Solid Cosmetic Antiperspirant Or Deodorant Stick Composition
Abstract:
Stick compositions having desirable sensory properties can be made by employing as primary gellant, a combination of amido structurants comprising (i) an N-acylaminoacid amide in which the N-acyl substituent has the formula -CO-Rx in which Rx represents a branched C6 to C₁₁ alkyl group and (ii) an N-acylaminoacid amide in which the N-acyl substituent contains a linear alkyl group and the cosmetic carrier oil comprising from 25 to 50% by weight of a water-immiscible monohydric alcohol that is liquid at 20o C and a boiling point of higher than 100o C.
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Notices, Deadlines & Correspondence
FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
STICK COMPOSITIONS
HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed.
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Stick Compositions
The present invention relates to stick compositions and in particular to such compositions containing a suspended antiperspirant or deodorant, and a carrier material therefor comprising a cosmetically acceptable water-immiscible oil that is solidified by an amido-substituted amino acid, and to their preparation and use.
Technical field Background and Prior Art
Cosmetic antiperspirant formulations are known and available to the public in several different physical forms for application using the corresponding type of applicator, including dispensers for powder mixes, foams, gelled or thickened liquids, liquids of low viscosity that can be sprayed, aerosol formulations, creams, soft solids and sticks. The preferred choice of physical form can often depend on the history of product, and local preferences, which may themselves vary over time as fashions change. One physical form which has been popular especially in North America for antiperspirant and deodorant compositions during the last twenty years is that of sticks. The term " stick" herein is employed in its natural meaning, that is to say a material that is firm to the touch, is often in the shape of a rod or bar and commonly is housed in a container comprising a barrel having an open end and an opposed piston which can be slid up the barrel to expel the stick, which retains its._ shape and integrity during its expulsion.
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Cosmetic antiperspirant sticks typically comprise an antiperspirant- active that is dissolved or suspended in a cosmetically acceptable carrier material of which at
5 least a fraction is a cosmetically acceptable water-immiscible oil.. In one highly desirable class of cosmetic sticks, the carrier material comprises either no polar liquid or no more than the proportion that can form a single liquid phase with the water-immiscible oil or
10 oil mixture.
One class of material that has hitherto been proposed for solidifying water-immiscible oils comprises non-polymeric fibre-forming structurants. A number of such
15 structurants comprise alkyl ester derivatives of certain saccharide, such as maltose or particularly cellobiose, and others comprise N-acyl amido derivatives of aminoacids, di- or tri-carboxylic acids or cyclohexane. The present invention is directed particularly to
20 compositions in which a continuous phase comprising a water-immiscible oil is solidified with N-acyl amido derivatives of aminoacids..
Many N-acyl amido derivatives of aminoacids that are
25 suitable for solidifying cosmetically-acceptable oils to a greater or lesser extent have been described by Ajinomoto Co Ltd in USP 3969087, including in particular derivatives of glutamic acid or aspartic acid. The derivative disclosed therein that was apparently the most
30 preferred by Ajinomoto was N-lauroylglutamic acid,-di-n-butylamide, as also indicated by the fact that for many years, it was the only such material that was commercially available from them (trade name GP-1).
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GP-1 structurant has been disclosed for use or used in structuring water-immiscible oils in cosmetic sticks, but often not by itself and instead in combination with one
5 or more structurants, for example providing the minor weight proportion of the structurant mixture. Thus, for example Hofrichter et al (Procter & Gamble) in USP 5650144, USP 5591424 and USP 5429816 describe the formation of sticks in which a cosmetic oil is solidified
10 with a mixture of a major proportion of 12-hydroxystearic acid or related compounds {primary gellant) and a minor proportion of an N-acyl aminoacid amide (secondary gellant), exemplifying GP-1 and related N-acyl glutamic acid di-amides in a weight proportion to 12-HSA of 2:6.
15 The combination of hydroxystearic acid and N-acyl
aminoacid amides gellants described in the Hofrichter patents supra can be processed under acceptable processing conditions, which is a very desirable attribute.
20
In the course of investigations leading to the instant invention, it was found that although sticks can be made using N-acyl aminoacid amides such as GP-1 as primary or sole gellant, the resultant product was comparatively
25 soft when made, depositing a "wet" oily film on skin when applied topically. Such a feel is disliked by consumers. Such disadvantageous properties tended to become worse during storage of the product.
30 The comparative softness of such products made using GP-1 has been recognised by Ajinomoto themselves. More recently, in USA-2002/0159961, Ajinomoto has described a selection of N-acyl amido derivatives of aminoacids from
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within the overall ranges described in USP 3969087. In this selection, the alkyl group R3 in the N-acyl substituent -CO-R3 is characterised by containing from 7
5 to 10 carbon atoms, and may be branched. The ^961 specification discloses that the new selection of aminoacid derivatives can be employed to gel non-polar organic liquids to produce harder gels. The '961. specification also discloses the formation of
10 antiperspirant compositions gelled by a representative
member of their selected gellants alone or mixed with GP-1, but as the minor gellant in combination with hydroxystearic acid as primary gellant (weight ratio of 2:7). Although compositions employing such a combination
15 of gellants can be processed relatively easily to form sticks, the resultant products exhibited unacceptable sensory properties, and deposited comparatively high weights of composition on a substrate.
20 in considering how to overcome the problem of poor sensory properties and high deposition of the composition, any investigator has also to make allowance for potential manufacturing difficulties when employing certain amido gellants. It becomes increasingly
25 difficult to form stick compositions as the concentration
of such gellants increases. The temperature at which a
water-immiscible cosmetic oil gels when employing N-acyl
aminoacid amide gellant having a branched N-acyl
substituent compared with the same amount of a like
30 gellant having a linear N-acyl substituent. For
otherwise identical compositions, the gellant having the
branched N-acyl substituent causes such a composition to
gel at a significantly higher temperature, for example a
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difference of over 20°C. A mixture of a gellant such as an N-acyl aminoacid amide and a carrier oil needs to be heated to substantially above its gelation temperature
5 before the gellant dissolves, and it is commonly
impractical for antiperspirant or deodorant compositions to be heated to amide dissolution temperatures, so that, in practice, it is impractical to redissolve the gellant by heating such a composition once it has gelled and it
10 accordingly remains gelled. Consequently, it is
inherently disadvantageous to employ a gellant that gels the composition at a significantly higher temperature, such as to above the boiling point of water. An elevated gelation temperature introduces a substantial risk that
15 the composition would be gelled before it has been cooled to a temperature at which an active constituent or a temperature sensitive constituent can be introduced, or that the very act of introduction of the active constituting a significant proportion of the overall
20 composition would lower the composition temperature rapidly below the oil gelation temperature, rendering subsequent operations extremely difficult if not impossible on a bulk scale, such as filling of product dispensers.
25
However, the formulator seeks also to take into account the sensory properties of the resultant formulation. In the course of devising the present invention, it has been found that the proportion of water-immiscible alcohol
30 that can be included in the carrier liquid is important in contributing to the sensory properties of the final formulation. In general terms, such properties become impaired as the proportion increases.
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Summary of the Invention
It is an object of the present invention to avoid or at
5 least ameliorate one or more of the difficulties or
disadvantages indicated hereinabove in the preparation of solidified water-immiscible oils containing a cosmetic active ingredient.
10 According to one aspect of the present invention, there is provided a cosmetic antiperspirant or deodorant • composition as described hereinafter in claim 1.
By the employment of the combination of fibre-forming
15 structurants as primary gellant in accordance with claim 1 together with the employment of the specified alcohol within the specified window of proportions of the water-immiscible carrier liquid, it is possible to prepare cosmetic sticks in a manner that ameliorates one or more
20 of the problems identified hereinbefore. Desirably,
enough water-immiscible alcohol is employed to enable the formulation to be processed, but not so much that the sensory properties of the resultant formulation are excessively impaired.
25
In the present .invention, the selected amido gellants (i) and (ii) together constitute the primary gellant, which is to say that they are employed by themselves or if a secondary gellant is present they together constitute the
30 major weight proportion of the total of primary and secondary gellants.
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The invention compositions herein*are anhydrous, by which is meant herein that the liquid carrier oils do not contain a polar phase such as a dispersed aqueous phase.
5
According to a second aspect of the present invention, there is provided a process for the preparation of an cosmetic antiperspirant or deodorant composition as described in claim 33,
10
According to a third aspect of the present invention there is provided a cosmetic method for inhibiting or controlling perspiration and/or body malodours by the topical application to skin of an effective amount of a
15 composition according to the first aspect.
Detailed Description of the Invention and Preferred Embodiments Thereof
20 The present invention relates to antiperspirant or
deodorant sticks containing a cosmetic antiperspirant or deodorant active ingredient in which the water-immiscible oil phase is solidified using a mixture of at least two classes of fibre-forming structurants containing an amido
25 linkage of which one class is gellant (i) an N-acyl aminoacid amide, the acyl group containing a branched alkyl group of 4 to 12 carbon atoms. The compositions include at least 4% by weight of amido fibre-forming gellants, of which at least 3% is constituted by the
30 primary gellant, i.e. classes (i) and (ii) together.
Herein, the term amido gellants includes cyclodipeptides.
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Gellant (i)
Gellant (i) is an N-acyl aminoacid amide that satisfies general formula (1) Ax-CO-Rx in which Ax represents the residue of an amino acid amide and Rx represents a branched alkyl group containing from 4 to 12 carbon atoms and sometimes 7 to 10 carbon atoms. In many instances, the aminoacid amide residue Ax can be represented by formula (2)
in which n represents an integer of 1 or 2 and Rz represents an alkyl group, which can be linear or
branched, containing from 1 to 10 and particularly from 3 to 5 carbon atoms, each of which Rz groups can be the same or different. Accordingly, such an amino acid from which the amide residue Ax is derivable is glutamic or aspartic acid. In some especially preferred embodiments, each R2 represents a butyl group, especially an n-butyl group, and particularly in the derivative of glutamic acid, which residue is represented by formula (3)
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In formula (1) , Rx preferably represents an alkyl group containing either. one or two or possibly three side chains, such as particularly one side chain. Desirably,
5 any side chain in Rx contains from 1 to 4 carbon atoms, such as methyl, ethyl propyl or butyl, and often from 1 to 3 carbon atoms, of which ethyl is very convenient. The alkyl backbone preferably contains from 4 to 8 carbon atoms, often from 4 to 7 carbon atoms and sometimes 7 or
10 8 carbon atoms. The location of the side chain along the alkyl group backbone is at the discretion of the producer, of which the 2 position is often favored. An especially desirable branched chain group for Rx is 1-ethylpentyl, so that the resultant acyl group is 2-
15 ethylhexanoyl. Other branched chain groups for Rx include 1-methylbutyl, isobutyl and 1-butylheptyl. It is particularly desirable to employ a gellant (i) in which Rx is according to one or more of the branched alkyl groups named above and the amide residue is derived from
20 glutamic acid di butylamide.
The weight proportion of gellant (i) in the composition is commonly selected in the range of at least 1.5% w/w, in many desirable embodiments is up to 8% and
25 particularly at least 2% w/w. It is often unnecessary to employ more than 6% w/w of gellant (i) in the composition. The proportion of gellant in the composition can also be determined by relation to the water-immiscible phase which it is structuring, i.e
30 excluding the weight of any material which is suspended in the carrier oils constituting that phase. The weight proportion of gellant (i) is usually selected in the range of from 3 to 15% w/w of the water-immiscible phase
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and is often present in a proportion of at least 4% w/w of that phase. Its weight proportion of that phase in a number of preferred embodiments is up to 9%. The weight
5 proportion of each gellant in the composition or water-immiscible phase will often be selected in concert with the proportion of co-gellant (ii) the choice and weight of any secondary gellants, and the desired hardness of the stick.
10
Gellant (i) is employed in conjunction with a second amide-fibre-forming structurant, (ii), that is an N-acyl aminoacid amide other than the branched-chain substituted N-acyl aminoacid amides of gellant (i).
15 N-acyl aminoacid amides according to gellant (ii) are described in US patent 3969087. A list of many of such amides and the general method of manufacture are described in said patent specification in column 1 line 63 to column 4 line 47, and specific amido derivatives
20 are named in Example 1 in column 6 to 8, which passages from the text are incorporated herein by reference. Herein, gellant (11a) often satisfies formula (4) Ay-CO-RY in which AY represents an amino acid amide and RY represents a linear alkyl group containing from 9 to 21
25 carbon atoms. Highly desirably, AY represents an amino acid amide residue in accordance with the formula (5)
30
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in which n represents an integer of 1 or 2 and R represents an alkyl group, which can be linear or branched, containing from 1 to 10 and particularly from 3 to 5 carbon atoms, each of which Rz groups can be the same or different. Accordingly, the amino acid from which such an amide residue is derivable is glutamic or aspartic acid. In some especially preferred embodiments, each Rz represents a butyl group, especially an n-butyl
group, and particularly in the derivative of.glutamic acid. Such a is represented by formula (3), given supra for residue Ax.
In formula (5) , RY often contains from 9 to 15 linear carbons, of which one preferred group comprises undecyl.
N-Lauroyl-L-glutamic acid di-n-butylamide, formula (6)
(n-Un = undecyl) employed in Example 14 of. ‘087, is an especially desirable amide structurant for employment in the instant invention compositions and is commercially available from Ajinomoto under their trade designation GP-1.
Herein, the weight proportion of gellant (ii) in the composition is commonly selected in the range of at least
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1.5% w/w and in many desirable embodiments is up to 8% and particularly at least 2% w/w. It is often unnecessary to employ more than 6% w/w of gellant (ii) in
5 the composition. The proportion of gellant (ii) in the composition can also be determined by relation to the water-immiscible phase which it is structuring. The weight proportion of gellant (ii) is usually selected in the range of from 3 to 12% w/w of the water-immiscible
10 phase and is often present in a proportion of at least 3.5% w/w of that phase. Its weight proportion of that phase in a number of preferred embodiments is up to 8%. The weight proportion of the gellant in the composition or water-immiscible phase will often be selected in
15 concert with the choice and proportion of any secondary gellant or gellants, and the desired hardness of the stick.
The weight ratio of gellant (i) to gellant (ii) is often 20 selected in the range of from 3:1 to 1:3. In many
instances the weight ratio is no higher than 2:1 and in such or other instances, the weight ratio is at least 1:2. A convenient weight ratio can be in the range of 1.1:1 to 1:1.1.
25
The combined weight proportion of gellants (i) and (ii) in the composition is often selected in the range of from 4 to 10% and in some well desired embodiments from 4.5 to 8%, particularly at least 5%. When expressed in terms of
30 the weight proportion of the two gellants in the water-immiscible phase, this is often from 6 to 15% w/w of the phase and in many desirable embodiments from 7.5 to 12% w/w.
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The primary gellant combination can be employed by itself, or if desired can be supplemented by a secondary gellant, i.e. a gellant or gellants other than gellants
5 (i) and (ii). Secondary herein indicates that such a gellant or gellants constitute the minor fraction of the total weight of gellants in the composition, and preferably not more than a third of the total weight of gellants. The primary gellants, i.e. the combination of
10 gellants (i) and (ii) always contribute at least 3% and often at least 3.5% by weight of the composition. In many desirable embodiments the proportion of secondary gellants is from 0 to 25% w/w of the total weight of gellants. Conveniently, the composition can be free or
15 nearly free from secondary gellants, such as containing from 0 to 5% w/w of the gellants (based on the weight of the composition).
The secondary gellants can, desirably, be selected from
20 gellant (iii) namely fibre-forming amide derivatives of carboxylic acids other than amino acid amides of gellants (i) and (ii) or from gellant (iv) namely hydroxystearic acids. The combined weight proportion of gellants (i), (ii) and (iii) is at least 4% of the composition. - -
25
Such other amide derivatives (iii) can conveniently be selected from, (iiia) diamido or triamido substituted cyclohexane, gellant (iiib), amide derivatives of di and tribasic carboxylic acids (iiic) hydroxystearic acid
30 amides, and (iiid) cyclodipeptides. It is often
convenient to select amide gellant (iii) from sub-classes (iiia) to (iiic).
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Secondary gellants, (iiia) comprise di-amido and triamido-substituted cyclohexane. Particular sub-classes of such compounds comprise -1,2 or -1,3 substituted
5 cyclohexane compounds, and 1,3,5-triamido-substituted cyclohexane in which the amido group desirably accords with the general formula - (CH2) v-CO-NH-Rm and -(CH2)V-NH-CO-R111) in which R111 represents an alkyl group of from 5 to 27 carbon atoms and v is an integer selected from zero
10 and one.
When the cyclohexane ring is substituted by two amido substituents, the substituents preferably satisfy -(CH2)v-NH-CO-Rnl) and are very desirably in the 1,2 or
15 1,3 positions relative to each other around the
cyclohexane nucleus. When they are in the 1,3 relative positions, v preferably represents 1. When the two substituents are in the 1,2 relative position, v preferably is zero.
20
When the cyclohexane ring is substituted by three amido groups, they each preferably satisfy - (CH2) v-CO-NH-R111. R111 can be linear or branched. Preferably the number of carbons in R1U is selected in the range of 8 to 20. For
25 example undecyl, dodecyl,octadecyl, or dimetyloctyl.
Secondary gellant (iiib) comprises amide derivatives of di and tribasic carboxylic acids. Such gellants are in accordance with the description either as set forth in
30 USP 5840288 and specifically the passage from column 12 line 37 to column 14 line 20 or as set forth in USP 6190673B1, specifically the passages col 1 line 47 to col 2 line 38 and col 3 line 47 to col 5 line 23. Their
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general methods of manufacture are as described in the passage in USP 5840288 in column 12 line 37 to 39 or as set forth in USP 6190673B1, in the passage in col 5 lines 28 to 43. Convenient carboxylic acid for the preparation of amide derivatives include succinic acid and aliphatic acids containing three vicinal carboxylic acid groups such as 1-propene-trioic acid. Each-amide substituent preferably contains an alkyl, especially linear alkyl group of from.3 to 12 carbons- Specific suitable gellants (iiib) are listed in column 13 line 62 to column 14 line 7 in USP 5840288 and in Table 1 in col 13 of USP 6190673B1. A particularly preferred gellant (iiib) is 2-dodecyl-N,N'-dibutylsuccinimde or 1-propene-l,2,3-trioctylamide or 2-hydroxy-l,2, 3-propane-tributylamide. Such passages are incorporated herein by reference.
Secondary gellant (iiic) of amido gellants within gellant (iii) comprises hydroxystearamides and in particular 12-hydroxy-stearamides. The amido substituent in such amides preferably contains an alkyl, particularly a linear alkyl group between 3 and 13 carbon atoms, such as propyl, butyl, heptyl or undecanyl.
Secondary gellants (iiid) suitable for employment in the instant invention comprises structurants which satisfy the following general formula:-
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10
in which one of Ri and R2 represents an alkyl, alkyl ester group and the other represents an alkyl or alkaryl group. Examples of such amides are described in two papers by Hanabusa et al, entitled respectively Cyclo(dipeptide)s as low molecular-mass Gelling Agents to harden Organic Fluids, J. Chem Soc. Commun,, 1994 ppl401/2, and Low Molecular Weight Gelators for Organic Fluids: Gelation using a Family of Cyclo(dipeptide)s, in the Journal of Colloid and Interface Science 224, 231-244 (2000), which descriptions of amide structurants are incorporated herein by reference.
15 However, it is especially preferred to employ herein a sub-class of cyclodipeptides not expressly disclosed by Hanabusa, which sub-class satisfies the general formula:-
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in which Rfl represents a carbocyclic or heterocyclic group containing not more than 2 rings. Such materials are sometimes herein referred to as DOPA derivatives.
In DOPA derivatives, RA can comprise two fused rings, but preferably comprises a single six membered ring, either carbocyclic or heterocyclic, or a bridged ring. When A is carbocylic, it can be either saturated or unsaturated, preferably unsaturated or aromatic. When RA is heterocyclic, it is preferably saturated.
Although the cyclic group within RA can be unsubstituted, it is preferably substituted by at least one alkyl substituent, which preferably contains no more that 16 carbon atoms. In some highly desirable embodiments the alkyl substituent has a longest chain length of up to 4 carbon atoms, and in certain or tho.se a total carbon content of up to 5 carbon atoms. The alkyl substituent may be linear or branched. Preferred examples include methyl, ethyl, propyl, isopropyl, butyl isobutyl or t-butyl or isopentyl. In a number of very suitable DOPA
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derivatives, RA contains two or more alkyl substituents and especially those selected from the above list of preferred examples. The alkyl substituents-may be the
5 same, such as two or more methyl substituents, or may be a combination of different substituents such as a methyl and isopropyl substituents. When RA is saturated, the substituents may depend from the same carbon atom in the ring, such as two methyl groups, or from different carbon
10 atoms. In several highly desirable derivatives, two alkyl substituents are meta or para to each other, for example meta methyl groups or a para methyl and isopropyl group. In yet other derivatives, the ring may include a methylene bridge, which preferably likewise completes a
15 six membered ring.
In some suitable DOPA derivatives, the or one alkyl substituent may be ortho or para to the bond with the DOPA residue, as in 4-methyl-phenyl-. In some or other
20 DOPA derivatives, the bond with the DOPA residue is meta to one or preferably two methyl substituents.
When RA is heterocyclic, the heterocyclic atom is suitably nitrogen. Conveniently, the heterocyclic atom can be '
25 para to the bond with the DOPA residue. Moreover, in a number of desirable derivatives, the heteroatom is ortho to at least one alkyl group, better in a saturated ring and especially to up to 4 ortho methyl groups.
30 The group RA is often most easily referred to as the residue from the corresponding alcohol which may be reacted with DOPA to form the ester linkage. Thus, desirable examples of RA include the residues from 4-alkyl
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phenol, such as 4-nonyl-phenol, and 2,6-dialkyr- or 2,2,6,6-tetraalkyl-4-piperidinol, such as .2,2,6,6-tetramethyl-4-piperidinol.
5
In some preferred DOPA derivatives, the ring in RA is carbocyclic, and is substituted by at least two alkyl groups of which at least one is methyl and the other or one of the others is isopropyl. Examples of such
10 preferred RA residues include menthol, isopinocamphenol and 3,5-dialkyl cyclohexanol such as 3,5-dimethyl cyclohexanol. Especially preferred Rfl residues include thymol. Yet others include the DOPA derivatives from carveol and carvacrol.
15
The DOPA derivatives used in this invention may be a mixture of compounds within the general formulae given, or may be a single compound.
20 The DOPA derivatives can be prepared by reacting the respective alcohol with DOPA in acid form (DOPAA), or possibly with an acid chloride, or possibly an anhydride or an ester containing a DOPA residue. DOPAA can be obtained by cyclising aspartame. DOPAA can be reacted
25 with the relevant alcohol of formula RAOH, preferably in a mole ratio to the DOPAA of at least 2:1 in dimethyl sulphoxide, in a ratio of from 6:1 to 12:1, in the presence of a promoter, such as a carbonyldiimidazole, in an amount preferably from 0.5 to 2 moles of promoter per
30 mole of DOPA acid. The reaction is conveniently carried out at a temperature from 40 to 60°C.
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Secondary gellant (iv) is a hydroxystearic acid, and more desirably 12-hydroxystearic acid.
5 Secondary gellants (iii) and (iv) can be employed without each other or together with each other, for example in a weight ratio of 3:1 to 1:3.
Herein, the total weight proportion of the secondary
10 gellants (iiia) to (iiid) and (iv) in the composition is commonly selected in the range of 0 to 5% and in many desirable embodiments is not more than 3% w/w, recognising that the weight still constitutes a minor proportion of the total weight of gellants. The
15 proportion of the secondary gellant (iiia) to (iiid) and (iv) in the composition can also be determined by relation to the water-immiscible oils which it is structuring. The weight proportion of said secondary gellant is usually selected in the range of from 0 to
20 7.5% w/w of the water-immiscible oils and is often
present in a proportion of not more than 4.5%% w/w of those oils. The weight ratio of gellant (iii) to gellant (iiv), if both are present, can conveniently be selected in the range of from 3:1 to 1:5.
25
The combined weight proportion of primary and secondary gellants in the composition is often selected in the range of from 4 to 10% and in some well desired embodiments from 5 to 8%. When expressed in terms of the
30. weight proportion of the two gellants in the water-immiscible oils, this is often from.6 to 15% w/w of the oils and in many desirable embodiments from 7.5 to 12% w/w.
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Water-immiscible Carrier Oils
Aliphatic alcohols which are liquid at 20°C are employed
5 herein within the proportion of from 25 to 50% w/w of the carrier oils. Especially desirably such materials are water-immiscible. These include branched chain alcohols of at least 10 carbon atoms and in many instances up to 30 carbon atoms, particularly 15 to 25, such as
10 isostearyl alcohol, hexyl-decanol octyl-dodecanol and decyl-tetradecanol. Other suitable water-immiscible alcohols include intermediate chain length linear alcohols, commonly containing from 9 to 13 carbon atoms, such as decanol or dodecanol. A further suitable alcohol
15 is benzyl alcohol. Such alcohols can assist in the
process of forming a solution of the amido-substituted gellants (i), (ii) and {iii), if present, in a water-immiscible carrier liquid during the manufacture of structured gels. Such alcohols can often constitute from
20 at least 30% to 45% by weight of the oils. In a number of compositions, the proportion is from 35 to 40% by weight of the oils. In addition to controlling the total proportion of monohydric alcohol that is present in the water-immiscible oils, it is highly desirable to. select
25 its content in relation to the total weight of amide gellants (i), (ii) and any (iii). The weight ratio of such monohydric alcohol to the combined weight of amido gellants is preferably from 3.5:1 to 5:1.
30 Aliphatic alcohols which are solid at 20°C, e.g. linear alcohols containing at least 12 carbons, such as stearyl alcohol can also be contemplated as secondary structurants, but they are preferably absent or present
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in no more than 3% by weight of the whole composition, as indicated hereinbefore, since they lead to or increase visible white deposits when a composition structured by
5 them is topically applied to-skin.
The water-immiscible carrier liquid comprises one or a mixture of materials which are relatively hydrophobic so as to be immiscible in water. Following partition
10 between the continuous phase and the disperse phase, a small fraction of hydrophilic liquid may remain in the continuous phase, provided "the overall carrier liquid mixture is immiscible with water. It will generally be desired that the carrier oils mixture is liquid (in the
15 absence of structurant) at temperatures of 15°C and above. It may have some volatility but its vapour pressure will generally be less than 4kPa (30 mmHg) at 25°C so that the material can be referred to as an oil or mixture of oils. More specifically, it is desirable that at least 80% by
20 weight of the hydrophobic carrier liquid should consist of materials with a vapour pressure not over this value of 4kPa at 25°C.
It is preferred that the hydrophobic carrier material 25 includes a volatile liquid silicone, i.e. liquid
polyorganosiloxane. To class as "volatile" such material should have a measurable vapour pressure at 20 or 25°C. Typically the vapour pressure of a volatile silicone lies in a range from 1 or 10 Pa to 2 kPa at 25°C.
It is desirable to include volatile silicone because it gives a "drier" feel to the applied film after the composition is applied to skin.
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Volatile polyorganosiloxanes can be linear or cyclic or mixtures thereof. Preferred cyclic siloxanes include polydimethylsiloxanes and particularly those containing
5 from 3 to 9 silicon atoms and preferably not more than 7 silicon atoms and most preferably from 4 to 6 silicon atoms, otherwise often referred to as cyclomethicones. Preferred linear siloxanes include polydimethylsiloxanes containing from 3 to 9 silicon atoms. The volatile
10 siloxanes normally by themselves exhibit viscosities of below 1(T5 m2/sec (10 centistokes), and particularly above 10"7 m2/sec {0.1 centistokes), the linear siloxanes normally exhibiting a viscosity of below 5 x 10~6 ra2/sec (5 centistokes). The volatile silicones can also comprise
15 branched linear or cyclic siloxanes such as the
aforementioned linear or cyclic siloxanes substituted by one or more pendant -0-Si(CH3)3 groups. Examples of commercially available silicone oils include oils having grade designations 344, 345, 244, 245 and 246 from Dow
20 Corning Corporation; Silicone 7207™ and Silicone 7158™
from Union Carbide Corporation; and SF1202™ from General Electric.
The hydrophobic carrier employed in compositions herein
25 can alternatively or additionally comprise non-volatile silicone oils, which include polyalkyl siloxanes, polyalkylaryl siloxanes and polyethersiloxane copolymers. These can suitably be selected from dimethicone and dimethicone copolyols. Commercially available non-
30 volatile silicone oils include products available under the trademarks Dow Corning 556 and Dow Corning 200 series. Other non volatile silicone oils include that bearing the trademark DC704. Incorporation of at least
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some non-volatile silicone oil having a high refractive index such as of above 1.5, eg at least 10% by weight (preferably at least 25% to 100% and particularly from 40
5 to 80%) of the silicone oils can be beneficial in some compositions.
Liquid silicone oils can constitute the balance of the water-immiscible liquid carrier oils, ie 50 to 75% w/w of
10 the oil, if desired. However, silicone oils may be supplemented, if desired, buy other oils, and in such instances, there is preferably, sufficient liquid silicone to provide at least 10%, better at least 15%, by weight of the whole composition.
15
Silicon-free hydrophobic liquids can be used, preferably in addition to liquid silicones. Silicon-free hydrophobic organic liquids which can be incorporated include liquid aliphatic hydrocarbons such as mineral
20. oils or hydrogenated polyisobutene, often selected to exhibit a low viscosity. Further examples of liquid hydrocarbons are polydecene and paraffins and isoparaffins of at least 10 carbon atoms. Hydrocarbon liquids preferably are present in a range of from 0 to
25 20% w/w and especially from 0 to 5% of the oils.
Other suitable hydrophobic carriers comprise liquid aliphatic or aromatic esters. Suitable aliphatic esters contain.at"least one long chain alkyl group, such as –
30 esters derived from Ci to C2o alkanols esterified with a CB to' C22 alkanoic acid or C6 to C10 alkanedioic acid. The alkanol and acid moieties or mixtures thereof are preferably selected such that they each have a melting
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point of below 20°C. These esters include isopropyl myristate, lauryl myristate, isopropyl palmitate, diisopropyl sebacate and diisopropyl adipate.
5
Suitable liquid aromatic esters, preferably having a melting point of below 20°C, include fatty alkyl benzoates. Examples of such esters include suitable CB to C18 alkyl benzoates or mixtures thereof, including in
10. particular Ci2 to Ci5 alkyl benzoates eg those available under the trademark Finsolv. Ester oils, be they aliphatic or aromatic desirably comprise from 0 20% and preferably 0 to 10% w/w of the oils.
15 Further instances of suitable hydrophobic carriers
comprise liquid aliphatic ethers derived from at least one fatty alcohol, such as myristyl ether derivatives e.g. PPG-3 myristyl ether or lower alkyl ethers of polygylcols such as an ether having named as PPG-14 butyl
20 ether by the CTFA. Such ethers desirably constitute from 0 to 20, and preferably from 0 to 10% w/w of the oils.
Antiperspirant or Deodorant Actives
25 The composition preferably contains an antiperspirant active. Antiperspirant actives, are preferably incorporated in an amount of from 0.5-60%, particularly from 5 to 30% or 40% and especially from 5 or 10% to 30 or 35% of the weight of the composition.
30
Antiperspirant actives for use herein are often selected from astringent active salts, including in particular aluminium, zirconium and mixed aluminium/zirconium salts,
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including both inorganic salts, salts with organic anions and complexes. Preferred astringent salts include aluminium, zirconium and aluminium/zirconium halides and
5 halohydrate salts, such as chlorohydrates and activated aluminium chlorohydrates.
Aluminium halohydrates are usually defined by the general formula Al2(OH)xQy.wH20 in which Q represents chlorine,
10 bromine or iodine, x is variable from 2 to 5 and x + y = 6 while wH20 represents a variable amount of hydration. Especially effective aluminium halohydrate salts, known as activated aluminium chlorohydrates, are described in EP-A-6739 (Unilever NV et al), the contents of which
15 specification is incorporated herein by reference. Some activated salts do not retain their enhanced activity in the presence of water but are useful in substantially anhydrous formulations, i.e. formulations which do not contain a distinct aqueous phase.
20
Zirconium actives can usually be represented by the empirical general formula: ZrO(OH) 2n-nzBz. wH20 in which z is a variable in the range of from 0.9 to 2.0 so that the value 2h-nz is zero or positive, n is the valency of B, and
25 B is selected from the group consisting of chloride, other halide, sulphamate, sulphate and mixtures thereof. Possible hydration to a variable extent is represented by WH2O. Preferable is that B represents chloride and the variable z lies in the range from 1.5 to 1.87. In practice,
30 such zirconium salts are usually not employed by
themselves, but as a component of a combined aluminium and zirconium-based antiperspirant.
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The above aluminium and zirconium salts may have coordinated and/or bound water in various quantities and/or may be present as polymeric species, mixtures or
5 complexes. In particular, zirconium hydroxy salts often represent a range of salts having various amounts of the hydroxy, group. Zirconium aluminium chlorohydrate may be particularly preferred.
10 Antiperspirant complexes based on the above-mentioned astringent aluminium and/or zirconium salts can be employed. The complex often employs a compound with a carboxylate group, and advantageously this is an amino acid. Examples of suitable amino acids include dl-
15 tryptophan, dl-β-phenylalanine, dl-valine, dl-methionine and β-alanine, and preferably glycine which has the formula CH2 (NH2) COOH.
It is highly desirable to employ complexes of a
20 combination of aluminium halohydrates and zirconium chlorohydrates together with amino acids such as glycine, which are disclosed in US-A-3792068 (Luedders et al). Certain of those Al/Zr complexes are commonly called ZAG in the literature. ZAG actives'generally
25 contain aluminium, zirconium and chloride with an Al/Zr ratio in a range from 2 to 10, especially 2 to 6, an Al/Cl ratio from 2.1 to 0.9 and a variable amount of glycine. Actives of this preferred type are available from Westwood, from Summit and from Reheis.
30
Other actives which may be utilised include astringent titanium salts, for example those described in GB 2299506A.
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The particle size of the antiperspirant salts often falls
within the range of 0.1 to 200join and particularly from
0.2 to 100μm, some desirable products having at least 95%
by weight of below 50pm with a mean particle size often
from 3 to 30μm and in many instances from 5 to 20pm. The weight of particulate active antiperspirant salt herein commonly includes any water of hydration present. .
Deodorant Actives
Suitable deodorant actives can comprise deodorant effective concentrations of antiperspirant metal salts, deoperfumes, and/or microbicides, including particularly bactericides, such as chlorinated aromatics, including biguanide derivatives, of which materials known as Igasan
DP300™ (triclosan), Tricloban™, and Chlorhexidine warrant specific mention. A yet another class comprises biguanide salts such as are available under the trade mark Cosmocil™. Deodorant actives are commonly employed at a concentration of from 0.1 to 25% by weight.
Optional Ingredients
Optional ingredients include wash-off agents, often present in an amount of up to 10% w/w to assist in the removal of the formulation from skin or clothing. Such wash-off agents are typically nonionic surfactants such as esters or ethers containing a C8 to C22 alkyl moiety
and'a hydrophilic moiety which can comprise a polyoxyalkylene group (POE or POP) and/or a polyol.
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The compositions herein can incorporate one or more cosmetic adjuncts conventionally contemplatable for cosmetic solids or soft solids. Such cosmetic adjuncts
5 can include skin feel improvers, such as talc or finely divided polyethylene, for example in an amount of up to about 10%; a moisturiser, such as glycerol, for example in an amount of up to about 5%; skin benefit agents such as allantoin or lipids, for example in an amount of up to
10 5%; colours; skin cooling agents other than the already mentioned alcohols, such a menthol and menthol derivatives, often in an amount of up to 2%, all of these percentages being by weight of the composition. A commonly employed adjunct is a perfume, which is normally
15 present at a concentration of from 0 to 4% and in many formulations from 0.25 to 2% by weight of the composition.
Suspension sticks made with the combination of gellants,
20 (i) and (ii) tend to exhibit low visible deposits,
compared for example with traditionally wax structured anhydrous compositions and have a good skin feel.
25 Composition Preparation
A convenient-process sequence for preparing a composition according to the present invention comprises first forming a solution of the structurant combination in the
30 water-immiscible liquid or one of the water-immiscible liquids. This is normally carried out by agitating the mixture at a temperature sufficiently high that all the structurants dissolve (the dissolution temperature) such
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as a temperature in a range from 70 to 14 0°C. Any oil-soluble cosmetic adjunct can be introduced into oil phase, either before or after the introduction of the
5 structurants. Commonly the resultant structurant solution is allowed to cool to a temperature that is intermediate between that at which the structurants dissolved and the temperature at which it would set, often reaching a temperature in the region of 60 to 90°C.
10
In some routes, the carrier oils can be mixed together prior to introduction of the gellants and the antiperspirant or deodorant active. In other preparative routes, it is desirable to dissolve all or a fraction of
15 the amide-substituted structurants in a first fraction of the composition, such as a branched aliphatic alcohol, eg isostearyl alcohol or octyldodecanol, optionally in conjunction with an alcohol having' some water-miscibility and boiling point above the dissolution temperature of
20 the amido gellant in the alcoholic fluid. This enables the remainder of the carrier fluids to avoid being heated to the temperature at which the structurants dissolve or melt. The proportion of the carrier fluids for dissolving the structurants is often from 25 to 50% by
25 weight of the carrier fluids.
In said other preparative routes the particulate material is introduced into preferably a second fraction of the carrier oils, for example silicone and/or ester and/or
30 hydrocarbon oils and thereafter, and thereafter the first fraction containing dissolved structurant and second fraction containing suspended particulate material are mixed at a temperature above that at which the
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composition gels, and often from 5°C to 30°C above the regular setting temperature of the composition, dispensing containers are filled and cooled or allowed to
5 cool to ambient temperature. Cooling may be brought about by nothing more than allowing the container and contents to cool. Cooling may be assisted by blowing ambient or even refrigerated air over the containers and their contents.
10
Product Dispenser
Suspension sticks according to the present invention are normally housed in dispensing containers-, the shape and
15 size of which, the materials of their construction and the mechanisms employed therein for dispensing the antiperspirant sticks are those commensurate with the cosmetic. An antiperspirant or deodorant stick is often housed in a barrel, commonly of circular or elliptical
20 transverse cross section, having an open end through which the stick can pass and an opposed closed end, commonly comprising a platform or elevator that is axially moveable along the barrel. The platform can be raised by the insertion of a finger or more commonly by
25 rotation of an externally exposed rotor wheel that
rotates a threaded spindle extending axially through a co-operating threaded bore in the platform. The barrel normally also has a removable cap that can fit over its open end. The barrel is normally made from an extrudable
30 thermoplastic such as polypropylene or polyethylene.
The present invention also provides translucent cosmetic antiperspirant or deodorant products comprising an
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invention cosmetic stick as described hereinbebefore disposed within a dispensing barrel.
Having summarised compositions according to the present invention and described preferred embodiments, specific embodiments thereof will now be described in more detail by way of example only.
The following constituents were. employed in exemplified and comparison suspension sticks hereinafter.
Ref CTFA or IUPAC name Trade name and/orsupplier '
CI Cyclomethicone DC245, Dow Corning
C2 2-hexyl-decanol Eutanol G16, Cognis
C3 Octyl dodecanol Eutanol G, Cognis
C4 C12-15 alkyl benzoate Finsolv TN: {Finetex
C5 PPG-14 Butyl Ether Fluid AP: {Amercol
C6 Sunflower Seed Oil Alembic
Gl N-(2-ethyl hexanoyl)-L~ glutamic acid di-n-"butylamide GA-01, Ajinomoto
G2 N-lauroyl-L-glutamic acid di-n-butylamide GP-1, Ajinomoto
G3 12-hydroxystearic acid 12-HSA, CasChem
G4 N N'-bis (dodecanoyl)-1, 2-diaminocyclohexane (non optically active cis/trans mixture). Preparation as in US 6410003
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G5 N N'-bis (2-ethylhexanoyl)-1,2-diaminocyclohexane {non optically active cis/trans mixture) Preparation as inUS 6410003
G6 2-octadecyl-N,N'-dibutylsuccinamide Preparation as in US 5840287
G7 n-propyl-12-hydroxystearamide standard preparation
G8 2-ethyl butanoyl-L-glutamic acid di-n-butylamide Preparationhereinbelow
S1 Al/Zr tetraachlorohydrex glycine complex Reach 908, Reheis
S2 Al/Zr tetraachlorohydrex glycine complex Westchlor ZR 30BDMCP5, Westwood
S3 Al/Zr Tetrachlorohydrexglycine complex Rezal 36 GP: Reheis
S4 Fumed Silica Aerosil 200: Degussa
F Fragrance
Measurements of payoff of the stick and visible deposits (whiteness) in the Examples and Comparisons were made on black cotton, 24 'hours after application of the stick.
5
The Example and Comparison sticks were made by the following technique. The carrier oils, CI and C2 or C3 were mixed together and all the gellants were introduced with stirring. The temperature of the mixture was
10 increased until the gellants dissolved. The resultant gellants solution was allowed to cool to 90°C, and the particulate antiperspirant was introduced. The temperature of the resultant mixture was kept constant at
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85°C, and it was stirred thoroughly and any fragrance was then added. The mixture was allowed to cool and then poured into stick barrels at the temperature stated below
5 which was about 5°C above the regular solidification
temperature of the mixture (obtained by allowing a sample to solidify under quiescent conditions, or from previous trials), and allowed to cool to ambient.
10 .The formulations expressed in parts by weight and the'
properties of the sticks are summarised in Table 1 below.
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Table 1
Ex 1.1 Comp l.A Comp l.B Comp l.C
CI 43 48 43 43
C2 24.5 24.5 24.5
C3 14
Gl 3.25 1 1 6.5
G2 3.25 1 1
G3 7 7
SI 25 25 25
S2 26
Fl 1 1 1
Processing Conditions
Stick Pour Temp (°C) 78 55 45 no stick
Stick Properties
Hardness (mm) 10.2 18.7 29.5 no stick
pay-off- (g) 0.563 0.74 1.37 nostick
whiteness 40.8 39.8 21.9 no stick
The stick produced in Exl.l was suitably hard with
5 acceptable pay-off, having good skin sensory properties, and only low white/greasy deposits on skin.
The stick produced in comparison Comp l.A was that of Example 11 in US2002/0159961, employing as primary
10 gellant 12-HSA. The stick exhibited inferior hardness, even though it employed more gellant in total, a higher
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pay-off, and inferior sensory properties on skin application - a thick, white and greasy deposit, when applied to the skin.
5
The stick produced in comparison Comp l.C employed the same carrier oils as in Example 1.1. It was even softer than Comp l.B, with a substantially greater pay-off and even worse sensory properties - the stick collapsed and
10 left a very thick, white and greasy deposit when applied to skin.
No stick could be produced in Comp l.C, because the gelation temperature of the solution of oils is
15 significantly above 100°C, ie well above the temperature at which the antiperspirant active could safely be introduced.
Examples 2.1 to 2.4
20
These Examples were made by the general method emp[loyed
for Example 1, additionally containing a secondary
gellant in class (iii). The formulations expressed in
parts by weight and the properties of the sticks are
25 summarised in Table 2 below.
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Table 2
Ex 2.1 Ex 2.2 Ex 2.3 Ex 2.4
Gl 2.5 2.5 2.875 2.5
G2 2.5 2.5 2.875 1
G4 1
G5 1
G6 2.5
G7 0.25
C2 24.75 24.75 24.75 24.75
CI 43.25 43.25 43.25 43.25
S3 25 25 25 25
F 1 1 1 1
Properties
Stick Pour Temp (°C) 68 70 70 70
Hardness (mm) 11.3 11.0 9.9 11.4
pay-off (black cotton)