Note: Descriptions are shown in the official language in which they were submitted.
WO 93/19728 ~ PCI/US93/03333
.,~ , :
Den~al Fc)rmulati~ ::
Area of the Invention
This invention concerns inhibiting tooth enamel deminerali~ation.
More specifically it relates to the use of a water soluble phosphate,
S particularly a pyrophosphate or tripolyphosphate, to inhibit
demineralization while not negatively impacting remineralization. This
provides a means for prevcnting or reducing dental caries.
Much work has been done to reduce tooth decay by chemical
means. Decay has a number of causes. One most com~nonly thought of
is enamel demineralization. The most widely used approach to - ;
preventing demineralization and to remineralize enamel is to present a
~uor~de ion to the oral cavity via a mouthwash or other short term
topical application means. Fluoridated drinking water has had a
material impact in reducing dental caries. Other approaches use
lS dentifiices, pastes applied directly to the teeth by professionals, or oral
r~nses which contain a fluoride ion as a means for fluoridating teeth.
Dentifrices, pastes and mouthwashes contain a low level of a fluoride
salt, most often as the alkali metal fluorides, alkali metal salts of
mono1uorophosphate and stannous fluoride. A usual, and ef~ective,
~uor~de concentration in these types of products is on the order of 1100
parts per million (ppm). To date no other chemical approach has been
developed as a means for inhibiting enamel demineralization and thus
preventing or treating dental caries. -~
It has been found that certain water soluble phosphates
exemplified by the alkali metal pyrophosphates and tripolyphosphates
i~ibit dem~neralization of enamel and they do not interfere with the
remineralization phenomena of the fluoride ion in subsurface caries-like
lesions. This finding makes it possible to pro~ride an anti-caries den~l
preparation which does not use fluoride. I
1; Ee~D:Q~h~ ;
This invention has two aspects. One is a method for reducing or ~ :
prevent;ing dental caries in humans by inhibiting enamel ~`-
demineralization, which method comprises treating the teeth with a
formulation containing a demineralization inhibitor consisting 2`
essentially of an effective non-toxic amount of a water soluble
pyrophosphate or tripolyphosphate in an orally acceptable carrier. In
the second aspect, this inven~ion covers an orally acceptable formulation
:
~.
WO 93/19728 .~ PCI/US93/03-3~
for preventing dental caries in humans by reducing or preventing
deminera1ization which comprises an orally acceptable carrier and an
inhibitor of enamel demineralization consisting essentially of an ef~ective
non-toxic amount o~ a water soluble pyrophosphate or tripolyphosphat~.
S ~pe~iç ~3m~odimçnts
In the broadest embodiment, this invention utilizes certain
phosphates as a means for inhibiting tooth enamel demineralization and
thus reducing or preventing dental caries. It has been found that the
presence of a orally acceptable water soluble phosphate is the critical
l 0 factor, not the acid or salt form in which it is presented. Such a
phosphat~ may be an orthophosphate, a pyrophosphate, a polyphosphate
(chain phosphates) or a metaphosphate (cyclic phosphates). The
preferred phosphates are pyrophosphate and tripolyposphate. So far as
the ionic form of the phosphate is concerned, the acid form of each of
these phosphates should not be used. That is acid phosphates such as
HsP3O1o or H4P2O7 should not be used. But the partially neutralized
~orms may be used, though the fully neutrali~ed forms are usually
preferred. The salts of Group Ia alkali metals of periods 2, 3 and ds are
preferred, particularly the sodium and potassium forms and mixtures
thereof. Most preferred is NasP3O1o alone or mixtures of Na4P2O7 and
K~P207. Notwithstanding this preference, several phosphate types and
ionic forms may be incorporated into a single preparation. The
phosphate may be anhydrous or hydrated.
Many cornmercial sources sell suitable phosphate preparations. In
particular sodium and potassium pyrophosphate and sodium
tripolyphosphate are available from a number of companies. Or the salts
may be custom prepared to define standards by a commercial source or
by the one who is doing the formulation work by usin~ published
techniques and processes. Pure phosphate preparations meeting local
regulatory requirements should be used in these dental preparations.
Ef~ecti~e conce~trations of phosphate will ~ary with the type of
phosphate selected, its water solubility, the type of product (i.e.,
toothpastes, ~nouthw~shes, cheu ing gums) and may be i~luenced by the
nature and chemical or phys;cal characteIistics of the camer and co- ;.-
35 formulated excipients. Some ingredieIlts or ~ormulations may have a
higher a~ailable phosphate content. In any event, an ef~ective amount is
that amount which wil1 reduce enamel demineralization to an e~tent
VO 93/1972~ PCI /US93/03333
that dental caries will be reduced in a statistically significant manner
over a phosphate-free control which is also free of any other
deminerali~ation inhibiting agent or remineralizing agent.
As a practical matter, though not intending to be bound by such
5 lower limit, about 2% by weight, or more, of a phosphate ion should
provide an ef~ective anti-caries preparation when used inco}porated into
orally acceptable preparations and when used in a normal, routine
fashion. A preferred baseline for toothpastes, gels and liquids is 5% by
weight. As regards sodium tripolyphosphate concentrations, 5~/o wlw is a
10 pre~erred amount. As for pyrophosphates, a preferred amount is about
1.8~o tetrasodium pryophosphate and 4.0% tetrapotassium
pyrophosphate. These amounts, when combined with the excipients
normally used to confect pastes and gels, should provide sufficient
available phosphate to inhibit enamel demineralization to a point where
15 denta~ caries will be usefully reduced. Variations and refinements in the
level of phosphates can be carried out as required or as appropriate to
maximize the ef~ectiveness of the phosphate in a given formulation.
Phosphates may represent a higher percentage of the overall ingredient
pro~le in dry formulatio~s such as dental tablets, lo~enges and chewing
20 gums.
These phosphates can be presented in any orally acceptable
carrier. The only limitation is that the phosphate must be a~ailable to
interact with tooth enamel and the forrnulation must not have any
deleterious OI' untoward af~ects on the teeth or the oral cavity when used
25 w~thin approved guidelines.
Many orally acceptable formulations are known in the dental arts.
Broadly speaking, these include denti~ices ~pastes, gels and liquids),
tooth powders, mouth rinses, dental tablets, dental lozenges, and dental
care chewing gums, for example. Three of the most preferred
30 formullations are toothpastes, gels, and mouthwashes. Thesq will be
specifically illustrated below as of orally acceptable formulations
contemplated in the use of this invention. ~-
Toothpastes, gels and liquid formulations may be prepared with
conventional ingredients, k eping in mind that certain abrasives may
35 not be compatible with certain water soluble phosphates. These
~otential limitations are detailed below. Aside from t~is one limitation,
one can use pretty much any combination of dentally acceptable
.
WO 93/197Z8 i~ 61 PCI`/US93/0333?~
abrasive7 humectant, detergent, sweetening agent, flavor, antimicrobial
agent, coloring agent and pigment and the like. A preferred toothpaste
or gel will contain about 5% of the pyrophosphate salt or
tripolyphosphate salt, about 10 to 80% of a humectant, about 0.~ to 5~o
S of a detergent, up to 2% sweetening and flavoring agents (in
combination), coloring agents, binders arld thickening agents, and water
in amounts su~icient to make a stable, flowable paste or gel.
The abrasive polishing material contemplated for use in the
present invention can be any material which does not excessively abrade ~-
dentin. These include, for example, silicas including gels and
precipitates, calcium pyrophosphate, calcium polymetaphosphate,
insoluble sodium polymetaphosphate, hydrated alumina, and resinous
abrasive materials such as particulate condensation products of urea and
formaldehyde, and others such as disclosed by in U.S. Pat. No. 3tO70,610
incorporated herein by reference. Mixtures of abrasives may also be
used. Certain abrasives may not ~e compatible with the metioned
phosphates. For example calcium carbonatej dicalcium orthophosphate
dihydrate, and tricalcium phosphate are best avoided if the ma~imum
ef~ect of the water soluble phosphates are to be realized.
Silica dental abrasives, of various types, can provide the un;que
benefits of exceptional dental cleaning and polishing performance
without unduly abrading tooth enamel or dentin. Silica abrasive
materials are also exceptionally compatible with many ionic mate~ials
including the phosphates which are the subject of this invention. For
2S these reasons they are preferred for use herein.
The silica abrasive polishing materials use~ul herein, as well as
the other abrasives, generally have an average particle size ranging
between about 0.1 and 30 miorons, preferably 5 and 15 microns. The
silica abrasive can be precipitated silica or silica gels such as the silica,
xeroge~s described in U.S. Pat. No. 3,638,230 and ~U.S. Pat. Nq.
3,862,207, both incorporated herein by reference. Preferred are the silica .
xerogels marketed under the trade name "Syloid" by the W.R. Grace &
Company, Davison Chemical DiYision. Preferred precipitated silica 1,-
mate~ials include those marketed by the J.l~. Huber Corporation under
the trade name, "Zeodent." Tbese silica abrasives are described in U.S. , 5,
Pat. No. 4,340,583, incorporated herein by reference.
` 4
: , '
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;WO 93ll9728 ~ 6 1 PC~/US93/03333
.. . I li,
. . .
The abrasive in the dentifrice compositions described herein is
present a~ a level of from about 6~o to about 70%, preferably from about
15Yo to about 25% when the dentifrice is a toothpaste. ~Iigher le~els, as I -`
high as 90~o, may be used if the composition is a tooth powder.
FlavoIing agents can also be added to the dentifrice and other
compositions of the present invention. Suitable flavoring agents include
oil of wintergreen, oil of peppermint, oil of spearmint, oil of sassafras,
and oil of clo~e. Sweetening agents are also useful and include
aspartame, acesulfam0, sacchalin, dextrose, levulose and sodium
cyclamate. Flavoring and sweetening agents are generally used in the
cornpositions herein at levels of from about 0.005% to about 2% by
weight.
The dentifrice compositions of this invention, may also contain
emulsifying agents. Suitable emulsifying agents are those which are
reasonably stable and foam throughout a wide pH range, including ~ ` `
anionic, nonionic, cationic, zwitterionic and amphoteric organic syIlthetic
detergents. Nonionic surfactants are preferred. Many of these suitable
surfactants are disclosed in U.S. Pat. No. 4,051,234 incorporated herein
by reference.
Water is also present in the toothpaste compositions of this
invention. Water employed in the preparation of commercially suitable
compositions should preferably be deionized and ~ree of organic
impurities. Water generally compr~ses from about 10~o to 70~o, -~ ;
preferably from about 20% to 40~o, by weight of a toothpaste. These
amounts of water include the free water which is added plus that which
is ~ntroduced with other mater~als such as when sorbitol or ot`her
polyhydric alcohols which are manufactured as dilutions where water is
the diluent.
Thickening agents generally are added to toothpastes and gels to
pro~ideadesirable~consistency. Preferredthickeningagentsare
carboxyviIlyl polymers, carrageenan, hydroxyethyl cellulose and water
soluble salts of cellulose ethers such as sodium carboxymethyl cellulose , -
and sodium carboxymethyl hydroxyethyl cellulose. Natural gums such 'f,
as gum karaya, gum Arabic, and gum tragacanth and polysacchande
~s such as xanthan ~m can also be used. Colloidal magnesium
alum~ntlm silicate or finely divided silica can be used as part of the
thickening agent to further improve te~tl~re. Hydroxyethyl cellulose is a
~ `
: :
WO93/197~8 j~ u~ PCI/US93/0333.',~
preferred binder. Thickening agents in an amount from 0.5% to 5.0% by
weight of the total composition may be used.
It is also desirable to include a humectant in a toothpaste to keep
it from hardening. Suitable humectants include glycerin, sorbitol, and
5 other edible polyhydric alcohols such as PEGs, at a level of from about
10% to about 70%.
~ ntibacterial agents may be added to these pastes and gels (and
mouthwashes). Any one of a number of antibacterial drugs or agents
may be used. Triclosan, 6-chloro-~-(2,4-dichlorpphenoxy)phenol, is one
10 example. A gro~lp of useful antibacterials is the cationic antibacterial
agent. Suitable cationic antibacterial agents for use in dentifrices
include: -
(i) quaternary ammorlium compounds, for instance those in
which one or two of the subsistent on the quaternary nitrogen has
between 8 and 20, preferably 10 and 18 carbon atoms and is preferably' -
an alkyl group, which may optionally be interrupted by an amine, ester,
oxygen, sulphur, or heterocyclic ring. The remaining nitrogen
substituents will have a lower number of carbon atoms, for instance
between 1 and 7, and are preferably alkyl, for instance methyl or ethyl,
20 or benzyl. The anion w~ll be an orally acceptable salt forming group.
:3xamples of such compounds include benzalkonium chloride, dodceyl
trimethyl ammonium chloride, benzyl dimethyl stearyl ammonium
chloride, cetyl trimethyl ammonium bromideJ benzethonium chloride ;~
(diisob~tyl phenoxyethoxyethyl dimethylbenzyl ammonium chloride3,
25 and methyl benzethonium chloride;
~: ~ iij pyridin~um and isoquinolinium compounds, exemplified by
hexadecylpy~idinium chlor~dej cetyl pyridiniurn chloride, and alkyl
isoquinolinium bromide; ~
(iii) pyrim~dine derivatives such as hexetidine (5-amino-1,3- , ;
30 Bi(~-ethylhexyl)-5-methylhe~ahydropyrimidine3
(iY) aniline deri~ratives such as hexamidine isothionate (4,4'-
diamonding-a,w-diphenoxyhexane isothionate);
(v) bispgridine derivati~es such as octenidine(N,N'[1,10-
decanediyldi-1(4H)-pyri:dinyl-4-ylidine]bis(1-octanamine
35 dihydrochloIide); and
(vi) biguanides including:
,~,
,` '' .WO ~3~1972~ PCl/US93/03333 j~ `
(a) rrlono-biguanides such as p-chlorobenzyl biguanide and N'-
(4-chlorobenzyl~N"-(2,d~-dichlorQbenzyl)bigllanide.
(b) bis-biguanides of the general ~ormula (I):
R R 1 i
A1~ )Zl N~C-NH-C-NH--(CH2)nQ-(CH2)n NH-C-NH-C-N-(X2)z2A? 5
S NH NH NH NH
(I)
wherein:
A1 and A2 are indeperldently a phenyl group optionally
10 substituted by (C1 4)alkyl, (C1 ~)alkoxy, nitro, halogen, C1 12)alkyl
group, or (C4~1~)alicylclic;
X1 and X2 are independently (Cl 3)alkylene;
R and Rl are independently hydrogen, (Cl l~)alkyl, or aryl(C
6)alkyl;
Z1 and Z2 are independently 0 or 1;
Q is CH2, oxygen, sulfur, or aryl;
n in each (CH2)n group is independently an integer ~rom 1 to 12
but the total of both n groups may not exceed 12;
aryl is phenyl, naphthyl or another aromatic ring; and orally
20 acceptable acid addit;on salts thereof. Preferred compounds are
chlorhexidine and alexidine.
(c) poly(bi~anides) such as polyhexamethylene biguanide :
hydrochloride.
An effective amount of a antibacterial agent is irl the range of
about 0.005 to 10% weight/weight (w/w), preferably 0.005 to 6%, more
preferably 0~005 to 2.5% and most preferably 1.05O w/w.
An optional ingredient which may be use~ul in any of the present
compositions which contains a catiorlic antimicrobial agent is an anti~
stain ~gent. Cationic antimicrobial materials may cause~ staining wher~
used at fairly high levels. Anti stain agents include carboxylic acids t
such as those dis~losed in U~S. Pat. No. 4,256,731, incorporated herein ~y ~ -
reference. Other agents include amino carboxylate compounds as
disclosed in U.S. Pzt~ No. 3,937,807; dicarboxylic acid esters as disclos~d
in U.S. Pat. No. 4,080,441; and phosphonoacetic acid as disclosed in U.S.
Pat. NoO 4,118,474. All of ~hese pa~Pnts are also incorporated herein by
reference.
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WO 93/19728 ~J 1 3 ~ C 1~ 1 PCI`/US93/0333:~: r
Conventional manufacturing techniques can be used in mixing
pastes an~ for filling them into flexible or solid tube-type containers, or
any other convenient container forrn, for cons~ er use. There are no
container limitations, so far as is known, for any form of toothpaste or gel
S prepared in accordance with this invention. A toothpaste of the present
invention may be prepared in a uniform color or in the form of a striped
toothpaste. ~ suitable apparatus for filling toothpaste tubes with striped
toothpaste is described in U.K. Patent Specification No. 962,757.
Conventional mouthwashs can be prepared with the phosphates of
this invention. Mouthwashes generally comprise about 20:1 to about 2:1
of a water/ethyl alcohol solution and preferably other ingredients such as
flavoring agents, sweeteners, humectants and surfactants. Suitable
flavoring agents include oil of wintergreen, oil of peppermint, oil of
spearmint, oil of sassafras, and oil of clove. Sweetening agents which
can be used include aspartame, acesulfame, saccharin, dextrose, levulose
and sodium cyclamate. Suitable humectants include sorbitol and
glycerin while suitable surfactants include oleate and laurate esters of
sorbitol and its a~hydride condensed with ethylene oxide as well as
~` ethylene oxide and propylene oxide condensates.
Another type of surfactant which may be used are the
amphoterics. The amphoteric sudsing agents useful in the present
~ invention can be broadly descFibed as derivatives of aliphatic secondary
; ~ ~ and tertiary amines in which the aliphatic radical can be straight chain
~; ~ or branched and wherein one of the aliphatic substituents contains from
about 8 to about 18 carbon atoms and one contains an anionic water-
~` ~ ` solubilizirl~ group, e.g., carboxylate? sulfonate, sulfate, phosphate, or
phosphonate.
Generally, on a weight basis, the mouthw~shes of the invention
comprise 0.5% to 5% of the phosphate, 5% to 30% (preferably 5% to 20%)
ethyl ~a~lcohol, 0% tol 25%;~preferably 3% to 20%) of ia humectant, 0~ to
25% ~preferably 0.01% to 2.0~o) surfactant, 0% to 5% (pre~erably 0.005%
to 0.3%) sweetening agent, 0% to a.3% (preferably 0.03% to ~0~3%) ~`
fla~oring agent, about 0.1% of a preser~ratiYe, pH adjusting agent as
needed, an~ the balance water.
3 S The pH of a mouthwash ~and/or its pH in the mouth can be any pH
which is safe for the mouth's hard and soft tissues. ~enerally the pH
8 ~ ~
`.``? ~
,wo 93/19728 ~ 6 6 1 PCI/US93~03333 'f'
will be adjusted to about 3 to about 10, preferably from about 4 to about
8. I
Conventional manufacturi~g techniques and packaging materials ¦`can be used for these mouthwashes. ~ I
S Other vehicles include lozenges and chewing gum~. Components
usefuI in such compositions are disclosed in U.S. Pat. No. 4,083,95~,
incol~orated herein by reference.
Product~i which employee these phosphates are to be used in a
conventional manner. For example, brushing the teeth with a toothpaste
containing such a water soluble phosphate makes the phosphate
available to the teeth and thus inhibits the formation of dental caries o~
reduces the development of dental caries in persons susceptible to the
forrnation of dental caries. Mo-lthwashes are also used in the normal
and accepted fashion to prevent caries i~ susceptible persons or to
prevent further development of dental caries in susceptible persons
Likewise dental powders, tablets, lozenges and dental care chewing
gums will be used in the normal fashion and with regularity, if the ef~ect
is to be realized to its fullest degree.
The present invention is illustrated in terms of its preferred
embodiments in the following Exarnples. All parts and percentages are
b~r weight, based on the total weight of the product, uIlless otherw~se
stated. These Examples are given to illustrate the invention, not to lirnit
its scope in any manner or fashion. Reference is made to the claims for
determining what is reserved to the inventors hereunder.
E~m les
Example 1
To~bp~s~e For~llla~ion~
A toothpaste can be prepared using the follow~ng ingredients and
two dif~erent phosphates.
j ;~ Table 1 - Tube FormulatiQns
In~redient ~ O y~T (~ri~alv~hQs~% YVfW (pyroDhQ~
PEG-8, FCC (PEG 400) 3.00 3.00 ~;
XanthanGum 0.700 0.6000
~` Sorbito} USP (70%) 29.9322 28.4761
Hydrated silicia (Zeofree 153) 8.000 7.000 `-
Hydratedsilicia (Zeofree 113)14.00û 14.0û0
Sodium tripolyphosphate~ 5.000
':
WO93/19728 ~ PCI/US93/0333 ~
. ~ ,
Sodium pyrophosphate 1.810
Ptassilxrn pyrophosphate 4.000
SodiumH~drvxide ~50~o solution) 0.900
Glycerin 10.000 10.000 ~ ,
Flavor 0.800 0.800 ~ t
Sodi~Lrn lauryl sulfate 1.150 1.150
Sodium saccharin 0.214 0.214
D&C ~ed # 30 Aluminum lake 0.025 0.02~
FD&C Blue #1(0.2%) 0.2478 0.2478
D&C Yellow ~10 (0.2%) 0.2015 0.2015
Titanium dioxide 0.7235 0.7235
Sodium benzoate 0.100 0.100
Deior~ized water qs 100.00% qs 100.00~
In these two ~ormulations) PEG-8 is a polyethylene glycol. It,
along with the sorbitol and glycerin, is a humectant. Xanthan gumi and
the Zeofree 153 are binders and thickening agents. Three dyes are
recited in this formulation as it is to be presented as a tri-colored product
much like that sold under the Aquafresh brand nam0 of Smith~ine
Beehcam Consumer Brands.
~` Because of the presence of pyrophosphates and tripolyphosphates,
clear gel-like forrnulations cannot be prepared. But one can prepare gel-
like toothpastes, albeit opaque gels, by eliminating the three dyes from
;~ the foregoing formulations.
Pump dispensers have gained favor with many toothpast users.
;~ The following formulatiorl can be used with a pump dispen~er system.
Table 2 - Pump~ .Dispenser Formulation
In~rçdient % W/W ~tri~olY~hos~% W/W (~roDhos)
, 30 ~ PEG 8, FCC (PEG 400)~ 3.00 3.00
~nthan Gum 0.700 0.6000
SorbitolUSP t70%) 29.609 28.253
Hydrated siliciatZeo~ree 153) 8.000 ~ 7.000
Hydrated silicia (Zeofre~ 113)14.000 1~.000 ~.
~ 35 Sodium tripolyphosphate 5.000
`~- Sodium pyrophosphate ~ ~ 1.810
Potassium pyrophosphate 4.000
0
..
~ ~ :
-
~, ~wo 93/t97~8 ~ l 3 3 ~ 6 ~ Pcr/lJS93/~3333
Sodium Hydroxide (~0~ solution) 0.900
Glycerin 10.000 10.000
:F`lavor 0.800 0.800
Sodium lauryl sulfate 1.150 1.150
S Sodium saccharin 0.214 0.214
D&C Red ~ 30 Alum~num lake 0.025 0.025
FD&C Blue #1 tO.2~o) 0.2478 0.2478
D&C Yellow #10 t0.2%) 0.2015 0.201
Titanium dioxide 0.9560 0.9560
Sodium benzoate 0.100 0.200
PurifiedWater qs 100.00% qs 100.00%
Example 2
_thwash Formulations
An anti^caries mouthwash employ~ng the pyrophosphates of this
invention is illustrated by the follow~ng formulation.
T~!e 3 - Pvrophosphate-containing Mouthwa~h,
Ingredients . .. ... _ _
Ethyl Alcohol, 190 proof 8.00
Glycerin, 99%U.S.P. 8.000
Sodium pyrophosphate 2.060
Potassium pyrophosphate 0.710
Flavor 0.200
Menthol 0.007
Cremophor R~I-60 0.200
Pluronic F-108 (surfactant) 0.100
Plurorlic F-127 ~surfactant~ Q.100
Benzoic acid 0.100 ~,
Sodium saccharin 0.060 ~.
j , FD&C #1(0.2% solution) 0.140
FD&Cyellow~5 (0.2% solution) 0.900
Phosphoric acid 25% ~olution
to adjust pH As needed
Deionized water qs lOO.OO~o $~
These ingredients, expect the phosphoric acid and a small ~mount
of the water are mixed together, the pH is adjusted to the de~ired figure,
11
.
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wO 93/ 1 9728 rJ ~ 6 1 PC~ Sg3/0333~ ~:
, .
then the solution is brought to volume with water. This mouthwash may
be packaged in any conventional bottle or container.
A similar mouthwash, but using a tripolyphosphate, is prepared
as per the ~ollow~ng formulation.
Tablç 4
Tripo yphosphate-cont~ining Mou~ash
In~redients . . % WIW ~;
Ethyl Alcohol, 190 proof 8.00
Glycerin, 99% U.S.P. 8 000
Sodium tripolyphosphate 0.50 ;-
Flavor 0.200
Menthol 0.007
Cremophor RH 60 0.200
Pluronic F-108 (surfactant) 0.100 `~
Pluronic F-127 (sur~actant) 0.100
Benæoic acid 0.100
Sodium saccharin 0.060
FD~C ~1(0.2% solution) 0.140
FD&C yellow ~5 (0.~% solution)0.900
Phosphoric acid 255'o solution
to adjust pH As needed
Deionized water qs 100.00~
Example ~ ;
~ethod f~r Testing the Efficacv of Phosphates
The ef~icacy nf these phosphates was determined using the
following protocol:
Dentifrices (toothpastes) were prepared in plain color-coded tubes.
All had the same base to which was added a tripolyphosphate~
pyrophosphate, or one of these phosphates ~ith NaF. The control was ,
the denti~ice base. The following table gives the concentrations of s-
actives in each fo~ulation.
, .
12
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'~WO 93/lg728 h ~ 6 1 PCr/US93/03333
Product Description
(FluQride as ~aF~ 1100 ppm F: where~shQ~n)
Sodium tripolyphosphate (5%) without F- i
Sodium/potassium pyrophosphate (1.8/4.0'~o) without F-
Toothpaste base
Sodium tripolyphosphate with F-
Sodiumfpotassium pyrophosphate with F-
The identity of the products was withheld from the technician
10 until all experiments were completely assessed and data assembled. All
experiments were conducted with color-coded tubes and all e~perirnental
racks and tubes similarly coded to keep the operatives blind. The only
partial breaking of the code was when it became necessary to inst~uct
the operative which was the correct radiotracer to add in the "hot"
15 experiments.
The pH cycling (demineralization/remineralization) model for the
in vitro study of fluoride-containing products and fluoride products
containing anticalculus agents was that of Featherstone et al, Caries
Xes. 1988; 22:337-3~1. This model has previously been shown to
20 simulate results found by us in vivo around orthodontic brackets
(O'Reilly and Featherstone, Am. J. Orthod. 1987; 92:33-40). Each test
cell consisted of ten human tooth crowns which were removed from the
roots, cleaned and painted with acid resistant varnish to lea~e test
windows as described in detail previously (Featherstone et al, Car~es P~es.
~5 1988; 22:337-341).
The study was divided into "cold" legs and "hot" legs. The "cold"
gs, w~th no radiotracer added, were used in order to determine whether
the test anticalculus agents (pyrophosphate and tr~polyphosphate)
indi~dually had a detrimental outcome on the net effect of
30 de~neralization/remineralization. In this case two windows, designated
"upper" (towards occlusal) and "lower" (towards cervical) were placed on .
the enamel sur~ace of each tooth crown. In the "hot" legs where 3~P ~ -
lab~lled potassium pyrophosphate or sodium tripolyphosphate was
added, on~ window approximately 3 x 7 mm was placed on each test -.
~ ~ 35 surface. ~ '
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wo 93/19728 Pcr/uss3/0333~- b
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The test regimen in each 24 hour period was as follows:
Demin~3~ Teeth were immersed indi~ridually for 6
hours daily at 37 C in 40 mL of a buffer containing 0.075 mol/L acetate,
~.0 mmollL CaHPO4 at pH 4~3. ~ ;~
2. Prgdll~ç~mmersion. The crowns were removed from solu~on,
thoroughly rinsed with double deionized water (DDW), and immersed
individually in 4 mL of a 1:3 slurry of dentifrice (one of the test or
placebo products, see below) in DDW, and stirred on an orbital shaker
for 5 minutes. The slurries were made fresh daily within 30 minutes of
immersion, and where appropriate, radiotracers were added and
dispersed by vortexing. APcer the product immersion, the samples were
again thoroughly washed in DDW and transferred to the remineralizing
solution.
3. :RemineralizatiQn. Each tooth was then immersed individually
for 17 hours at 37 C in 20 mL of a mineralizing solution containing 1.5
mmoVL calcium, 0.9 mmol/L phosphate, 150 mmol/L KCI (to maintain
ionic strength), 20 mmol/L cacodylate to buffer to pH 7Ø This solution
simulates the remineralizing phase (ten Cate and Duijsters, Caries Res.
1982; 16:201-210) of the caries process (by salivary minerals).
Duration Qf pH çyçl,ing. The above pH cycling was repeated for 3
weeks, consisting of 14 cycling days and two weekend periods in
mineralizing solution. The test scheme was designed to model, a total
daily demineralization challenge of 6 hours, a once per day fluoride (or
non fluoride) treatment, and 17 hours daily of repair (remineralization).
Test Groups. The experiments were carried out in duplicate, one
group of each pair using sodium tripolyphosphate and one using
pyrophosphate salts. The groups were designed to give four"cold" legs
(A1, A2, B1, B2, below) which were assessed by cross-sectional
microhardness testin~ tsee below) to det~rmine the degree of
demineralization, and four identical "hot" legs (Cl, C2, 1:)1, D2) using ~ -
radiolabeled sodium t~polyphosphate or pyrophosphate salts to
determine the degree of penetration OI the t~polyphosphate or ¦ -
p~rophosphate into the enamel during treatment with and without
fluo~ide present. A fifth "cold" leg (E below) ser~ed as the baseline
control and used a placebo dentifIice with no fluoride, no
tripolyphosphate, and no pyrophosphate ions.
1~ .
WO 93/19728 ;~ 3 3 ~ 6 1 P~/US93/03333
A1- Demineralization/remineralization cycling as above with 5
minutes daily immersion prior to remineralization in a 1:3 slurry of a
sodium tripolyphosphate/sodium fluoride dentifrice (4 mL of solu~ion per
tooth indiv~dually).
S A2. In the duplicate experiment a pyrophosphate salt/NaF
dentifrice was used. i
Bl. Demineralization/remineralization cycling with 5 minutes
dail~ immersion prior to remineralizatiQn in a 1:3 slurry of an sodium
tripolyphosphat~ non-fluoride dentifrice (sodium tripolyphosphate
present as in A but with no added sodium fluoride) (4 mL of solution per
tooth indi~ridually).
B2. In the duplicate experiment pyrophosphate salts containing
dentifrice without an added fluoride ion was similarly used.
Cl. Demineralization/remineralization cycling with 5 minutes
daily imrnersion prior to remineralization in a 1:3 slurry of an sodium
tripolyphosphate/sodium fluoride dentifrice (4 mL of solution per tooth
individually). In this group the sodium tripolyphosphate slurry was
labeled w~th 32p as sodium tripolyphosphate added as a radiotracer
prior to irnrnersion of the teeth.
C2. In the duplicate experiment pyrophosphate salts were used
and similarly radiolabeled with 32p as pyrophosphate salts.
D}. Demineralization/remineralization cycling with 5 minutes
daily immersion prior to remineralization in a 1:3 slurry of sodium
tripolyphosphate (as in C, but with no added sodium fluoride) dentifrice
t4 mL of solution per tooth individually) and with 32p labeled sodium
tripolyphosphate added as desc~bed above.
D2. In the duplicate experiment pyrophosphate salts were used,
similarly radiolabeled.
E. DemiIleralization/remineralization cyclin~ with 5 minutes
daily immersion prior to remineralizatian in a 1:3 slurry of a placebo
dentifrice ~no added sodium fluoride, no added sodium tripolyphosphate ~-
or pyrophosphate salts, 4 mL per toot~ individually).
All groups used freshly made treatment slurries daily. s -
Demineralization and remineralization solutions were replaced weekly.
Assessrrlçnt Me~hodolQgy
C~ : Al} demin~ralization and remineralization
~olutions were analyzed for fluoride ion by specific ion electrode before
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WO93/19728 f~ 61 PCT/US93/0333
use. Each individual test tube was analyzed for F- aflcer 7 and 14 days of
cycling. Changes in F- solution were calculated by subtracting the
starting values.
PhYsical analYses: Groups Al, A2, Bl, B2, and E were assessed by
cross-sectional microhardness profiles, as described below. The duplicate
radiotracer groups (Cl, C2, Dl, and D2) obviously could not be assessed
in this manner. They were assessed by radiotracer counting as desclibed
separately below.
At the end of the cycling period, teeth from groups A, B, and E
were thoroughly rinsed in DDW, sectioned longitudinally through the
center of the lesions produced, and embedded in epoxy resin w~th the cut
face exposed as described in detail previously (ten ~ate et al; Caries P~es.
1985: 19:335~341). After serially polishing the embedded teeth, each
lesion was assessed by cross-sectional microhardness) according to the
published methods in the references above. Indents were commenced at
25 ,um from the anatomical surface and repeated at 25 ~m intervals to a;
depth of 30Q llm, across the sectioned lesion and ;nto the sound
underlying enamel. This method has been shown to give results
comparable with microradiography (White and Featherstone, Caries P~es.
1987; 21:502~512).
The indentation lengths were converted as per our published
formula to volume percent, ~nineral and mineral loss ~Z) values (tlm x
vol % mineral) were calculated using Simpson's rule for each profile, for
each lesion on each tooth, as described previously (White and
Featherstone, Caries Res. 1987; 21:502-512). Mean values of ~Z for each
group were calculated, and mineral loss profiles were plotted as vol %
rr~neral vs. depth from the outer surface.
~iQ~ra~er ~n~ly$e~ s: Teeth from groups C and D were
thoroughly washed in DDW and the varnish was removed individually ,-
from each tooth by acetone. Eight stepwise abrasions were made for
each s~mple using small preweighed circles of silicon carbide paper (600
grade) to remove layers approximately 5 ~m thic~. Each sample was
weighed, dissolved into a scintillation cocktail and the radioactiYity
counted in a Searle scintillation counter. ~ ~
Results for sodium tripolyphosphate and pyrophosphate salt , ! `
products, with and without fluonde present, were compared. The
amount of lesion ~ormation was measured by the duplicate "cold" legs (A
16
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"wO 93/197~8 ~ 3 ~ 6 i PCI`/US93/03333
and B) described above as radiotracer material cannot be used in the
other laboratories.
Upt~ke of ~ripolyphosphate or pvrQ~kos~hate into çaries-likQ le~i~n~, I
This assay assessed the amount of upt~ke of sodium ~ ¦
S tripolyphosphate or pyrophosphate salts into preformed caries-like
lesions in human enamel in v~tro:
Test materi~l: Human dental enamel from molars with ca~es free
(by stereo microscope) buccal or lingual gurfaces. Teeth were cleaned
and prepared as described above for the pH cycling study.
Artifiçia}~eslesionformat~o~,: Artificialcaries-likelesionswere
produced in one wirldow (3 x 7 mm) on one enamel surface of molars
prepared in our standard manner by immersion for 5 days in a pH 5.0
bt~er (0.05 mollL lactate), 50 percent saturated with hydroxyapatite,
and with 0.2% carbopol, as per the method of White (Caries Res. 1987:
21:228-242). This system produced lesions approximately 100 1lm deep
in 5 days.
Immersion in tripolvphosphate or pvrQphQsphate salts: Teeth
with preformed caries-like lesions were individually immersed in 20mL
of a ~:3 slurry of sodium tripolyphosphate or pyrophosphate salts
20 dentifrice with 32p labeled sodium tripolyphosphate or pyrophosphate
salts added at similar concentration as used in the pH cycling
exper~ments above. Groups of 10 teeth each were used. The first group
was immersed for one hour and the second group for 4 hours for each of
sodit~n tripolyphosphate and pyrophosphate salts. ~t the end of the
25 immersion period the teeth were removed, rinsed in DDW alld
immediately air dried. They were assessed for radiotracer uptake using
the abrasion method as described above.
t,`
1. ;
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17
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WO g3/19728 ,~ S ~ ~ li i Pcr/us93/0333~
T~ble ~ ,
~elative mineral loss, ~Z (~olume % x 11m) as mean ~ralues
(SD _ standard deviation) for each group for upper and lower
w~ndows. Values are arranged iIl ascending order of ~Z
Svalues for the upper window.
Test Group Product Description Mean ~Z (vol % x ~lm)
Upper Window Lower Window
A2 PPil Toothpaste, with NaF3 29~ (346) 318
(368) .
Al STPPZ toothpaste, with NaF 597 (425) 273
(638)
Bl STPP without NaF 1300 (814) 1996 (834)
B~ PPi without NaF 1399 (6~2) 2671 (1643)
E Placebo, no NaF, no
STPP, no PPi 3809 (584) 5069 (1092) ~ -
1 PPi means potassium pyrophosphate/sodium pyropho~phate (4.0~o/1.81%)
2 STPP means sodium tripolyphosphate (5%).
3 NaF at a concentration su~cient to g~ve 1100 ppm F-.
Both sodium tripolyphosphate and potassium/sodium
pyrophosphate mix demonstrated sigrlificant reduction in caries as
compared w~th the placebo, and approaching that demonstrated by the
combination of these phosphates and NaF.
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