Pharmaceutical Compositions for Nasal Administration Comprising Calcitonin and an Absorption-Promoting Substance

1. Field of the Invention

The present invention relates to a intranasal pharmaceutical composition comprising calcitonin as an active ingredient and more particularly, to an excellent calcitonin intranasal composition containing a specific absorption enhancer.

2. Description of the Related Art

Calcitonin is a polypeptide hormone having various pharmaceutical activities which is used for treatment of osteoporosis, hypercalcemia, Paget's disease, etc.

Calcitonin is decomposed in the gastrointestinal tract by digestic juice, like ordinary pharmacologically active peptides so that oral administration of calcitonin is not available therapeutically. In addition, due to poor absorption, calcitonin is generally administered by injection. However, injections are extremely painful and this route of administration is not used.

Thus inconvenience and a cost problem is encountered.

Recently, it has been found that by application of calcitonins via intranasal route, effects similar to conventional intramuscular injection are exhibited and, various compositions of intranasal calcitonin composition have been proposed. However, a polypeptide having a large molecular weight such as calcitonin is absorbed intranasally only with difficulty. Therefore, as absorption enhancers, for example, surface active agents are generally incorporated (Published Unexamined Japanese Patent Application Nos. 89691/84 and 130820/84). In this case, both amphoteric and cationic surface active agents are employed; it is said, however, that nonionic type surface active agents, inter alia, polyoxyethylene lauryl ether, are particularly excellent in absorption acceleration properties. However, this polyether type surface active agent exhibits the undesirable property of destroying the nasal membrane. Thus, the surface active agent has a strong toxicity to tissue and is therefore undesirable for use as it is.

As a result of extensive investigations of dosage forms for intranasal administration capable of enhancing absorption of calcitonin and providing for practical use, the present inventors have found that excellent results can be achieved by incorporating a certain absorption enhancer into the calcitonin-containing intranasal medical composition. The present invention relates to a intranasal medical composition comprising (a) calcitonin and (b) at least one absorption enhancer selected from the group consisting of benzyl alcohol, ethanol, thiamine or a salt thereof, salicylic acid or a salt thereof, capric acid or a salt thereof, Macrogol 400, pyridoxal or a salt thereof, malic acid or a salt thereof and pyrophosphoric acid or a salt thereof, which are contained in a liquid dilution or a carrier suitable for applying to nasal membrane.

As calcitonins used in the present invention, various kinds of calcitonins such as salmon calcitonin, human calcitonin, elcatonin, porcine calcitonin, etc. can be used.

The substance that enhances absorption of calcitonins is selected from benzyl alcohol, ethanol, thiamine, salicylic acid, capric acid, Macrogol 400*, pyridoxal, malic acid and pyrophosphoric acid. Among these absorption enhancers, compounds capable of forming salts may be used in the form of the salts thereof. In the case of basic compounds such as pyridoxal, thiamine, etc., the hydrochloride, the nitrate, etc. are employed. In the case of acidic substances such as pyrophosphoric acid, salicylic acid, malic acid, capric acid, etc., the sodium salts, potassium salts, etc. are employed.

The absorption enhancers may be used singly or in combination of two or more other enhancers.

The pernasal composition of the present invention may be in the form of an aqueous solution, hydrogel or solid powders.

The aqueous solution is prepared by dissolving calcitonins and the absorption enhancers in water or a buffer solution in a conventional manner. In this case, additives are added to and dissolved in the aqueous solution, if necessary. It is preferred that pH of the aqueous solution is between 3 and 5 in view of stability.

As the buffer, citrates, tartarate, malates, etc. are employed, in a preferred pH range of 3 to 5.

As the additives, sterilizers, preservatives, tackifiers, surface active agents, stabilizers, etc. conventionally used for pernasal agents can be incorporated.

As the sterilizer and the preservative, conventional ones may be used and examples include p-oxybenzoates, propylene glycol, benzetonium chloride, sorbic acid (Na), etc.

As the tackifier, polyvinyl alcohol, polyvinyl pyrrolidone, dextran, etc. may be employed.

The surface active agent is added as a dispersing and emulsifying agent for various additives; nonionic surface active agents that have little irritation to the membrane are preferred. As these nonionic surface active agents, for example, polyoxyethylene monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene-hydrogenated castor oil, etc. are used.

As the stabilizer, mention may be made of gelatin or albumin.

As the mode of administration, there may be used a method for dropwise addition or spraying using a dropping container, a sprayer or a nasal aerosol applicator for intranasal administration.

In the case of a powdery form, mannitol, inositol, glucose, etc. are additionally added in a manner similar to the case of ordinary powders; after dissolving and then freeze-drying, the resulting solid is pulverized into fine powders, which are administered by a intranasal route. Such powders are administered in such a manner that they are packed in a capsule, the capsule is set in a spraying device and a needle is penetrated through the capsule to make pores at the top and the bottom of the capsule and air is sent via rubber balls, etc. to blow the powders out; etc. In case that volatile liquid components such as ethanol, benzyl alcohol, etc. are used as the absorption enhancers, the powdery form is not suitable.

In the case of an aqueous gel, calcitonin is formed into an aqueous gel using gel bases conventionally used, for example, natural gums, methyl celluloses, acrylic polymers, vinyl polymers or polysaccharides, etc.

The proportions of calcitonin as an active ingredients, the absorption enhancer and various additives to be used in the medical composition of the present invention are not particularly limited but appropriately determined depending upon dosage form of a solution, a gel or powders, etc. In case that the composition of calcitonins for pernasal drops is in the form of an aqueous solution, calcitonin is formulated in a concentration of generally from 200 to 6000 IU/ml, preferably 500 to 2000 IU/ml; the dose is preferably 0.05 to 0.2 ml/time and the number of administration is preferably 1 to 5 times daily. The amount of incorporated absorption enhancer varies but in the case of an aqueous solution, it is appropriate that the absorption enhancer be used in a range of 0.05 to 15% (w/v); a particularly preferred range is 1.0 to 10% (w/v) with respect to ethanol and 0.1 to 5% (w/v) with respect to the other absorption enhancers.

By the use of a specific absorption promoter in the calcitonin intranasal composition, efficiency of absorbing from the membrane of the nasal cavity is enhanced and it can be said that the calcitonin intranasal composition is excellent.

Hereafter the present invention will be described in more detail with reference to the examples but is not deemed to be limited thereto.

Salmon calcitonin and the absorption enhancer were dissolved in a solution of citric acid monohydrate and sodium citrate in a concentration twice that shown in the table, respectively. After pH was adjusted to 4.0 using a 1N aqueous hydrochloric acid solution or a 1N aqueous sodium hydroxide solution, water is added to make 1 ml. Both are mixed in equal volumes. The salicylic acid preparation was a suspension. The sodium caprate preparation was adjusted to a pH of 8.

Sprague Dawley strain male rats (115-145 g) fasted for 18 hours were anesthesized with pentobarbital (50 mg/kg, intraperitoneal injection). Aqueous calcitonin preparations a through m prepared in Preparation Example 1 were administered to the rats in a dose of 5 IU/kg.

Administration was performed by using a microsyringe (2 .mu.l) having a connected a polyethylene tube (PE 10, Clay Adams) therewith and injecting about 2 .mu.l at a distance of 5 to 6 mm from the nasal septum depending upon the body weight. Evaluation of absorption of the calcitonin preparation through the nasal membrane was performed by measuring the concentration of calcium in serum. The calcium concentration was quantitatively determined using a calcium meter (CA-30, Joko). The rats were sacrificed prior to administration and 1, 2 and 3 hours after administration,. Blood was collected from the descending large vein. The results are shown in Table 2. The data shown in Table 2 are mean values of 3 or more rats.

Calcium concentration in serum prior to administration: 10.67 mg%

From Table 2, it is noted that Ca concentration in serum is significantly reduced by the addition of a specific absorption enhancer as compared to the control.

In a manner similar to Preparation Example 1, calcitonin intranasal compositions shown in the following preparation examples were prepared. These calcitonin solutions provide reduction of the calcium concentration in serum as in Example 1.

A 1N aqueous sodium hydroxide solution was added to adjust pH to 4.0. Water was added to make the final volume 1 ml.

A 1N aqueous sodium hydroxide solution was added to adjust pH to 4.0. Water was added to make the final volume 1 ml.

Water was added to make the final volume 1 ml.

5N hydrochloric acid was added to adjust pH to 4.0. Water was added to make the final volume 10 ml.

5N Hydrochloric acid was added to adjust pH to 4.0. Water was added to make the final volume 10 ml.