CLEANSING FOAM FOR TEETH

Abstract: The invention relates to a cleansing foam for teeth in aerosol form comprising an aerating gas and a liquid composition comprising an alcohol component, a pharma­ ceutically acceptable surfactant, a pharmaceutically acceptable humectant,a pharmaceutically acceptable effective anti-­ plaque, bacteriostatic agent, and water. The outstanding character­ istics of the foam allows the use of it as a denture cleansing foam as well as a toothpaste.

Description: The invention relates to a cleansing foam for teeth in aerosol form, composed of a propellant and a liquid composition comprising an alcohol, a pharmaceutically acceptable surfactant, a pharmaceutically acceptable humectant, a pharmaceutically acceptable bacteriostatic agent, and water. Cleansers for natural or artificial teeth have conventionally been available in the form of liquids, powders, pastes or effervescent tablets. A substantially complete removal of plaque or tobacco-film with a known cleansing means is either not obtainable or requires extensive brushing and/or a considerable period of soaking of the dentures. Furthermore, none of the known cleansing means provides an effective activity against candida species and/or a really lasting bacteriostatic activity. The US-A-4511 486 and GB-A-1 465 495 disclose a cleaning composition for teeth using aerated foams. Although it seems to realise a rapid and effective cleansing, there is no specific improvement in the anti-plaque and /or lasting bacteriostatic acticity. It is known from a number of publications in various journals (Holbeche, J. D., Rulijancich, M. K., Read, P. C., Austral. Dent. J. 20 , 397 (1975); Lobene R. R. et al., Pharmacol. and Therapeutics in Dentistry 4 , 33 (1969); Llewelyn, J., Br. Dent. J. 148 , 103 (1980), Volpe, A. R. et al.,J. Dent. Res. suppl. 5 , 832 (1969)) that cetyl pyridinium chloride may have some anti-plaque activity but at a rather low level. It especially lacks equipotency with chlorhexidine. Furthermore, all the above applications relate to the use of mouthwash containing cetyl pyridinium chloride. No anti-plaque activity is found when cetyl pyridinium chloride is used in lozenges (Barnes, G. P., Radentz, W. H., Perkins, B. E., J. Prev. Dents. 2 , 2 (1975)) or in pastes (Rebstein, F., et al., Acta Paradentol. 10 , 51 (1981)). Thus, the problem of the invention is to provide a cleansing foam for teeth effecting a lasting bacteriostatic and effective anti-plaque activity without extensive brushing and/or a considerable period of soaking of the dentures, in case of using the cleansing foam in its most preferable form, namely for artificial teeth. According to the invention this problem is solved by a cleansing foam of the above-mentioned kind which is characterized in that the alcohol component is selected from ethanol, isopropanol, and mixtures thereof, wherein its concentration is in the range of 28 to 32 percent by volume; the pharmaceutically acceptable surfactant is a mixture of cetyl stearyl alcohol ethoxylate (20 moles ethylene oxide) and the disodium salt of a dicarboxylic coconut imidazoline derivative, wherein the concentration of the first component of this mixture is in the range of 6.5 to 10.0 percent by weight and the concentration of the second component of this mixture is in the range of 4.5 to 8.0 percent by weight; the pharmaceutically acceptable humectant is glycerol in a concentration of 0.5 to 4.0 percent by weight; and the bacteriostatic agent is cetyl pyridinium chloride in a concentration of 0.55 to 0.70 percent by weight. Preferred embodiments of the cleansing foam are subject of the respective dependent claims. The invention further relates to the methods of using the cleansing foam as cleansing means for artificial teeth, i.e. dentures, or as cleansing means for natural teeth, i. e. in a kind of tooth paste. The cleansing foam according to the invention provides an excellent tobacco film removal of 85 % with a three minute soak or 83 % with brushing of dentures. The removal of simulated agressive food stain mordanted onto s. mutans plaque shows, with a three minute soak only, equivalent results to a fifteen minute soak in a commercial two phase denture cleanser. There is found a reduction from 10⁸ to 10⁴ of s. mutans on the whole set of teeth using a one minute brush. Moreover the cleansing foam for teeth according to the invention has a lasting bacteriostatic activity which is unique with dentures. Furthermore it is effective against candida species. No denture cleansing tablet has this activity. The cleansing foam for teeth according to the invention does not cause any chemical attack or any damage by brushing with it on fine, highly polished acrylic surfaces or on surfaces of natural teeth. Surprisingly there has been found a very high plaque inhibiting efficacy when using the cleansing foam according to the invention: 75 % inhibition, by weight, of the growth of a s. mutans plaque on paladon acrylic tiles incubated in a high sucrose medium; 54 % inhibition, by weight, of the growth of the plaque cultured from natural mouth flora on paladon acrylic tiles incubated in a high sucrose medium; significant inhibition of natural plaque on real teeth during an eight hour period using human volunteers; and proven inhibition of s. mutans plaque on prosthesis metal, all dental acrylics and silicon denture liners. All these advantageous effects can be achieved by 0.55 to 0.70 percent by weight of cetyl pyridinium chloride in the above mentioned liquid composition. The presence of a surfactant in this liquidcomposition acts to generate the foam and permits penetration of the foam cleanser into the cracks and crevices of the teeth, thereby assisting in the removal of stains, debris and food particles from exposed surfaces. Although several commercially available surfactants can be used, a mixture of a non-ionic type and an amphoteric type detergent is preferred in the present invention whereby the non-ionic type detergent provides the initial rich foaming characteristic to the product while the amphoteric type detergent provides the second foaming generated during the brushing cycle. In a particularly preferred embodiment of the invention, the surfactant is a mixture of 6.5 - 10.0 percent by weight of the non-ionic type detergent and 4.5 - 8.0 percent by weight of the amphoteric type detergent. The employed detergents are cetyl stearyl alcohol ethoxylate (20 moles ethylene oxide) as a non-ionic type detergent and the disodium salt of an dicarboxylic coconut imidazoline derivative as an amphoteric type detergent. The alcohol component of the said liquid composition, namely ethanol, has several useful purposes. Firstly, ethanol acts together with cetyl pyridinium chloride to provide an effective anti-microbial action. Secondly, the alcohol component solubilizes the flavouring oils and other adjuvants that may not be water soluble. Thirdly, the alcohol component acts together with a flavouring adjuvant to impart a pleasant fresh taste to the cleansed teeth. The ethanol employed in the present invention ranges from 28 - 32 percent by volume of the said liquid composition. The presence of a humectant helps to stabilize the foam. A typical water soluble pharmaceutically acceptable humectant, suitable for use in the said liquid composition is glycerol in an amount of 0.5 - 4.0 percent by weight. Since the cleansing foam for teeth according to the invention is to be stored finally in a metalic can, it is useful to add a corrosion inhibitor to the liquid composition. Sodium nitrate or sodium benzoate, single or in combination, is suitable for this purpose when used in an amount from 0 - 1.0 percent by weight, preferably less than 0.25 percent by weight, in the case of sodium nitrate or in an amount from 0 - 2.0 percent by weight, preferably less than 0.5 percent by weight, in the case of sodium benzoate. Any colouring and flavouring adjuvants used in cleansing powders or tooth-pastes are also suitable herein. In the preferred embodiment of the present invention a mixture of FD+C Yellow No. 5 in an amount from 0 -0.002 percent by weight and FD+C Green No. 3 in an amount from 0 - 0.0002 percent by weight is selected as colouring adjuvant. A combination of several essential oils is selected to give the product a pleasant very characteristic aromatic odor when used in an amount from 1.0 - 2.0 percent by weight, preferably 1.4 - 1.9 percent by weight, most preferably 1.80 percent by weight. This special formulation is shown in the following table whereby the amounts are given in percent by weight of the liquid composition relating to the preferred amounts of the ingredients of the flavouring adjuvant: In order to assure a constantly high quality of the product the liquid composition is filled up to 100 percent by weight with demineralized water and the pH-value is adjusted to a range from 6.5 - 7.5 with nitric acid (20 %). Since the cleansing foam for teeth according to the invention has an excellent cleansing effect, a specific anti-plaque, bacteriostatic activity, a pleasant and fresh colour and flavour and since it is not toxic or agressive, it can be used as cleansing means for artificial as well as for natural teeth. Further features and advantages of the invention can be gathered from the following description of a performance example. To the alcohol (288 ml) add the cetyl stearyl alcohol ethoxylate (70 g); disodium dicarboxylic coconut imidazoline (50 g) and the flavour blend (18 g); mix until the detergents are dispersed. Add water to approx. half of the final volume and mix until the mixture becomes clear. Add glycerol (10 g), add cetyl pyridinium chloride (6 g) and mix until dissolved. Into a separate vessel mix the colours FD&C Green No. 3 (0.0015 g), FD&C Yellow No. 5 (0.015 g), sodium nitrate (5 g) and sodium benzoate (10 g), add a small amount of water (100 ml) and mix until dissolved. Add to the main mixture and mix until totally dissolved. Add water to 90 % of final volume (900 ml), adjust pH of mixture to 7.00 using a 10 % nitric acid solution. Make up to 1 litre with water, mix and store. An aerosol foam composition is: The features disclosed in the foregoing description, in the following claims and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.

Claims: A cleansing foam for teeth in aerosol form, composed of a propellant and a liquid composition comprising an alcohol, a pharmaceutically acceptable surfactant, a pharmaceutically acceptable humectant, a pharmaceutically acceptable bacteriostatic agent, and water, characterized in that the alcohol component is selected from ethanol, isopropanol, and mixtures thereof, wherein its concentration is in the range of 28 to 32 percent by volume; the pharmaceutically acceptable surfactant is a mixture of cetyl stearyl alcohol ethoxylate (20 moles ethylene oxide) and the disodium salt of a dicarboxylic coconut imidazoline derivative, wherein the concentration of the first component of this mixture is in the range of 6.5 to 10.0 percent by weight and the concentration of the second component of this mixture is in the range of 4.5 to 8.0 percent by weight; the pharmaceutically acceptable humectant is glycerol in a concentration of 0.5 to 4.0 percent by weight; and the bacteriostatic agent is cetyl pyridinium chloride in a concentration of 0.55 to 0.70 percent by weight. A cleansing foam according to claim 1, characterized in that the alcohol is ethanol. A cleansing foam according to claim 1 or 2, characterized in that a liquid composition is filled up to 100.00 percent by weight with demineralized water. A cleansing foam according to one of the preceding claims, characterized in that the liquid composition further comprises a corrosion inhibitor. A cleansing foam according to claim 4, characterized in that the corrosion inhibitor is sodium nitrate or sodium benzoate or a mixture thereof. A cleansing foam according to claim 5, characterized in that the concentration of a sodium nitrate is between 0.0 and 1.0 percent by weight, preferably less than 0.25 percent by weight, and the concentration of sodium benzoate is between 0.0 and 2.0 percent by weight, preferably less than 0.5 percent by weight. A cleansing foam according to one of the preceding claims, characterized in that the liquid composition further comprises a colouring adjuvant. A cleansing foam according to claim 7, characterized in that the colouring adjuvant is a mixture of FD&C Yellow No. 5 and FD&C Green No. 3. A cleansing foam according to claim 8, characterized in that the concentration of FD&C Yellow No. 5 is in the range of 0.0 to 0.002 percent by weight and the concentration of FD&C Green No. 3 is in the range of 0.0 to 0.0002 percent by weight. A cleansing foam according to one of the preceding claims, characterized in that the liquid composition further comprises a flavouring adjuvant. A cleansing foam according to claim 10, characterized in that the concentration of the flavouring adjuvant is between 1.0 and 2.0 percent by weight, preferably between 1.4 and 1.9 percent by weight, most preferably 1.80 percent by weight. A cleansing foam according to claim 11, characterized in that the flavouring adjuvant has in its preferred formulation (all amounts in percent by weight): A cleansing foam according to one of the preceding claims, characterized in that the pH-value of the liquid composition is adjusted to a range from 6.5 to 7.5. A cleansing foam according to claim 13, characterized in that the pH-value is adjusted with nitric acid. A cleansing foam according to one of the preceding claims, characterized in that the propellant is a mixture of dichlorodifluoromethane and dichlorotetrafluoroethane.

Inventors: AGAR, JOSEPH THOMAS HENRY
Applicants: RICHARDSON GMBH
Application year: 1985
Main classification: A61K7
IPC codes: A61K8, A61Q11, C11D1