Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ORAL COMPOSITIONS
Technical Field
The present invention relates to oral compositions such as toothpastes,
toothpowders, liquid dentifrices, mouthwashes, denture cleansers, chewing
gums, candies and the like. In particular, the invention relates to oral
compositions having enhanced antiplaque activity together with excellent
cleansing performance, physical characteristics, and in-use performance
characteristics.
B ack~zound
Plaque is initiated when bacteria adhered to pellicle form a proteinaceous
film
on the surface of teeth. The adherent bacteria metabolise dietary constituents
and reproduce and aggregate to form the tenacious deposit known as plaque.
Plaque generally consists of bacteria, bacterial end products such as
polysaccharides, inorganic salts and salivary proteins. Plaque bacteria
ferment
dietary carbohydrates to organic acids which demineralise enamel resulting in
tooth decay.
Calculus is essentially plaque that has been mineralised with calcium
phosphates salts. As calculus matures and hardens, it tends to stain
noticeably
due to adsorption of dietary chromagens. In addition to their unattractive
appearance, calculus deposits at the gum line are a contributing source of
gingivitis and periodontal disease. Besides the hygienic and health problems
resulting from plaque, research has shown that the primary source of bad
breath is the retention and subsequent degradation of dead cellular material
sloughed o~ continuously by the normal, healthy mouth.
Modern dental hygiene and denture preparations typically contain antiplaque
and/or antitartar agents, as well as antimicrobial agents and flavorants.
Antimicrobial action could affect plaque formation by either reducing the
number of bacteria in the mouth/dentures or by killing those bacteria trapped
in
the film to prevent further growth and metabolism. Flavorants may alleviate
the problem of bad breath via a deodorising action. Some antimicrobial agents,
e.g. menthol may, also serve as breath deodorisers. However, the efficacy of
antimicrobial agents depends largely on their intraoral/denture retention,
particularly their retention on the surface of the teeth or dentures where
plaque
is formed.
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A typical disadvantage of known dental preparations is that only a relatively
short time during which the teeth are being cleaned or the mouth is being
rinsed is available for antimicrobial agents in the preparations to take
effect.
The problem is compounded by the fact that dentifrice preparations are used
infrequently: most are used once or, perhaps, twice daily. Consequently, the
long time period between brushings for a majority of the population provides
optimum plaque forming conditions.
There has been a need, therefore, for developing an oral formulation which has
a. prolonged, residual antimicrobial and/or flavour impact effect.
Oral compositions, if not aqueous themselves, are required to act within an
aqueous environment. Many ingredients of such compositions act more
effectively if they can first be effectively dispersed within an aqueous
medium.
Once dispersed, those ingredients which act by depositing on the teeth or
other
surfaces within, or for use within, the mouth, are then required to be
deposited
from aqueous dispersion in effective amounts.
There is a further need, therefore, for developing an oral formulation from
which active agents can be dispersed into aqueous solution and then effciently
deposited onto teeth, gums or dentures.
It is known to include silicones in dentifrice compositions, allegedly to coat
the
teeth and prevent cavities and staining. For instance, GB-A-689,679 discloses
a mouthwash containing an organopolysiloxane for preventing adhesion of, or
for removing tars, stains, tartar and food particles from the teeth. The
mouthwash may include antiseptic compounds, such as thymol, and flavouring
and perfiiming agents.
US-A-2,806,814 discloses dental preparations including, in combination, a
higher aliphatic acyl amide of an amino carboxylic acid compound as an active
and a silicone compound. The patent notes that silicone compounds have been
proposed for prevention of adhesion or to facilitate the removal of tars,
stains,
tartar and the like from teeth. The silicone compound is said to act as a
synergist in improving the antibacterial and acid inhibiting activity of the
active
ingredient. Dimethyl polysiloxanes are said to be particularly effective.
Flavouring oils and/or menthol may be included.
US-A-3624120 discloses quaternary ammonium salts of cyclic siloxane
polymers for use as cationic surfactants, bactericides and as anticariogenic
agents.
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EP-A-376,363 discloses dentifrices containing amino alkyl silicones and
sarcosinate surfactants which form a hydrophobic barrier on the surface of
teeth.
Nevertheless, a need still exists for improved oral compositions from which
active agents can be dispersed into aqueous solution and then efficiently
deposited onto teeth, gums or dentures.
Accordingly, the present invention provides oral compositions, comprising an
aminoalkylsilicone, having improved efficacy on plaque, mucilaginous and
bacterial deposits and which further comprise a surface active agent chosen to
enhance the dispersion of the aminoalkylsilicone, whilst at the same time
providing improved substantivity and efficacy on teeth, gums and dentures;
together with excellent physical characteristics, and in-use performance
characteristics.
Summary Of The Invention
According to a first aspect of the invention, there is provided an oral
composition in the form of a toothpaste, powder, liquid dentifrice, mouthwash,
denture cleanser, chewing gum or candy comprising one or more oral
composition components selected from abrasives, binders, humectants,
surfactants, fluoride ion sources, anti-calculus agents and sweeteners and
additionally comprising:
i) an aminoalkylsilicone; and
ii) a silicone surfactant having the general formula (I)
N3 IH3 ~ H3 CH3 H3
CHI Si0 Si0 Si0 i i -CH3
IH ~ H
CH3 3 ~ 2)3 CH3
n
(C2H4~-)X~C3H60-)yX 4
m
wherein X is selected from hydrogen, alkyl, alkoxy and acyl groups having
from about 1 to about 16 carbon atoms, Y is CH3, q is 0, n is from about 1
to about 100, m is from about 1 to about 40, the molecular weight of the
residue (C2H40-}x(C3H60-}yX is from about 50 to about 2000, and x and
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y are such that the weight ratio of oxyethylene:oxypropylene is from about
100:0 to about 0:100.
All percentages and ratios herein are by weight of total composition, unless
otherwise indicated.
Detailed Description of the invention
The oral compositions of the invention thus comprise an aminoalkylsilicone
antiplaque agent and a dimethicone copolyol surfactant, while preferred
compositions additionally comprise a lipophilic compound and/or one or more
oral composition components selected from abrasives, binders, humectants,
surfactants, fluoride ion sources, anti-calculus agents and sweeteners. Each
of
these will be discussed in turn.
In general terms, the aminoallcylsilicone is selected from noncyclic, hydro-
phobic aminoallcysilicones having a formula comprising two basic units:
1) (R1)m(R)nSiO(4_m_n)/2 wherein m+n is 1, 2 or 3; n is l, 2 or 3; m is
0,1,2; and
2) (Rl)a(R2)bSiO(q._a_b)/2 wherein a+b is l, 2, or 3, and a and b are
integers,
wherein Rl and R2 are independently selected from H ,alkyl and alkenyl of
about 1 to about 10 carbons optionally substituted with fluoro or cyano
groups,
hydroxy, alkoxy, and acetoxy, for example, wherein Rl and R2 are
independently selected from methyl, ethyl, phenyl, vinyl, trifluoropropyl and
cyanopropyl, and R is
R4 R4
R3-N-R5 or -R3-N~-R5 X
~6
R
wherein R3 is a divalent alkylene of about 1-20, preferably about 3-5 carbon
atoms optionally substituted or interrupted by O atoms, R4, RS and R6 which
may be the same or different are selected from H, alkyl of about 1-20,
preferably about 1-10, more preferably about 1-4 carbons optionally
substituted or interrupted by N and/or O atoms, and X- is a monovalent anion
such as halide, hydroxide, and tosylate, said aminoalkylsilicone including
about
60% or less, preferably from about 0.1-30%, more preferably from 0.2-10%
and especially from about 0.5-2% of unit (1) on a repeating unit basis.
SUBS iI'TtUTE SHEET tRULE 2~3
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In a preferred embodiment, the aminoalkylsilicones comprise amo-
dimethicones. Amodimethicones are polydimethylsiloxane polymers
containing aminoalkyl groups. The aminoalkyl groups may be present either
pendant or at one or more ends of the polydimethylsiloxane chain. Preferred
are aminoalkylsilicones in which aminoalkyl moiety R is selected from
(CH2)3~2~ (CH2)3~CI 2CH2NH2, (CH2)3N(CH2CH20H)2,
(CH2)3NH3'~X-, and (CH2;)3N(CH3)2(C18H3~)+X-, and especially from
(CH2)3NH2 and (CH2)3NHCH2CH2NH2. Also preferred are aminoalkyl
silicones having an average molecular weight of about 5,000 and above,
preferably from about 5000 to about 100,000, more preferably from about
5000 to about 30,000.
Aminoalkylsilicone compounds suitable for use herein are well known.
Methods of preparing aminoallcylsilicones are given in, for example, US-A-
2,930,809.
TM
Examples of amodimethicones include OSI's Magnasoft fluid. These polymers
comprise aminoalkyl groups af~ced to a predominantly polydimethylsiloxane
structure. The typical structure of Magnasoft's aminoallcyl group-containing
units is
-OSi(Me)C3H6NHCH2CH2NH2.
The aminoalkylsilicone is generally present in a level of from about 0.01 % to
about 25%, preferably from about 0.1% to about 5%, more preferably from
about 0.5% to about 1.5% by weight.
A second essential ingredient of the oral compositions of the invention is a
silicone surfactant having the general formula (I)
CH3 CH3 CHg CH3 H3
I I I I
CH3- Si0 Si0 SiO i i-CH3
H
CH3 3 (CH2)3 CH3
n (
~C2H4~')x~C3H6~-)yX 4
m
wherein X is selected from hydrogen, alkyl, alkoxy and acyl groups having
from about 1 to about 16 carbon atoms, Y is CH3, q is 0, n is from about 1 to
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about 100, m is from about 1 to about 40, the molecular weight of the residue
(C2H40-}x(C3H60-h,X is from about 50 to about 2000, and x and y are such
that the weight ratio of oxyethylene:oxypropylene is from about 100:0 to about
0:100.
The silicone surfactant assists in dispersing the aminoalkylsilicone
antiplaque
agent in aqueous media whilst still allowing the antiplaque agent to deposit
onto surfaces such as teeth, gums or artificial dentures. Suitable dimethicone
copolyols are those marketed under the Trade Mark Silwet by Union Carbide.
The silicone surfactant is generally present in a level of from about 0.01 %
to
about 25%, preferably from about 0.3% to about 10%, more preferably from
about 0.5% to about 5% by weight. It will be appreciated that the precise
amount will depend on the amount of the aminoalkylsilicone antiplaque agent
used. In general the ratio c~f silicone surfactant to aminoalkylsilicone
antiplaque agent will be from about 0.5:1 to 15:1, more preferably from about
1:1 to 10:1, most preferably from about 2:1 to 8:1 by weight.
The oral compositions of >t~e invention preferably also include a lipophilic
compound. in general terns, lipophilic compounds suitable for use herein are
oil-like materials which are soluble or solubilisable in the
aminoalkylsilicone,
preferably at a level of at least about 1 %, more preferably at least about 5%
by
weight at 25°C. Preferred :lipophilic compounds are selected from
flavorants,
physiological cooling agent and antimicrobial compounds. The aminoalkyl-
silicone acts to enhance the substantivity of the lipophilic compound to teeth
and/or dentures, thereby providing enhanced and/or sustained flavour impact
and antimicrobial efficacy.
Lipophilic flavorants suitable for use herein comprise one or more flavour
components selected from wintergreen oil, oregano oil, bay leaf oil,
peppermint
oil, spearmint oil, clove oil, sage oil, sassafras oil, lemon oil, orange oil,
anise
oil, benzaldehyde, bitter almond oil, camphor, cedar leaf oil, marjoram oil,
citronella oil, lavender oil, mustard oil, pine oil, pine needle oil, rosemary
oil,
thyme oil, cinnamon leaf oil, and mixtures thereof.
Lipophilic antimicrobial compounds suitable for use herein include thymol,
menthol, triclosan, 4-hexylresorcinol, phenol, eucalyptol; benzoic acid,
benzoyl
peroxide, butyl paraben, methyl paraben, propyl paraben, salicylamides, and
mixtures thereof.
Physiological cooling agent suitable for use herein include carboxamides,
menthane esters and menthane ethers, and mixtures thereof.
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Suitable menthane ethers for use herein are selected from those with the
formula:
X
y
ORS
where RS is an optionally hydroxy substituted aliphatic radical containing up
to
25 carbon atoms, preferably up to 5 carbon atoms, and where X is hydrogen or
hydroxy, such as those commercially available under the trade mark Takasago,
from Takasago International Corporation. A particularly preferred cooling
agent for use in the compositions of the present invention is Takasago 10 [3-1-
menthoxy propan-1,2-diol (W'D)]. MPD is a monoglycerine derivative of 1-
menthol and has excellent cooling activity.
The carboxamides found most useful are those described in US-A-4,136,163,
January 23, 1979 to Wason et al., and US-A-4,230, 688, October 28, 1980 to
Rawsell et al.
The level of lipophilic compound in the compositions of the invention is
generally in the range from about 0.01 % to about 10%, preferably from about
0.05% to about 5%, more preferably from about 0.1 % to about 3% by weight.
Compositions in the form of toothpastes, denture cleansing liquids and pastes
and the like wall generally comprise a binder or thickening agent. Binders
suitable for use herein include carboxyvinyl polymers, carrageenan, hydroxy-
ethyl cellulose and water soluble salts of cellulose ethers such as sodium
carboxymethy:l cellulose and sodium carboxymethyl hydroxyethyl cellulose.
Natural gums such as gum kaxaya, xanthan gum, gum arabic, and gum
tragacanth can also be used. Colloidal magnesium aluminium silicate or finely
divided silica c;an be used as part of the thickening agent to further improve
texture. Binders/thickening agents can be used in an amount from about 0.1
to about 5.0%" preferably from about 0. I to about 1 % by weight of the total
composition.
It is also desirable to include some humectant material in a toothpaste to
keep
the composition from hardening upon exposure to air. Certain humectants can
also impart a desirable sweetness to toothpaste compositions. Liquid dentifi-
ice
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and mouthwashes can also contain a quantity of humectant. Suitable
humectants include glycervle, sorbitol, xylitol, polyethylene glycols,
propylene
glycol, other edible polyhydric alcohols, and mixtures thereof. When present,
humectants generally represent from about 10% to about 70%, by weight of the
compositions of the invention.
Toothpastes., liquid dentifrices and denture cleansers in liquid or paste form
will generally comprise an abrasive polishing material. The abrasive polishing
material contemplated for use herein can be any material which does not
excessively abrade dentine or denture acrylic. These include, for example,
silicas including xerogels, hydrogels, aerogels and precipitates, calcium and
magnesium carbonates, calcium ortho-, pyro- meta- and polyphosphates such
as dicalcium orthophosphate dihydrate, calcium pyrophosphate, tricalcium
phosphate, and calcium polymetaphosphate, insoluble sodium
polymetaphosphate, alumina and hydrates thereof such as alpha alumina
trihydrate, aluminosilicates such as calcined aluminium silicate and aluminium
silicate, magnesium and zirconium silicates such as magnesium trisilicate and
thermosetting polymerised resins such as particulate condensation products of
urea and fonnaldehyde, polymethylmethacrylate, powdered polyethylene and
others such as disclosed in LfS-A-3,070,510, December 25, 1962. Mixtures of
abrasives can also be used. 'The abrasive polishing materials generally have
an
average particle size of from about 0.1 to about 30 microns, preferably from
about 5 to 15 microns.
Silica dental abrasives of various types offer exceptional dental cleaning and
polishing performance without unduly abrading tooth enamel or dentine. The
silica abrasive can be precipitated silica or silica gels such as the silica
xerogels described in Pader et al., US-A-3,538,230, issued March 2, 1970 and
DiGiulio, US-A-3,862,307, .Tune 21, 1975, for example silica xerogels
marketed under the trademark "Syloid" by W. R. Grace & Company, Davison
Chemical Division. Suitable precipitated silica materials include those
marketed by the J. M. Huber Corporation under the trademark, "Zeodent",
particularly the silica carrying the designation "Zeodent 119". These silica
abrasives are; described in LJS-A-4,340,583, July 29, 1982.
Highly preferred herein from the viewpoint of providing good cleansing
performance combined with excellent compatibility with the antiplaque agent
are calcium carbonate abrasives.
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The abrasive is generally present in dentifrice formulations of the invention
at a
level of from about 10% to about 70%, preferably from about 15% to about
25% by weight.
The present compositions can also contain surfactants. Suitable surfactants
are
those which are reasonably stable and foam throughout a wide pH range,
including non-soap anionic, nonionic, cationic, zwitterionic and amphoteric
organic synthetic detergents. Many of these suitable agents are disclosed by
Gieske et al. in US-A-4,051,234, September 27, 1977.
Examples of suitable surfactants include alkyl sulphates; condensation
products
of ethylene oxide with fatty acids, fatty alcohols, fatty amides, polyhydric
alcoho~(e.g. sorbitan monostearate, sorbitan oleate), alkyl phenols~(e.g.
Tergitol) and :polypropyleneoxide or polyoxybutylene (e.g. Pluronics); amine
oxides such as dimethyI coc~~rnine oxide, dimethyl lauryl amine oxide and
cocoalkyldimethyl amine oxide (Aromox); polysorbates such as Tween 40 and
Tween 80 (Hercules); sorbit;m stearates, sorbitan monooleate, etc.;
sarcosinates such as sodium cocoylsarcosinate, sodium lauroyl sarcosinate
(Hamposyl-9~ ex W. R. Grace); cationic surfactants such as cetyl pyridinium
chloride, cetyl trimethyl ammonium bromide, di-isobutyl phenoxy ethoxy ethyl-
dimethyl benzyl ammonium chloride and coconut alkyl trimethyl ammonium
W trate
A soluble fluoride ion source: can also be incorporated in the present
compositions. The soluble fluoride ion source is used in amounts sufficient to
provide from about 50 to about 3500 ppm of the fluoride ion. Preferred
fluorides are sodium fluoride, stannous fluoride, indium fluoride, zinc
ammonium fluoride, tin ammonium fluoride, calcium fluoride and sodium
monofluorophosphate. Norri;s et al., US-A-2,946,735, issued July 26, 1960 and
Widder et al., US-A-3,678,154, issued July 18, 1972 disclose such salts as
well as others.
The present compositions can also include an anti-calculus agent. Suitable
anti-calculus agents include the di- and tetra-alkali metal pyrophosphates as
set
out in EP-A-097476. Specific salts include tetra alkali metal pyrophosphate,
dialkali metal diacid pyrophosphate, trialkali metal monoacid pyrophosphate
and mixtures thereof, wherein the alkali metals are sodium or potassium. The
salts are useful in both their hydrated and unhydrated forms. The amount of
pyrophosphate salt useful in these compositions is any effective amount and is
generally enough to provide iti composition at least 1.0% P207-4, preferably
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from about 1.5% to about 10%, more preferably from about 3% to about 6%
by weight of composition. The pyrophosphate salts are described in more
detail in Kirk & Othmer, Encyclopedia of Chemical Technolo~y, Second
Edition, Volume 15, Interscience Publishers (1968).
Other anti-calculus agents suitable herein are zinc salts. Zinc salts are
disclosed in US-A-4,100,269, US-A-4,416,867, US-A-4,425,325 and US-A
4,339,432. A preferred agent of the zinc variety is zinc citrate. Zinc
compounds can be present in amounts sufficient to provide from about 0.01
to about 4%, preferably from about 0.05% to about 1% by weight of zinc ion.
Other suitable anti-calculus agents include the synthetic anionic polymers
(including polyacrylates and copolymers of malefic anhydride or acid and
methyl vinyl ether (e.g. Gantrez) as described in US-A-4,627,977, polyamino
propane sulphonic acid, polyphosphates (e.g. tripolyphosphate, hexameta-
phosphate), diphosphonates (e.g. EHDP, AHP), polypeptides ( e.g. poly-
aspartic and polyglutamic acids), and mixtures thereof.
Sweetening agents which can be used include aspartame, acesulphame,
saccharin, dextrose, levulose and sodium cyclamate. Sweetening agents are
generally used at levels of from about 0.005% to about 2% by weight of
composition.
Other optional components for use herein include water-soluble antibacterial
agents, such as chlorhexidine digluconate, quaternary ammonium antibacterial
compounds and water-soluble sources of certain metal ions such as zinc,
copper, silver and stannous (e.g., zinc, copper and stannous chloride, and
silver
nitrate); pigments such as titanium dioxide; orally acceptable dyes/colorants
such as FD&C Blue #l, FD&C Yellow #10, FD&C Red #40; antioxidants,
vitamins such as vitamin C and E, other antiplaque agents such as stannous
salts, copper salts, strontium salts and magnesium salts; pH adjusting agents,
anticaries agents such as urea, calcium glycerophosphate, sodium
trimetaphosphate, plant extracts, desensitising agents for sensitive teeth
such as
potassium nitrate and potassium citrate, and mixtures thereof.
Typically, mouthwashes comprise a water/alcohol solution, flavour, humectant,
sweetener, sudsing agent, and colorant as described above. Mouthwashes can
include ethanol at a level of from 0 to 60%, preferably from 5 to 30% by
weight.
SUgSTI~UTE SHEE1 (RULE 2~)
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Denture cleanser compositions of the invention can additionally include one or
more bleaching agents, organic peroxyacid precursors, effervescence
generators, chelating agents, etc.
The bleaching agent takes the form of an inorganic persalt and can be selected
from any of the well-known bleaching agents known for use in denture
cleansers such as the alkali metal and ammonium persulphates, perborates,
percarbonates and perphosphates and the alkali metal and alkaline earth metal
peroxides. Examples of suitable bleaching agents include potassium,
ammonium, sodium and lithium persulphates and perborate mono- and
tetrahydrates, sodium pyrophosphate peroxyhydrate and magnesium, calcium,
strontium and zinc peroxides. Of these, however, the alkali metal
persulphates,
perborates and mixtures thereof are preferred for use herein, highly preferred
being the alkali metal perborates. Indeed, it is a feature of the invention
that
the tablet compositions herein will provide excellent antimicrobial activity
even
in the absence of alkali metal persulphates.
The amount of bleaching agent in the total composition is generally from about
to about 70% preferably from about 10% to about 50%. In compositions
comprising a mixture of alkali metal persulphates and perborates, the overall
persulphate:perborate ratio is suitably from about 5:1 to about 1:5, more
especially from about 2:1 to about 1:2.
The denture cleansing compositions can also incorporate an effervescence
generator, i.e. a material which in the presence of water releases carbon
dioxide or oxygen with effervescence. The effervescence generator can be
selected from generators which are effective under acid, neutral or alkaline
pH
conditions, but preferably it consists of a combination of a generator which
is
effective or most effective under acid or neutral pH conditions and a
generator
which is effective or most effective under alkaline pH conditions.
Effervescence generators which are effective under acid or neutral pH
conditions include a combination of at least one alkali metal carbonate or
bicarbonate, such as sodium bicarbonate, sodium carbonate, sodium
sesquicarbonate, potassium carbonate, potassium bicarbonate, or mixtures
thereof, in admixture with at least one non-toxic, physiologically-acceptable
organic acid, such as tartaric, fumaric, citric, malic, malefic, gluconic,
succinic,
salicylic, adipic or sulphamic acid, sodium fumarate, sodium or potassium acid
phosphates, betaine hydrochloride or mixtures thereof. Of these, malic acid is
preferred. Effervescence generators which are effective under alkaline pH
conditions include persalts such as alkali and allcaline earth metal
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peroxoborates as well as perborates, persulphates, percarbonates,
perphosphates and mixtures thereof as previously described, for example, a
mixture of an alkali metal perborate (anhydrous, mono- or tetrahydrate) with a
monopersulphate such as Caroat ~ marketed by E 1 du Pont de Nemours Co.
and which is a 2:1:1 mixture of monopersulphate, potassium sulphate and
potassium bisulphate and which has an active oxygen content of about 4.5%.
In preferred denture cleansing compositions in tablet form, the effervescence
generator takes the form of a solid base material which in the presence of
water
releases carbon dioxide or oxygen with effervescence. Suitably, the solid base
material incorporates a (bi)carbonate/acid effervescent couple optionally in
combination with a perborate/persulphate oxygen effervescence generator.
The combination of generators is valuable for achieving optimum dissolution
characteristics and pH conditions for achieving optimum cleaning and
antimicrobial activity. The (bi)carbonate components generally comprise from
about 5% to .about 65%, preferably from about 25% to 55% of the total
composition; the acid components generally comprise from about 5% to about
50%, preferably from about l 0% to about 30% of the total composition.
The denture cleansing compositions of the invention can be supplemented by
other known components of such formulations. An especially preferred
additional component is an organic peroxyacid precursor, which in general
terms can be defined as a compound having a titre of at least I .Sml of O.1N
sodium thiosuphate in the following peracid formation test.
A test solution is prepared by dissolving the following materials in 1000 mls
distilled water:
sodium yrophosphate (Na4P20~.1 OH20) _ 2.5
sodium perborate (NaB02.H202.3H20) having
10.4%
available o en 0.615
sodium dodec lbenzene sul honate 0.5
To this solution at 60°C an amount of activator is added such that
for each
atom of available oxygen present one molecular equivalent of activator is
introduced.
The mixture obtained by addition of the activator is vigorously stirred and
maintained at 60°C. After 5 minutes from addition, a 100 ml portion of
the
solution is withdrawn and immediately pipetted onto a mixture of 250 g
cracked ice and 15 ml glacial acetic acid. Potassium iodide (0.4 g) is then
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added and the liberated iodine is immediately titrated with 0.1 N sodium
thiosulphate with starch as indicator until the first disappearance of the
blue
colour. The amount of sodium thiosulphate solution used in ml is the titre of
the bleach activator.
The organic peracid precursors are typically compounds containing one or
more acyl groups, which are susceptible to perhydrolysis. The preferred
activators are those of the N-acyl or O-acyl compound type containing a acyl
radical R-CO wherein R is a hydrocarbon or substituted hydrocarbon group
having preferably from about 1 to about 20 carbon atoms. Examples of
suitable peracid precursors include:
1 ) Acyl organoamides of the formula RCONR 1 R2, where RCO is carboxylic
acyl radical, R1 is an acyl radical and R2 is an organic radical, as
disclosed in US-A-3,117,148. Examples of compounds falling under this
group include:
a) N,N - diacetyianiline and N-acetylphthalimide;
b) N-acylhydantoins, such as N,N' -diacetyl-5,5-dimethylhydantoin;
c) Polyacylated alkylene diamines, such as
N,N,N'N' -tetraacetylethylenediamine (TAED) and the corresponding
hexamethylenediamine (TAHD) derivatives, as disclosed in GB-A-
907,356, GB-A-907,357 and GB-A-907,358;
d) Acylated glycolurils, such as tetraacetylglycoluril, as disclosed in GB-
A-1,246,338, GB-A-1,246,339 and GB-A-1,247,429.
2) Acylated sulphonamides, such as N-methyl-N-benzoyl-menthane
sulphonamide and N-phenyl-N-acetyl menthane sulphonamide, as
disclosed in GB-A-3,183,266.
3) Carboxylic esters as disclosed in GB-A-836,988, GB-A-963,135 and GB-
A-1,147,871. Examples of compounds of this type include phenyl acetate,
sodium acetoxy benzene sulphonate, trichloroethylacetate, sorbitol
hexaacetate, fructose pentaacetate, p-nitrobenzaldehyde diacetate,
isopropenyl acetate, acetyl aceto hydroxamic acid, and acetyl salicylic
acid. Other examples are esters of a phenol or substituted phenol with an
alpha-chlorinated lower aliphatic carboxylic acid, such as
chloroacetylphenol and chloroacetylsalicylic acid, as disclosed in USA-
3,130,165.
4) Carboxylic esters having the general formal Ac L wherein Ac is the acyl
moiety of an organic carboxylic acid comprising an optionally substituted,
CA 02226160 2001-07-09
- 14-
linear or branched C6-C2p alkyl or alkenyl moiety or a C6-C2p alkyl-
substituted aryl moiety and L is a leaving group, the conjugate acid of
which has a pKa in the range from 4 to 13, for example oxy-
benzenesulphonate or oxybenzoate. Preferred compounds of this type are
those wherein:
a) Ac is R3-CO and R~ is a linear or branched alkyl group containing
from 6 to 20, preferably 6 to 12, more preferably 7 to 9 carbon atoms
and wherein the longest linear alkyl chain extending from and
including the carbonyl carbon contains from 5 to 18, preferably 5 to
10 carbon atoms, R~ optionally being substituted (preferably alpha to
the carbonyl moiefiy;l by Cl, Br, OCH3 or OC2H5. Examples of this
class of material include sodium 3,5,5-trimethylhexanoyioxybenzene
sulphonate, sodium 3,5,5-trimethylhexanoyloxybenzoate, sodium 2-
ethylhexanoyl oxybenzenesulphonate, sodium nonanoyl oxybenzene
sulp:honate and sodium octanoyl oxybenzenesulphonate, the acyloxy
group in each instance preferably being p-substituted;
b) Ac has the formula R3(AO)mXA wherein R3 is a linear or branched
alkyl or alkylaryl soup containing from 6 to 20, preferably from 6 to
15 carbon atoms in the alkyl moiety, R5 being optionally substituted
by C',1, Br, OCH3, or OC2H5, AO is oxyethylene or oxypropylene, m
is from 0 to 100, X is O, NR4 or CO-NR4, and A is CO, CO-CO,
R6-CO, CO-R6-CO, or CO-NR4-R6-CO wherein R~ is C1-C4 alkyl
and R6 is alkylene, alkenylene, arylene or alkarylene containing from
1 to 8 carbon atoms in the alkylene or alkenylene moiety. Bleach
activator compounds of this type include carbonic acid derivatives of
the formula R3(AO}mOCOL, succinic acid derivatives of the formula
R30C0(CH2)2COL, glycollic acid derivatives of the formula
R30CH2COL, hydroxypropionic acid derivatives of the formula
R30CH2CH2COL, oxalic acid derivatives of the formula
R30COCOL, malefic and fumaric acid derivatives of the formula
R30COCH=CHCOL, acyl aminocaproic acid derivatives of the
formula R3CONR1(CH2)6COL, acyl glycine derivatives of the
formula R3CONR1CH2COL, and amino-6-oxocaproic acid
derivatives of the formula R3N{Rl)CO(CH2)4COL. In the above, m
is preferably from 0 to 10, and R3 is preferably C6-CI2, more
preferably C6-C 1 p alkyl when m is zero and C9-C 15 when m is non-
zero. The leaving soup L is as defined above.
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5) Acyl-cyanurates, such as triacetyl- or tribenzoylcyanurates, as disclosed
in
US patent specification No. 3,332,882.
6) Optionally substituted anhydrides of benzoic or phthalic acid, for example,
benzoic anhydride, m-ch(orobenzoic anhydride and phthalic anhydride.
Of all the above, preferred are organic peracid precursors of types 1 (c) and
4(a).
Where present, the level of peroxyacid bleach precursor by weight of the total
composition i s preferably from about 0.1 % to about 10%, more preferably
from about 0.5% to about 5a/o and is generally added in the form of a bleach
precursor agglomerate.
The bleach precursor agglomerates preferred for use herein generally comprise
a binder or agglomerating agent in a level of from about 5% to about 40%,
more especially from about 10% to about 30% by weight thereof. Suitable
agglomerating agents include polyvinylpyrrolidone, poly(oxyethylene) of
molecular weight 20,000 to 500,000, polyethyleneglycols of molecular weight
of from about 1000 to about 50,000, CarbowaX having a molecular weight of
from 4000 to 20,000, nonionic surfactants, fatty acids, sodium carboxymethyl
cellulose, gelatine, fatty alcohols, phosphates and polyphosphates, clays,
aluminosilicates and polymeric polycarboxylates. Of the above,
polyethyleneglycols are highly preferred, especially those having molecular
weight of from about 1,000 to about 30,000, preferably 2000 to about 10,000.
Preferred from the viewpoint of optimum dissolution and pH characteristics are
bleach precursor agglomerates which comprise from about 10% to about 75%,
preferably from about 20% to about 60% by weight thereof of peroxyacid
bleach precursor, from about 5% to about SO% preferably from about 5% to
about 50%, more preferably from about 10% to about 40% of a (bi)
carbonate/acid effervescent couple, from about 0% to about 20% of a
peroxoborate, and from about 5% to about 40%, preferably from about 10% to
about 30% of an agglomerating agent. The final bleach precursor granules
desirably have an average particle size of from about 500 to about 1500,
preferably from about S00 to about 1,000 um, this being valuable from the
viewpoint of optimum dissolution performance and aesthetics. The level of
bleach precursor agglomerates, moreover, is preferably from about 1 % to
about 20%, more preferably from about 5% to about 15% by weight of
composition.
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The denture cleansing compositions of the invention can be in paste, tablet,
granular or powder form, although tablet-form compositions are highly
preferred herein. Compositions in tablet form can be single or multiple
layered
tablets.
Denture cleansing compositions of the invention can be supplemented by other
usual components of such formulations, especially surfactants, chelating
agents, enzymes, flavorants, physiological cooling agents, antimicrobial
compounds, dyestuffs, sweeteners, tablet binders and fillers, foam depressants
such as dimethylpolysiloxanes, foam stabilisers such as the fatty acid sugar
esters, preservatives, lubricants such as talc, magnesium stearate, finely
divided amorphous pyrogenic silicas, etc. The free moisture content of the
final composition is desirably less than about 1 % and especially less than
about
0.5%.
Tablet binders and fillers suitable for use herein include
polyvinylpyrrolidone,
poly (oxyethylene) of molecular weight 20,000 to 500,000,
polyethyleneglycols of molecular weight of from about 1000 to about 50,000,
Carbowax having a molecular weight of from 4000 to 20,000, nonionic
surfactants, fatty acids, sodium carboxymethyl cellulose, gelatine, fatty
alcohols, clays, polymeric polycarboxylates, sodium carbonate, calcium
carbonate, calcium hydroxide, magnesium oxide, magnesium hydroxide
carbonate, sodium sulphate, proteins, cellulose ethers, cellulose esters,
polyvinyl alcohol, alginic acid esters, vegetable fatty materials of a
pseudocolloidal character. Of the above, polyethyleneglycols are highly
preferred, especially those having molecular weight of from about 1,000 to
about 30,000, preferably from about 12,000 to about 30,000.
The surface active agent used in the denture cleansing compositions of the
invention can be selected from the many available that are compatible with the
other ingredients of the denture cleanser, both in the dry state and in
solution.
Such materials are believed to improve the effectiveness of the other
ingredients of the composition by aiding their penetration into the
interdental
surfaces. Also, these materials aid in the removal of food debris attached to
the teeth. Between 0.1 and 5 percent by weight of the dry composition of a dry
powder or granular anionic surface active agent, such as sodium lauryl
sulphate, sodium N-lauroylsarcosinate, sodium lauryl sulphoacetate or dioctyl
sodium sulphosuccinate or ricinoleyl sodium sulphosuccinate, may, for
example, be included in the composition and preferably the surface active
agent comprises between 0.5 and 4 percent of the composition.
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Suitable cationic, non-ionic and ampholytic surface active agents include, for
example, quaternary ammonium compounds such as cetyltrimethylammonium
bromide, condensation products of alkylene oxides such as ethylene or
propylene oxide with fatty alcohols, phenols, fatty amines or fatty acid
alkanolamides, the fatty acid alkanolamides themselves, esters of long-chained
(Cg-C22) fatty acids with polyalcohols or sugars, for example glyceryl-
monostearate or saccharose monolaurate or sorbitolpolyoxyethylenemono-or
di-stearate, betaines, sulphobetaines or long-chain alkylaminocarboxylic
acids.
Chelating agents beneficially aid cleaning and bleach stability by keeping
metal
ions, such as calcium, magnesium, and heavy metal cations in solution.
Examples of suitable chelating agents include sodium tripolyphosphate, sodium
acid pyrophosphate, tetrasodium pyrophosphate, aminopolycarboxylates such
as nitrilotriacetic acid and ethylenediamine tetracetic acid and salts
thereof, and
polyphosphonates and aminopolyphosphonates such as
hydroxyethanediphosphonic acid, ethylenediamine tetramethylenephosphonic
acid, diethylenetriaminepentamethylenephosphonic acid and salts thereof. The
chelating agent selected is not critical except that it must be compatible
with
the other ingredients of the denture cleanser when in the dry state and in
aqueous solution. Advantageously, the chelating agent comprises between 0.1
and 60 percent by weight of the composition and preferably between 0.5 and
30 percent. Phosphoric acid chelating agents, however, preferably comprise
from about 0.1 to about 1 percent, preferably from about 0.1% to about 0.5%
by weight of composition.
Enzymes suitable for use herein are exemplified by proteases, alkalases,
amylases, lipases, dextranases, mutanases, glucanases etc.
The following Examples further describe and demonstrate the preferred
embodiments within the scope of the present invention.
EXAMPLES I TO V
The following are representative denture cleansing tablets according to the
invention. The percentages are by weight of the total tablet. The tablets are
made by compressing a mixture of the granulated components in a punch and
dye tabletting press at a pressure of about 105 kPa.
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I n _III _V
Malic Acid 12 10 IV 14
Citric Acid - 10 12 -
-
-
12
Sodium Carbonate 10 8 8 10 '
6
Sul hamic Acid 5 - - 3
3
PEG 20,000 - 3 5 5
4
PVP 40,000 5 3 - -
_
Sodium Bicarbonate 21 23.2 23.9 20
13.9
Sodium Perborate Monoh drate 15 12 13 14
27
Potassium Mono ersul hate 14.4 16 11 - 13.5
o epic Silica 0 0.3 0.1 0.1 -
Talc 2 _ _ _ _
EDTA _
EDTMP 1 _ 1 - 3
1 _ _ 1
Flavours 2 1 2 1 2
Ma aloft Fluid4 0.6 1.5 5 8 0.5
Silwet L76006 - - - 12 5
Silwet L72307 3 4 9 - _
Bleach Precursor A lomerate
TAED2 2 - 4 5 2.5
TMHOS3 2 3 - _ _
Sul hamic Acid 2 2 2 2 3.5
Sodium Bicarbonate 0.5 0.2 0.2 0.5 2
PEG 6000 2.5 2 2.4 2.5 1.5
D a - 0.8 1.4 2 0.5
Total 100 100 100 100 100
1. Ethylenediaminetetramethylenephosphonic acid
2. Tetraacetylethylene diamine
3. Sodium 3,5,5-trimethyIhexanoyloxybenzene sulphonate
4. Magnasoft Fluid - supplied by OSI
5. Peppermint-based flavour
6. CAS Registry No. 68938-54-5 from Union Carbide
7. CAS Registry No. 68937-55-3 from Union Carbide
In Examples I to V above, the overall tablet weight is 3 g; diameter 25 mm.
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The denture cleansing tablets of Examples I to V display improved antiplaque,
cleansing and anti-bacterial activity together with excellent cohesion and
other
physical and in-use performance characteristics.
EXAMPLES VI TO VIII
The following are representative toothpaste/denture cleansing pastes according
to the invention. The percentages are by weight of total composition.
VI VII VIII
Calcium Carbonate 20 25 15
Gl cerine 10 12 8
Sodium CMC 3.5 3 4
Titanium Dioxide 0.7 0.5 0.6
Meth 1/Pro 1 Parabens 0.1 0.1 0.1
Sodium Saccharin 0.3 0.4 0.2
Flavours 1 1 2
Ma asoft Fluid4 1 1.5 0.3
Silwet L76006 3 2.5 2
Triclosan - 0.5 -
Water _ ~____
To
100%
-___>
The toothpastes/denture cleansing pastes of Examples VI to VIII display
improved antiplaque, flavour impact and anti-bacterial activity together with
excellent cleansing characteristics.
