Anesthetic oral compositions

Abstract: Disclosed are oral anesthetic pharmaceutical compositions compris­ ing: (a) from about 0.02% to about 25% of a pharmaceutically accept­ able acid salt of a β-aminopropiophenone, such as dyclonine HCl; (b) from about 0.02% to about 20% of saccharin; and (c) from about 1% to about 99% of a pharmaceutically acceptable oral carrier. Also provided are methods for providing an anesthetic effect in humans or animals which comprises orally administering to said human or animal a safe and effective amount of these pharmaceutical compositions. Also provided is a novel process for the manufacture of anesthetic lozenges contain­ ing a β-aminopropiophenone along with saccharin.

Description: The present invention relates to stable anesthetic oral pharmaceutical compositions containing β-aminopropiophenones. Sore throat, or pharyngitis, is the result of inflammation with pain of the throat (especially on swallowing), perceived dryness and congestion of the mucous membrane. Sore throat is a common complaint in the upper respiratory tract and can range from mild irritation to incapacitating pain. Oral sore throat preparations, such as lozenges, sprays and solutions containing topical anesthetic/analgesic agents have long been used for the symptomatic relief of sore throat. Dyclonine HCl, a member of a class of compounds known as β-aminopropiophenones and which is chemically denoted as 3-piperidino-4'-butoxypropiophenone hydrochloride, is a well known anesthetic/analgesic agent for topical use on the mucous membranes of the mouth and throat (see Federal Register, Vol. 47, No. 101, Proposed Rules, pages 22810-13, 1982). Oral pharmaceutical compositions of dyclonine HCl commercially available in the United States include an aqueous liquid spray containing 0.1% dyclonine HCl and solid lozenges containing 1.2 mg per lozenge for children and 3.0 mg per lozenge for adults (see Physicians' Desk Reference for Non-prescription Drugs, 8th Ed., 1987, pages 518-9). The benefit of dyclonine HCl is that it provides long-acting topical anesthetic relief. The use of certain acids, particularly citric acid, to stabilize dyclonine HCl in anesthetic lozenges is reported in US-A- 4,139,627 to Lane et al., issued February 13, 1979. In addition to its anesthetic/analgesic properties, dyclonine HCl is reported to possess antimicrobial activity. In this regard, US-A- 2,868,689 to Florestane et al., issued January 13, 1959 discloses stabilized aqueous preparations of dyclonine HCl (0.1-5%) having topical anesthetic and antimicrobial action, the stabilization aspect being provided by the addition of chlorobutanol (0.1-0.5%). US-A- 2,928,767 to Gulesich et al., issued March 15, 1960 teaches the stabilization of phenothiazines (compounds totally unrelated to β-aminopropiophenones), which are subject to light-catalyzed decomposition by use of saccharin or preferably, a saccharin salt. It has now surprisingly been found that saccharin is a very satisfactory stabilizer for β-aminopropiophenones, particularly dyclonine. It is therefore an object of the present invention to provide oral anesthetic pharmaceutical compositions comprising β-aminopropiophe- nones. It is a further object of the present invention to provide dyclonine-containing oral anesthetic pharmaceutical compositions which provide improved stability. It is still a further object of the present invention to provide a novel process for the manufacture of anesthetic lozenges. According to the present invention there is provided an oral anesthetic pharmaceutical composition comprising: (a) from 0.02% to 25% of a pharmaceutically acceptable acid salt of a β-aminopropiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; (b) from 0.02% to 20% of saccharin; and (c) from 1% to 99% of a pharmaceutically acceptable oral carrier. Also provided is a process for the manufacture of anesthetic lozenges comprising steps of: (a) heating a candy base suitable for said composition; and (b) adding from 0.02% to 20% saccharin either prior to or simultaneous with the addition of from 0.02% to 25% of a pharmaceutically acceptable acid salt of a propiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7. All percentages and ratios used herein are by weight and all measurements at 25°C unless otherwise indicated. More specifically, the present invention provides oral anesthetic pharmaceutical compositions comprising: (a) from 0.02% to 25% of a pharmaceutically acceptable acid salt of a β-aminopropiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; (b) from 0.02% to 20% of saccharin; and (c) from 1% to 99% of a pharmaceutically acceptable oral carrier. The oral anesthetics useful in the present invention are the β-aminopropiophenones of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; Preferred propiophenones include: 3-piperidino- p -n-butoxypropiophenone, 3-piperidino- p -n-octyloxypropiophenone, 3-piperidino- p -n-ethoxypropiophenone, 3-piperidino- p -n-amoxypropiophenone, 3-piperidino- p -isobutoxypropiophenone, 3-piperidino- p -sec.-butoxypropiophenone, 3-piperidino- p -n-propoxypropiophenone, 3-piperidino- p -isoamoxypropiophenone, 3-piperidino- p -isopropoxypropiophenone, 3-piperidino- p -n-heptyloxypropiophenone, and 3-piperidino- p -n-hexyloxypropiophenone, mixtures thereof, and salts thereof. Even more preferred propiophenones are selected from 3-piperidino- p -n-butoxypropiophenone and 3-piperidino- p - n-propoxypropiophenone, mixtures thereof, and salts thereof. The most preferred propiophenone is 3-piperidino- p -n-butoxy- propiophenone, and pharmaceutically acceptable salts thereof. The hydrochloride salt of these propiophenones is preferred since it is readily available; however, other pharmaceutically acceptable salts of these compounds, such as those formed with hydrobromic acid, fumaric acid, malic acid, tartaric acid, lactic acid, adipic acid, phosphoric acid, sulfuric acid, methane sulfonic acid, naphthalene disulphonic acid and acetic acid may also be utilized in a similar manner. Saccharin, chemically denoted as 2,3-dihydroxy-3-oxobenzoisosulfonazole, has the following structure: Saccharin is generally known as a non-nutritive sweetener ( see Merck Index, ninth edition; Handbook of Pharmaceutical Excipients, American Pharmaceutical Association and the Pharmaceutical Society of Great Britain, 1986). The saccharin component is present at a level of from 0.02% to 20.0 %, preferably from 0.03% to 10.0%, more preferably from 0.05% to 1.0% and most preferably from 0.1% to 0.5%. Combinations of dyclonine and other conventional oral anesthetics may optionally also be used in the compositions of the present invention. Oral anesthetic drugs suitable for use in combination with dyclonine include hexylresorcinol, aspin (RTM), menthol, phenol, benzyl alcohol, benzocaine, butamben, dibucaine, tetracaine, butacaine, phenolate sodium, salicyl alcohol, eucalyptol, methyl salicylate and thymol, and mixtures thereof. The most preferred optional oral anesthetic drug is phenol. The β-aminopropiophenone and optional oral anesthetic drug are combined in a ratio of propiophenone to oral anesthetic drug of from 1 to 150, preferably from 1 to 75, and most preferably from 1 to 15. Various oral dosage forms can be used, including such solid forms as tablets, capsules, granules, lozenges and bulk powders and liquid forms such as syrups, suspensions and solutions. The preferred solid oral dosage form is a lozenge or troche which can be dissolved slowly in the mouth thereby permitting the anesthetic to have a local or topical effect. Suitable methods for manufacturing such lozenges are described in US-A- 4,139,627 to Lane et al. issued February 13, 1979. These oral forms comprise a safe and effective amount, usually at least 0.05% of the active component. Techniques and compositions for making solid oral dosage forms are described in Marshall, "Solid Oral Dosage Forms," Modern Pharmaceutics , Vol. 7 , (Banker and Rhodes, editors), 359-427 (1979). Techniques and compositions for making tablets (compressed, formulas and molded) and pills are described in Remington's Pharmaceutical Sciences (Arthur Osol, editor), 1553-1593 (1980). Solid oral dosage forms preferably contain from 0.05% to 95%, more preferably from 0.01% to 95%, and most preferably from 25% to 95% of the active component. Liquid oral dosage forms include aqueous and nonaqueous solutions, emulsions, suspensions, solutions and/or suspensions reconstituted from non-effervescent granules, and can contain suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweetening agents, coloring agents, and flavoring agents. Preferred carriers for oral administration include propylene glycol. Specific examples of pharmaceutically acceptable carriers and excipients that may be used to formulate these oral dosage forms, are described in US-A- 3,903,297, Robert, issued September 2, 1975. Liquid oral dosage forms preferably contain from 1% to 50% and more preferably from about 1% to 25% and most preferably from about 3% to 10% of the active component. In preparing the liquid pharmaceutical compositions of the present invention, the oral anesthetic drug is incorporated into an aqueous-based orally acceptable pharmaceutical carrier consistent with conventional pharmaceutical practices. An "aqueous-based orally acceptable pharmaceutical carrier" is one wherein the entire or predominant solvent content is water. Typical carriers include simple aqueous solutions, syrups, dispersions and suspensions, and aqueous based emulsions such as the oil-in-water type. While the amount of water in the compositions of this invention can vary over quite a wide range depending upon the total weight and volume of the active ingredients and other optional non-active ingredients, the total water content, based on the weight of the final composition, will generally range from 20 to 95%, and, preferably, from 30 to 95%, by weight/volume, and more preferably from 50 to 95%. Although water itself may make up the entire carrier, typical formulations preferably contain a co-solvent, for example, propylene glycol, glycerin and sorbitol solution, to assist solubilization and incorporation of water-insoluble ingredient and flavoring oils into the composition. Such co-solvents are well known to those skilled in the art. In general, therefore, the compositions of this invention preferably contain from 5 to 25 volume/ volume percent and, most preferably, from 10 to 20 volume/ volume percent, of the co-solvent. Water-insoluble or poorly soluble components may also be incorporated into aqueous-based orally acceptable pharmaceutical carriers such as dispersions, suspensions and oil-in-water emulsions by means of suitable dispersing, suspending or emulsifying agents, respectively, which are readily apparent to those skilled in the art of pharmaceutical formulations. The compositions of this invention may also optionally contain one or more other known therapeutic agents, particularly those commonly utilized in cough/cold preparations, such as, for example, a decongestant such as pseudoephedrine hydrochloride, phenylpropanolamine HCl, phenylephrine hydrochloride and ephedrine hydrochloride; an analgesic such as acetaminophen, ibuprofen, naproxen and aspirin (RTM); an expectorant or mucolytic such as glyceryl guaiacolate, guaiacolate, terpin hydrate, ammonium chloride, N-acetylcysteine and ambroxol; and an antihistamine such as chlorpheniramine maleate, promethazine, doxylamine succinate, brompheniramine maleate and diphenhydramine hydrochloride: all of which are described in US-A- 4,619,934 to Sunshine et al., issued October 28, 1986. Also useful are bronchodilators such as theophylline and albuterol and oral antitussive drugs. As used herein, the term "oral antitussive drug" means a drug that is taken by mouth and acts systemically to relieve cough ( see Federal Register, Vol. 52, No. 155, 12 August 1987, page 30055). Useful recognized oral antitussive drugs include, but are not limited to, for example, the non-narcotic types such as dextromethorphan and its acid salts, preferably the hydrobromide, noscapine, chlophedianol hydrochloride, carbetapentane citrate, caramiphen edisylate, diphenhydramine and its hydrochloride salt and fominoben, and the narcotic types such as codeine and its sulfate or phosphate salts, noscapine hydrochloride, hydrocodone and its bitartrate salt, and hydromorphone hydrochloride. The usual adult dosages for such antitussives, which may also be utilized per dose in the subject compositions, are indicated in the following table: Preferred oral antitussive agents are dextromethorphan, codeine and diphenhydramine and pharmaceutically acceptable salts thereof and mixtures thereof. Even more preferred are dextromethorphan and codeine, pharmaceutically acceptable salts thereof and mixtures thereof. Most preferred is dextromethorphan and its pharmaceutically acceptable salts. Other optional ingredients well known to the pharmacist's art may also be included in amounts generally known for these ingredients: for example, natural or artificial sweeteners, flavoring agents and colorants to provide a palatable and pleasant looking final product; antioxidants, for example, butylated hydroxy anisole or butylated hydroxy toluene, and preservatives, for example, methyl or propyl paraben or sodium benzoate, to prolong and enhance shelf life. The present invention also includes a process for the manufacture of topical anesthetic lozenges. This process comprises the steps of: (a) heating a candy base suitable for said composition; and (b) adding from 0.02% to 20% saccharin either prior to or simultaneous with the addition of from 0.02% to 25% of a pharmaceutically acceptable acid salt of a propiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; Preferably the saccharin component is added prior to the propiophenone and comprises from 0.05% to 10%. Preferably, the β-aminopropiophenone component comprises from 0.05% to 5% of the composition. The compositions described herein are used in an art-recognized manner to provide anesthetic activity. EXAMPLE I A. Preparation of candy base. The ingredients were combined in a cooking pan and heated until the temperature reached 149°C. A portion of this molten mass was allowed to cool and solidify for use as salvage. B. Preparation of the lozenge composition with simultaneous addition of the stabilizer. The molten candy base was poured into a stainless steel beaker. The dyclonine hydrochloride and stabilizer (saccharin or citric acid) previously combined and triturated with the salvage candy base, were added to the molten candy base at the end of the heating period and the mixture was stirred. Just prior to solidification, the mixture was poured onto a cooling slab. The hardened lozenge composition was analyzed for dyclonine by HPLC. Recoveries of dyclonine for compositions containing no stabilizer and concentrations of saccharin or citric acid ranging from 0.10% to 0.30% by weight are shown in the table below. These data demonstrate that saccharin is not only an effective stabilizer of dyclonine, but is superior to citric acid when used in the same concentrations. EXAMPLE II A. Preparation of the lozenge composition with prior addition of stabilizer. The stabilizer was triturated with one-half the quantity of salvage candy base, and the dyclonine was triturated with the other half. The stabilizer-salvage mixture was added to the candy base at 145°C on the heating leg of the cycle. Heating was discontinued when the temperature of the mixture reached 149°C. The dyclonine hydrochloride-salvage mixture was then added to the molten candy base containing stabilizer. The mixture was stirred, and was poured onto a cooling slab just prior to solidification. Recoveries of dyclonine were determined by HPLC. The recovery values for compositions containing no previously added stabilizer and for compositions containing concentrations of saccharin or citric acid ranging from 0.10% to 0.40% by weight are given in the table below. These data demonstrate that saccharin is not only an effective stabilizer of dyclonine, but is superior to citric acid when used in the same concentrations. EXAMPLE III A lozenge is made as follows: Colorant is mixed with 396.4 mg of purified water. The sucrose and corn syrup are added to this mixture, which is then cooked to 149°C. Dyclonine hydrochloride and saccharin are mixed into the cooked candy base. When this mixture cools to 130°C, phenol is added as a 90% w/w solution and mixed in. Flavorant is mixed in immediately after. The resulting molten material is formed into a 2.3 g lozenge. Substantially similar results are obtained when the dyclonine HCl is replaced, in whole or in part, with 3-piperidino- p -n-butoxypropiophenone, 3-piperidino- p -n-octyloxypropiophenone, 3-piperidino- p -n-ethoxypropiophenone, 3-piperidino- p -n-amoxypropiophenone, 3-piperidino- p -isobutoxypropiophenone, 3-piperidino- p -sec.-butoxypropiophenone, 3-piperidino- p -n-propoxypropiophenone, 3-piperidino- p -isoamoxypropiophenone, 3-piperidino- p -isopropoxypropiophenone, 3-piperidino- p -n-heptyloxypropiophenone, and 3-piperidino- p -n-hexyloxypropiophenone, mixtures thereof, and salts thereof. EXAMPLE IV A stable liquid composition for oral administration is prepared by combining the following ingredients: 3.5 ml of this liquid is administered to a human in need of treatment, by, for example, spraying directly on the afflicted area, thereby providing anesthetic relief. EXAMPLE V A stable liquid composition for oral administration is prepared by combining the following ingredients 3.5 ml of this liquid is administered to a human in need of treatment, by, for example, spraying directly on the afflicted area, thereby providing anesthetic relief.

Claims: An oral anesthetic pharmaceutical composition comprising: (a) from 0.02% to 25% by weight of a pharmaceutically acceptable acid salt of a β-amino propiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; (b) from .02% to 20% by weight of saccharin; and (c) from 1% to 99% by weight of a pharmaceutically acceptable oral carrier. An oral anesthetic pharmaceutical composition according to Claim 1 which comprises from 0.05% to 10% by weight of saccharin and which comprises from 0.05% to 5.0% by weight of the propiophenone. An oral anesthetic composition according to Claim 2 wherein said propiophenone is selected from 3-piperidino- p -n-butoxypropiophenone, 3-piperidino- p -n-octyloxypropiophenone, 3-piperidino- p -n-ethoxypropiophenone, 3-piperidino- p -n-amoxypropiophenone, 3-piperidino- p -isobutoxypropiophenone, 3-piperidino- p -sec.-butoxypropiophenone, 3-piperidino- p -n-propoxy- propiophenone, 3-piperidino- p -isoamoxypropiophenone, 3-piperidino- p -isopropoxypropiophenone, 3-piperidino- p -n-heptyloxypropiophenone, and 3-piperidino- p -n-hexyloxypropiophenone, mixtures thereof, and salts thereof. An oral anesthetic composition according to Claim 3 which comprises from 0.05% to 1.0% by weight of saccharin and wherein the propiophenone is selected from 3-piperidino- p -n-butoxypropiophenone and 3-piperidino- p -n-propoxypropiophenone, mixtures thereof, and salts thereof. An oral anesthetic composition according to Claim 4 wherein the propiophenone is 3-piperidino- p -n-butoxypropiophenone, and pharmaceutically acceptable salts thereof. An oral anesthetic composition according to Claim 5 wherein the propiophenone is the hydrochloride salt of 3-piperidino- p -n-butoxypropiophenone. An oral anesthetic composition according to Claim 3 which further comprises from 0.2% to 20% by weight of an oral anesthetic drug selected from hexylresorcinol, acetyl salicylic acid, menthol, benzyl alcohol, phenol, benzocaine, butamben, dibucaine, tetracaine, butacaine, phenolate sodium, salicyl alcohol, eucalyptol, methyl salicylate and thymol and mixtures thereof. An oral anesthetic composition according to Claim 7 wherein said oral anesthetic drug is phenol. A process for the manufacture of a topical anesthetic lozenge composition comprising the steps of: (a) heating a candy base suitable for said composition; and (b) adding from 0.02% to 20% by weight saccharin either prior to or simultaneous with the addition of from 0.02% to 25% by weight of a pharmaceutically acceptable acid salt of a propiophenone of the formula: wherein R₁ is a C₂-C₈ alkyl, R₂ and R₃ are independently C₁-C₆ alkyl or R₁ and R₂ are (CH₂) n where n is an integer from 3 to 7; A process according to Claim 9 which comprises from 0.05% to 10% by weight of saccharin. A process according to Claim 10 which comprises from 0.05% to 5.0% by weight of the propiophenone. A process according to Claim 11 wherein said propiophenone is selected from 3-piperidino- p -n-butoxypropiophenone, 3-piperidino-p-n-octyloxypropiophenone, 3-piperidino- p -n-ethoxypropiophenone, 3-piperidino- p -n-amoxypropiophenone, 3-piperidino- p -isobutoxypropiophenone, 3-piperidino- p -sec.-butoxypropiophenone, 3-piperidino- p -n-propoxypropiophenone, 3-piperidino- p -isoamoxypropiophenone, 3-piperidino- p -isopropoxypropiophenone, 3-piperidino- p -n-heptyloxypropiophenone, and 3-piperidino- p - n-hexyloxypropiophenone, mixtures thereof, and salts thereof. A process according to Claim 12 wherein the propiophenone is selected from 3-piperidino- p -n-butoxy- propiophenone and 3-piperidino- p -n-propoxypropiophenone, mixtures thereof, and salts thereof. A process according to Claim 13 which comprises from 0.05% to 1.0% by weight of saccharin. A process according to Claim 14 wherein the propiophenone is 3-piperidino- p -n-butoxypropiophenone, and pharmaceutically acceptable salts thereof. A process according to Claim 15 wherein the propiophenone is the hydrochloride salt of 3-piperidino- p -n-butoxypropiophenone. A process according to Claim 12 which further comprises from 0.2% to 20% by weight of an oral anesthetic drug selected from hexylresorcinol, acetyl salicylic acid, menthol, benzyl alcohol, phenol, benzocaine, butamben, dibucaine, tetracaine, butacaine, phenolate sodium, salicyl alcohol, eucalyptol, methyl salicylate and thymol and mixtures thereof. A process according to Claim 17 wherein said oral anesthetic drug is phenol.

Inventors: KELLEHER WILLIAM JOSEPH, MCCLINTOCK WILLIAM JOHN, KELLEHER, WILLIAM JOSEPH, MCCLINTOCK, WILLIAM JOHN
Applicants: RICHARDSON VICKS INC, RICHARDSON-VICKS, INC.
Application year: 1990
Main classification: A61K31
IPC codes: A61K31, A61K47, A61P23, A61P25, A61K9