Oral compositions

The invention relates to the use of stannous compounds to combat bad breath. Preferably, the stannous compound is used together with a zinc compound. A preferred stannous compound is stannous pyrophosphate, and a preferred zinc compound is zinc citrate. The compounds are preferably included in an oral care composition such as a dentifrice or a mouth wash.

This application is filed pursuant to 35 USC S. 371 as a United States 
National Phase Application of International Application No. PCT/ED 
94/03027 filed Sep. 9, 1994 which claims priority EPO 93307329.8 filed 
Sep. 16, 1993. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the use of stannous compounds alone or in 
combination with zinc compounds as effective agents against bad breath and 
to the use of oral compositions such as dentifrices, mouthwashes, gels, 
subgingival rinse compositions, toothpastes, toothpowders, chewing gum, 
prophylactic pastes, lozenges, flosses, toothpicks comprising a stannous 
compound, either alone or in combination with a zinc compound to combat 
bad breath (malodour). 
2. The Related Art 
In the prior art several proposals have been made to combat bad breath 
(malodour). Many of these proposals have however not resulted in a 
reasonably effective composition against bad breath (malodour). One of the 
few really effective oral compositions is based upon the use of a zinc 
compound. E.g. in U.S. Pat. No. 4,689,214 and EP-A-0,074,082 oral care 
products are described which contain a zinc salt and a fluoride, such 
products having anti-malodour properties. The fluoride can be any of many 
examples of fluorides, including stannous fluoride. There is, however, no 
disclosure that the stannous compound as such is the effective agent. It 
is clear that only zinc was intended to function as effective agent 
against malodour in combination with fluoride. 
Oral compositions which comprise a stannous compound, either alone or in 
conjunction with a zinc compound, are disclosed in EP-A-0426213, 
EP-A-0514966, EP-A-0417833 and WO-A-9307852, but these references do not 
disclose or teach the use of stannous compounds as active agent against 
bad breath. 
SUMMARY OF THE INVENTION 
It has now been found that a stannous compound when used alone or in 
combination with a zinc compound provides an improved anti-bad breath 
efficacy. Volatile sulphur compounds are considered to be mainly 
responsible for malodour and bad breath. These may originate from saliva, 
or from the oral cavity or even the stomach. We have found that stannous 
compounds are very effective in reducing the level of these volatile 
sulphur compounds. Not only the effectiveness of the stannous compound 
alone or particularly in combination with a zinc compound for reducing the 
level of these volatile sulphur compounds was surprising, but also the 
long term activity of malodour-inhibition achieved by regular application 
of an oral composition comprising the active agent(s) according to the 
present invention was found to be totally unexpected. 
DETAILED DESCRIPTION 
The stannous compound, suitable for use in the present invention, can be 
any stannous compound with inorganic or organic counter ions. It can be a 
highly soluble stannous salt, or it can be a sparingly soluble stannous 
salt. Highly soluble stannous salts are e.g. stannous fluoride, stannous 
chloride, stannous chloride fluoride, stannous acetate, sodium stannous 
fluoride, potassium stannous fluoride, stannous hexafluorozirconate, 
stannous sulfate, stannous tartrate, stannous gluconate, disodium 
monostannous citrate, etc. Of these highly soluble stannous salts stannous 
fluoride is the preferred stannous salt. 
Sparingly soluble stannous salts are e.g. stannous pyrophosphate, stannous 
metaphosphate, stannous oxalate, stannous phosphate, distannous citrate, 
etc. Stannous pyrophosphate is a preferred sparingly soluble stannous 
salt. Mixtures of various highly soluble stannous salts may also be used, 
as well as mixtures of various sparingly soluble stannous salts and 
mixtures of highly and sparingly soluble stannous salts. A preferred 
mixture is the mixture of stannous fluoride and stannous pyrophosphate. 
Although highly soluble stannous salts can be used in the present 
invention, they tend to be not sufficiently stable upon storage. The 
stannous ions, dissolved in an aqueous solution tend to be converted 
therein to inert tin compounds, which do not provide for an anti-bad 
breath activity. Therefore, if a highly soluble stannous salt is used, 
care should be taken to reduce the quantity of active dissolved stannous 
ions during storage of the oral composition, or to stabilize the stannous 
ions by other means. 
When using a sparingly soluble stannous salt, care should be taken that 
there is a sufficient level of active dissolved stannous ions in the 
composition without giving rise to precipitation thereof as e.g. stannous 
oxide or stannous oxide hydrate. One way of achieving this is by 
solubilising the stannous salt, e.g. the stannous pyrophosphate with a 
certain amount of an alkalimetal pyrophosphate, or an alkalimetal citrate, 
or a fluoride source. 
In general, the stannous salt is used in such an amount in the oral 
composition, that there is an effective amount of active dissolved 
stannous ions available in the composition to achieve an anti-bad breath 
effect. For the highly soluble stannous salts this amount will generally 
range from 0.01-10%, preferably from 0.02-5 and particularly preferably 
from 0.1-3% by weight of the oral composition. As regards the sparingly 
soluble stannous salts these ranges are 0.05-10, preferably 0.1-5 and 
particularly 0.1-3% by weight of the oral composition. 
The zinc compound, suitable for use in the present invention can be any 
highly soluble or sparingly soluble zinc compound having inorganic or 
organic counter ions. Suitable examples of such zinc salts are enumerated 
in U.S. Pat. No. 4,022,880 (Vinson et al), which is hereby incorporated by 
way of reference. A preferred zinc salt is zinc citrate trihydrate. In 
general, the amount of zinc salt used in the present invention ranges from 
0.05-5% (calculated as zinc ion), preferably from 0.1-4% and particularly 
preferably from 0.1-3% by weight of the oral composition. 
The oral composition of the present invention may contain an orally 
acceptable medium which contains usual additional ingredients in 
conventional amounts, depending upon the final form of the composition, 
i.e. a dentifrice, a mouthwash, a gel and the like. Thus, as dentifrice it 
will usually comprise an abrasive cleaning agent in an amount of from 
3-75% by weight. Suitable abrasive cleaning agents are milled or unmilled 
particulate aluminas; silica xerogels, hydrogels and aerogels and 
precipitated particulate silicas; calciumpyrophosphate; insoluble sodium 
metaphosphate; calcium carbonate; dicalcium orthophosphate; particulate 
hydroxyapatite and so on. 
Furthermore, the dentifrice may contain a liquid phase comprising water and 
a humectant in an amount of 10-99% by weight. Typical humectants are 
glycerol, sorbitol, polyethyleneglycol, polypropyleneglycol, 
propyleneglycol, hydrogenated partially hydrolyzed polysaccharides and so 
on. 
Binders or thickening agents such as sodium carboxymethylcellulose, 
hydroxyethylcellulose, hydroxypropylcellulose, xanthan gums, Irish moss, 
gum tragacanth, finely-divided silicas and hectorites may also be included 
in the dentifrice in an amount of 0.5-10% by weight. Another conventional 
ingredient in a dentifrice is an organic surfactant such as a soap, an 
anionic, nonionic, cationic, ampholytic and/or a zwitterionic synthetic 
detergent surfactant in an amount of 0.2-5% by weight. 
When the composition is in the form of a mouthwash, it will usually contain 
an alcohol, a solubilizer, and when in the form of a gel it will usually 
contain a thickening agent. 
Various other optional ingredients may be included in the compositions of 
the invention, such as flavouring agents, sweetening agents such as sodium 
saccharinate, whitening agents such as titanium dioxide or zinc oxide, 
preservatives, vitamins such as vitamin C and E, anti-plaque agents such 
as copper salts, sanguinarine, allantoin, p-aminobenzoic acid derivates, 
hexetidine, chlorhexidine, 
3-(4-propylheptyl)-4-(2-hydroxyethyl)-morpholine, anti-bacterial agents 
such as Triclosan (2',4,4'-trichloro2-hydroxy-diphenyl ether), 
anti-calculus agents such as di- and/or tetra-alkalimetalpyrophosphates, 
pH adjusting agents, colouring agents, anti-caries agents such as casein, 
casein digests, sodium trimetaphosphate, sodium fluoride and 
monosodiumfluorophosphate, anti-staining compounds such as silicone 
polymers, anti-inflammatory agents such as substituted salicylanilides, 
plant extracts, desensitizing agents for sensitive teeth such as potassium 
nitrate and potassium citrate, polymers such as 
polyvinylmethylether-maleic anhydride copolymers and so on. 
When the preferred combination of a stannous salt and a zinc salt is used, 
the stannous salt and zinc salt may be used in the same phase of the oral 
composition, or they may each be present in a separate phase, e.g. one of 
them may be present in the stripe phase of a so-called striped toothpaste 
and the other one may be present in the main phase of such a striped 
toothpaste. When a fluoride source is also present in the composition, 
this may also be present in the phase, separate from the stannous salt 
containing phase. 
The oral compositions of the present invention can be formulated to any 
desirable pH-value. It is preferred that the compositions have a pH of 
between 3.5 and 5.5. 
The present invention will now be further illustrated by the following 
Examples.