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Description  |
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FIELD OF INVENTION
The invention relates to emulsions which are suitable for topical
application to skin or hair, more particularly to emulsions comprising a
2-hydroxyalkanoic acid or a salt thereof or other skin benefit agents.
BACKGROUND AND PRIOR ART
The use of 2-hydroxyoctanoic acid in products for topical application to
human skin has been proposed in EP-A 0 007 785 (Unilever). There remains,
however, a problem in delivering this acid to subcutaneous regions of the
skin, where its benefit of increasing the extensibility of stratum corneum
is maximised.
An attempt has subsequently been made, as described in EP-A-0 117 080
(Unilever), to improve the delivery of amphiphylic compounds such as
2-hydroxyoctanoic acid by the use of an emulsifier having an average HLB
value of from 5 to 11, which is capable with water of forming a gel phase
having an X-ray reflection of from 0.37 to 0.44, and which permits
substantially no co-crystallisation with the amphiphylic compound.
Although improved delivery of 2-hydroxyoctanoic acid has been demonstrated
with compositions based on the emulsifier system disclosed in this
reference, their shelf life is limited, in that syneresis tends to occur
after storage at 45.degree. C. (the normal maximum storage temperature for
testing stability) for only a few weeks. Such limitations as to storage
stability virtually rule out the possibility of employing such systems in
products where many weeks or months may elapse during storage prior to
sale or prior to use by the consumer.
We have now discovered that by selecting a special emulsifier not
previously proposed for use with 2-hydroxyoctanoic acid and related
substances, that emulsions can be prepared which are completely stable
during storage at 45.degree. C. for at least 12 months, or longer at lower
storage temperatures, and which also show excellent freeze-thaw stability
following cooling to -22.degree. C., thus providing an answer to a long
felt need for superior storage stability characteristics. Furthermore,
emulsions containing certain other skin benefit agents in place of or in
addition to 2-hydroxyalkanoic acids such as 2-hydroxyoctanoic acid, also
benefit from exceptional storage stability when using the special
emulsifier.
DEFINITION OF THE INVENTION
Accordingly, the invention provides an emulsion suitable for topical
application to human skin or hair, which comprises in addition to water:
(i) from 0.01 to 20% by weight of a skin benefit ingredient chosen from:
Retinoic acid
Retinyl palmitate
Ascorbic acid
Ascorbyl palmitate
Tocopherol
Tocopherol acetate
Pyroglutamic acid and salts thereof
Amino acids
Sunscreens
Hyaluronic acid and salts thereof
Perfluoropolyether
Hydrocortisone acetate and
a 2-hydroxyalkanoic acid having from 3 to 20 carbon atoms, or a salt
thereof; and
mixtures thereof;
(ii) from 0.1 to 20% by weight of polyoxyethylene-21-stearyl ether as a
principle emulsifier; and
(iii) from 0.5 to 70% by weight of an emollient oil.
DISCLOSURE OF THE INVENTION
The Emulsion
The emulsion according to the invention will normally contain an aqueous
phase and an oily phase and will comprise a selected skin benefit
ingredient, a special emulsifier and an emollient oil.
The emulsion preferably possesses a continuous aqueous phase in which case
it is an oil-in-water emulsion, the aqueous phase comprising from 98 to
60% by volume and the oily phase from 2 to 40% by volume of the emulsion.
Alternatively, the emulsion can possess a continuous oily phase, in which
case it is a water-in-oil emulsion, the aqueous phase usually comprising
from 25 to 70% by volume and the oily phase from 75 to 30% by volume of
the emulsion. However, the emulsion can also be a high internal phase
water-in-oil emulsion, in which case the aqueous phase can comprise up to
98% by volume of the emulsion, the oily phase then forming as little as 2%
by volume of the emulsion.
The form of the emulsion, whether oil-in-water or water-in-oil, will
largely depend upon the average HLB value of the emulsifier(s) which is
employed, values greater than 8 generally giving rise to oil-in-water
emulsions and values of up to 8 generally giving rise to water-in-oil
emulsions.
The Emulsion Ingredients
(i) The skin benefit ingredient
The emulsion according to the invention comprises a skin benefit ingredient
chosen from
Retinoic acid
Retinyl palmitate
Ascorbic acid
Ascorbyl palmitate
Tocopherol
Tocopherol acetate
Pyroglutamic acid and salts thereof
Amino acids
Sunscreens
Hyaluronic acid and salts thereof
Perfluoropolyether
Hydrocortisone acetate and
a 2-hydroxyalkanoic acid having from 3 to 20 carbon atoms, or a salt
thereof; and
mixtures thereof;
The emulsion can also comprise a mixture of two or more skin benefit
ingredients. Particularly preferred examples of amino acids include:
glycine
alanine
valine
leucine
isoleucine
phenylalanine
tyrosine
proline
hydroxyproline
serine
threonine
cysteine
cystine
methionine
tryptophan
aspartic acid
glutamic acid
arginine
lysine, and
histidine.
The amount of amino acid that can be employed in accordance with the
invention will normally be from 0.01 to 20%, preferably from 0.1 to 10% by
weight of the emulsion. Particularly preferred examples of sunscreen
active ingredients include:
p-Aminobenzoic acid
Ethyl dihydroxypropyl p-aminobenzoic acid (such as Amerscreen P)
Glyceryl p-aminobenzoic acid (such as Escalol 106)
2,4-Dihydroxy benzophenone (such as Uvinul 400)
2-Ethoxyethyl-p-methoxycinnamate (such as Giv Tan F)
Di-ethanolamine p-methoxycinnamate (such as Parsol Hydro)
2-Ethylhexyl salicylate (such as Sun Arome WMO)
Homomethyl salicylate (such as Filtrosol A)
2-Phenylbenzimidazole-5-sulphonic acid (such as Eusolex 232)
Octyl methoxycinnamate (such as Parsol MCX).
3-(4-Methylbenzylidine) camphor (such as Eusolex 6300)
2-Hydroxy-4-methoxy benzophenone (such as Eusolex 4360)
Butylmethoxydibenzoylmethane (such as Parsol 1789)
4-isopropyl dibenzoylmethane (such as Eusolex 8020).
The amount of the sunscreen active ingredient that can optionally be
employed in accordance with the invention, as a therapeutically effective
amount, will normally be from 0.01 to 10%, preferably from 0.1 to 5% and
most preferably from 1 to 5% by weight of the emulsion.
Particularly preferred examples of 2-hydroxyalkanoic acids include
2-hydroxypropanoic acid, 2-hydroxyhexanoic acid and 2-hydroxyoctanoic
acid. Further examples include 2-hydroxy-N-butanoic acid,
2-hydroxydecanoic acid, 2-hydroxydodecanoic acid and 2-hydroxyoctadecanoic
acid.
Examples of salts of the above 2-hydroxyalkanoic acids are the sodium,
potassium and triethanolamine salts, although it is to be understood that
other metallic, ammonium or alkanolammonium salts are useful.
The emulsion according to the invention can comprise mixtures of
2-hydroxyalkanoic acids and/or salts and/or an acid soap complex thereof.
The most preferred 2-hydroxyalkanoic acid is 2-hydroxyoctanoic acid or its
acid soap complex having the empirical formula
C.sub.16 H.sub.31 O.sub.6 M
where M is a cation chosen from sodium, potassium and ammonium.
The amount of skin benefit ingredient present in the emulsion according to
the invention is usually from 0.01 to 20%, preferably from 0.1 to 10% by
weight of the emulsion.
(ii) The Principle Emulsifier
The emulsion according to the invention comprises as the principle
emulsifier polyoxyethylene-21-stearyl ether, also known as
polyoxyethylene-21-stearyl alcohol, an example of which is Brij 721
(available from ICI). This emulsifier has an HLB value of about 15.5 and
if used alone will yield an oil-in-water emulsion.
The amount of polyoxyethylene-21-stearyl ether present in the emulsion
according to the invention is usually from 0.1 to 20%, preferably from 0.5
to 10% by weight of the emulsion.
(iii) The Emollient Oil
The emulsion according to the invention comprises an emollient oil, that is
an oily substance that is substantially insoluble, or only slightly
soluble in water, and which usually constitutes the major ingredient of
the oily phase of the emulsion.
Examples of emollient oils include the following:
1. Hydrocarbon oils and waxes: examples of which include, mineral oil,
petrolatum, paraffin, ozokerite, microcrystalline wax, polyethylene and
perhydrosqualene (squalane).
2. Silicone oils: examples of which include, dimethyl polysiloxanes,
methylphenyl polysiloxanes.
3. Triglyceride esters: examples of which include, vegetable and animal
fats and oils, such as caprylic and capric triglycerol (available as
Migliol 812), wheatgerm oil, apricot kernel oil, avocado oil, sunflower
seed oil, arnica oil, evening primrose oil and jojoba oil.
4. Acetoglyceride esters: examples of which include, acetylated
monoglycerides.
5. Alkyl esters: examples of which include, methyl, isopropyl, and butyl
esters of fatty acids; hexyl laurate, isohexyl laurate, isopropyl
myristate, isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl
(isocetyl) stearate, diisopropyl adipate, diisohexyl adipate, dihexadecyl
adipate, diisopropyl sebacate, lauryl lactate, myristyl lactate, and cetyl
lactate.
6. Alkenyl esters: examples of which include, oleyl myristate, oleyl
stearate, and oleyl oleate.
7. Fatty acids: examples of which include, lauric, myristic, palmitic,
stearic, isostearic, hydroxystearic, oleic, linoleic, linolenic,
.gamma.-linolenic, ricinoleic, arachidic, behenic, erucic, and lanolin
acids.
8. Fatty alcohols: examples of which include, lauryl, myristyl, cetyl,
hexadecyl (isocetyl), stearyl, isostearyl, hydroxystearyl, oleyl,
ricinoleyl, behenyl and erucyl alcohols, and 2-octyl dodecanol.
9. Fatty alcohol ethers: examples of which include, ethoxylated lauryl,
cetyl, stearyl, isostearyl, oleyl, and lanolin alcohols; and cholesterol;
propoxylated cetyl, oleyl, and lanolin alcohols; and also
polypropylene-15-stearyl ether.
10. Ether-esters: examples of which include, fatty acid esters of
ethoxylated fatty alcohols.
11. Lanolin and lanolin derivatives: examples of which include, lanolin,
lanolin oil, lanolin wax, lanolin alcohols, lanolin fatty acids and
acetylated lanolin derivatives.
12. Wax esters: examples of which include, lanolin (de-oiled wax fraction),
beeswax, spermaceti, myristyl myristate, stearyl stearate.
13. Beeswax derivatives: examples of which include, polyoxyethylene
sorbitol beeswax. These are reaction products of beeswax with ethoxylated
sorbitol of varying ethylene oxide content, forming a mixture of
ether-esters.
14. Vegetable waxes: examples of which include, carnauba, candelilla.
15. Phopholipids: examples of which include, lecithin and derivatives.
16. Sterols: Cholesterol, cholesterol fatty acid esters.
The amount of emollient oil present in the emulsion according to the
invention is usually from 0.5 to 70%, preferably from 1 to 60% by weight
of the emulsion.
Other emulsion ingredients
(i) Secondary Emulsifiers
The emulsion according to the invention can also comprise one or more
secondary emulsifiers, in addition the principle emulsifier
polyoxyethylene-21-stearyl ether.
Examples of secondary emulsifiers include:
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HLB value
______________________________________
BRIJ 72 (Polyoxyethylene-2-stearyl ether)
4.9
BRIJ 52 (Polyoxyethylene-2-cetyl ether)
5.3
______________________________________
The presence of a secondary emulsifier can result in the formation of a
water-in-oil emulsion, if the average HLB of all emulsifiers present does
not exceed 8. The preferred emulsions according to the invention are,
however oil-in-water emulsions.
The amount of secondary emulsifiers that optionally can be present in the
emulsion according to the invention is up to 20%, preferably from 0.1 to
10% by weight of the emulsion.
(ii) Thickeners
The emulsion according to the invention can also optionally comprise a
thickener, examples of which include:
xanthan gum, such as Rhodopol 23,
aluminum starch octenylsuccinate, such as Dry Flo starch,
carboxyvinyl polymer, such as Carbopol 938, 940 & 941
carboxymethyl cellulose, and
hydroxypropylmethyl cellulose.
The amount of thickener that optionally can be present in the emulsion
according to the invention will depend upon which thickener is chosen, the
amount being that conventionally employed as recommended by the respective
manufacturer. Generally, the amount of thickener will be up to 10%,
preferably from 0.1 to 5% by weight of the emulsion.
(iii) Skin Delivery Enhancers
The emulsion according to the invention can also optionally comprise one or
more substances to enhance delivery of the skin benefit ingredient to the
stratum corneum. Examples of skin delivery enhancers, which can function
in a variety of ways, include:
2-methyl propan-1-ol
Propane-1,2-diol
Ethyl-2-hydroxypropanoate
Hexane-2,5-diol
POE (2) ethyl ether
Di (2-hydroxypropyl) ether
Pentane-2,4-diol
POE (2) methyl ether
Tetrahydrofuran
Butane-1,3-diol
Propylene glycol dipelargonate
Octyl alcohol
POE ester of oleyl alcohol
Oleyl alcohol
Lauryl alcohol
Dioctyl adipate
Dicapryl adipate
Diisopropyl adipate
Diisopropyl sebacate
Dibutyl sebacate
Diethyl sebacate
Dimethyl sebacate
Dioctyl sebacate
Dibutyl suberate
Dioctyl azelate
Dibenzyl sebacate
Dibutyl phthalate
Dibutyl azelate
Ethyl myristate
Dimethyl azelate
Butyl myristate
Dibutyl succinate
Didecyl phthalate
Decyl oleate
Ethyl caproate
Ethyl salicylate
Ethyl laurate
2-ethyl-hexyl pelargonate
Isopropyl isostearate
Butyl laurate
Benzyl benzoate
Butyl benzoate
Hexyl laurate
Ethyl caprate
Ethyl caprylate
Butyl stearate
Benzyl salicylate
Glycerol.
The amount of skin delivery enhancer, when employed in accordance with the
invention, will normally be from 0.1 to 50%, preferably from 0.5 to 25%
and most preferably from 0.5 to 15% by weight of the emulsion.
(iv) Perfume
The emulsion according to the invention can also optionally comprise a
perfume in an amount sufficient to make the emulsion acceptable to the
consumer and pleasant to use. Usually, the perfume when present will form
from 0.01 to 10% by weight of the emulsion.
(v) Further optional ingredients
The emulsion according to the invention can also optionally comprise
further ingredients in addition to those already described, such as
colourants, whiteners, preservatives, antioxidants, or aerosol
propellants, in amounts which are conventional in the cosmetics art.
pH
The emulsion according to the invention should normally have a pH value of
from 3 to 7, preferably from 3.8 to 5 and ideally from 4 to 4.5.
When the emulsion is an oil-in-water emulsion, the continuous phase being
the aqueous phase, then the pH value can be measured directly from a pH
electrode placed in the emulsion.
When the emulsion is a water-in-oil emulsion, the continuous phase being
the oily phase, then direct pH measurement of the emulsion is not
possible. In this case, the pH value refers to that of the aqueous phase
before emulsifying in the presence of the oily phase.
PRODUCT FORMS AND PACKAGING
The topical skin treatment emulsion of the invention can be formulated as a
fluid, for example in a product such as a lotion, with or without an
applicator such as a roll-ball applicator, or a propellant-driven aerosol
device or a container fitted with a pump to dispense the composition, for
example as a mousse or simply for storage in a non-deformable bottle or
squeeze container. Alternatively, the composition of the invention may be
solid or semi-solid, for example a cream or ointment, for use in
conjunction with a suitable applicator, or simply for storage in a tube or
lidded jar.
More particularly, the viscosity of the emulsion will determine whether it
is a lotion or a cream. For example, when the viscosity of the emulsion is
measured using the Brookfield Viscometer (10 rpm, measured at 20.degree.
C. using spindles A to D as appropriate) then the following viscosity
values provide a guide to the nature of the emulsion.
______________________________________
Viscosity (mPas) Description of emulsion
______________________________________
up to 2,000 milk
2,000 to 5,000 thin lotion
5,000 to 8,000 normal pourable lotion
8,000 to 10,000 thick lotion*
10,000 to 15,000 thin cream
15,000 to 30,000 normal cream
30,000 to 100,000 thick cream
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*dispensible from a squeeze container.
The invention accordingly also provides a closed container containing a
cosmetically acceptable composition as herein defined.
PREPARATION AND PRODUCT FORM OF THE EMULSION
The emulsion of the invention can be prepared in the form of a lotion,
cream, gel, ointment, solid stick or aerosol, or in any other form suited
to administration topically to human skin.
Accordingly, the invention also provides a process for the preparation of
an emulsion suitable for topical application to human skin or hair, which
process comprises the steps of:
i. preparing an aqueous phase, buffered to a pH value of from 3 to 7,
comprising a skin benefit ingredient as herein defined, preferably a
2-hydroxyalkanoic acid or derivative thereof having from 3 to 20 carbon
atoms, together with further water-soluble or water-dispersible
ingredients as necessary.
ii. preparing an oily phase comprising emollient oil and
polyoxyethylene-21-stearyl ether as emulsifier, together with other oil
soluble ingredients;
iii. adding the oily phase preheated to a temperature of at least
70.degree. C. to the aqueous phase, also preheated to a temperature of at
least 70.degree. C., with high shear mixing to form an emulsified mixture;
iv. cooling the emulsified mixture to a temperature of from 35.degree. to
50.degree. C. and adding the aqueous buffer with low shear mixing;
v. cooling to a temperature of not greater than 35.degree. C. and adding
preservatives and perfume as required with further mixing;
to obtain emulsion as herein defined.
EVIDENCE TO DEMONSTRATE SUPERIOR STORAGE
STABILITY OF EMULSIONS
As has been stated earlier, the emulsions of the invention exhibit superior
stability during storage at 45.degree. C. to any other emulsion containing
skin benefit ingredients, such as 2-hydroxyalkanoic acids.
This superiority was demonstrated using a formulation comprising the
principle emulsifier, namely, polyoxyethylene-21-stearyl ether, compared
with two similar formulations, in which this principle emulsifier had been
replaced by other emulsifiers.
The basic lotion formulation contained the following ingredients
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% w/w
______________________________________
2-hydroxy alkanoic acids
2-hydroxy propanoic acid
4.0
2-hydroxy octanoic acid
1.0
Emulsifier as selected*
1.8
Emollient oils
lanolin derivative 0.95
wheatgerm oil 0.05
isopropyl myristate 1.0
cetyl palmitate 2.0
wax 2.0
fatty alcohol 1.2
silicone oil 6.0
Thickeners
aluminium starch octenyl succinate
3.0
xanthan gum 0.1
Delivery enhancer
butane-1,3-diol 9.45
Other ingredients
whitener 0.15
preservatives 0.36
water to 100
______________________________________
Three lotions were prepared based on the above formula: these were
identical except for the emulsifiers which were as follows:
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Lotion Emulsifier*
______________________________________
A Brij 58 (polyoxyethylene-20-cetyl ether)
B Brij 78 (polyoxyethylene-20-stearyl ether)
C Brij 721 (polyoxyethylene-21-stearyl ether)
______________________________________
Results
The following results were obtained after storage:
(i) Stability data
The results of storage tests at -22.degree. C.(4 F/T cycles), 20.degree.
C., 35.degree. C. and 45.degree. C. on the three basic lotion models are
given in Table 1.
TABLE 1
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Stability Data for Lotion Models
Freeze-Thaw
Cycles (.times. 4)
Lotion
at -22.degree. C.
20.degree. C.
35.degree. C.
45.degree. C.
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A Stable Stable Stable for
Stable for
after for 18 months
1 mth then
1 mth then
4 .times. oil on separated
surface
B Stable Stable Stable for
Stable for
after for 18 months
3 mths then
2 mths then
4 .times. separated
separated
C Stable Stable for 20
Stable for
Stable for
after months 13 months
13 months
4 .times. (storage ongoing)
______________________________________
Table 1 shows that all three lotions survived four freeze-thaw cycles at
-22.degree. C. With regard to the storage data, there appears to be a
trend in the stability conferred by the emulsifiers on the o/w emulsions
such that, that containing Brij 721 was clearly far more stable, even when
stored at 45.degree. C., than those containing either Brij 78 or Brij 58.
This confirmed that Lotion C in accordance with the invention exhibited
unexpected superior storage characteristics.
(ii) Microstructure of Lotions
The microstructure of each lotion was studied 24 hours after preparation,
and then after 3 months storage at 20.degree. C., and after 6 months
storage at 20.degree. C. The results obtained are given in Table 2.
TABLE 2
______________________________________
Results from Microstructure Studies (magnification .times. 100)
24 hr after
After 3 mths After 6 mths
Lotion
preparation
storage at 20.degree. C.
storage at 20.degree. C.
______________________________________
A Emulsion Flocculation Islets of coalesced
appeared and some oil droplets; some
stable coalescence phase separation.
B Emulsion Flocculation Coalescence of
appeared of oil oil droplets
stable droplets
C Emulsion Microstructure
No gross changes in
appeared unaltered. microstructure and
stable. no evidence of
Particle flocculation or
size smaller coalscence.
than for
Lotions A
or B
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The microstructure results reported above provide further evidence to
support the finding that the most stable lotion was Lotion C in accordance
with the invention.
(iii) Rheology of lotions
All three lotions A, B and C showed some thickening during storage see
Table 3. Of the three, Lotion C showed the least change after six months
storage. The results obtained are given in Table 3.
TABLE 3
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Viscosity Data using Brookfield Viscometer
(at 20.degree. C., 10 rpm using Spindle B)
VISCOSITY
24 hr after
After 6 mths
preparation
storage at 20.degree. C.
Lotions (mPas) (mPas)
______________________________________
A 4200 6200
B 1200 8400
C 6000 7200
______________________________________
The viscosity measurements reported above indicate that Lotion C, whose
initial viscosity was ideal to enable it to be used as a normal pourable
lotion, showed the least change in viscosity during prolonged storage,
whereas the comparative Lotions A and B, both of which were too thin for
use 24 hours after preparation, showed unacceptable increases in viscosity
during storage.
Evidence to Demonstrate Increase in Extensibility of Stratum Corneum
The ability of the emulsion according to the invention to enhance the
delivery to skin of 2-hydroxyoctanoic acid, as an example of the 2-hydroxy
alkanoic acids, or salts thereof, as herein defined, was measured in terms
of the increase in extensibility of heat-separated guinea pig foot pad
stratum corneum following contact with the emulsion, as compared with
another emulsion which did not contain polyoxyethylene-21-stearyl ether.
In this experiment, pieces of guinea pig foot pad stratum corneum,
equilibrated at a relative humidity of 64%, were immersed in each emulsion
or control for 3 hours at 20.degree. C., and then removed, blotted dry and
re-equilibrated at the same relative humidity. The extensibility of each
piece of guinea pig foot pad stratum corneum was measured before and after
this treatment in an extensiometer according to the method described in
EP-A-0 007 785.
Results
The results of this experiment are tabulated below:
TABLE 4
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In Vitro Extensibility Data (20.degree. C., 64% RH)
Lotion Extensibility ratio
(.+-. 2 Standard errors)
______________________________________
A 6.6 (+1.8)
C 8.1 (+1.4)
______________________________________
The above results indicate that there is an 23% increase in extensibility
in vitro when the principle emulsifier, as herein defined, is employed
(i.e. Lotion C in accordance with the invention), compared with control
Lotion A containing an ordinary emulsifier. This confirms significantly
enhanced delivery to the stratum corneum of 2-hydroxyoctanoic acid using
the emulsion of the invention as compared with a control emulsion.
EXAMPLES
The invention is further illustrated by the following examples.
EXAMPLE 1
This example illustrates an oil-in-water skin cream according to the
invention.
______________________________________
% w/w
______________________________________
Skin benefit ingredients
2-hydroxypropanoic acid
4.0
2-hydroxyoctanoic acid
1.0
Principle emulsifier 2.4
polyoxyethylene-21-stearyl ether
Secondary emulsifier 2.6
polyoxyethylene-2-stearyl ether
Emollient oils
polyoxypropylene-15-stearyl ether
8.0
fatty alcohol 4.0
silicone oil 0.1
Delivery enhancer 5.0
butane-1,3-diol
Other ingredients
preservative 0.36
pH adjustant 3.36
perfume 0.1
water 69.08
100.00
______________________________________
The cream had a pH value of 4.
EXAMPLE 2
This example illustrates an oil-in-water skin lotion according to the
invention.
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% w/w
______________________________________
Skin benefit ingredients
2-hydroxy propanoic acid
4.0
2-hydroxy octanoic acid
1.0
Principle emulsifier 1.8
polyoxyethylene-21-stearyl ether
Emollient oils
lanolin derivative 0.95
wheatgerm oil 0.05
isopropyl myristate 1.0
cetyl palmitate 2.0
wax 2.0
fatty alcohol 1.2
silicone oil 6.0
Thickeners
Aluminium starch octenyl succinate
3.0
xanthan gum 0.1
Delivery enhancer 9.45
butane-1,3-diol
Other ingredients
whitener 0.15
preservatives 0.36
pH adjustant 3.36
perfume 0.1
water 63.48
100.00
______________________________________
The lotion had a pH value of 4.
______________________________________
Viscosity: Brookfield Viscometer, 10 rpm, Spindle B
measured at 20.degree. C.
Storage time: 24 hrs 6 months
______________________________________
Viscosity (in mPas)
6000 7200
______________________________________
EXAMPLE 3
This example illustrates on oil-in-water fluid skin cream according to the
invention.
______________________________________
% w/w
______________________________________
Skin benefit ingredients
2-hydroxy propanoic acid
4.0
2-hydroxy octanoic acid
1.0
Principle emulsifier 1.8
polyoxyethylene-21-stearyl ether
Emollient oils
lanolin derivative 0.95
wheat germ oil 0.05
cetyl palmitate 2.0
isopropyl myristate 1.0
wax 3.0
fatty alcohol 1.2
silicone oil 5.0
Thickeners
aluminium starch octenyl succinate
3.0
xanthan gum 0.1
Delivery enhancer 9.45
butane-1,3-diol
Other ingredients
whiteners 0.15
preservative 0.36
pH adjustant 3.36
perfume 0.1
water 63.48
100.00
______________________________________
The emulsion had a pH value of 4.
______________________________________
Viscosity: Brookfield Viscometer, 10 rpm, Spindle B
measured at 20.degree. C.
Storage time: 24 hrs 13 weeks
______________________________________
Viscosity (mPas) 5800 22,000
______________________________________
EXAMPLE 4
This example illustrates an oil-in-water skin cream according to the
invention.
______________________________________
% w/w
______________________________________
Skin benefit ingredients
2-hydroxy propanoic acid
4.0
2-hydroxyoctanoic acid
1.0
Principle emulsifier 0.94
polyoxyethylene-21-stearyl ether
Secondary emulsifier 0.86
polyoxyethylene-2-stearyl ether
Emollient oils
lanolin derivative 0.95
wheat germ oil 0.05
isopropyl myristate 1.0
cetyl palmitate 2.0
ozokerite wax 3.0
fatty alcohol 1.2
silicone oil 5.0
Thickeners
aluminium starch octenyl succinate
3.0
xanthan gum 0.1
Delivery enhancer 9.45
butane-1,3-diol
Other ingredients
whitener 0.15
preservatives 0.36
pH adjustant 3.36
perfume 0.1
water 63.48
100.00
______________________________________
The cream had a pH value of 4.
______________________________________
Viscosity: Brookfield Viscometer, 10 rpm, Spindle D
measured at 20.degree. C.
Storage time: 24 hrs
______________________________________
Viscosity (mPas) 50,000
______________________________________
EXAMPLE 7
This example illustrates an oil-in-water emulsion according to the
invention.
______________________________________
% w/w
______________________________________
Skin benefit ingredients
retinyl palmitate 0.10
octyl methoxy cinnamate
3.00
butylmethoxydibenzoylmethane
1.50
Emulsifiers
polyoxyethylene-21-stearyl ether
2.40
polyoxyethylene-2-stearyl ether
2.60
Emollient oils
wheatgerm oil 0.10
caprylic/capric triglycerides
5.00
silicone oil 2.50
evening primrose oil 0.40
Delivery enhancer 5.00
glycerol
Other ingredients
allantoin 0.50
preservatives 0.36
perfume 0.15
water to 100%
______________________________________
The emulsion will have a pH value of from 3 to 7.
EXAMPLE 8
This example illustrate an oil-in-water emulsion according to the
invention.
______________________________________
% w/w
______________________________________
Skin benefit ingredients
L-proline 0.1
octyl methoxycinnamate
1
Emulsifiers
polyoxyethylene-21-stearyl ether
3
polyoxyethylene-2-stearyl ether
2
Emollient oils
stearyl alcohol 1
polyoxypropylene-15-stearyl ether
10
silicone oil 0.5
evening primrose oil 1
Delivery enhancer 4
propane-1,4-diol
Other ingredients
preservative and perfume
qs
water to 100
______________________________________
This emulsion will have a pH value of from 3 to 7.
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