BASE COMPOSITION FOR PREPARING MEDICINE FOR EXTERNAL APPLICATION, MEDICINAL COMPOSITION FOR EXTERNAL APPLICATION, AND METHOD FOR ACCELERATING PERCUTANEOUS ABSORPTION OF MEDICINAL AGENT

Abstract: A composition for raising skin permeability or ac­ celerating percutaneous absorption of a medicinal agent, which comprises at least one member selected from among optionally halogen-substituted, saturated aliphatic hydro­ carbons containing 5 to 20 carbon atoms, monohydric lower alcohol esters of aliphatic carboxylic acids containing 13 to 24 carbon atoms, and ethers containing 8 to 16 carbon atoms and having one ether bond within the molecule and a lower alcohol; and a medicine for external application containing said composition as a base.

Description: This invention relates to a base composition capable of increasing the percutaneous absorption of drugs, to a pharmaceutical composition for external use in which said base composition is used, and to a method of promoting the percutaneous absorption of drugs. The drugs so far administered to the outer skin have served the purpose of producing a local effect on the outer skin or hypodermal tissues, such as a bactericidal, disinfecting or analgesic effect. However, in recent years, attempts have been made to administer also drugs having a systemic activity to the outer skin instead of peroral administration or injection. The percutaneous administration of a drug, particularly a systemic drug, have the following advantages, among others: that the drug efficacy can easily be maintained for a long while; that the rate of drug absorption can easily be controlled, so that adverse effects due to overdosage can be minimized; that since the drug is sparingly metabolized in the liver by the first pass effect as found in the case of oral administration, so that the drug can be used effectively; and that even a drug possibly causing gastrointestinal disorders upon oral administration, such as indomethacin, can be administered safely. However, the normal skin, which has a body-protecting action is generally capable of resisting drug absorption or permeation. Therefore, drugs (especially systemic drugs, when simply administered in the conventional forms of ointment, lotion and so on, can scarcely be absorbed into the body in amounts sufficient to produce a satisfactory pharmacological effect. Under these circumstances, the present inventors conducted intensive research and, as a result, obtained the following findings: (1) That a composition comprising a lower alcohol and at least one adjuvant according to claim 1, 2 or 4 and an ether can and (2) That the above-mentioned composition can be used as a base for drugs to be applied to the skin. These findings have led to the present invention. Accordingly, a primary object of the present invention is to provide a base composition for external preparations which is capable of increasing the skin permeation and percutaneous absorption of drugs. A second object of the invention is to provide a pharmaceutical composition for external use which is satisfactory in the skin permeation and percutaneous absorption of drugs. A third object of the invention is to provide a method of increasing the skin permeation and percutaneous absorption of drugs. The lower alcohol to be used in the practice of the present invention is a monohydric alcohol containing 1 to 4 carbon atoms, including methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol and t-butyl alcohol. Among these, ethyl alcohol is particularly preferred. The saturated aliphatic hydrocarbon containing 5 to 20 carbon atoms, which may optionally be halogen-substituted, may be straight-chained, branched or cyclic. The straight-chained one includes among others n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecane, n-octadecane and n-eicosane, among which those containing 6 to 16 carbon atoms are preferred. The branched one includes among others 2-methylpentane, 2,3-dimethylhexane, 2,2,4,4,6,8,8-heptamethylnonane and limonene, and preferably contains 6 to 16 carbon atoms. The cyclic one includes monocyclic or bicyclic ones which contain 6 to 12 carbon atoms, such as cyclohexane, cyclododecane and decalin. The halogen as the substituent is, for example, chlorine or bromine. As the halogen-substituted adjuvant, there may be mentioned saturated, straight-chained, halogenated hydrocarbons containing 8 to 16 carbon atoms, such as octyl bromide, dodecyl bromide, hexadecyl bromide and dodecyl chloride. The number of the halogen substituents is 1 or 2, preferably 1. The ether includes ethers containing 8 to 16 carbon atoms with one ether bondage per molecule, such dibutyl ether, dihexyl ether, dioctyl ether, methoxydodecane, ethoxydodecane and 1,8-cineole. The base composition in accordance with the present invention is prepared by adding the adjuvant to the lower alcohol. The adjuvant is incorporated in an amount of 1 to 50 percent by weight, preferably 5 to 30 percent by weight, based on the lower alcohol. Said base composition may of course contain any other pharmaceutically acceptable additives. The pharmaceutical composition for external use in accordance with the present invention is prepared by incorporating a drug into the above base composition. The drug to be incorporated is not particularly limited so long as it is applicable to the skin. However, the drug should preferably have a solubility in the above monohydric alcohol of 0.5 to 10%, more preferably 1 to 5%. The drug species having a solubility in the above range, when incorporated into the base composition according to the present invention, can be distributed to the skin to an increased extent, hence percutaneously absorbed to an improved extent. The "solubility" as used herein means the solubility as measured by adding the drug in excess to the alcohol warmed at 20°C for dissolution, stirring the mixture occasionally and, after 24 hours, separating the supernatant and assaying the same for the drug by absorptiometry. The drug is incorporated in an amount sufficient to produce the desired pharmacological effect. Such amount may vary depending on the drug species, body weight and condition of the patient. Therefore, the drug amount may be adequately selected depending on these conditions. Generally, from the percutaneous absorption viewpoint, the drug is preferably used in an amount of 0.01 to 20 percent by weight, more preferably 0.1 to 10 percent by weight, based on the total amount of the lower alcohol and adjuvant. Since the dose of a drug can be adjusted by increasing or decreasing the skin surface area to which the pharmaceutical composition is applied, the incorporation amount of the drug is not always limited to the above range. For those drugs that are used for producing a local effect against diseases of the outer skin or hypodermal tissues, for instance, the conventional external preparations are also effective to a certain extent. Therefore, the pharmaceutical composition in accordance with the present invention becomes more significant when it contains a drug which is expected to produce a systemic effect. To be concrete, the drugs used in connection with hydrocarbons and mono hydri alcohols only are benzodiazepines (e.g. diazepam, nitrazepam, flunitrazepam, lorazepam, prezepam, fluidazepam, clonazepam), diuretics [e.g. thiazides (e.g. bendioflumethazide, polythiazide, methyclothiazide, trichlormethiazide, cyclopenthiazide, benzylhydrochlorothiazide, hydrochlothiazide, bumetanide)], hypotensives, (e.g. clonidine), antihistaminics [e.g. aminoethers (e.g. diphenhydramine, carbinoxamine, diphenylpyraline), ethylenediamines (e.g. phenbenzamine), monoamines (e.g. chlorpheniramine)], nonesteroid antiinflammatories (e.g. indomethacin, ibuprofen, ibufenac, alclofenac, dichlofenac, mefenamic acid, flurobiprofen, flufenamic acid, ketoprofen), anti-malignant-tumor agents (e.g. 5-fluorouracil, 1 - (2 - tetrahydrofuryl) - 5 - fluorouracil, cytarabine, broxuridine), steroidal antiinflammatories (e.g. cortisone, hydrocortisone, prednisolone, prednisone, triamcilonone, dexamethasone, betamethasone), antiepileptics (e.g. ethosuximide), antiarrythmic agents (e.g. ajmalin, prajmalin, pindolol, propranolol, quinidine), phsychotropic agents (e.g. clofluperidol, trifluperidol, haloperidol, moperone), scopolamines (e.g. methylscopolamine, butylscopolamine), chlorpromazine, atropines (e.g. methylatropine bromine, methylanisotropine bromide), vasodilators (e.g. isosorbide dinitrate, nitroglycerin, pentaerythritol tetranitrate, propatyl nitrate, dipyridamole), antibiotics [e.g. tetracyclines (e.g. tetracyline, oxytetracycline, metacycline, doxycycline, minocycline)], chloramphenicol and erythromycins. The pharmaceutical composition for external use in accordance with the present invention is administered to the skin either as it is or in the form of an external preparation, such as ointment, plaster, lotion, adhesive tape preparation, impregnation or gel, made by addition of a known third component. The impregnation is prepared, for example, by allowing an appropriate adsorbent (e.g. gauze, filter paper, porous membrane) to be impregnated with said pharmaceutical composition for external use as it is or with a composition prepared by further incorporating a known third component into said pharmaceutical composition, and is generally applied to the skin under fixation to the skin by means of an adhesive tape. The gel is prepared, for instance, by producing a gel using a gelling agent for alcohols [e.g. Gelol D (Shin Nippon Rika Kogyo)] and spreading the gel onto a support member. The base for the adhesive tape, preparation may be a per se known one, such as an acrylic copolymer, a polyvinyl ether compound or an adhesive rubber mixture. Other external preparations also can be prepared easily by the per se known techniques. The following examples and test examples illustrate the present invention in more detail. However, they are by no means limitative of the present invention. Additional comparative experiments have been marked with "*". Examples 1-27 Basic formulation (1) Diazepam 3 g (2) C₁₋₄ alcohol 72 g (3) Adjuvant 25 g Liquid compositions were prepared by first mixing component (3) with component (2) and further dissolving component (1) in accordance with the above basic formulation using the alcohols and adjuvants specifically indicated in Table 1. Comparative Examples 1-3 (1) Diazepam 3 g (2) C₁₋₄ alcohol 97 g Liquid compositions were prepared by dissolving the above component (1) in component (2) specifcally indicated in Table 1. Comparative Example 4 (1) Diazepam 3 g (2) Dimethyl sulfoxide 97 g Test Example 1 The liquid composition each of Examples 1-20 and Comparative Examples 1-3 was tested for the skin permeation of the drug using a diffusion cell, 2 cm in inside diameter, fitted with an excised rat abdominal skin piece, and 0.5 ml of the composition. The results are shown in Table 1. (Method of measurement) The glass diffusion cell was fitted with the rat skin piece in the manner such that the outer side of the skin was brought into contact with the above liquid composition and the inner side of the skin with physiological saline, and the drug portion that had permeated the skin into the physiological saline was extracted with benzene and assayed by spectrophotometry. Example 2 A 4 cm² piece of gauze impregnated with one of the compositions of Example 2 and Comparative Examples 1 and 4 was fixed on the clipped back of an albino rabbit weighing 3.5 kg. Blood samples were taken at time intervals, extracted and concentrated in the conventional manner, and assayed for the drug by gas chromatography using an electron capture detector. The results obtained are shown in Table 2. Example 21 (1) Indomethacin 1.0 g (2) Ethyl alcohol 76.0 g (3) n-Dodecane 23.0 g The above components were mixed for dissolution in one and the same vessel to give a liquid composition. Comparative Example 5 (1) Indomethacin 1 g (2) Ethyl alcohol 99 g The above component (1) was dissolved in (2). Comparative Example 6 (1) Hiviswako 104® (Wako Pure Chemical Industries) 1.0 g (2) Indomethacin 1.0 g (3) Propylene glycol 12.0 g (4) Ethyl alcohol 30 g (5) Diisopropyl adipate 2.0 g (6) Diisopropanolamine 1.1 g (7) Purified water A sufficient amount to make 100 g (A) The above (1) was allowed to swell in 20 g of water. (B) The above (2) was dissolved in the above (3), (4) and (5). (C) The above (B) was added to the above (A) and the mixture was stirred until complete hydration. (D) The above (6) was dissolved in 10 g of water and the solution was added to the above (C). After addition of the remaining amount of water, the whole mixture was stirred until it became homogeneous. Test Example 4 Rat skin permeation of indomethacin The abdominal area of a Wistar strain male rat weighing 200 g was clipped with a manual hair clipper and an electric hair clipper (Braun) and then the abdominal skin was peeled off and mounted on a glass-made drug permeation cell. One of the liquid compositions of Example 29 and Comparative Examples 7 and 8 was applied to the skin in a dose of 150 mg per cm² and the skin permeation of indomethacin was determined. The results are shown in Table 3. Examples 22-35 [Basic formulation] (1) n-Decane 25 g (2) Ethyl alcohol 72 g (3) Drug 3 g A base was prepared by mixing component (2) with component (1), and component (3), namely the drug specifically indicated in Table 4, is added thereto to give a liquid composition. Comparative Examples 7-20 Liquid compositions were produced in which the n-decane in Examples 20-35 was not used but instead 97 g of ethyl alcohol. Test Example 5 The skin permeation of the drug in each of the liquid compositions of Examples 20-35 and. Comparative Examples 7-20 was measured using an excised rat abdominal skin piece mounted on a diffusion cell, 0.95 cm in inside diameter, and 0.1 ml of each composition. The results are shown in Table 4. (Method of measurement) The glass-made diffusion cell was fitted with the rat skin piece in the manner such that the outer side of the skin was brought into contact with the above liquid composition and the inner side with physiological saline, and the drug portion which had permeated the skin into the physiological saline was extracted with chloroform. The extract was evaporated to dryness, and the residue was dissolved in methanol and assayed for the drug by spectrophotometery.

Claims: Pharmaceutical composition increasing the percutaneous absorption of drugs selected from benzodiazepines, diuretics, hypotensives, antihistamines, ethylenediamines, monoamines, nonsteroidal antiinflammatories, antimalignant tumor agents, steroidal antiinflammatories, antiepilectics, antiarrhytmic agents psychotropic agents, scopolamines, chlorpromazine, atropines, vasodilators, antibiotics, chloramphenicol and erythromycins comprising a monohydric alcohol having 1 to 4 carbon atoms and at least one adjuvant of a saturated aliphatic hydrocarbon containing 5 to 20 carbon atoms, which may be optionally substituted by 1 or 2 halogen atoms. Composition increasing the percutaneous absorption of drugs comprising a monohydric alcohol having 1 to 4 carbon atoms and at least one adjuvant of an ether having 8 to 16 carbon atoms and 1 ether linkage per molecule. The composition of Claim 1, wherein the adjuvant is incorporated in an amount of 1 to 50 percent by weight based on the monohydric alcohol. Phamaceutical composition enabling increased percutaneous absorption of a drug being included therein comprising the drug, a monohydric alcohol having 1 to 4 carbon atoms and an adjuvant comprising a saturated aliphatic hydrocarbon containing 5 to 20 carbon atoms, which may optionally be substituted by 1 or 2 halogen atoms, and an ether having 8 to 16 carbon atoms and 1 ether linkage per molecule. The pharmaceutical composition of Claim 3, wherein the adjuvant is incorporated in an amount of 1 to 50 percent by weight based on the monohydric alcohol. The pharmaceutical composition of Claim 4, wherein the drug has a solubility in the alcohol of 0.5 to 10 percent. Use of compositions according to Claims 1 to 5 in preparations to be externally administered to increase the percutaneous absorption of drugs.

Inventors: NISHIU, YUMIKO NITTO ELECTRIC INDUSTRIAL CO., LTD., SATO, SUSUMU NITTO ELECTRIC INDUSTRIAL CO., LTD., TAMADA, MITSURU NITTO ELECTRIC IND. CO., LTD.
Applicants: NITTO DENKO CORPORATION
Application year: 1982
Main classification: A61K9
IPC codes: A61K9, A61K31, A61K47