PERCUTANEOUS ABSORPTION PREPARATION AND PROCESS FOR PREPARING SAME

Abstract: A percutaneous absorption preparation which comprises calcium salt of an acidic anti-inflammatory or analgesic drug having carboxyl group as the active ingre­ dient and present in an amount of 0.3 - 10% by weight; a medium for the active ingredient which is selected form the group consisting of an ethylene glycol mono-lower alkyl ether, propylene glycol, polyethylene glycol and dimethyl­ sulfoxide, the medium being present in an amount at least sufficient to dissolve the active ingredient; an absorption promotor selected from the group consisting of 1-dodecyl­ azacycloheptan-2-one, hexamethylenelauramide, N-methyl-2-­ pyrrolidone, a sucrose aliphatic acid ester, dimethylsulfoxide and a nonionic surfactant and present in an amount of 0.5 - ­ 10% by weight; and the remaining being other reagents and/or carriers required for a desired form of the preparation.

Description: This invention relates to a percutaneous absorption preparation. More particularly, it relates to a percutaneous absorption preparation which comprises calcium salt of an acidic non steroidal anti-inflammatory or analgesic drug having carboxyl group as the active ingredient and to the process for preparing same. Acidic non steroidal anti-inflammatory drugs such as indomethacin, mefenamic acid, flufenamic acid or ketoprofen have been widely used orally. However, the benefit of the full therapeutic effect thereof is often limited because of gastrointestinal side effects. Accordingly, the introduction of rectal suppositories has allowed increased utilization for therapeutic purposes, but it is shown that the manifestations of peptic ulceration and rectal bleeding also occur with these suppositories. A rectal suppository of calcium salts of the acidic non steroidal anti-inflammatory drugs is proposed and disclosed in Japanese Unexamined Patent Publication N° 162,560/1983, which however states that blood concentration on application of the rectal suppository is nearly equal to that of the rectal suppository of the corresponding free acid type drug. Gel preparations for external use of the acidic non steroidal anti-inflammatory drugs or sodium salts thereof are also known (e.g., USP 4,545,992 and USP 4,543,251). This invention provides a percutaneous absorption preparation which comprises the calcium salt of an acidic non steroidal anti-inflammatory or analgesic drug having a carboxyl group as the active ingredient and present in an amount of 0.3 - 10 % by weight; a medium for the active ingredient which is selected from an ethylene glycol mono-lower alkyl ether, propylene glycol, polyethylene glycol and dimethylsulfoxide, the medium being in an amount at least sufficient to dissolve the active ingredient; a penetration enhancer selected from 1-dodecylazacycloheptan-2-one, hexamethylenelauramide, N-methyl-2-pyrrolidone, a sucrose aliphatic acid ester, dimethylsulfoxide and a nonionic surfactant and present in an amount of 0.5 - 10 % by weight. Other reagents and/or carriers required for a desired form of the preparation may also be present. When the preparation according to the invention is percutaneously applied, it can maintain a therapeutically effective concentration in the blood of the active ingredient and exert systematic effect thereof, e.g., over 24 hours after application once a day, with less irritating action to the skin. The invention also provides a process for preparing said percutaneous absorption preparation. Brief Description of the Drawings FIG. 1 is a graph illustrating the plasma concentrations of indomethacin after application of the gel ointment of Example 1, the control ointment (Rp.1) and the comparable ointment (Rp.2) to rat abdominal skin (see Example 6); FIG. 2 is a graph illustrating the plasma concentrations of indomethacin during multiple dosing of the gel ointment of Example 1 and indomethacin ointment to rat abdominal skin; FIG. 3 is a graph illustrating the effect of carrageenan-induced paw edema of the gel ointment of Example 1 and indomethacin ointment applied to rat abdominal skin. Description of the Preferred Embodiment The percutaneous absorption preparation of the invention may be in the form of gel ointment, gel cream, solution or aerosol, or in other known forms which can be pharmaceutically and topically used. Examples of the calcium salt of acidic anti-inflammatory or analgesic drug having carboxyl group as the active ingredient include calcium salt of ibufenac, alclofenac, metiazinic acid, suxibuzone, oxepinac, sulindac, fentiazic, indomethacin, diclofenac, bendazac, mefenamic acid, flufenamic acid, zomepirac, tolmethin, fenbufen, ibuprofen, ketoprofen, oxaprozin, flurbiprofen, naproxen, benoxaprofen, pranoprofen, suprofen, fenoprofen, CN-100 [2-(10,11-dihydro-10-oxodibenzo[b,f]thiepin-2-yl)propionic acid], Y-9213 [2-{4-[2-imidazo-(1,2-a)-pyridyl]phenyl}propinoic acid], tiaprofenic acid or protizinic acid. The preferred ones are calcium salt of indomethacin, diclofenac, bendazac, mefenamic acid, ketoprofen or alcofenac. The calcium salts of acidic anti-inflammatory or analgesic drugs can be prepared, for example, by treating the corresponding sodium salt with calcium acetate in an non steroidal aqueous medium. The amount of the active ingredient in the preparation is in the range of 0.3 - 10% by weight, preferably 0.4 - 5%, more preferably 0.5 - 2.0%. The medium for the active ingredient is an diethylene glycol mono-lower alkyl ether such as diethylene glycol monoethyl ether, propylene glycol, polyethylene glycol or dimethylsulfoxide, or a mixture thereof. The preferred ones are diethylene glycol monoethyl ether or dimethylsulfoxide. It is found that the use of such a medium is essential in order to dissolve the active ingredient and exert the aimed effects of the invention. For example, when a conventional ointment base is used for the calcium salt as the active ingredient, it will result in an ointment with very poor absorption of the active ingredient. The medium is used in an amount at least sufficient to dissolve the active ingredient, depending upon the kind of medium and the active ingredients. It is also found that the use of specific penetration enhancers is effective for the preparation of the invention. For example, the addition of calcium thioglycolate which is known as a penetration enhancer will dramatically decrease the absorption of the active ingredient such as indomethacin calcium. The preferred penetration enhancers are from 1-dodecylazacycloheptan-2-one (available as Azone® Nelson Research and Development), hexamethylenelauramide, sucrose aliphatic acid ester (e.g., sucrose laurate or sucrose palmitate), N-methyl-2-pyrrolidone, dimethylsulfoxide and/or a nonionic surfactant (e.g., polyethylene glycol oleoyl ester, polyethylene glycol oleoyl ether, polyethylene glycol lauryl ether or sorbitan monostearate). The more preferred examples are l-dodecylazacycloheptan-2one, hexamethylenelauramide, Nmethyl-2pyrrolidone and sucrose laurate (or palmitate). The most preferred are 1-dodecylazacycloheptan-2-one or hexamethylenelauramide. The penetration enhancers may be used as mixtures thereof and are usually used in an amount of 0.5 - 10% by weight in the preparation. When the preparation is in a gel ointment or gel cream from, the reagents and carriers required are used. The reagents comprise a gelatinizing agent, an adjuvant for for absorption and optionally a neutralizing agent. Examples of the gelatinizing agents include carboxyvinyl polymers such as Carbopol® 934, 940 or 941 (available from Goodrich Chemical Co., USA) and Hiviswako® 103, 104, 105 or 106 (available from Wako Junyaku Kogyo KK., Japan), cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose or methyl cellulose; or propylene glycol alginate. The preferred ones are carboxyvinyl polymers. The gelatinizing agent is usually used in an amount of 0.5 - 2% by weight in the final preparation and also generally used in a dilute solution in water, glycols such as propylene glycol or butylene glycol or a lower alkanol such as ethanol, or mixture thereof. Such solvents for the gelatinizing agent are also deemed to be carriers of the preparation when carboxyvinyl polymers are employed; the resulting preparation will be acidic and therefore it is preferred to neutralize it to pH about 6.0 - 7.5 by addition of the neutralizing agent in order to avoid a possible decomposition of the calcium salt as the active ingredient. Examples of the neutralizing agent include an organic amine such as diisopropanolamine, and an inorganic base such as aqueous ammonia. In any case, the use of the neutralizing agent which does not cause any side effect on skin is desirable. It is found that the use of an adjuvant for absorption in gel ointment or gel cream is effective. Example of adjuvants for absorption include C 1-5 alcohol esters of C 4-14 aliphatic monocarboxylic acids or C 1-3 alcohol diesters of C 4-10 aliphatic dicarboxylic acids, such as ethyl caproate, diisopropyl adipate or diethyl sebacate. The adjuvant for absorption is preferred to be in an amount of 0.5 - 5% by weight in the final preparation. Gel ointment or gel cream may contain conventional carriers such as lanolin, vaselin or the hydrophilic ointment (Japanese Pharmacopeia). When the preparation is in solution form, lower alcohols such as ethanol are preferably used as a carrier. In the case of an aerosol form, fluorohydrocarbons such as trichlorofluoromethane (available as Freon 11 from du Pont) or dichlorodifluoromethane (available as Freon 12 from du Pont), or liquefied petroleum gas may be used as propellant. In addition, the preparation of this invention may be included in an adhesive tape. The percutaneous preparation in the present invention exerts remarkable anti-inflammatory and analgesic activities after percutaneous application, due to the excellent absorption of drugs, as shown in the following examples. The preparations thus make it possible to decrease the gastro-intestinal irritation and ulceration and to administer percutaneously antiinflammatory drugs in patients requiring parenteral therapy. Accordingly, in one aspect of the invention, a method is provided for treating a patient suffering rheumatoid arthritis, osteoarthritis, acute musculo-skeletal disorders, contusion or sprain which comprises percutaneously applying the above mentioned preparation to the patient. The amount to be applied depends upon the condition of the disease, age and the kind of preparation application. In the case of a gel ointment containing 2% of the active ingredient, is generally 0.14 g or less of the gel ointment, per 1 cm square of skin, whereby a similar effect to the oral administration . will be achieved. The following examples are given to illustrate the present invention but are not intended to limit the invention in any manner. Method of Preparation Sorbitan monooleate is mixed with Azone® to give (A). Hiviswako 104 is swollen with 200 g of water to give (B). (A) and (B) are mixed and stirred sufficiently to mix homogeneously to give(C). The calcium salt of indomethacin is dissolved in dimethylsulfoxide to give (D). (D) is added to (C) and mixed, followed by addition of ethanol and diisopropyl adipate to give (E). Diisopropanolamine dissolved in 100 g of water and the remaining water are added to (E) and homogeneously mixed. Method of Preparation Carbopol® 940 and hydroxyethyl cellulose are swollen with 300 g of water to give (A). Calcium mefenamate is dissolved in diethylene glycol monoethyl ether to give (B). N-Methyl-2-pyrrolidone is dissolved in ethanol to give (C). Diisopropanolamine is dissolved in 100 g of water to give (D). (A) is added to (B) and mixed to homogeneity. (C) and (D) are added to the mixture and then the remaining water is added and mixed to homogeneity. Method of Preparation Sucrose palmitate is dissolved in 200 g of hot water to give (A). Hiviswako 104 is swollen with 200 g of water to give (B). (A) is added to (B) followed by thorough mixing to give(C). Ketoprofen Ca is dissolved in polyethylene glycol 400 to give (D). (D) is added to (C) and sufficiently mixed, to which ethanol and diisopropyl adipate are added and mixed to give(E). Diisopropanolamine is dissolved in 100 g of water, to which (E) and the remaining water are added and stirred well. EXAMPLE 6 Plasma Concentrations of Anti-inflammatory Drugs After Percutaneous Application Male Wistar rats weighing 250 - 300 g were divided at random into three groups, each containing 5 rats. On the day before the experiment, the hair of the abdominal area of rats was carefully removed with an electric clipper and an electric razor to prevent damage to the stratum corneum. 0.5 g of the gel ointment described in Example 1 was uniformly spread over the shaved abdominal skin (3 × 1.2 cm area) and immediately occluded with a sheet of aluminium foil and adhesive tape. The ointment remained in contact with the skin for 8 hours, and then the unabsorbed ointment was wiped off with adsorbent cotton soaked in warm water. Blood samples were collected periodically for 48 hours after dosing through polyethylene tubing cannulated to the rat jugular vein, and indomethacin in plasma was determined by gas chromatography. The control gel ointment (Rp. 1) (Hiviswako 104® 10g, indomethacin 20 g, propylene glycol 120 g, ethanol 300 g, diisopropanolamine 11 g, diisopropyl adipate 20 g and purified water q.s. to 1000 g) as a standard preparation and the comparable ointment (Rp. 2) (the preparation excluded Azone® and sorbitan monooleate from Example 1) were applied in the same way. The results of the examination are shown in FIG. 1. The precutaneous preparation (Example 1) in the present invention gave much higher plasma levels of indomethacin over a 48-hour period than those of the control (Rp. 1) and comparable (Rp. 2) ointments. EXAMPLE 7 The Area Under The Plasma Drug Concentration-time Curve (AUC) After Percutaneous Application of Gel Ointments The drug concentrations in plasma after percutaneous application of the calcium salts of various drugs (2%, w/w equivalent) in the form of gel ointment as described in Example 1 were measured by the procedure shown in Example 6, and compared with that of indomethacin ointment (standard preparation, Rp. 1). In Table 1, the results obtained are shown. These calcium salts of anti-inflammatory drugs in ointment were absorbed much more than indomethacin (Rp. 1). Therefore, the AUC's after topical application of these ointments were significantly greater than that after indomethacin ointment (Rp. 1). EXAMPLE 8 Plasma Concentration of Indomethacin during Multiple Percutaneous Dosing of Ointment to Rats The hair of the abdominal area of male Wistar rats weighing 250 - 300 g was removed by the same manner as described in Example 6. 0.14 g of each of the ointments described in Example 1 and indomethacin ointment (indomethacin 2.0 g was used instead of the calcium salt of the drug in the gel ointment of Example 1) were uniformly spread over the shaved abdominal skin (1.0 x 1.0 cm area) and immediately occluded with a sheet of aluminum foil and adhesive tape. The rats were fixed in Bollman cages for 24 hours. The ointment remained in contact with the skin for 24 hours, and then the unabsorbed ointment was wiped off. Subsequently, the second and third applications of ointment (0.14 g, 1.0 × 1.0 cm area) were done on different position of the abdomen similar to the first application. The drug concentrations were determined by the same procedure as described in Example 6. FIG. 2 depicts the plasma indomethacin concentrations after the topical application of these ointments. The results demonstrated that calcium salt of indomethacin was readily and quickly absorbed through the skin compared with indomethacin, and that much higher plasma levels were obtained after the gel ointment of the calcium salt of the drug. EXAMPLE 9 The Anti-inflammatory Effect of Drug Ointment on the Carrageenan-induced Edema in the HindPaw of Rats Experimental carrageenan edema was induced in groups of six male Wistar rats weighing 150 - 160 g. The gel ointments (0.14 g ) of the calcium salt of indomethacin (Example 1) and indomethacin (described in Example 8) were separately applied to the shaved abdominal skin. The gel without the drug was similarly applied to the control group. The treated area was immediately covered by the aluminum foil and adhesive tape. Six hours later, 1% carrageenan solution was injected subcutaneously into the sole of right hind paw. The volumes of both hind paws were measured hourly using a plethysmometer and the edema volume was calculated from the difference between the injected and non-injected paws. FIG. 3 indicates the effect on the carrageenan-induced paw edema of these ointment applied topically. The calcium salt of indomethacin in ointment produced significantly inhibitory effect. EXAMPLE 10 The Anti-inflammatory Effect of Drug Ointment on Adjuvant Arthritis Induced with M. butyricum M. butyricum (Dfico Lab., USA) suspended in paraffin oil was injected into the sole of the right hind paw of male Wistar rats weighing 150 - 160 g. Rats with established adjuvant arthritis were taken 11 days after the injection of adjuvant (6 rats in each group) and the gel ointments (0.14 g ) of the calcium salt of indomethacin (Example 1) and indomethacin (described in Example 8) were separately applied to the shaved abdominal skin (1 × 1 cm area) for 24 hours, every other day from day 11 to day 15 after the injection of adjuvant and the edema volumes were calculated by measuring the volumes of both hind paws on day 16, according to the same procedure as described in Example 9. The calcium salt of indomethacin in ointment produced a significant inhibitory effect, to the same extent as the indomethacin ointment, on the adjuvant arthritis as shown in Table 2. EXAMPLE 11 The Primary Skin Irritation of Gel Ointment The primary skin irritation was measured after a 24-hours application of gel ointments (1 g each) of the calcium salt of indomethacin from Example 1 and indomethacin described in Example 8 on the shaved back skin (2.5 × 2.5 cm area) of male rabbits weighing 1.8 - 2.2 kg under the occulusion. The evaluation of skin reactions was done by the erythema and edema scores 24 and 72 hours after application. The results are shown in Table 3. These ointments produced only slight erythema, the total erythema scores being 1.5 and 2.1, indicating that the irritation of these ointments was almost negligible. The present invention provides percutaneous formulations containing the calcium salt of anti-inflammatory drug as effective components. By the application of the percutaneous formulations, therapeutic concentrations of the drug are maintained over prolonged time, and thus make it possible to decrease the frequency of administration and side effects such as gastro-intestinal troubles. It is possible from the present invention that the systematic effect of the anti-inflammatory drug is exerted by the percutaneous application. Additionally the preparation can also be used for topical therapy so that these formulations are very useful phamacologically.

Claims: A percutaneous absorption preparation which comprises the calcium salt of an acicic non steroidal anti-inflammatory or analgesic drug having a carboxyl group as the active ingredient and present in an amount of 0.3 - 10% by weight; a medium for the active ingredient which is selected from an ethylene glycol mono-lower alkyl ether, propylene glycol, polyethylene glycol and dimethylsulfoxide, the medium being present in an amount at least sufficient to dissolve the active ingredient; a penetration enhancer selected from 1-dodecyl-azacycloheptan-2-one, hexamethylenelauramide, N-methyl-2-pyrrolidone, a sucrose aliphatic acid ester, dimethylsulfoxide and a nonionic surfactant and present in an amount of 0.5 - 10% by weight. A preparation of claim 1 which is in the form of gel ointment or gel cream, and further contains a gelatinizing agent in an amount sufficient to make a gel, an adjuvant for absorption and optionally a neutralizing agent. A preparation of claim 2 in which the gelatinizing agent is a carboxyvinyl polymer, a cellulose derivative or propylene glycol alginate. A preparation of claim 2 in which the gelatinizing agent is a carboxyvinyl polymer and is present in an amount of 0.5 - 5% by weight in the final preparation. A preparation of claim 2 in which the adjuvant for absorption is diisopropyl adipate, diethyl sebacate or ethyl caproate and is present in an amount of 0.5 - 5% by weight in the final preparation. A preparation of claim 2 in which the neutralizing agent is added when the gel ointment or cream is acidic. A preparation of claim 1 in which the penetration enhancer is 1-dodecylazacycloheptan-2-one or hexamethylenelauramide. A preparation of `claim 1 which is in the form of solution, and contains ethanol as a carrier. A preparation of claim 1 which is in the form of an aerosol. A preparation of claim 1 in which the active ingredient is the calcium salt of indomethacin, diclofenac, bendazac, mefenamatic acid, ketoprofen or alclofenac. A preparation of claim 1 in which the active ingredient is present in an amount of 0.5 - 2% by weight.

Inventors: OGISO, TARO
Applicants: MARUHO CO., LTD., OGISO, TARO
Application year: 1987
Main classification: A61K47
IPC codes: A61K31, A61K45, A61K47, A61K9, A61P29, A61P25