Pharmaceutical compositions containing N-(3,4-dimethoxycinnamoyl) anthranilic acid

Abstract: This invention provides a pharmaceutical composition for the treatment of allergic conjunctivitis or allergic rhinitis. The composition is an aqueous solution containing N-(3,4-dimethoxycinnamoyl)anthranilic acid or a pharmaceutically acceptable salt thereof as an active ingredient. The composition additionally contains as essential components polyvinylpyrrolidone, a basic compound and a surface active agent and the composition has a pH of about 6.5-8.5.

Description: This invention relates to pharmaceutical compositions containing N-(3,4-dimethoxycinnamoyl)anthranilic acid (hereinafter referred to as TRANILAST) or a pharmaceutical acceptable salt thereof. More particularly, this invention provides pharmaceutical compositions, such as eye drops and nasal drops for treatment of allergic diseases such as allergic conjunctivitis and allergic rhinitis, containing TRANILAST represented by the formula: or a pharmaceutically acceptable salt thereof; (ii) polyvinylpyrrolidone; (iii) sodium borate or tribasic sodium phosphate; and (iv) a surface active agent; and has a pH in the range of 6.5-8.5, the composition containing 4-8 weight units of polyvinylpyrrolidone per weight unit of the N-(3,4-dimethoxycinnamoyl)anthranilic acid component. It is well known that TRANILAST exhibits anti-allergic action (JP-A-1096724; US-A-32,944; US-A-4,070,484), and thus, TRANILAST is used as a therapeutical agent for the treatment of allergic diseases such as bronchial asthma, atopic dermatitis and the like. However, TRANILAST is so insoluble in water that only pharmaceutical compositions for oral administration have been employed in the treatment of allergic diseases, and any pharmaceutical compositions other than those for oral administration have not been developed as yet. Recently, a rising number of patients suffering from allergic conjunctivitis and allergic rhinitis have increased the need for pharmaceutical compositions in a form for topical application, such as eye drops and nasal drops containing TRANILAST. Accordingly, this invention seeks to provide pharmaceutical compositions such as eye drops, nasal drops and the like, containing TRANILAST for the treatment of allergic conjunctivitis and rhinitis. Other features and advantages of this invention will be apparent from the following description of the invention. TRANILAST and pharmaceutically acceptable salts thereof are too insoluble in water to prepare an aqueous solution. Until recently any pharmaceutical compositions in an aqueous form have not existed for the treatment of allergic diseases such as allergic conjunctivitis and allergic rhinitis. Our unpublished Japanese Patent Application Number Sho 63-122698 filed on 19th May 1988 describes a pharmaceutical composition in an aqueous form containing dissolved TRANILAST in a therapeutic amount which is prepared by employing polyvinylpyrrolidone as a solubilizing aid, in more than 4 times the amount by weight of TRANILAST or a pharmaceutically acceptable salt thereof, in the presence of a basic compound. However, these aqueous compositions have certain disadvantages. Thus, when a quaternary ammonium salt such as benzalkonium chloride or benzethonium chloride is used as a preservative, a precipitate of insoluble materials occurs in these compositions. Furthermore, if sodium chloride is added to these aqueous compositions to make them isotonic, a precipitate of insoluble materials is evident. In Japanese patent application Sho 63-122698, it is stated that this precipitation of insoluble materials from aqueous compositions can be reduced by using a surface active agent. However, it has since been found that the precipitation of insoluble materials from the compositions can not be accomplished completely and reliably solely by utilizing a surface active agent. Thus, there remains a need for aqueous pharmaceutical compositions for topical application, which are stable in the presence of additives used in making aqueous pharmaceutical compositions adapted for eye drop or nasal drop formulations. In accordance with the present invention, it has been found that an aqueous solution can be prepared by dissolving TRANILAST in water together with selected quantities by weight of (1) polyvinylpyrrolidone, (2) sodium borate or tribasic sodium phosphate, and (3) a surface active agent, and adjusting the pH of the solution in the range between 6.5-8.5 by the use of an appropriate reagent such as a buffer. The aqueous solution of the invention is stable when blended with additives which are used in preparing eye drop and nasal drop solutions, and therefore can be formulated into pharmaceutical compositions such as eye drops and nasal drops for topical application. In accordance with the present invention an aqueous pharmaceutical composition for topical application can be prepared by admixing TRANILAST, a basic compound and a surface active agent with sterilized water; heating the mixture at a temperature of 60°-80°C to form a homogeneous solution; dissolving polyvinylpyrrolidone and a buffer in the solution with heating; optionally adding a preservative and a stabilizing agent to the solution; and diluting the solution with sterilized water to provide a pharmaceutical composition containing TRANILAST at a desired concentration level, e.g., 0.1-2 weight percent, based on the composition volume. In the preparation of pharmaceutical compositions of this invention, polyvinylpyrrolidone is employed in a quantity between 4-8 weight units per unit of TRANILAST or pharmaceutically acceptable salt thereof. Polyvinylpyrrolidone is a polymer having an average molecular weight in the range of 25,000-40,000. A preferred polyvinylpyrrolidone is one having an average molecular weight of about 25,000. The basic component is employed in a quantity between 0.7-3 weight units per unit of TRANILAST. As required, the pH of the aqueous compositions of the invention is adjusted to 6.5 to 8.5 with a buffering reagent such as those based on acetic acid, phosphoric acid, boric acid, tartaric acid, citric acid and the basic salts thereof. A boric acid based buffering reagent is a preferred type. Of the different types of surface active components, non-ionic surface active agents are preferred for use in the invention. Examples of preferred non-ionic surface active agents which may be used in the aqueous compositions of the invention are those having a HLB value of 10-16, such as polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monopalmitate and polyoxyethylene sorbitan monolaurate; and amphoteric surface active agents such as lauryldimethylaminoacetic acid betaine, lauryldimethylamine oxide and laurycarboxymethylhydroxyethylimidazolinium betaine. Polyoxyethylene sorbitan monooleate (Polysorbate 80, Hart Products; Tween® 80, ICI America) is particularly preferred. "HLB" used above stands for the hydrophile-lipophile-balance, that is, the balance of the hydrophilic property and the lipophilic property of a surface active agent. In the preparation of pharmaceutical compositions of the invention, e.g., an eye drop formulation, the quantity of surface active component is minimized to reduce or prevent any irritation effect during usage. The concentration of surface active component in aqueous pharmaceutical compositions of the invention may be preferably in the range of 0.025-0.075 weight percent, based on the composition volume, for non-ionic surface active agents, and preferably in a range of 0.075-0.1 weight percent for amphoteric surface active agents. The aqueous pharmaceutical compositions of the invention if desired contain other constituents such as osmotic pressure adjusting agents, stabilizing agents, preservatives, antioxidants, and viscosity control agents. The aqueous pharmaceutical compositions of this invention are useful in the treatment of allergic conjunctivitis or allergic rhinitis. The compositions can be formed into stable formulations for eye drop or nasal drop applications, and can be used with safety and comfort without any irritant effects. The following examples are further illustrative of the present invention. The components and specific ingredients are presented as being typical. Example I Eye Drop Formulation Containing 0.25% TRANILAST TRANILAST 0.25% Boric acid 1.5% Sodium borate 0.6% Polyvinylpyrrolidone(K-25) 1.5% Polysorbate 80 0.05% Benzalkonium chloride 0.005% Sodium edetate 0.01% Water 100 ml volume NB. Sodium edetate is disodium (ethylenedinitrilo) tetraacetate dihydrate A mixture of 0.25 g of TRANILAST, 0.18 g of sodium borate and 0.05 g of polysorbate 80 was added to about 50 ml of sterilized water, and was heated at 60°-80°C to form a clear solution. This was followed by the successive addition of 1.5 g of polyvinylpyrrolidone (K-25), 1.5 g of boric acid, 0.42 g of sodium borate, 0.005 g of benzalkonium chloride and 0.01 g of sodium edetate, and then sterilized water was added to a total volume of 100 ml. The aqueous solution contained 0.25% of TRANILAST, and had a pH of 7.4 and an osmotic pressure ratio of about 1.0. Example II Eye Drop Formulation Containing 0.5% TRANILAST TRANILAST 0.5% Boric acid 1.3% Sodium borate 0.75% Polyvinylpyrrolidone(K-25) 3% Polysorbate 80 0.05% Benzalkonium chloride 0.005% Sodium edetate 0.01% Water 100 ml volume A mixture of 0.5 g of TRANILAST, 0.35 g of sodium borate and 0.05 g of polysorbate 80 was added to about 50 ml of sterilized water and was heated at 60°-80°C to form a clear solution. This was followed by the successive addition of 3.0 g of polyvinylpyrrolidone (K-25), 1.3 g of boric acid, 0.4 g of sodium borate, 0.005 g benzalkonium chloride and 0.01 g of sodium edetate, and then sterilized water was added to a total volume of 100 ml. The aqueous solution contained 0.5% of TRANILAST, and had a pH of 7.4 and an osmotic pressure ratio of about 1.0. Example III Eye Drop Formulation Containing 1% TRANILAST TRANILAST 1% Boric acid 0.9% Sodium borate 0.9% Polyvinylpyrrolidone(K-25) 6% Polysorbate 80 0.05% Benzalkonium chloride 0.005% Sodium edetate 0.01% Water 100 ml volume Following the formulation procedures previously described, an eye drop solution was prepared which contained 1% of TRANILAST, and had a pH of 7.4 and about a 1.0 osmotic pressure ratio relative to a 0.9 w/v % sodium chloride aqueous solution having about 290 milliosmoles. The osmotic pressure for the above Examples was measured in accordance with the freezing-point depression method described on pages 1595-1597 of the "Supplement to the Pharmacopoeia of Japan", Eleventh Edition, 1988. An osmometer was calibrated by a two-point calibration method using two different standard solutions of 100 milliosmoles and 500 milliosmoles. The osmotic pressures of a test sample and a 0.9 w/v % sodium chloride aqueous solution were measured: where O T is the osmotic pressure of the test sample, and O S is the osmotic pressure of the sodium chloride aqueous solution.

Claims: A pharmaceutical composition characterised in that it is an aqueous solution for nasal or eye administration containing (i) N-(3,4-dimethoxycinnamoyl)anthranilic acid or a pharmaceutically acceptable salt thereof; (ii) polyvinylpyrrolidone; (iii) sodium borate or tribasic sodium phosphate; and (iv) a surface active agent; and has a pH in the range of 6.5-8.5, the composition containing 4-8 weight units of polyvinylpyrrolidone per weight unit of the N-(3,4-dimethoxycinnamoyl)anthranilic acid component. A pharmaceutical composition as claimed in claim 1 which includes a buffer to adjust the pH to 6.5-8.5. A pharmaceutical composition as claimed in claim 2 characterised in that the buffer is a boric acid based buffer. A pharmaceutical composition as claimed in any one of claims 1 to 3 characterised in that it comprises 0.1-2 weight percent, based on the composition volume, of N-(3,4-dimethoxycinnamoyl)anthranilic acid or a pharmaceutically acceptable salt thereof, 4-8 weight units of polyvinylpyrrolidone per weight unit of the N-(3,4-dimethoxycinnamoyl)anthranilic acid component, 0.7-3 weight units of sodium borate or tribasic sodium phosphate per weight unit of N-(3,4-dimethoxycinnamoyl)anthranilic acid component and 0.025-0.1 weight percent, based on the composition volume, of the surface active agent. A pharmaceutical composition as claimed in any one of claims 1 to 4 characterised in that the surface active agent comprises 0.025-0.075 weight percent of polyoxyethylene sorbitan monooleate. A method of preparing an aqueous pharmaceutical composition as claimed in any one of claims 1 to 5 comprising (a) admixing N-(3,4-dimethoxycinnamoyl)anthranilic acid or a pharmaceutically acceptable salt thereof, sodium borate or tribasic sodium phosphate and a surface active agent with water; (b) heating the mixture at a temperature in the range 60 to 80°C to form a homogeneous solution; (c) dissolving polyvinylpyrrolidone and optionally a buffer in the solution with heating; (d) optionally adding a preservative and/or a stabilising agent to the solution; (e) if necessary, diluting the solution with water to produce the desired concentration of N-(3,4-dimethoxycinnamoyl)anthranilic acid. Use of N-(3,4-dimethoxycinnamoyl)anthranilic acid or a pharmaceutically acceptable salt thereof in the preparation of an aqueous solution as claimed in any of claim 1 to 5 for the topical treatment of allergic diseases.

Inventors: AJISAWA YUKIYOSHI, KINOSHITA YUKUHIKO, SHIBAZAKI TAIHEI, YAMAMOTO RYOJI, YAMAMOTO TOKIHIKO - AZA KANNOK, AJISAWA, YUKIYOSHI, KINOSHITA, YUKUHIKO, SHIBAZAKI, TAIHEI, YAMAMOTO, RYOJI, YAMAMOTO, TOKIHIKO 3-1062 AZA KANNOKURA
Applicants: KISSEI PHARMACEUTICAL, NITTEN OPHTHALMIC RESEARCH INS, KISSEI PHARMACEUTICAL CO., LTD., NITTEN OPHTHALMIC RESEARCH INSTITUTE COMPANY
Application year: 1989
Main classification: A61K31
IPC codes: A61K9, A61P37, A61P27, A61K47, A61K31