WO2005072690A1

WO2005072690A1 - Antimicrobial oral rinse solid composition

Info

Publication number: WO2005072690A1
Application number: PCT/CA2005/000104
Authority: WO
Inventors: Bernard Charles Sherman
Original assignee: Bernard Charles Sherman
Priority date: 2004-02-02
Filing date: 2005-01-28
Publication date: 2005-08-11
Also published as: NZ530915A

Abstract

Solid composition for treatment or prevention of microbial infection in the oral cavity comprising an anti-microbial agent, intended for use by adding to water to form a dispersion, rinsing or gargling with the dispersion and expectorating the dispersion. The anti-microbial agent may be an anti-bacterial agent and/or an anti-fungal agent, such as metronidazole or nystatin, respectively.

Description

TITLE OF INVENTION ANTIMICROBIAL ORAL RINSE SOLID COMPOSITION

FIELD OF THE INVENTION

This invention relates to an oral rinse or mouthwash composition, and method for treating or preventing microbial (bacterial and fungal) infections in the oral cavity, which cause conditions such as bad breath, also referred to as halitosis or oral malodour, and periodontal disease, including gingival inflammation or bleeding.

BACKGROUND OF THE INVENTION

Oral malodour is a condition that affects many people. Most individuals afflicted with oral malodour also experience psychosocial problems related to this condition. In addition to breath odour, individuals may have a foul taste, and they associate this taste with the presence of tainted breath, even when the mouth air has no detectable odour.

One of the common causes of this condition is the presence of anaerobic bacteria within the oral cavity. These bacteria degrade the sulfur-containing amino acids, methionine and cysteine found in foods, to generate pungent compounds collectively known as volatile sulfur compounds (VSC). Hydrogen sulfide (H-S-H), methyl mercaptan (CH₃-S-H) and dimethyl sulfide (CH₂-S-CH₃) are the principal odorous components generated. These compounds have an unpleasant odour, even in low concentrations, and the exhalation of these compounds is perceived as bad breath.

Oral microorganisms also contribute to the initiation and progression of periodontal diseases, which further contribute to oral malodour.

Various oral rinse preparations are known for treating oral malodour. US Patent 4,525,342 discloses a composition comprising an aqueous phase and an oily phase in a double compartment double squirt bottle that allows an emulsion to be generated in the mouth during rinsing. US Patent 5,401 ,496 discloses a preparation comprising a synthetic oil. US Patent 5,738,840 discloses an aqueous composition comprising molecular chlorine dioxide and a metal chlorite salt. US Patent 6,071,500 discloses a breath cleansing spray that includes xylitol as a sweetener and calcium hydroxide to raise the pH of the saliva. US Patent 6,132,701 discloses a method of reducing halitosis by rinsing the oral cavity with an aqueous solution of calcium hydroxide. In general, known anti-halitosis mouthwashes may not remove the foul taste that causes distress to the individual, suggesting that they leave microorganisms in numbers large enough to produce byproducts that continue to affect the taste perceptions of the individual.

Metronidazole has been used systemically for the treatment of anaerobic bacterial infections in the oral cavity. Short-term, systemic use of metronidazole administered orally in humans caused a sustained reduction of anaerobic gram-negative microorganisms, for weeks to months, with improved periodontal health (J. Clin Periodontol. 8:29-44, 1981 ). US Patent 4,997,830 discloses a pharmaceutical composition comprising metronidazole and amoxicillin for the treatment of periodontitis.

However, systemic use of metronidazole can have undesirable side effects such as nausea, headaches and gastrointestinal discomfort. US Patent 4,568,535 discloses a slow release film for placement in the oral cavity in a periodontal pocket, the film including metronidazole. However, such a film requires a dental professional to fit it and may be uncomfortable.

Fungal infections of the oral cavity also require treatment. Many individuals who complain about bad breath and bad taste have substantial numbers of yeast organisms, in addition to gram-negative anaerobic bacteria. Gingival bleeding is often also present in these individuals. The Candida species are aerobic yeasts that can also grow anaerobically. C. albicans is the species most often responsible for infections in the oral cavity and may cause a variety of disorders including gingival bleeding and denture stomatitis. Oral candidiasis is a virulent and uncomfortable condition, especially prevalent in the aged and those with chronic debilitating ailments.

The establishment of a mycotic infection in the oral cavity presents a serious health problem to the individual. Thus, it is desirable to treat and contain this infection through both mechanical methods such as proper oral cleansing and chemical therapy in the form of anti-fungal drugs. However, systemic administration of antimycotics, in doses high enough to control oral infections, is costly and can induce undesirable side effects.

Nystatin is commonly used for the treatment of fungal infections. Nystatin binds to the covering membrane of fungi, altering the cell membrane thus leading to cell death. It is both fungicidal and fungistatic against a variety of yeasts and fungi. Nystatin is applied topically, as it is not absorbed after oral administration.

Canadian Patent Application 2,008,772 discloses a sustained-release oral antifungal varnish that includes nystatin in a sustained-release polymer. US Patent 4,725,440 discloses an antifungal pastille formulation for treating oral candidiasis by a relatively slow release of the anti-microbial agent, including nystatin. PCT publication WO99/61491 discloses an anti-microbial denture adhesive, for the treatment of denture stomatitis, that includes nystatin as the active ingredient.

International Application WO 03/017960 discloses a mouthwash liquid in the form of a suspension comprising effective amounts of metronidazole and nystatin in combination. It is disclosed that these two ingredients in combination, one being an anti-bacterial agent and the other being an antifungal agent, act synergistically. It is thus clear that anti-microbial mouthwash compositions comprising one or more anti-microbial agents dissolved or suspended in a suitable liquid are known in the prior art.

However, there are some disadvantages of such liquid compositions.

In particular:

1. Liquid compositions are cumbersome for patients to carry with them and to dispense, particularly when administration is required several times daily.

2. Some anti-microbial agents are less stable against chemical degradation when in an aqueous liquid composition than they are in dry form.

3. In most cases the solubility of the anti-microbial agent in aqueous media is insufficient to allow it to be completely dissolved in the liquid composition, so that the composition must be a suspension. The composition must thus include suspending agents or thickeners to increase viscosity and reduce settling rate. However, thick suspensions are less suitable than low viscosity liquids for use in rinsing the oral cavity and gargling. 4. Liquid formulations are prone to microbial contamination, even though they contain anti-microbial agents.

The objective of the present invention is to provide compositions which overcome such disadvantages.

DESCRIPTION OF THE INVENTION

The present invention provides a solid composition for treatment or prevention of microbial infection in the oral cavity. The solid composition comprises one or more anti-microbial agents, and is intended to be used by following the steps of:

i) dispersing the solid composition in water; ii) rinsing the oral cavity or gargling with the dispersion (or both rinsing and gargling); and iii) expectorating the dispersion.

The anti-microbial agent may be either an anti-bacterial agent or an antifungal agent. The anti-bacterial agent will preferably be metronidazole, and the anti-fungal agent will preferably be nystatin. The composition will preferably comprise both an anti-bacterial agent and an anti-fungal agent. In addition to the anti-microbial agent or agents, the composition will comprise suitable excipients (i.e. inactive ingredients).

The excipients will preferably comprise a filler, such as lactose.

The excipients will further preferably comprise a sweetener, such as, aspartame, acesulfame potassium, saccharin or a salt thereof, or cyclamate or a salt thereof.

The excipients will further preferably include a flavouring agent, such as peppermint flavour or menthol.

The solid composition may be in the form of a powder, which will preferably be packaged in a sachet or other unit-dose package. The patient will open the package, add the contents to water to form a dispersion, (which may be a solution or suspension), rinse the oral cavity or gargle with the dispersion, and then expectorate the dispersion.

Alternatively and preferably, the solid composition may be in the form of a tablet, which may similarly be used by adding the tablet to a suitable quantity of water, allowing the tablet to disintegrate and disperse in the water, rinsing the oral cavity and gargling with the dispersion, and then expectorating the dispersion. When the solid composition is in the form of a tablet, the solid composition may alternatively be used by placing the tablet directly in the mouth, preferably under the tongue, sipping a suitable quantity of water, allowing the tablet to disintegrate and disperse in the water, rinsing the oral cavity and gargling with the dispersion, and then expectorating the dispersion.

When the solid composition is in the form of a tablet, the solid composition will preferably also comprise further excipients.

Such further excipients will preferably comprise a binder such as microcrystalline cellulose, which serves to enable formation of a tablet of suitable hardness under compression on a tablet press.

The further excipients will also preferably comprise a disintegrant to cause the composition to rapidly disintegrate and disperse when added to water. Suitable disintegrants include croscarmellose sodium, sodium starch glycolate, crospovidone, carmellose calcium, and starch.

The further excipients will also preferably include a lubricant, such as magnesium stearate, to prevent sticking to the tooling in the tabletting process.

The further excipients will also preferably include a glidant, such as colloidal silicon dioxide, to improve flow in the tabletting process. The invention will be better understood from the following example, which is intended to be illustrative and not limiting:

Example:

Ingredients were mixed in the proportions by weight as follows:

Nystatin 32.0 Metronidazole 120.0 Microcrystalline Cellulose 51.25 Croscarmellose Sodium 10.0 Magnesium Stearate 1.0 Colloidal Silicon Dioxide 0.75 Peppermint Flavour 10.0 Menthol Crystals 10.0 Aspartame 10.0 Acesulfame Potassium 5.0 250.0

The mixture was compressed into tablets of weight 250 mg each on a tablet press. Each tablet thus comprised 32 mg of nystatin and 120 mg of metronidazole. The content of croscarmellose sodium, as disintegrant, causes the tablet to disintegrate rapidly when added to water. The tablet thus may be conveniently used by placing it under the tongue, sipping a small amount (a few mL) of water, allowing the tablet to disintegrate in the water to form a dispersion, rinsing the mouth and gargling with the dispersion, and expectorating the dispersion.

Claims

1. A solid composition for treatment or prevention of microbial infection in the oral cavity of a patient comprising one or more anti-microbial agents, said composition when used by having the patient follow the steps of adding the composition to water, allowing the composition to disperse in the water to form a dispersion, rinsing the oral cavity or gargling with the dispersion, and expectorating the dispersion.

2. A composition of claim 1 wherein the anti-microbial agent is an antibacterial agent.

3. A composition of claim 1 when the anti-microbial agent is an anti-fungal agent.

4. A composition of claim 2 comprising metronidazole.

5. A composition of claim 3 comprising nystatin.

6. A composition of any of claims 1 to 5 comprising both an antibacterial agent and an anti-fungal agent.

7. A composition of any of claims 1 to 6 comprising a sweetening agent.

8. A composition of any of claims 1 to 7 comprising a flavouring agent.

9. A composition of any of claims 1 to 8 in the form of a powder.

10. A composition of claim 9 in a sachet or other unit-dose package.

11. A composition of any of claims 1 to 8 in the form of a tablet.

12. A composition of claim 11 when used by having the patient follow the steps of placing the tablet in the mouth, sipping water, allowing the tablet to disintegrate in the water to form a dispersion, rinsing the oral cavity or gargling with the dispersion, and expectorating the dispersion.

13. A composition of claim 11 or 12 comprising a binder.

14. A composition of claim 13 comprising microcrystalline cellulose.

15. A composition of any of claims 11 to 14 comprising a disintegrant.

16. A composition of claim 15 wherein the disintegrant is selected from the group consisting of croscarmellose sodium, sodium starch glycolate, crospovidone, carmellose calcium, and starch.

7. A composition of any of claims 11 to 16 comprising a lubricant.