DRUGS INHIBITING PROGRESS OF PTERYGIUM AND POSTOPERATIVE RECURRENCE OF THE SAME

Abstract: Drugs inhibiting progress of pterygium and postoperative recurrence of the same. N-(3,4-Dimethoxycinnamoyl)anthranilic acid represented by formula (I) or its pharmacologically acceptable salt has the effect of inhibiting the multiplication of pterygium tissues and medicinal compositions containing the same as the active ingredient are useful as drugs inhibiting progress of pterygium and postoperative recurrence of the same.

Description: Technical Field The present invention relates to the manufacture of a pharmaceutical composition for inhibiting progress of pterygium and postoperative recurrence of the same, which comprises as the active ingredient N-(3,4-dimethoxycinnamoyl)anthranilic acid (generic name: tranilast) represented by the formula: or a pharmaceutically acceptable salt thereof. Background Art Pterygium is an ocular disease which is characterized by the encroachment of a fleshly and congestively triangular portion of the bulbar conjunctiva onto the cornea and caused by external stimuli such as ultraviolet light, dry atmosphere, heat, cold and dust. Especially, pterygium has been largely observed on the cornea at the nasal side along the palpebral fissure. Pterygium progresses gradually toward the top of the cornea from the conjunctiva and reaches the pupillary area causing visual loss. However, at the present time, there is no therapeutic agent which inhibits and is surely effective against progress of pterygium. Therefore, development of an effective therapeutic agent has been desired. Accordingly, in the field of . pterygium treatment, only surgical operations such as erasion of pterygium tissues have been performed. In pterygium surgery, high incidence of recurrence of pterygium, about 30-50 %, has been pointed out as a serious problem. Therefore, in the field of pterygium medication, earnest study has been actively promoted in order to find substances inhibiting recurrence of pterygium. Up to this time, for example, it has been confirmed that anti-tumor agents such as mitomycin are effective. However, these drugs have caused concern about serious side effects such as scleromalacia [Connective Tissue, Vol.26, pp135-137 (1994) etc.] and are not sufficient to use clinically. In addition, it has been reported that beta-ray radiation using strontium 90 is effective in inhibiting postoperative recurrence of pterygium. However, injuries such as cataract have been pointed out [Ganka, Vol.24, pp917-923 (1982) etc.]. On the other hand, tranilast has been widely used as a drug for the treatment of allergic disorders such as bronchial asthma, allergic rhinitis, atopic dermatitis and allergic conjunctivitis, and cutaneous disorders such as keloid and hypertrophic scar. For example, it is known that tranilast has inhibitory activities on chemical mediator release caused by an allergic reaction, excessive collagen accumulation by fibroblast cells in cutaneous tissues and excessive proliferation of smooth muscle cells in coronary artery vessels. EP-A-0 391 002 describes pharmaceutical compositions such as eye drops containing tranilast for the treatment of allergic conjunctivitis or allergic rhinitis, and Miyazawa, K., et al in the journal "Atherosclerosis", NL, Amsterdam, Vol.118, No. 2, 1st December 1995 (1995-12-01), pages 213-221 describe the inhibition of PDGF- and TGF-β1-induced proliferation of vascular smooth muscle cells by tranilast. However, it has been in no way disclosed that tranilast has an inhibitory activity on the progress of pterygium and post operative recurrence of the same and it is not known at all that tranilast is useful as an agent inhibiting progress of pterygium and postoperative recurrence of the same. Disclosure of Invention The present invention relates to the manufacture of a pharmaceutical composition for inhibiting progress of pterygium and postoperative recurrence of the same, which comprises as the active ingredient N-(3,4-dimethoxy-cinnamoyl) anthranilic acid represented by the formula: of a pharmaceutically acceptable salt thereof. The present inventors have earnestly studied to find compounds having an inhibitory activity on proliferation of pterygium tissues. As a result, it was found that tranilast has a marked inhibitory effect on proliferation of pterygium tissues and is extremely useful as an agent inhibiting progress of pterygium and postoperative recurrence of the same, thereby forming the basis of the present invention. Accordingly, the present inventors confirmed that tranilast significantly suppressed proliferation of pterygium tissues in the in vitro test for inhibition of cell proliferation using rat pterygium tissue-derived cells. As a consequence, tranilast has an excellent inhibitory effect on proliferation of pterygium tissue-derived cells and is an extremely useful compound as an agent inhibiting progress of pterygium and postoperative recurrence of the same. Therefore, pharmaceutical compositions which are useful as agents inhibiting progress of pterygium and postoperative recurrence of the same can be prepared by including as the active ingredient tranilast or a pharmaceutically acceptable salt thereof. Various methods for the preparation of tranilast and salts thereof which are active ingredients are known, and these compounds can be readily prepared according to methods described in the literature and the like (Japanese Patent Application Publication ( kokoku ) No.Sho.56-40710; ibid. No.Sho.57-36905; ibid. No.Sho. 58-17186; ibid. No.Sho.58-48545; ibid. No.Sho.58-55138; ibid. No.Sho.58-55139; ibid. No.Hei.01-28013; ibid. No.Hei.01-50219; ibid. No.Hei.03-37539 etc.). As examples of pharmaceutically acceptable salts of tranilast, salts with inorganic bases such as a sodium salt and' a potassium salt, salts formed with organic amines such as morpholine, piperazine, piperidine and pyrrolidine and salts formed with amino acids can be illustrated. When the pharmaceutical compositions prepared according to the present invention are employed in practical treatment, they may be administered orally, preferably, topically as eyedrops, eye ointments and the like. For example, eyedrops can be formulated by dissolving tranilast or a pharmaceutically acceptable salt thereof together with a basic substance with heating in an appropriate quantity of sterilized water in which a surface active agent is dissolved, adding polyvinylpyrrolidone, and optionally adding appropriate pharmaceutical additives such as a preservative, a stabilizing agent, a buffer, an isotonicity, an antioxidant and a viscosity improver to dissolve completely. Eye ointments can be appropriately formulated by using bases which are generally used in eye ointments. Eye ointments can be also used as reversible thermally gelling water-base pharmaceutical compositions. When the pharmaceutical composition prepared according to the present invention are employed in practical treatment, the dosage of tranilast or a pharmaceutically acceptable salt thereof as the active ingredient is appropriately decided depending on the age, degree of symptoms of each patient to be treated, therapeutic value and the like. The dosage should be fixed at an appropriate concentration for a cure. For example, in the case of eyedrops, preferably 0.001-2 weight % eyedrops are instillated 1 to several times per day and applied 1 to several droplets per time. Brief Description of Drawings Figure 1 is a graph illustrating inhibitory activity on proliferation of human pterygium tissue-derived cells by tranilast. The axis of the ordinates shows number of human pterygium tissue-derived cells (x 10 4 cells), and the axis of the abscissas shows tranilast concentrations (µg/ml). The symbol * in the graph shows the significant difference at p<0.01. Best Mode for Carrying Out the Invention The present invention is further illustrated in more detail by way of the following Example. Example Inhibitory activity on proliferation of pterygium tissue-derived cells 1 ○ Culture of pterygium tissue-derived cells Human pterygium tissues were cut into narrow strips. The strips were adhered to a culture plate and subcultured in Dulbecco's modified Eagles Medium (DMEM) containing 10 % fetal calf serum (FBS) at 37 °C in an atmosphere of 5 % CO 2 in air. At the point that cells were migrated and proliferated from the tissues, the medium was aspirated and cells were washed with phosphate-buffered saline (PBS(-)) gently. Then, the PBS(-) was aspirated, an aliquot of 0.25% trypsin solution containing 0.02 % EDTA was added to the culture plate, and the morphology of cells was observed under phase-contrast microscopy. When cells were going to be round, an equal value of DMEM containing 10 % FBS was added to the trypsin solution to stop the action of trypsin. Attached cells were harvested from the plate by pipetting the medium using a slender pasteur pipette. The cell suspension was transferred into a spit, then medium was added to the spit, and the cell suspension was mixed about 20 times vigorously by pipetting with a pasteur pipette and centrifuged at 100-110xg for 1 minute. After the supernatant was discarded, fresh medium was added to the precipitate, and pterygium-derived cell suspension was prepared by pipetting using a pasteur pipette. The suspension was further subcultured in DMEM containing 10 % FBS to use for experiment. 2 ○ Preparation of test drugs Tranilast was added to 1 % aqueous sodium bicarbonate solution at a final concentration of 1.0 % and dissolved by warming at 70 °C. The solution was sterilized with a millipore filter and diluted with DMEM containing 10 % FBS to a final prescribed concentration. 3 ○ Experimental method DMEM medium (2 ml) containing cells (2 x 10 4 cells) and 10 % FBS was added to each well using a culture plate (6-well), and cultured. After 1 day, the medium was aspirated, DMEM medium (2 ml) containing various concentrations of tranilast and 10% FBS was added to the plate, and cultured at 37 °C in an atmosphere of 5 % CO 2 in air. After 2 days, the medium was aspirated, the cells were washed with PBS (-), and 1 ml of 0.25 % trypsin solution containing 0.02 % EDTA was added to the plate. After harvesting cells from the plate by pipetting using a pasteur pipette, the number of viable cells was counted under phase-contrast microscopy using a hemocytometer. 4 ○ Assessment of effect The mean and standard error value of each group were calculated. Statistical analysis of significance was performed by a one-way analysis of variance and statistical significance was confirmed. Thereafter, analysis of significance between groups was performed by Dunnett's multiple test. 5 ○ Results As shown in Figure 1, tranilast significantly suppressed the proliferation of pterygium tissue-derived cells in a concentration-dependent manner. Industrial Applicability A pharmaceutical composition prepared according to the present invention comprising as the active ingredient tranilast has a marked inhibitory activity on proliferation of pterygium tissues and is suitable as an agent inhibiting progress of pterygium and postoperative recurrence of the same.

Claims: The use of N-(3,4-dimethoxycinnamoyl)anthranilic acid represented by the formula: or a pharmaceutically acceptable salt thereof for the manufacture of a pharmaceutical composition for the prevention or treatment of pterygium or postoperative recurrence of the same.

Inventors: AJISAWA YUKIYOSHI, ISAJI MASAYUKI, MIYATA HIROSHI, AJISAWA, YUKIYOSHI, ISAJI, MASAYUKI, MIYATA, HIROSHI
Applicants: KISSEI PHARMACEUTICAL, KISSEI PHARMACEUTICAL CO., LTD.
Application year: 1998
Main classification: A61K31
IPC codes: A61K31