids are present in a composition according to the present invention in an amount of 0.1-20% by weight, preferably 1-10% by weight, more preferably 2-5% by weight, expressed relative to the weight of the total composition.

In a preferred form, a composition according to the invention comprises 0.05 to 0.10 weight percent of biotin, 2-5 weight percent to lipids and 1 to 3 weight percent of penetration-promoting agent, expressed relative to the weight of the total composition.

In a preferred form, the composition comprises a carboxylic acid selected from the list of acetic acid, lactic acid, citric acid, tartaric acid, fumaric acid, formic acid, and mixtures thereof. Preferably the carboxylic acid is acetic acid or lactic acid. This acid helps to acidify the nail and makes it so inhospitable for dermatophytes.

In a preferred form, the composition comprises 1-10% by weight of carboxylic acid, more preferably 1-5% by weight, most preferably 1-3% by weight, expressed relative to the total composition. Preferably, the composition comprises 1-10% by weight acetic acid, more preferably 1-3% by weight acetic acid, expressed relative to the weight of the total composition. Preferably, the composition comprises 1 to 10% by weight of lactic acid, more preferably 1-3% by weight of lactic acid, expressed relative to the weight of the total composition.

The present composition can further comprise a solvent that has a sufficiently low vapor pressure so that it can evaporate quickly after application, has a great affinity for the nail so that it penetrates easily, is a good solvent for the penetration enhancer, which is not harmful and is moreover compatible with the package.

This solvent is preferably selected from acetone, ethanol, isopropyl alcohol or from the group of molecules that satisfy the following structural formula (I): RJ-0-R2, wherein R1 is a straight or branched alkyl group of one to six and at preferably one to three carbon atoms, and R 2 is a group derived from an organic acid or from hydroxy acid such as but not limited to acetic acid, lactic acid, formic acid.

In a preferred embodiment of a topical composition according to the invention, said solvent, preferably of the above formula (I), has a Log P comprised between 0 and 1.

In another preferred embodiment, the invention provides a topical composition wherein said solvent has a vapor pressure at 20 ° C that is lower than 5 mm Hg, and preferably lower than 4 mm Hg.

The aforementioned solvent is preferably present in an amount of 50-99% by weight and preferably 60-90% by weight relative to the weight of the total composition. Water is not counted as a solvent.

The present composition may also comprise a moisturizing agent, this may be water or an emollient. The presence of a moisturizing agent helps to hydrate the nail and causes the keratin matrix to swell. This opens the way to the underlying layers of the nail plate. This is advantageous in combating nail fungal diseases, whereby the encapsulated dermatophytes can be achieved. Preferably the composition comprises an emollient, more preferably selected from the list propylene glycol, hexylene glycol, butylene glycol, glyceryl triacetate, aloe vera gel, urea, vinyl alcohol, glycerol, sugar alcohols and polyols, sorbitol, xylitol, maltitol, polydextrose , quillaia or mixtures thereof. Water and the emollients have the effect of swelling the nail plate, which additionally promotes penetration of the composition.

Preferably a composition according to the invention comprises 0.1-10% by weight, more preferably 1-5% by weight of moisturizing agent, expressed with respect to the total weight of the composition.

Since the product according to the invention can be brought into contact for a long time with a (potentially) infected surface, it is advantageous for the composition to be adequately stored. To that end, the composition preferably comprises one or more preservatives. A suitable preservative can be selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), phenylmercuriborate, phenylmercuriacetate, phenylmercurinitrate, thiomersal, methyl parahydroxybenzoate, propyl parahydroxybenzoate, ethyl parahydrobenzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, sodium benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, sodium benzoate, benzoate chlorocresol, benzyl alcohol, chlorobutanol, ethanol, phenylethyl alcohol, phenoxyethanol, glycerol, propylene glycol, butanediol, pentane diol, hexane diol, heptanediol, octane diol, nonane diol, decane diol, caprylyl glycol, sucrose, bronopol, hexamethylene tetramine, nitric sodium nitrate. In a preferred form, benzoic acid is present in a composition according to the invention. In another preferred form, caprylyl glycol is present in a composition according to the invention. The preservative is preferably provided in an amount of 1-10 weight percent, more preferably in 0.5-5 weight percent, most preferably 1-3 weight percent expressed relative to the total composition.

Film former is added to the composition to ensure that the active ingredients remain on the nail surface after the solvent has evaporated and thus have time to penetrate. For this purpose, a water-insoluble substance is preferably selected from the list of polyurethane derivatives, dimethicone, butyl ester of polyvinyl methyl ether and malic acid copolymer, copolymers of acrylates and of ammonium methacrylates, and hydroxyethyl cellulose, nitrocellulose and ethylcellulose.

Preferably, in a composition according to the invention, 0.1-10% by weight, more preferably 0.5-5% by weight and most preferably 1-3% by weight of film former are present, expressed in relation to the total weight of the composition.

In a preferred embodiment, the invention provides a topical composition comprising: - 0.001-10% by weight of biotin, or other nail nutrients as defined above; 0.1-10% by weight and preferably 1-3% by weight of an penetration-promoting agent as defined above; - wherein preferably 1-3 weight percent, is a carboxylic acid as defined above; 0.1-10% by weight and preferably 1-5% by weight of moisturizing agent as defined above; - 50-95% by weight and preferably 60-90% by weight of a solvent as defined above; 0.1-10% by weight and preferably 1-3% by weight of a preservative as defined above; 0.1-10% by weight and preferably 1-3% by weight of a film former as defined above; - 0.1-20% by weight and preferably 1-5% by weight of a lipid as defined above; - the sum of the ingredients being 100% by weight of the total composition.

In a preferred form of a composition according to the invention, the composition is for the treatment of fungal nails.

In a preferred embodiment, the topical composition according to the invention is filled into an applicator pin of the marker pen type that allows the composition to be applied to the nail easily, quickly and in a user-friendly manner. This is important since the success of the treatment depends to a large extent on the compliance of the patient.

The present invention further relates to a topical, biotin or other nail nutrient and lipid-containing composition and to an applicator pen as defined herein for use for treatment of onychomycosis.

The invention preferably relates to the use of a topical composition for the treatment, prevention, after-treatment or supportive treatment of onychomycosis. Moreover, the present invention also relates to the use of a topical composition according to the invention for the treatment of fungal infections of hooves, claws and nails of animals. Topically applicable compositions according to the invention are suitable, for example, for the treatment, prevention and after-treatment of onychomycosis caused by dermatophytes, yeasts or fungi or mixed infections.

The frequency of use of the compositions according to the invention is partly determined by the location of the disease. In general, applying one, two or three times a day is sufficient. The solution is applied directly to the sick nail, hoof or claw, and if desired also to areas around the nail if they are also affected by the fungal disease.

The topically applicable biotin and lipid-containing agents according to the invention have the advantage that they immediately penetrate and saturate the diseased nail together with any active substances present. This enables the active substances of the present composition to develop their action in the nail bed and at the nail root. Due to the better penetration and the associated faster functioning of the current composition, the total treatment of onychomycosis can proceed faster. Furthermore, biotin and other nail nutrients promotes faster growth of the nail which speeds healing of the nail. The added lipids repair the damaged nail surface and prevent fungal spores from causing an infection through the nail. The increased ease of use also promotes patient compliance.

The present invention also relates to a method of manufacturing the biotin or other nail nutrient and lipid-containing composition of this invention. For this purpose, biotin or other nail nutrient, lipids and an penetration-promoting agent for transporting biotin through a finger or toenail are brought together. Optionally, other ingredients may be present in the composition. The sum of the components is equal to 100% by weight of the total composition.

EXAMPLES

The present invention is illustrated by the following non-limitative examples. Examples given below represent embodiments of a composition according to the invention. EXAMPLE 1:

This example relates to a composition for treating fungal nails which per 100 g comprises biotin 0.05 g acrylate / ammonium methacrylate copolymer 0.5 g acetic acid 1.0 g lanolin derivatives (lipid) 1.0 g glycerol 1.0 g polyoxypropylene-15- stearyl ether (lipid) 3.0 g pentylene glycol 3.0 g dimethyl sulfoxide 3.0 g ethyl acetate 87.45 g EXAMPLE 2:

Process for obtaining the compositions of Example 1. All compositions of this invention are prepared by mixing all components in the solvent, biotin being added last in each case together with the penetration enhancer.

EXAMPLE 3: ACTIVITY

To determine the penetration of molecules through various substrates, diffusion cells such as Franz cells are used as standard. The latter consist of a donor compartment and an acceptor compartment separated by a membrane of your choice.

In the arrangement used for a composition according to this invention, the acceptor compartment was filled with demineralized water. The membrane was cut into a cow's hoof as a model for a nail. The donor compartment was filled with a composition with biotin and penetration-promoting agent according to the invention.

After the test, the acceptor fluid was analyzed by a microbiological method (FDA LST AB 256.1, 1995). The analysis showed that biotin diffused through the hoof disc within 90 minutes.

Claims (9)

A topical composition for treating onychomycosis applied to a toe or finger nail by means of an applicator pen, comprising: - 0.001-10% by weight of nail nutrients selected from the list of biotin, keratin derivatives, amino acids such as cysteine, cystine or a mixture thereof; - 0.1-20% by weight of lipids selected from the list of triglycerides, fatty acids, ceramides, squalane, squalene, sterols, waxes and fatty alcohols or a mixture thereof; 1-10 weight percent of an penetration-promoting agent; supplemented with other components from the list of solvents, film former, carboxylic acid, preservative or moisturizing agent; wherein the sum of nail nutrient, the penetration-promoting agent, lipids and other constituents is 100% by weight of the total composition, and wherein the penetration-promoting agent is selected from the group of glycols, monoethers of glycols, diethers of glycols, dimethylsulfoxide, caprolactam , dimethyl isosorbitol, pentylene glycol isopropylidene glycerol, glycerol, dimethyl imidazolidinone, N-methyl pyrrolidone, pyrrolidone, ethyl lactate, glycerides of C9-C10 polyoxyethylenes, polyethylene glycol glyceryl laurate and dimethylacetamide. A composition according to any one of the preceding claims, wherein further comprises a solvent that is a C 1 -C 6 alkyl ester of an organic acid or of a hydroxy acid, which satisfy the following structural formula: F 4 -O-R 2, wherein R 1 is a straight or branched alkyl group having one to six and preferably one to three carbon atoms, and R 2 is a group derived from an organic acid or from acetic acid, lactic acid, or formic acid as well as acetone ethanol and isopropyl alcohol, and more preferably ethyl lactate. A composition according to any one of the preceding claims, wherein said solvent has a Log P comprised between 0 and 1. A composition according to any one of the preceding claims, wherein said solvent is provided in the form of a solution with a vapor pressure at 20 ° C that is lower than 5 mm Hg. A composition according to any one of the preceding claims, wherein the composition comprises a film former selected from the list of polyurethane derivatives, dimethicone, butyl ester of polyvinyl methyl ether and malic acid copolymer, copolymers of acrylates and ammonium methacrylates, hydroxy ethyl cellulose, nitrocellulose and ethyl cellulose . A composition according to any one of the preceding claims, wherein said composition comprises a carboxylic acid, preferably selected from acetic acid, formic acid, lactic acid, citric acid, tartaric acid, fumaric acid. A composition according to any one of the preceding claims, wherein said composition comprises a preservative selected from the list of ethylenediaminetetraacetic acid (EDTA), phenylmercuriborate, phenylmercuriacetate, phenylmercurinitrate, thiomersal, methyl parahydroxybenzoate, propyl parahydroxy benzoate, benzoate benzoate, sodium benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, benzoate, etc. potassium sorbate, calcium sorbate, sodium sorbate, sorbic acid, chlorocresol, benzyl alcohol, chlorobutanol, ethanol, phenylethyl alcohol, phenoxyethanol, glycerol, propylene glycol, butanediol, pentane diol, hexane diol, heptane diol, octane diol, nonane diol, decane diol, sucrose , bronopol, hexamethylene tetramine, sodium nitrite, sodium nitrate, and butylene glycol. A composition according to any one of the preceding claims, wherein the composition comprises a moisturizing agent, preferably selected from the list of water or an emollient: propylene glycol, hexylene glycol, butylene glycol, glyceryl triacetate, aloe vera gel, urea, vinyl alcohol, glycerol , sugar alcohols and polyols, sorbitol, xylitol, maltitol, polydextrose, quillaia or mixtures thereof. A method for producing a topical composition for treating onychomycosis applied to a toe or finger nail by means of an applicator pen according to any of claims 1-8, wherein the following constituents are mixed together: - 0.001-10% by weight of nail nutrients, selected from the list of biotin, keratin derivatives, amino acids such as cysteine, cystine or a mixture thereof; - 0.1-20% by weight of lipids selected from the list of triglycerides, fatty acids, ceramides, squalane, squalene, sterols, waxes and fatty alcohols or a mixture thereof; 1-10 weight percent of an penetration-promoting agent; supplemented with other components from the list of solvents, film former, carboxylic acid, preservative or moisturizing agent; wherein the sum of nail nutrient, the penetration-promoting agent, lipids and other constituents is 100% by weight of the total composition, and wherein the penetration-promoting agent is selected from the group of glycols, monoethers of glycols, diethers of glycols, dimethylsulfoxide, caprolactam , dimethyl isosorbitol, pentylene glycol isopropylidene glycerol, glycerol, dimethyl imidazolidinone, N-methyl pyrrolidone, pyrrolidone, ethyl lactate, glycerides of C9-C10 polyoxyethylenes, polyethylene glycol glyceryl laurate and dimethylacetamide.