Note: Descriptions are shown in the official language in which they were submitted.
Wo 92/15280 2 1 0 ~ ~ 7 3 PCT/EP92/qO~56
A topiaal ~o~p gel pr~paratio~
This invention relates to a shaped preparation
based on a soap gel for the application of active
cosmetic and pharmaceutical substances, particularly in
stick form, which, by virtue of its composition, shows
very good dimensional stability at normal temperature
coupled with good trans~er properties and which is
substantially free from lower alcohols.
Soap gels as carriers ~or topical cosmetic and
pharmaceutical active substances h~ve long been known.
Sodium stearate gels in aqueous lower alcohols and
glycols are normally used as the soaps. Unfortunately,
gels such as these have the disadvantage that they are
generally too stiff and, when applied to the skin, only
transfer very little product thereto. In order to
improve the transfer properties of soap gel preparations
Q~ the type in question, it was proposed in US 2,900,306
to incorporake a water-soluble myristic a~id soap in the
preparation. Other documents recommended the addition
of fatty acid esters and ethylene oxide and propylene
oxi~e condensates to improve ~he gel time and to reduce,
syneresis and;tackine s (U8 4,617~1~5). Some of these
additives have an unfavorable ~ffect on the transparency
of the preparation.
Accordingly, the problem addressed by the present
invention was to provide a~shaped soap gel preparation
~` which ~would~ show high transparency, high dimensional
stability and satisfactory trans~er on contact with ~he
skin. ~ ~
~ According to the invention, this problem has been
. .
sol~ed by a soap gel preparation~for the topical appli-
cation of cosmetic and pharmaceutical substances based
on a gel of alkali metal soaps containing
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3 to 10% by weight of a mixture of Cl622 fatty acids in
the form of their alkali metal
soaps,
30 to 90% by weight polyols containing 3 to 6 carbon
atoms and 2 to 6 hydro~yl groups,
1 to 30% by weight water
and active cosmetic or pharmaceutical substances and,
optionally, other typical auxiliaries,
characterized in that the fatty acid mixture contains
60 to 95% by weight linear saturated fatty acids and
5 to 40% by weight branched ~akurated fatty acids.
The effect o~ the presence of soaps of branched-
chain fatty acids is that, although the preparations
; retain their firmness at temperatures below 35C, they
:~ immediately melt to a limited extent and become slippery
on contact with the skin SG that a thin film of the
prepar~tion can easily b~ applied to the skin.
Suitable linear saturated fatty acids are pal-
mitic acid,~stearic acid, arachic acid and behenic acid
~: ; or technical mixtures predominantly consisting of such
~ ~ : fatty acids, for e~ample hydrogenated palm oil fatty
:~ 25 acid or hydrogenated tallow fatty acid~ Stearic acid is
preferably used.~ ~
` Suitable branched saturated fatty acids are, for
example, 2-hexyl decano:ic acid, 2-octyl dodecanoic acid
or~other branched fatty acids containing 16 to 22 carbon
;: 30 atoms. ; ;~
` ~ However,~ :isostearic acid is particularly suit-
able. Isostea~ric a~id is mainly understood to be a
mixture of l~iquid,~ branched-~chain isomers of stearic
a~id~which~ may be obtain~ed by hydrogenation of the
`~ 35 ~isomexic liquid monomer fatty acids formed as secondary
:~ ;
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Wo 92/15280 3 PCT/EP92/OQ456
product in the dimerization of unsaturated fatty acids.
This isostearic acid and other branched ~atty acids are
described in detail in J. ~m. Qil~ Chem. ~QC. November
lg79 (Vol. 56), pages ~23A - ~27A~ Accordingly, the
branched fatty acid in question is a mixture of which
the principal constituents are methyl-branched isomers.
Isostearic acid is a commercial product and is marketed,
for example, under the n~me ~mersol 875 ~Henkel Corp.~.
The mixture of linear and branched fatty acids is
completely or predominantly present in ~he form of an
alkali metal salt (alkali metal soap), preferably in the
form of sodium soap. However, a cerkain percentage
content o~ free unsaponi~ied fatty acid, for example of
the order of 0~01 to 0.5% by weight, based on the
preparation as a whole, is not problematical.
The quantity ratio o~ linear to branched fatty
acids in the fatty acid mixtuL~e to be used in accordance
with the invention has a bearing on the firmness of the
soap gel preparation and on its transfer behavior.
Firmness decreases and transfer to the skin increases
,
with increasing isostearic acid content. However, these
parameters are also inf1uenced by the total content of
fatty acids ~in the gel. ~The ~atty acid mixture is
preferably;used in a ~uantity of 5 to ~ by weiyht. The
-~ 25 fatty acid mixture preerably consists of 80 to 95% by
weight stearic acid ~and 5 to 20% by weight branched
saturated fatty acids. ~ ~
Suitable pol~yols containing 3 ~o 6 carbon atoms
and 2 to 6~hydroxyl groups~;are, for example, ethylene
glycol, 1,2-propylene glycol, 1,3-propylene glycol,!l,2-
I' / . ,~ ' I / , ': ~ ~
butylene glycol, 1,3-butylene glycol, 1,4-butylene gly-
col~, glycerol, erythritol,~pentaerythritol, trimethylol
propane, sorbitol, anhydrosorbitol, cyclohexane triol,
inositol. Propyle~e glycols and glycerol individually
or in admixture with sorbitol and/or butylene glycol are
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wo g2,l5280 2 1 0 ~ 8 7 3 PCT/EP92/00456
particularly preferred. These polyols are preferably
present in a total quantity of 70 to 90% by weight,
based on the soap gel preparation as a whole. Particu-
larly favorable performance properties are obtained when
mixtures of 10 to 80~ by weight glycerol, 10 to 80% by
weight propylene ylycol and 5 to 20% by weight sorbitol
and/or 1,4~butylene glycol are present as the polyols.
A particularly dimensionally stab.le, transparent
soap gel preparation showing ~avorable trans~er proper-
ties to the skin contains:
5 to 8% by weigh~ of the fatty acid mixture in the
form of the sodium so~ps,
70 to 90% by weight polyols from the group con-
sisting of glycerol, 1,2-
propylene glycol, 1,3-propylene
glycol or mixtures thereo~ with
sorbitol and/or 1,4-butylene
glycol and
20 5 to 25~ by weight water.
The soap: gel preparations according to the
invention ar~ used for the topical application of active
: cosmetic and~pharmaceutical substances. The substances
2S in question are:incorporated în the soap gel prepara~ion
in the dosage required:fvr the particular application.
Active casmeti~c substances in the context of the inven-
tion are, for example, antimicrobial, deodorizing, skin-
moisturizin~ perspiration-inhibiting, depilating,
~: 30 coloring; and~ perfuming substances and also cosmetlc
oils. Active~pha~maceutical substances in the context
of the invention:are~,~for example, antibiotics, cortico-
~ ,. .
steroids:, local~anaesthetics and other substances which
may be used against skin disorders. The quantity in
~, ~
~ 35 which the cosmetic or: pharmaceutical substances are
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Wo 92/15280 5 PCT/EP92/l00456
incorporated is generally of the order of 0.1 to 5% by
weight and preferably in the range from 0.1 to 1% by
weight, based on the preparation as a whole.
In a particularly preferred embodiment, the soap
gel preparations according to the invention are used as
stick deodorants. According to the invention, deodoriz-
ing substances are present as active cosmetic substances
in products such as theæe. Suitable deadorizing sub-
stances are, for example, antimicrobial agents such as,
for example, 2,4,4'-trichloro-2'-hydroxydiphenyl ether
(Irgasan ~P300), chlorhexldine diglucona~e or phenoxy-
ethanol, deodorizing antimicrobial ethereal oils,
farnesol, lipase inhibitors such as, for example,
triethyl citrate or triacetin, astringent substances
such as, for example, sodium aluminium chlorohydroxylac-
tate and o~her known persunal deodorants or antiper-
spirants.
In addition to~the active substances mentioned,
the soap gel preparations according to the invention may
contain other auxiliaries to improve their appearance
and stability in storage. The auxiliarîes in question
are, for example, complexing agents, antioxidants,
preservatives; fragrances, colorants, opacifiers"
pearlescing pigments;or fine-particle pyrogenic silica.
It has also been found that clouding and crysta~lization
in storage can be prevented by adding a water-soluble
salt, preferably sodium chloride, in a quantity of
approx. O.l;~to 0.3% by weight, based on the soap gel
preparation, as a further auxiliary. The total quantity
of auxiliaries should~make up no more than 5% by weight
` ' of the soaip gel preparation as a whole, the auxiliaries
n question preferably heing present in the preparation
in a total quantity of approximately 1 to 3% by weight.
The soap gel prepara~ions according to the
invention are preferably free from lower alcohols.
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wo g2/l5280 6 PCT/EPg2~00456
However, up to 10% by weight lower alcohols, for exampleethanol or isoprapanol, may optionally be incorporated
in the preparations.
The soap gel preparations according to the
invention are best produced by mixing polyols, water and
~atty acid mixtures in a vessel while heating to approx.
50 to ~0C, adding the alkali metal hydroxide to the
resulting mixture in the form of a concentrated aqueous
solution and stirring until saponification of the fatty
acids tQ form a clear solution is complete. The acti~e
subskances and auxiliaries may then be successively
incorporated during cooling. Finally, the product is
poured into a mold, for example into a stick tube, at a
temperature above its gel forming temperature and is
left to cool therein to a temperature at which it
solidifies into a dimensionally stable gel.
The invention is illustrated by the following
Examples:
E x a m p 1 e ~
: Soap gel preparations having the composition
shown in Table I were prepared as follows:
Polyols, water and fatty acids were mixed in a
: 25 vessel and heated to 70~C~ ~ The sodium hydroXide was
: added in portions to the resulting mix~ure, the paste
becoming clear and homogeneous through saponification.
- After the other additives and the perfume oil had been
added, the paste~was poured into stick tubes and left to
cool to +20C.
'oap gel sticks com~ining good dimensional
: ~ stability with very favorable transfer properties were
obtained.
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