Drug – bio-affecting and body treating compositions – Dentifrices – Oxygen or chlorine releasing compound containing
Reexamination Certificate
2002-01-16
2002-10-29
Rose, Shep K. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
Oxygen or chlorine releasing compound containing
C424S049000, C424S052000
Reexamination Certificate
active
06471947
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oral composition containing peroxides.
2. The Related Art
Peroxyl species, in particular hydrogen peroxide and sources thereof, are well-known antimicrobial agents, although they have not been widely used in deodorant products for use on the human body. It is also known that the stability of such materials can be improved by the addition of small amounts of transition metal chelator. The use of dipicolinic acid for such purpose is described in several publications, for example EP 666,307 A (Procter and Gamble). Dipicolinic acid is also claimed to improve the antimicrobial effect hydrogen peroxide—see EP 845,526 A (Eka Chemicals).
Picolinic acid has been described in WO9007501 (Solvay Interox) as a stabiliser for percarboxylic acid bleaching compositions. The picolinic acid is added in minor amounts to sequester transition metals which catalyse peroxygen compound decomposition. Picolinic acid is also listed as an optional component for this purpose in EP 1,074,607 (Ausimont S.p.A.).
SUMMARY OF THE INVENTION
We have discovered that synergistic mixtures of picolinic acid and a peroxyl species or equivalent source thereof can achieve the target of providing an excellent antimicrobial benefit and subsequent protection against plaque, caries and gingivitis. We have also found that synergistic mixtures of picolinic acid and a peroxyl species or equivalent source thereof can achieve the target of providing an excellent tooth whitening benefit.
None of the prior art discloses or suggests the products of the present invention, nor the excellent antimicrobial and tooth whitening benefits obtainable by the use thereof.
DETAILED DESCRIPTION OF THE INVENTION
We have found that use of a synergistic mixture of picolinic acid and a peroxyl species or equivalent source thereof gives an excellent tooth whitening antimicrobial benefit—much greater than that obtained from either of the two components individually. In addition, the addition of picolinic acid at such a level as to give said synergistic benefit enables less of the peroxyl species or equivalent source thereof to be used in the product—a significant benefit for products used on the human body.
Thus, in a first aspect of the invention, there is provided an oral composition comprising picolinic acid and a peroxyl specifes or equivalent source thereof, wherein the molar ratio of picolinic acid to peroxyl species or equivalent source thereof is from 1:30 to 100:1.
In a second aspect of the present invention, there is provided a cosmetic method of whitening the teeth comprising the use of picolinic acid and a peroxyl species or equivalent source thereof.
In a third aspect of the present invention, there is provided a method for the manufacture of an oral composition for the treatment of gingivitis, caries and/or plaque by mixing picolinic acid and a peroxyl species or equivalent source thereof with a cosmetically acceptable carrier material.
The antimicrobial and tooth whitening benefit derived from use of the present invention may be gained by independent application of picolinic acid and the peroxyl species or equivalent source thereof. Such application may be concurrent or consecutive, provided that the treated substrate experiences the presence of both components at the same time. When the components are applied from independent compositions, it is preferred that the product also comprises a means for, and/or instruction for, both of the compositions to be applied to the human body. Where the peracid and picolinic acid are stored independently from one another the formulatory requirements may be such that the stability of either is optimised. For example, if one formulation comprises a peracid such as PAP the pH of the formulation will be between 3.5 and 5, preferably 4. The formulation of the formulation comprising picolinic acid will then be modified such that when the two components are mixed they provide an oral composition according to the invention and having an acceptable pH of between 6.5 and 7.5.
It is preferred that the picolinic acid and the peroxyl species or equivalent source thereof are applied from the same composition. A preferred product according to the invention is a single composition comprising both the picolinic acid and the peroxyl species or equivalent source thereof.
The cosmetic method of gaining an antimicrobial benefit on the human body referred to in the second aspect of the present invention preferably uses the picolinic acid and the peroxyl species or equivalent source thereof at a molar ratio of from 1:30 to 100:1. This molar ratio, and that present in the composition according to the first aspect of the invention, is more preferably from 1:20 to 50:1 and most preferably from 1:10 to 20:1.
Picolinic acid is an essential component in the products of the invention. It may be used at a level of from 0.01% to 10%, particularly from 0.1% to 8%, and especially from 0.15% to 5%, by weight based on total weight of the composition. The picolinic acid may be used in its acid form or as its salt. Suitable salts include alkaline metal salts, alkaline earth metal salts, amine salts, and quaternary ammonium salts. When the picolinic acid is partially or totally in its salt form, the preferred amount is equivalent to the aforementioned preferred levels, on a molar basis.
The products of the invention comprise a peroxyl species per se or a material that generates a peroxyl species in situ. A peroxyl species is one that comprises a peroxy (—O—O—) group. Examples of suitable peroxyl species include hydrogen peroxide and peracids. Examples of equivalent sources thereof are compounds that produce hydrogen peroxide on dissolution in water, such as sodium perborate monohydrate, sodium perborate tetrahydrate, sodium percarbonate and percarbamide (urea-hydrogen peroxide addition compound). Further examples are enzymatic hydrogen peroxide generating systems such as peroxidases, oxidases and other oxido-reductase enzyme systems, in conjunction with their appropriate substrates. Preferred products comprise a peracid, in particular a peracid of formula (1)
(1)
in which R is hydrogen or C
1
-C
4
alkyl; n is 1 to 5; and X is C=O or SO
2
.
The peroxy amido phthalamides of formula 1) are known per se and have been described in EP-A-325,288 and EP-A-325,289. A preferred compound of this formula is N-phthalimido hexanoic peroxy acid (“PAP”) of formula 1), in which R=H, n=5 and x=C=0. An example of a compound according to formula 1) wherein x=SO
2
is saccharin-perhexanoic acid (“saccharin PAP”), as described in EP-A-485,927. Alternatively, a compound that produces hydrogen peroxide on dissolution in water, rather than hydrogen peroxide itself. Suitable peracids include any of those mentioned in WO96/05802 the contents relating to peracids being hereby incorporated by reference.
Particularly preferred products comprise a compound that produces hydrogen peroxide on dissolution in water, especially products from which hydrogen peroxide is absent, prior to application.
The amount of peroxyl species or equivalent source thereof in compositions of the invention may range from 0.0001% to 5%, more preferably from 0.001 to 1.5%, most preferably from 0.005% to 0.5%, by weight based on total weight of the composition.
Where the oral composition is to be used for its antimicrobial effect the composition may also comprise a transition metal chelator. Whilst picolinic acid is a transition metal chelator, performance may be increased by the use of a further material of this class, in particular a material having a high binding constant for iron (III); that is to say, a binding constant for iron (III) of greater than 10
15
, preferably greater than 10
20
, and most preferably greater than 10
26
. A particularly preferred material of this class is diethylenetriaminepentaacetic acid (DTPA). Salts of such materials may also be employed, suitable salts being analogous to those described as suitable picolinic acid salts (vide
Bhakoo Manmohan
Joiner Andrew
Steele Karen Anne
Taylor David
Thompson Katherine Mary
Honig Milton L.
Rose Shep K.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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