WO2008104591A2

WO2008104591A2 - Novel cosmetic cream composition comprising c12-c20 fatty acid

Info

Publication number: WO2008104591A2
Application number: PCT/EP2008/052433
Authority: WO
Inventors: Bivash Ranjan Dasgupta; Lei Huang; Vibhav Ramrao Sanzgiri; Simone Dosu Sethna; Pankaj Chandrakant Shah
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited
Priority date: 2007-02-28
Filing date: 2008-02-28
Publication date: 2008-09-04
Also published as: JP5481202B2; WO2008104591A3; MY152878A; JP2010520231A; MX2009008999A; KR20090116755A

Abstract

Disclosed is a cosmetic cream base comprising: i) 4-10 % by weight C12-C20 fatty acid; ii) 1-5 % by weight fatty acid soap and iii) 2.5-10 % by weight particulate matter selected from talc, starch or its derivatives, and well as a cream composition comprising the cream base, and a method for improving the appearance of skin using the cream composition.

Description

NOVEL COSMETIC CREAM COMPOSITION

The present invention relates to cosmetic cream bases, particularly to improvements on existing vanishing cream bases, and cosmetic cream compositions obtained there from.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Vanishing creams remain one of the most widely used cosmetics, as they provide unique sensory and tactile benefits. These include inter alia, a dry and matte end-feel, which helps to overcome the oily and shiny appearance of the skin. Vanishing creams spread easily on the skin and get rapidly absorbed therein. Moreover, use of such creams help to reduce the dryness of skin thereby alleviating flakes, cracks and roughness. Owing to their widespread use, they serve as effective vehicles for delivery of actives.

Traditional vanishing creams contain high levels of fatty acid, generally stearic acid or a combination thereof with palmitic acid, typically ranging from 16 to 20 % by weight. They also contain salts of fatty acids, generally alkali metal soap, which acts as the emulsifier. The emulsifier is important for the physical stability of the product. The soap is formed by in situ neutralization of a portion of the fatty acid with caustic potash or any other base.

Although vanishing creams offer several benefits as mentioned above, there are some drawbacks and disadvantages associated with their use. The high level of fatty acids, typically used in the formulation, poses problems with chemical and physical stability of some actives, especially acidic actives. Therefore some attempts were made in the past to make vanishing creams with relatively low levels of fatty acids. The present inventors have observed that on reducing fatty acids, certain consumer desired sensory benefits, such as rub-in effect and the viscosity of the cream, are adversely affected. In addition to the above, it is known that in vanishing creams containing high levels of stearic acid, especially containing high levels of actives such as niacinamide, the end-feel and sensorial aspects of the cream are also adversely affected.

US 2005/0036971 (Beiersdorf AG) describes pearlescent cosmetic compositions containing up to 12 % by weight fatty acids. A portion of the fatty acids is neutralized to form alkali metal salts. The composition includes associative polymers, amphiphilic polymers and fatty alcohols as other major ingredients to meet the desired product attributes. Amphiphilic polymers and associative polymers are specialty materials. Their usage in cosmetics is likely to offset the benefits by an increase in cost.

The present inventors have found that vanishing creams containing relatively lower amounts of fatty acid can be made by including particulate matter selected from talc, starch or its derivatives, along with a relatively higher amount of fatty acid soap, without significantly affecting the above-mentioned benefits desired by the consumers. The present inventors have also found that on application of the composition to the skin, an instant glow is observed, which is a much sought after product attribute.

A combination of talc and fatty acids in cosmetic compositions has been reported, inter alia for make-up creams, foundation creams and soaps. Such cream formulations generally require very high content of talc, which ranges from 10 to 30%, and low amount of fatty acids, typically less than 5%.

US 4 800 076 (1989, Johnson & Johnson Consumer Products Inc) describes skin care compositions in the form of creams and lotions containing very low amounts of fatty acids and significantly higher amounts of talc, with a specific ratio of non-volatile ingredients to talc. It is said to enhance the desired characteristics of the skin care compositions. The teaching of this patent cannot be extended to vanishing cream compositions, as this patent essentially describes cosmetic compositions containing relatively higher amount of talc. There is no specific disclosure relating to fatty acid based vanishing creams and the optimal balance between fatty acids and talc to be incorporated therein.

The present inventors have provided a solution to a problem in the area of fatty acid based vanishing creams. In addition the reduction of stearic acid with a corresponding increase in levels of particulate matter, which is a relatively inexpensive raw material, would also lead to substantial savings in the cost of raw materials.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art vanishing cream bases, or to provide a useful alternative.

It is an object of the present invention to provide a cream base including relatively lower amount of fatty acids, without significantly affecting the sensory benefits associated with their use. It is an object of the present invention to provide a vanishing cream composition including relatively lower amount of fatty acids, without adversely affecting the viscosity of the cream composition.

It is an object of the present invention to provide a vanishing cream composition that enhances the brightness of the skin.

It is an object of the present invention to provide a vanishing cream composition that is capable of incorporation and delivery of relatively higher levels of benefit agents, whilst retaining the essential sensory attributes.

These and other objects of the present invention will become more readily apparent from consideration of the following summary and detailed description.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a cosmetic cream base for topical application that includes: i. 4.0 to 12.0 % by weight Ci₂-C₂₀ fatty acid; ii. 1.0 to 5.0 % by weight fatty acid soap; and iii. 2.5 to 10.0 % by weight particulate matter selected from talc, starch or its derivatives.

Preferably the particulate matter is talc. Preferably the composition includes from 6.0 to 10.0 % by weight Ci₂-C₂₀ fatty acid. Preferably the composition includes from 3.0 to 5.0 % by weight talc. Preferably the ratio of fatty acid to fatty acid soap is from 10:1 to 1.5:1 parts by weight, and more preferably from 3:1 to 2:1 parts by weight.

According to another aspect of the invention, there is provided a cosmetic cream composition that includes the cosmetic cream base and a benefit agent.

According to yet another aspect of the invention, there is provided a method of improving appearance of skin by applying to the skin the cosmetic cream composition. - A -

DETAILED DESCRIPTION OF THE INVENTION

Fatty Acid

It is preferred that the composition includes 4-12% by weight C12-C20 fatty acid, more preferably from 5.0 to 8.0 % by weight. It is further preferred that the fatty acid is 6% by weight of the composition. It is preferred that C14-C18 fatty acids are used. This could be a single fatty acid, such as palmitic acid or a mixture thereof with stearic acid, which mixture is referred to as hysteric acid. It is more preferred that the fatty acid is stearic acid, which has 18 carbon atoms.

Fatty Acid Soap

It is preferred that the composition includes 1.0 to 5.0% by weight fatty acid soap, more preferably from 2.0 to 3.0%. The term "fatty acid soap" is used to denote alkali metal salts and alkaline earth metal salts of the fatty acid. It is preferred that the soap is a sodium or potassium salt. The fatty acid and fatty acid soap are preferably saturated. Soap of the fatty acid is obtained by neutralizing a portion of the fatty acid with a suitable base such as sodium hydroxide or potassium hydroxide. This forms a system that includes the fatty acid in combination with its soap, which acts as an emulsifier and stabilizer for the cream.

The weight ratio of fatty acid to fatty acid soap is from 10:1 to 1.5:1 and preferably from 3:1 to 2:1.

Particulate Matter.

It is preferred that the particle size of the particulate matter is below 50 microns, more preferably between 5 and 15 microns.

It is preferred that the starch is obtained from rice or maize. The preferred derivative of starch is aluminum octenyl succinate available as Dry-Flo PC (National Starch). Talc is the preferred particulate matter. It is preferred that the cosmetic cream composition includes 3.0 to 5.0 % by weight talc, more preferably from 3.0 to 4.0 %. The talc which is useful in the present invention is cosmetic grade talc which conforms to the Cosmetic Toiletry and Fragrance Association Inc. specifications. Such talc is essentially a white, odorless, fine powder ground from a naturally occurring rock ore and it typically consists of about 90% hydrous magnesium silicate having a structural formula of Mg₆(Si_SC^o)-(OH)₄ with the remainder consisting of naturally associated minerals such as calcite, chlorite, dolomite, kaolin and magnesite. It is preferred that the talc contains no asbestos minerals. The preferred particle size is from 4 to 8 microns.

Benefit Agent The present invention also provides an effective cream base for incorporation and delivery of higher levels of benefit agents such as vitamins without significantly affecting the end-feel of the product.

The cream base provides for incorporation and delivery of higher levels of benefit agents, typically from 2 to 10.0 % by weight. Suitable benefit agents include skin lightening agents, UV absorbers, moisturizers and emollients. It is preferred that the benefit agent is a skin lightening agent or a UV absorber material. Suitable skin lightening agent are selected from niacin, alkali or alkaline earth metal salts of lactic acid and/or acyloxyl lactylate, hydroquinone and derivatives (e.g. arbutin), kojic acid, dicarboxylic acids (e.g. azelaic acid, sebacic acid), represented by the formula HOOC-(CxHy)-COOH where x ranges from 4 to 20 and y ranges from 6 to 40, ascorbic acid and derivatives thereof or ferulic acid. Further skin lightening agents may be retinol and derivatives, organic sunscreens such as 4-t-butyl-4'-methoxydibenzoylmethane, and/or 2-ethylhexyl methoxycinnamate, inorganic sunscreens such as micronised titanium dioxide, zinc oxide, typically included below 0.5% weight. Further preferred skin lightening agents are niacin and niacinamide. Niacinamide is also known as pyridine-3-carboxylic acid amide. It is a known skin lightening agent which is preferably included from 0.1 to 3.0 % by weight.

The skin lightening effected by the composition of the invention is reversible and without any side effects. The composition according to the invention is active during both day and night.

Other Adjuvants and Emotive Materials

In addition to the above essential elements, the cosmetic cream composition can also include cosmetically compatible preservatives, thickeners, perfume and colour. The composition may also comprise small amounts of other cosmetically acceptable emulsifiers selected from the group consisting of sorbitan ester, ethoxylated sorbitan ester, ethoxylated alkyl ether, ethoxylated fatty acid ether, fatty alcohol, ethoxylated fatty alcohol and esters of glycerine and fatty acid. Examples of moisturisers and humectants include polyols, glycerol, cetyl alcohol, paraffin oils, lanolin and its derivatives, fatty acid esters, etc. Silicone compounds such as silicone oil, cyclomethicones, dimethicones, dimethiconols may also be included.

Emollient materials (fluid oils) selected from the groups of silicone oils or synthetic esters may be incorporated into the compositions of the present invention.

Silicone oils may be included in the compositions as emollient materials. These are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. Other silicone oils may be also included, such as polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers (e. g. dimethicone copolyol). The polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from 5 to 100,000 centistokes at 25⁰C, preferably, polydimethyl siloxanes having viscosities from 10 to 400 centistokes at 25⁰C.

Suitable ester emollients include: esters of fatty acids or alcohols and hydrocarbons, preferably C8-C20 alkyl ester of fatty acids such as, isopropyl myristate, isopropyl palmitate, isostearyl palmitate, tridecyl salicylate, C12-15 octanoate and isopropyl stearate, or any mixtures thereof.

The oils may be employed singly or in mixtures with one another.

The inventive composition most preferably further includes an ingredient selected from the group consisting of antioxidants, reducing agents, chelating agents, and mixtures thereof to improve the stability of the cosmetic cream. These ingredients provide additional level of protection against oxidation of skin benefit agents in the cosmetic cream. Common examples of antioxidants, reducing agents and chelating agent for the present composition can be found in the CTFA International Cosmetic Ingredient Dictionary (4th Edition, The Cosmetic, Toiletry, and Fragrance Association Inc., Washington D. C, 1991 ).

Preferred reducing agents are sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium thiosulfite or other thiols, such as thioglycerol, thiourea, thioglycolic acid, cysteine and the like. Preferable antioxidants are 6-hydroxy-2,5,7,8-tetra-methylchroman-2- carboxylic acid (trolox), propyl gallate, n-propyl trihydroxybenzoate, t-butyl hydroquinone and butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tocopheryl acetate, ascorbyl palmitate, hydroquinone, dibutyl hydroquinone and the like. Suitable examples of chelating agents include, but are not limited to, EDTA, citric acid, tartaric acid, organo aminophosphonic acids and organo phosphonic acid components including certain of the commercially available compounds, marketed by Monsanto. Preferred is 1-hydroxyethylene, (1.1-diphosphonic acid). Organo-aminophosphonic acid is an organic compound including of at least one phosphonic acid group and at least one amino group.

Suitable organo-aminophosphonic acid components for use herein include the amino alkylene poly(alkylene phosphonic acids) and nitrilo-trimethylene phosphonic acids. Examples of this type of organo-aminophosphonic acid components include certain of the commercially available Dequest compounds marketed by Monsanto. Preferred are amino tri(methylene phosphonic acid) (Dequest T2006), diethylene triamine penta(methylene phosphonic acid) and hexamethylene diamine tetra(methylene phosphonic acid).

Other suitable additional heavy metal ion sequestrants for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid or ethylenetriamine pentacetic acid. Still other suitable additional heavy metal ion sequestrants for use herein are iminodiacetic acid derivatives such as 2-hydroxyethyl diacetic acid or glyceryl imino diacetic acid.

Antioxidants are included in the inventive composition in an amount from 0.01 to 10%, preferably from 0.1 to 5%, and most preferably from 0.2 to 4% by weight. Reducing agents are included in the inventive composition in an amount from 0.01 to 10%, preferably from 0.1 to 5%, and most preferably from 0.2 to 4% by weight. Chelating agents are included in the inventive compositions in an amount of from 0.01 to 1%, preferably from 0.05 to 0.5%, and most preferably from 0.05 to 0.3% by weight.

The invention will now be illustrated by way of examples. The examples are for illustration only and do not, in any way, restrict the scope of the invention. All the percentages referred to herein are in w/w of the composition, unless otherwise indicated.

EXAMPLE 1 Cosmetic cream compositions containing varying levels of fatty acid, talc and fatty acid soap were prepared. The details of the formulations are given in table 1 below. Table 1

The product attributes of compositions 1 to 6 are given in table 2 below.

Table 2

Procedure

Phase A ingredients were heated to 75⁰C. Phase B was heated to 75⁰C in a container, separate from that of phase A. Phase B was added to phase A at 75⁰C and stirred for 20 minutes followed by the addition of phase C at 7O⁰C. The temperature was reduced to 55⁰C and slurry of talc in water was added. Thereafter the phases were combined while mixing with the heat being turned off. Phase E was heated to 5O⁰C and mixed into phases A and B. The mixture was cooled to 4O⁰C and then the minor ingredients were added. The formulation was cooled to 35⁰C and packed.

The viscosity of the compositions was measured and the results have been included in table 2 above. Composition 1 is the control product, which has ideal viscosity and other desirable product attributes. It will be apparent that the viscosity of compositions 2 and 3 was very low and below acceptable limits, while composition 6 was found to be watery in consistency. The viscosity of composition 5 was within acceptable limits, but the product produced a draggy feel on the skin and therefore it could not spread easily upon application.

Hysteric acid is a commercially available product, which is a 55:45 mixture of palmitic acid and stearic acid. The average equivalent weight of hysteric acid is 270 g/equivalent. Therefore 270 g of this product reacts with a stoichiometrically equivalent amount i.e. 56.1 g of potassium hydroxide (KOH) forming 308g of potassium salt of hysteric acid (soap).

Therefore in the above compositions hysteric acid would react with the potassium hydroxide to form some soap of hysteric acid and the unreacted hysteric acid would remain in the fatty acid form in the composition. Based on this calculation, the amount of hysteric acid and potassium salt of hysteric acid (soap) in the compositions 2 to 6 were calculated and have been indicated in table 3 below.

Table 3

It is apparent that compositions 2, 3, 5 and 6 are outside the scope of the invention. On the other hand composition 4, where the ratio of free acid to soap is 1.68:1 , meets the preferred viscosity profile and also provides the desirable sensorial benefits. Sensory evaluation of the compositions listed in table 1 by expert panellists indicated that product attributes of composition 1 (control) and that of composition 4 were comparable.

EXAMPLE 2: Evaluation of product attributes

Composition 4 was evaluated for the product attributes which are generally desired by the consumers. In an experiment which was conducted with the help of 220 in-house panelists, the individual attributes were tested and rated vis-a-vis the attributes afforded by use of commercially available skin lightening and skin care creams. Products were distributed amongst all panelists randomly and they used the product for 8 days, with two applications on the face, per day. In each application ~0.5g of the product was used. At the end of 8 days, they were asked to rate the product that they had used on a scale from 1 to 5, one being low and 5 being high, for the desirable product attributes. The data set was then statistically treated. The results have been compiled and set forth in table 4 below.

Table 4

It can be seen that the composition according to the invention was rated consistently high on all the desired product attributes and in some cases, it was rated higher than the other products. Therefore, by using a relatively inexpensive material, it is possible to provide these attributes. EXAMPLE 3: Measurement of the brightness index of the cosmetic cream according to the invention and comparison of the same against commercially- available skin lightening vanishing creams.

A thin film of the cosmetic cream composition was drawn on Leneta black/white cards (Form 2A) using a 75 microns applicator. The opacity of this film was measured by using a Hunterlab Labscan XE instrument under the following conditions: D65 Lighting, Cielab 10 degree color scale. Measured area = 0.7" diameter circle. Reflection mode (45 degrees)

The opacity of the wet film was measured after five minutes of application and that of the dried film after 24 hours by placing the film on the machine illumination port. Opacity measurements were carried out according to a standard Hunterlab protocol, i.e. comparison between black and white substrates. The color measurements were carried out on white substrates. The results have been included in table 5 below.

Table 5

It will be appreciated that the brightness index, as measured by the L^* values, indicate that the instant brightness afforded by the cream according to the invention is comparable to conventional commercially available creams, which are high in stearic acid content and which are devoid of any talc. It will also be appreciated that the L^* values of these commercially available creams decreases significantly after 24 hours, whereas the same value for composition 4 remains appreciably high. This therefore indicates that the illustrated composition provides for instant glow as well as retaining the same for an appreciable amount of time. EXAMPLE 4: Study of extended stability of the product

The effect of temperature on the viscosity of composition 4 was studied over a period of 12 weeks and the results are presented in table 6 below.

Table 6

In the table "V" stands for viscosity and "CV" stands for cohesion value. It will be readily appreciated that even when the product was stored at 50 ⁰C for 12 weeks, there was no major change in viscosity or cohesion value, which would render the product unfit for use.

The protocol for measuring viscosity and cohesion value are provided below.

Viscosity

A BROOKFIELD viscometer LVDV-1 + was used in Helipath mode and a T-bar spindle attached to the viscometer using a special coupling. The drive motor slowly lowers or raises the viscometer so that the T-bar spindle creates a helical path through the test samples thus eliminating the problem of chanelling. The spindle was kept in contact with about 100g of the product in a beaker and the spindle was rotated at 4 rpm. Before use, SMC 1000 and Code 96 adjustments were done on the viscometer.

The movement of the Helipath was adjusted so that it traveled up and down in one minute. As the Helipath moved, three readings were noted when the Helipath made a sound after completing one 30 second movement up or down. The readings were averaged out and two repeat measurements were made. It was ensured that the beaker did not contain any air pockets within the cream by tapping the beaker before and after each reading. All viscosities were measured at 27 ⁰C. Protocol for Cohesion Value - Creams

This instrument measures a compound property which is dependent on a number of rheological parameters. It affords a useful control on the correctness of cream manufacture.

A layer of cream is sandwiched between a circular disc, hanging from the spring balance, and a platform which can be moved downwards at a constant rate. As the platform moves, the pull exerted on the cream breaks. The reading at this point is the cohesion value.

A Parco^® Spring Balance CV Meter or similar instrument from Labfine^® Instruments can be used for this study. The platform is moved by means of an electric motor. The disc has a diameter of 2.5 inches and the distance between disc and platform was 3/16 inches, determined by three round studs on the disc.

Around 5Og of cream was required to measure the cohesion value at 27 ⁰C. The value was measured and has been reported in grams.

EXAMPLE 5

Composition 4 was modified to form new composition 7 falling within the scope of the invention. Various functional attributes and properties of this product were determined. The formulation is given in table 7 below. The process employed to make the cream is as reported earlier. For comparison composition 8, which has high amounts of fatty acid and a high free fatty acid: fatty acid soap ratio, was prepared as a control cream.

Table 7: % weight

BESTA TaIc was procured from Kingslay Corp, Kolkata, India

The levels of fatty acid, fatty acid soap, talc and ratio of fatty acid to fatty acid soap is presented in table 8 below.

Table 8

An expert sensory evaluation panel of 20 trained members observed that composition 7 showed a smooth feel and a non-draggy feel which is highly desired by the consumers compared to composition 8. This was achieved by a significant reduction in free fatty acid level, but while maintaining the desired ratio between free fatty acid and fatty acid soap in the composition. The same panel also observed that the following desirable attributes of composition 7 were found to be comparable to that of composition 8: colour; creamy appearance; thickness in container; creamy in-use feel; in-use greasiness; in-use stickiness; in-use thickness; skin temperature upon application; wet-feel; ease of spreading; absorption rate; soft-feel; odour; final post-use greasiness; final post-use stickiness; and after-feel. It will be appreciated that the illustrated example, provides for a vanishing cream composition including relatively lower amount of fatty acids, without significantly affecting the sensory benefits associated with their use and viscosity of the product.

It will also be appreciated that the illustrated example provides for a vanishing cream composition that enhances the brightness of the skin.

In use, a small quantity of the composition, e.g. 1 to 5 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers.

Although the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A cosmetic cream base comprising: i. 4.0 to 10.0 % by weight Ci₂-C₂₀ fatty acid; ii. 1.0 to 5.0 % by weight fatty acid soap; and iii. 2.5 to 10.0 % by weight particulate matter selected from talc, starch or its derivatives.

2. A cosmetic cream base as claimed in claim 1 , wherein the particulate matter is talc.

3. A cosmetic cream base as claimed in claim 1 or claim 2 comprising 3.0 to 5.0 % by weight talc.

4. A cosmetic cream base as claimed in any one of the preceding claims wherein the weight ratio of the fatty acid to the fatty acid soap is from 10:1 to 1.5:1.

5. A cosmetic cream base as claimed in claim 4 wherein the ratio is from 3:1 to 2:1.

6. A cosmetic cream base as claimed in any one of the preceding claims comprising 5.0 to 8.0 % by weight Ci₂-C₂₀ fatty acid.

7. A cosmetic cream base as claimed in any of the preceding claims comprising 2.0 to 3.0 % by weight fatty acid soap.

8. A cosmetic cream base as claimed in any one of the preceding claims wherein the fatty acid is stearic acid.

9. A cosmetic cream composition comprising a cosmetic cream base as claimed in any one of the preceding claims and 0.1 to 10.0 % by weight benefit agent.

10. A cosmetic cream composition as claimed in claim 9, wherein the benefit agent is niacinamide.

1 1. A method of improving appearance of skin by applying to skin a cosmetic cream composition according to claim 9 or claim 10.