FOURNIAL ARNAUD (FR)
SEDERMA S A S (FR)
WO2014001725A1 | 2014-01-03 |
DE10305965A1 | 2004-08-26 | |||
US20060104937A1 | 2006-05-18 | |||
JP2012176995A | 2012-09-13 |
HAGIWARA HISAHIRO ET AL: "Revisit to (Z)-civetone synthesis", NATURAL PRODUCT COMMUNICATIONS, NATURAL PRODUCT INC, US, vol. 7, no. 7, 1 January 2012 (2012-01-01), pages 913 - 915, XP008177518, ISSN: 1934-578X
"PHARMACEUTICAL AND COSMETIC USES OF DIOIC ACIDS", RESEARCH DISCLOSURE, MASON PUBLICATIONS, HAMPSHIRE, GB, no. 444, 1 April 2001 (2001-04-01), pages 575 - 577, XP001111312, ISSN: 0374-4353
CLAIMS 1 . An anti-dandruff composition comprising an effective amount of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers. The anti-dandruff composition according to claim 1 wherein the concentration of the unsaturated dicarboxylic acid mixture is 0.01 % to 20% by weight. The anti-dandruff composition according to either one of claim 1 or 2 wherein the concentration of the trans isomer is at least 40% by weight and/or the concentration of the cis isomer is no more than 60% by weight. The anti-dandruff composition according to any one of the preceding claims wherein the ratio by weight of trans to cis isomers is 0.5 to 10:1 . The anti-dandruff composition according to any one of the preceding claims wherein the unsaturated dicarboxylic acid mixture comprises at least 80% of at least one C12 to C24 monounsaturated dicarboxylic acid and/or less than 20% of at least one C12 to C24 diunsaturated dicarboxylic acid and C12 to C24 tri unsaturated dicarboxylic acid, both by weight based on the total concentration of unsaturated dicarboxylic acids. The anti-dandruff composition according to any one of the preceding claims wherein the unsaturated dicarboxylic acid mixture comprises 0.1 % to 4% by weight of at least one saturated dicarboxylic acid. The anti-dandruff composition according to any one of the preceding claims wherein the unsaturated dicarboxylic acid mixture comprises 0.1 % to 3% by weight of at least one monocarboxylic acid. 8. The anti-dandruff composition according to any one of the preceding claims comprising at least one C16 to C20 monounsaturated dicarboxylic acid. 9. The anti-dandruff composition according to any one of the preceding claims wherein the at least one monounsaturated dicarboxylic acid is 9-octadecene- 1 ,18-dicarboxylic acid. 10. The anti-dandruff composition according to any one of the preceding claims wherein the unsaturated dicarboxylic acid mixture has an iodine value of 50 to 120 g iodine/100 g and/or an acid value of 310 to 380 mg KOH/g and/or a saponification value of 315 to 380 mg KOH/g. 1 1 . The anti-dandruff composition according to any one of the preceding claims additionally comprising zinc pyrithione. 12. The anti-dandruff composition according to claim 1 1 wherein the ratio by weight of unsaturated dicarboxylic acid mixture to zinc pyrithione is 0.5 to 2:1 . 13. The anti-dandruff composition according to any one of claims 1 to 10 wherein the anti-dandruff active present in the composition consists of the unsaturated dicarboxylic acid mixture. 14. A method of forming an anti-dandruff composition which comprises mixing together (i) an unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, (ii) at least one surfactant, and (iii) water. 15. The method according to claim 14 wherein the unsaturated dicarboxylic acid mixture is formed by mixing metathesis derived trans isomer of C12 to C24 monounsaturated dicarboxylic acid with fermentation derived cis isomer of C12 to C24 monounsaturated dicarboxylic acid. 16. The method according to either one of claim 14 or 15 wherein the ratio by weight of trans to cis isomers is 2 to 6:1 . 17. The use of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, as an active ingredient in an anti-dandruff composition. 18. The use according to claim 17 wherein the unsaturated dicarboxylic acid mixture is the only anti-dandruff active ingredient in the composition. 19. The use of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, to provide a synergistic anti-dandruff effect in combination with a different anti-dandruff active, preferably zinc pyrithione. 20. The use according to claim 19 wherein the ratio by weight of unsaturated dicarboxylic acid mixture to zinc pyrithione is 0.5 to 2:1 . 21 . An anti-dandruff shampoo comprising (i) the trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the ratio by weight of trans to cis isomers is 2 to 10:1 , (ii) an anionic surfactant; and (iii) optionally one or more of a betaine, a non-ionic surfactant, an amphoteric surfactant, and a cationic surfactant. 22. The anti-dandruff shampoo according to claim 21 wherein the anionic surfactant is an alkyl ether sulphate and/or an alkyl sulphate. 23. An unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of (i) the trans isomer is at least 40% by weight and the cis isomer is no more than 60% by weight, both based on the total concentration of the trans and cis isomers, (ii) at least one saturated dicarboxylic acid is 0.1 % to 4% by weight based on the total weight of the composition, (iii) at least one monocarboxylic acid is 0.1 % to 3% by weight based on the total weight of the composition. 24. The unsaturated dicarboxylic acid mixture according to claim 23 having at least one of (i) an iodine value of 50 to 120 g iodine/100 g, (ii) an acid value of 310 to 380 mg KOH/g, and (iii) a saponification value of 315 to 380 mg KOH/g. 25. The unsaturated dicarboxylic acid mixture according to either one of claim 23 or 24 comprising 0.001 % to 5% by weight of at least one anti-oxidant or radical scavenger. 26. The unsaturated dicarboxylic acid mixture according to claim 25 wherein the anti-oxidant or radical scavenger is selected from the group consisting of tocopherol, bisabolol, tocopheryl acetate, ascorbyl palmitate, butylated hydroxytoiuene, pentaerythrityi tetra-di-t-butyl hydroxyhydrocinnamate, and mixtures thereof. 27. A method of providing anti-dandruff efficacy which comprises the steps of (i) wetting the hair with water; (ii) applying an effective amount of an anti-dandruff composition comprising an unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, to the hair; (iii) rinsing the anti-dandruff composition from the hair using water; and optionally (iv) repeating steps (ii) and (iii). |
Field of Invention The present invention relates to an anti-dandruff composition, in particular to such a composition comprising a monounsaturated dicarboxylic acid.
Background Anti-dandruff compositions, particularly shampoos, are well known and have been commercially available for many years. Many anti-dandruff actives have been used commercially such as ketoconazole, zinc pyrithione, piroctone olamine, octopirox, salicylic acid, selenium sulfide, coal tar, and azelaic acid. These actives generally function as antimicrobial agents, being effective against certain species and strains of fungi and/or bacteria. For example, the yeast-like fungus Malassezia lives on the scalp of most adults, but for some people it irritates the scalp and can cause more skin cells to grow. These extra skin cells die and fall off, making them appear white and flaky in hair and on clothes. Thus, materials which are antimicrobial against Malassezia, e.g. Malassezia furfur, can reduce the severity of dandruff. Some anti- dandruff actives may function by a method other than by antimicrobial effects.
There is a continual requirement for improved anti-dandruff actives and end-use products containing such actives. There is a need for anti-dandruff actives that have improved, including broad spectrum, activity against fungi and/or bacteria, or that function other than by antimicrobial effects; that do not have the environmental concerns of some existing actives, and/or in use are non-irritant to the skin.
Thus, despite the many options currently available, consumers still require a product with improved anti-dandruff efficacy, particularly as dandruff is still prevalent in the general population. There is also a need for an anti-dandruff effect to be obtained from the use of a wide range of hair care products such as a shampoo, conditioner, 2-in-1 shampoo/conditioner, leave-on hair tonic, spray, liquid rinse, gel or mousse etc. Ideally, an anti-dandruff active should be capable of being effective in a wide range of hair care products. Summary of the Invention
We have surprisingly discovered an anti-dandruff composition that overcomes or significantly reduces at least one of the aforementioned problems.
Accordingly, the present invention provides an anti-dandruff composition comprising an effective amount of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers.
The invention also provides a method of forming an anti-dandruff composition which comprises mixing together (i) an unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, (ii) at least one surfactant, and (iii) water.
The invention further provides the use of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, as an active ingredient in an anti-dandruff composition. The invention still further provides the use of an unsaturated dicarboxylic acid mixture which comprises trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, to provide a synergistic anti-dandruff effect in combination with zinc pyrithione.
The invention yet further provides an anti-dandruff shampoo comprising (i) the trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the ratio by weight of trans to cis isomers is 2 to 10:1 , (ii) an anionic surfactant; and (iii) optionally one or more of a betaine, a non-ionic surfactant, an amphoteric surfactant, and a cationic surfactant. The invention even further provides an unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of (i) the trans isomer is at least 40% by weight and the cis isomer is no more than 60% by weight, both based on the total concentration of the trans and cis isomers, (ii) at least one saturated dicarboxylic acid is 0.1 % to 4% by weight based on the total weight of the composition, (iii) at least one monocarboxylic acid is 0.1 % to 3% by weight based on the total weight of the composition. The invention even more further provides a method of providing anti-dandruff efficacy which comprises the steps of (i) wetting the hair with water; (ii) applying an effective amount of an anti-dandruff composition comprising an unsaturated dicarboxylic acid mixture comprising trans and cis isomers of at least one C12 to C24 monounsaturated dicarboxylic acid wherein the concentration of the trans isomer is at least 25% by weight based on the total concentration of the trans and cis isomers, to the hair; (iii) rinsing the anti-dandruff composition from the hair using water; and optionally (iv) repeating steps (ii) and (iii).
The unsaturated dicarboxylic acid (dioic acid) mixture used as an anti-dandruff active in the present invention preferably comprises, consists essentially of, or consists of, at least one C1 2 to C24, more preferably C14 to C22, particularly C1 6 to C20, and especially C18 dicarboxylic acid. The unsaturated dicarboxylic acid mixture comprises both the trans isomer (E isomer) and cis isomer (Z isomer) of at least one C12 to C24, preferably C14 to C22, more preferably C16 to C20, and particularly C18 monounsaturated dicarboxylic acid.
The C or carbon chain number referred to also includes the carboxyl group carbons, i.e. C18 monounsaturated dicarboxylic acid means a compound having a 16 carbon hydrocarbylene group, preferably linear, containing one carbon-carbon double bond, with a carboxyl group at two ends of the hydrocarbylene group, e.g.
(HO(0)C(CH 2 ) n CH=CH(CH 2 ) m C(0)OH) where n + m = 14.
As used herein, the term "unsaturated dicarboxylic acid" includes derivatives thereof which for the present purposes includes esters, salts, and mercapto-compounds in which one or both of the carboxyl groups have been derivatised. In particular, lower, i.e. C1 to C4, alkyl esters and salts are preferred. Salts, e.g. alkali metal, are especially preferred derivatives, since these may form spontaneously depending upon the pH of the medium in which the dicarboxylic acids are present. The position of the carbon-carbon double bond may vary along the hydrocarbylene group, is preferably in the middle portion of the group, and particularly in the exact centre of a linear hydrocarbylene group. One preferred C18 monounsaturated dicarboxylic acid is 9-octadecene-1 ,18-dicarboxylic acid (i.e.
HO(0)C(CH 2 ) 7 CH=CH(CH 2 ) 7 C(0)OH).
In one embodiment, the at least one trans isomer of monounsaturated dicarboxylic acid defined herein is present in the unsaturated dicarboxylic acid mixture at a concentration of at least 40%, more preferably at least 55%, particularly at least 65%, and especially at least 75% by weight based on the total concentration of the trans and cis isomers in the mixture. One preferred trans isomer is the trans isomer of 9-octadecene-1 ,18-dicarboxylic acid.
In one embodiment, the at least one cis isomer of monounsaturated dicarboxylic acid defined herein is present in the unsaturated dicarboxylic acid mixture at a concentration of no more than 75%, preferably no more than 60%, more preferably no more than 45%, particularly no more than 35%, and especially no more than 25% by weight based on the total concentration of the trans and cis isomers in the mixture. One preferred cis isomer is the cis isomer of 9-octadecene-1 ,18- dicarboxylic acid.
In one embodiment, the concentration by weight of trans/cis isomers defined herein present in the unsaturated dicarboxylic acid mixture is preferably 25% to 95%:5% to 75%, more preferably 50% to 90%:10% to 50%, particularly 65% to 85%:15% to 35%, and especially 76% to 82%:18% to 24%.
In one embodiment, the ratio by weight of trans to cis isomers defined herein present in the unsaturated dicarboxylic acid mixture is suitably 0.5 to 19:1 , preferably 2 to 10:1 , more preferably 3 to 6:1 , particularly 4 to 5:1 , and especially 4.5 to 4.6:1 . In addition to monounsaturated dicarboxylic acid, the unsaturated dicarboxylic acid mixture used herein may also contain at least one diunsaturated dicarboxylic acid and/or at least one triunsaturated dicarboxylic acid. The unsaturated dicarboxylic acid mixture suitably comprises (i) at least 65%, preferably at least 80%, more preferably at least 90%, particularly in the range from 95% to 99.5%, and especially 96% to 98% of at least one C12 to C24, more preferably C14 to C22, particularly C16 to C20, and especially C18
monounsaturated dicarboxylic acid; (ii) suitably less than 25%, preferably less than 15%, more preferably less than 8%, particularly in the range from 0.4% to 4%, and especially 1 .7 to 3.4% of at least one C12 to C24, more preferably C14 to C22, particularly C16 to C20, and especially C18 diunsaturated dicarboxylic acid; and/or (iii) suitably less than 10%, preferably less than 5%, more preferably less than 2%, particularly in the range from 0.1 % to 1 %, and especially 0.3% to 0.6% of at least one C12 to C24, more preferably C14 to C22, particularly C16 to C20, and especially C18 triunsaturated dicarboxylic acid, all by weight based on the total amount of unsaturated dicarboxylic acids in the mixture.
In one embodiment, the combined concentration of diunsaturated dicarboxylic acid and triunsaturated dicarboxylic acid defined herein in the unsaturated dicarboxylic acid mixture is suitably less than 35%, preferably less than 20%, more preferably less than 10%, particularly in the range from 0.5% to 5%, and especially 2% to 4% by weight based on the total amount of unsaturated dicarboxylic acids in the mixture.
The unsaturated dicarboxylic acid mixture suitably comprises less than 10%, preferably less than 6%, more preferably in the range from 0.1 % to 4%, particularly 1 % to 3%, and especially 1 .5% to 2.5% by weight of at least one C12 to C24, more preferably C14 to C22, particularly C16 to C20, and especially C18 saturated dicarboxylic acid, based on the total weight of the mixture.
The unsaturated dicarboxylic acid mixture suitably comprises less than 5%, preferably less than 3%, more preferably in the range from 0.01 % to 1 %, particularly 0.15% to 0.5%, and especially 0.25% to 0.35% by weight of at least one C12 to C24, more preferably C14 to C22, particularly C16 to C20, and especially C18 monocarboxylic acid, based on the total weight of the mixture.
The unsaturated dicarboxylic acid mixture suitably has an iodine value (measured as described herein) of less than 200, preferably in the range from 30 to 150, more preferably 50 to 120, particularly 60 to 100, and especially 70 to 90 g iodine/100 g.
The unsaturated dicarboxylic acid mixture suitably has an acid value (measured as described herein) of less than 450, preferably in the range from 290 to 400, more preferably 310 to 380, particularly 330 to 360, and especially 340 to 350 mg KOH/g.
The unsaturated dicarboxylic acid mixture suitably has a saponification value (measured as described herein) of less than 450, preferably in the range from 295 to 400, more preferably 315 to 380, particularly 335 to 360, and especially 345 to 350 mg KOH/g.
In one embodiment, the unsaturated dicarboxylic acid mixture may additionally comprise at least one anti-oxidant or radical scavenger agent to protect the mixture against oxidation and allow long-term storage without significant degradation. The unsaturated dicarboxylic acid mixture preferably comprises in the range from
0.001 % to 5%, and more preferably 0.01 % to 1 % by weight of anti-oxidant or radical scavenger, based on the total weight of the mixture.
Suitable anti-oxidants/radical scavengers may be selected from the group consisting of ascorbic acid (vitamin C) and its salts, fatty esters of ascorbyl as palmitate ascorbyl, ascorbic acid derivatives (e.g. magnesium ascorbyl phosphate, sodium ascorbyl phosphate, ascorbyl sorbate), tocopherol (vitamin E), tocopherol sorbate, tocopheryl acetate, other esters of tocopherol, tocofrienols associated or not with tocopherols, bisabolol, iinoleic acid, 6-hydroxy-2,5,7,8-tetramethylchroman- 2-carboxylic acid (commercially available under the tradename Troiox), gallic acid and its aikyl esters, especially propyl gallate, uric acid and its salts and alkyl esters, sorbic acid and its salts; iipoic acid, amines (e.g. N, N-diethylhydroxylamine, amino- guanidine), the sulfhydryl compounds (e.g. glutathione), dihydroxy fumaric acid and its salts, lysine pidolate, amino acids, silymarin, lysine, 1 -methionine, proline, olive extracts, tea extracts, polyphenols such as proanthocyanidins from pine bark, carotenoids, compounds curcumin such as tetrahydrocurcumin, OCTA (acid L-2- oxo-4-thiazolidine carboxylic acid), glutathione, melanin, rosemary extracts, grape skin/seed extracts, the pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, butylated hydroxytoluene and butylated hydroxyanisole, orizanol, hexyl ethyl ferulate, and mixtures thereof.
Preferably the anti-oxidant/radical scavenger is selected from the group consisting of tocopherol (as Coviox T70), bisabolol, tocopheryl acetate, ascorbyl palmitate, butylated hydroxytoluene (BHT), pentaerythrityl tetra-di-t-butyl
hydroxyhydrocinnamate, and mixtures thereof.
The anti-dandruff composition according to the present invention suitably comprises in the range from 0.001 % to 20%, preferably 0.01 % to 10%, more preferably 0.1 % to 5%, particularly 0.5% to 2%, and especially 0.8% to 1 .2% by weight of the unsaturated dicarboxylic acid mixture defined herein, based on the total weight of the composition.
The anti-dandruff composition suitably comprises in the range from (i) 0.4% to
1 .25%, preferably 0.5% to 1 .15%, more preferably 0.6% to 1 .1 %, particularly 0.65% to 1 .0%, and especially 0.7% to 0.9% by weight of at least one trans isomer of C12 to C24, preferably C14 to C22, more preferably C16 to C20, and particularly C18 monounsaturated dicarboxylic acid, and/or (ii) 0.1 % to 0.26%, preferably 0.12% to 0.24%, more preferably 0.13% to 0.22%, particularly 0.14% to 0.20%, and especially 0.15% to 0.19% by weight of at least one cis isomer of C12 to C24, preferably C14 to C22, more preferably C16 to C20, and particularly C18 monounsaturated dicarboxylic acid, both based on the total weight of the composition.
In one embodiment, the ratio by weight of trans to cis isomers defined herein present in the anti-dandruff composition is suitably 0.5 to 19:1 , preferably 2 to 10:1 , more preferably 3 to 6:1 , particularly 4 to 5:1 , and especially 4.5 to 4.6:1 .
Naturally sourced monounsaturated fatty acids, e.g. oleic acid, generally contain 100% of cis isomers. Cis isomers of monounsaturated dicarboxylic acids can be produced by a biological route, for example as a metabolic product of the fermentation of yeast cells of the Candida genus, e.g. Candida cloacae, grown on oleic acid feedstock. Trans isomers of monounsaturated dicarboxylic acids can be produced by a metathesis, preferably self-metathesis, reaction using a ruthenium based catalyst, e.g. using oleic acid (or methyl oleate) starting material, as described in WO2013/140144. The particular ratio of trans to cis isomers required in the unsaturated dicarboxylic acid mixture used in the anti-dandruff composition of the present invention can be obtained by mixing a composition comprising metathesis derived trans isomer of monounsaturated dicarboxylic acid with a composition comprising fermentation derived cis isomer of monounsaturated dicarboxylic acid.
In one embodiment, the unsaturated dicarboxylic acid mixture defined herein is the only anti-dandruff active present in the anti-dandruff composition, i.e. the antidandruff composition comprises an anti-dandruff active that consists essentially of, or consists of, the unsaturated dicarboxylic acid mixture defined herein.
In another embodiment, the unsaturated dicarboxylic acid mixture defined herein may be used in combination with at least one "other" (i.e. chemically different) antidandruff active material, e.g. selected from the group consisting of ketoconazole, zinc pyrithione (ZPT), piroctone olamine, octopirox, salicylic acid, selenium sulfide, coal tar, azelaic acid, climbazole, salicylic acid, undecylenic acid, and mixtures thereof. A synergistic anti-dandruff effect may be observed when the unsaturated dicarboxylic acid mixture is used together with at least one other anti-dandruff active, in particularly zinc pyrithione (ZPT).
In one embodiment, the anti-dandruff composition according to the present invention suitably comprises in the range from 0.01 % to 15%, preferably 0.1 % to 5%, more preferably 0.2% to 2%, particularly 0.3% to 1 %, and especially 0.4% to 0.6% by weight of at least one other anti-dandruff active (i.e. other than the unsaturated dicarboxylic acid mixture defined herein), based on the total weight of the composition.
One preferred other anti-dandruff active is pyrithione and/or a metal salt thereof. Any form of metal, preferably polyvalent, pyrithione salts may be used, including those in platelet and needle form. Preferred salts include those formed from the polyvalent metals magnesium, barium, bismuth, strontium, copper, zinc, cadmium, zirconium, and mixtures thereof. Zinc is preferred, particularly the zinc salt of 1 - hydroxy-2- pyridinethione (known as zinc pyrithione (ZPT)). In one embodiment, the ratio by weight of unsaturated dicarboxylic acid mixture to pyrithione and/or a metal salt thereof, preferably ZPT, present in the anti-dandruff composition is suitably 0.1 to 10:1 , preferably 0.33 to 3:1 , more preferably 0.5 to 2:1 , particularly 0.8 to 1 .2:1 , and especially 0.9 to 1 .1 :1 . The anti-dandruff composition may also comprise a zinc-containing layered mineral, for example zinc carbonate (basic), hydrozincite (zinc carbonate hydroxide), aurichalcite (zinc copper carbonate hydroxide), and rosasite (copper zinc carbonate hydroxide). In one embodiment, the anti-dandruff composition comprises in the range from 0.01 % to 10%, preferably 0.2% to 5%, more preferably 0.4% to 2%, particularly 0.5% to 1 %, and especially 0.6% to 0.8% by weight of a zinc-containing layered mineral, preferably zinc carbonate, based on the total weight of the composition. The anti-dandruff composition is preferably a hair care product such as a shampoo, conditioner, 2-in-1 shampoo/conditioner, hairspray, hair spritz, hair colouring product, leave-on hair tonic, hair sunscreen product, styling mousse or gel, or other hair treatment composition. Typically, the anti-dandruff composition according to the present invention comprises at least one surfactant, such as anionic, non-ionic, amphoteric and/or cationic surfactants. In one embodiment, the composition comprises the
unsaturated dicarboxylic acid mixture as defined herein, in combination with at least one anionic surfactant.
Suitable anionic surfactants include alkyl sulphates, alkyl ether sulphates, alpha olefin sulphonates, sulphosuccinates, isethionates, acyl amides, acyl glutamates, alkyl ether carboxylates and alkyl phosphates. The alkyl group preferably comprises in the range from 6 to 30, more preferably 8 to 20, particularly 10 to 14, and especially 12 carbon atoms. Alkyl ether sulphates and/or alkyl sulphates are preferred, particularly alkali metal, e.g. sodium, and/or ammonium salts thereof. Lauryl ether sulphate and/or lauryl sulphate are particularly preferred anionic surfactants. In one embodiment, the anti-dandruff composition comprises both alkyl ether sulphate and alkyl sulphate, preferably lauryl ether sulphate and lauryl sulphate, suitably present at a weight ratio of 1 to 15:1 , preferably 3 to 10:1 , more preferably 4 to 8:1 , particularly 5 to 7:1 , and especially 5.5 to 6.5:1 . The concentration of anionic surfactant in the anti-dandruff composition is suitably in the range from 0.5% to 25%, preferably 3% to 20%, more preferably 7% to 18%, particularly 10% to 16%, and especially 12% to 14% by weight based on the total weight of the composition. The anti-dandruff composition may also contain at least one secondary surfactant such as a nonionic, amphoteric, betaine, and/or cationic surfactant. The total concentration of anionic surfactant and secondary surfactant(s) in the composition is suitably in the range from 3% to 50%, preferably 8% to 40%, more preferably 12% to 30%, particularly 16% to 25%, and especially 18% to 22% by weight based on the total weight of the composition.
Suitable betaines include alkyl betaines, alkylamido betaines, alkyl sultaines, alkylamido sultaines, and mixtures thereof. Alkylamido betaines are preferred. The alkyl group preferably comprises in the range from 6 to 30, more preferably 8 to 20, and particularly 10 to 14 carbon atoms. The concentration of betaine surfactant in the anti-dandruff composition is preferably in the range from 0% to 20%, more preferably 0.5% to 10%, particularly 1 % to 12%, and especially 1 .5% to 2.5% by weight based on the total weight of the composition. Suitable nonionic surfactants include the fatty alcohol acid or amide ethoxylates, alkanolamides and alkoxylated alkanolamides, monoglyceride ethoxylates, sorbitan ester ethoxylates, alkyl polyglycosides, ethylene glycol monoesters, ethylene glycol diesters, and mixtures thereof. The concentration of nonionic surfactant in the anti- dandruff composition is preferably in the range from 0% to 30%, more preferably 0.5% to 10%, particularly 1 % to 5%, and especially 1 .5% to 2% by weight based on the total weight of the composition.
Suitable amphoteric surfactants include alkylimino-diproprionates,
alkylamphoglycinates, alkylamphoproprionates, alkylamphoacetates (mono- and di-), N-alkyl beta -aminoproprionic acids, alkylpolyamino carboxylates,
phosphorylated imidazolines, and mixtures thereof. The concentration of amphoteric surfactant in the anti-dandruff composition is preferably in the range from 0% to 20%, more preferably 0.5% to 10%, particularly 1 % to 5%, and especially 1 .5% to 2% by weight based on the total weight of the composition.
Suitable cationic surfactants include alkyl quaternaries, benzyl quaternaries, ester quaternaries, ethoxylated quaternaries, alkyl amines, and mixtures thereof. The alkyl group preferably comprises in the range from 6 to 30, more preferably 8 to 22, and particularly 10 to 20 carbon atoms.
The cationic surfactant may also be a polyquaternium material (or polyquat).
Polyquats include polymers based on acrylamide and/or dimethyl allylamonium chloride such as Polyquaternium 6, Polyquaternium 7, and the like. Polymeric quaternium ammonium salts of guar gum, such as guar hydroxypropyltrimonium chloride, may be used. Polymeric quaternium ammonium salts of cellulose such as Polyquaternium 10 and the like, and polymeric quaternium ammonium salts of starch, may also be used.
The concentration of cationic surfactant in the anti-dandruff composition is preferably in the range from 0% to 20%, more preferably 0.1 % to 10%, particularly 0.3% to 3%, and especially 0.5% to 1 % by weight based on the total weight of the composition.
The amount of the water in the anti-dandruff composition is suitably in the range from 10% to 97%, preferably 30% to 95%, more preferably 50% to 90%, particularly 65% to 85%, and especially 72% to 78%, by weight based on the total weight of the composition. The anti-dandruff composition of the present invention may be used with one or more of the other standard ingredients or carriers used in hair care products, including shine enhancers, moisturisers, herbal additives, hair strengtheners, vitamin additives, colorants, hair thickening agents; setting and styling agents; ultraviolet absorbers; silicone oils; essential oils and fragrances; thickening or viscosity-enhancing agents; detergents; stabilising agents; emollients; chelating agents; sequestering agents; preservatives; disinfectants; anti-oxidants/radical scavengers (e.g. those described above for use in the unsaturated dicarboxylic acid mixture); antistatic agents; conditioning agents; detangling ingredients; emulsifying or dispersing agents; stimulants; soothers; solvents; carriers and the like.
In particular, the anti-dandruff composition may comprise a silicone fluid or oil such as dimethylpolysiloxane, dimethyl silicone, highly polymerized methyl polysiloxane, and methyl polysiloxane, known generically as dimethicone, cyclic oligomeric dialkylsiloxanes, such as the cyclic oligomers of dimethylsiloxane, known generically as cyclomethicone. The concentration of silicone oil in the anti-dandruff
composition is preferably in the range from 0% to 40%, more preferably 0.3% to 20%, particularly 0.5% to 5%, and especially 1 % to 1 .5% by weight based on the total weight of the composition.
The anti-dandruff composition may be in the form of an aqueous "leave on" or an aqueous "rinse off" end-use product. For such compositions, a dilute solution of the unsaturated dicarboxylic acid mixture in water may be used. The concentration of the unsaturated dicarboxylic acid mixture defined herein in such a product is preferably in the range from 0.01 % to 5%, more preferably 0.2% to 2%, particularly 0.5% to 1 .5%, and especially 0.9% to 1 .1 % by weight based on the total weight of the composition. Preferably, a buffered solution is used, in which the pH of the solution is adjusted to mildly acidic, with a pH in the range of from 4 to 6. In the case of rinse-off formulations, instructions are provided to wash off the diluted unsaturated dicarboxylic acid mixture after application. Depending on the level of treatment required, such instructions may also require the product to remain on the hair for some time, such as from 1 to 30 minutes. For leave-on formulations, the washing off step is omitted. One preferred anti-dandruff product is a hair conditioner, which functions to make the hair more shiny and manageable. The conditioner may be in the form of a dispersion, emulsion or solution. One preferred system is one that forms liquid crystals. The liquid crystals are preferably lyotropic liquid crystals (i.e. both concentration and temperature dependent), more preferably lamellar phase liquid crystals, and particularly L alpha phase (neat) liquid crystals. The concentration of the unsaturated dicarboxylic acid mixture in the conditioner is preferably in the range from 0.1 % to 10%, more preferably 0.3% to 2%, particularly 0.4% to 1 .5%, and especially 0.5% to 1 % by weight based on the total weight of the composition.
The conditioner may contain many different types of functional ingredients such as;
(i) cationic hair conditioning agents, e.g. ethoxylated phosphate fatty quats, such as those sold by Croda as Arlasilk™; fatty amido amines, such as those sold by Croda as Incromine™; fatty quats, such as those sold by Croda as Incroquat™, Crodazosoft™, Rejuvasoft™ or VibraRiche™ typically used at a concentration in the range from 1 % to 5% by weight based on the total weight of the composition.
These are typically combined with polymeric hair conditioning cationic materials such as quaternised cellulose sold by Croda as Crodacel™, quaternised proteins, such as those sold by Croda, as Croquat™, Crolactin™, Crosilkquat™,
Keramimic™ and Hydrotriticum™.
(ii) fatty alcohols, e.g. stearyl, cetearyl, cetyl, oleyl alcohols, used typically at a concentration range of 2% to 5% by weight based on the total weight of the composition.
(iii) humectants or solvents, e.g. alcohols and polyols such as glycerol and polyethylene glycols, when used typically at a concentration in the range from 1 % to 10% by weight based on the total weight of the composition;
(iv) reconstructors, e.g. hydrolyzed proteins such as wheat protein, which function to penetrate the hair and strengthen the hair structure through polymer crosslinking;
(v) glossing or detangling materials which bind to the hair and reflect light, e.g. silicones such as dimethicone, phenyltrimethicone, dimethiconol and/or
trimethylsilylamodimethicone, usually at a concentration in the range from 0.2% to 10% by weight based on the total weight of the composition;
(vi) acidity regulators, e.g. citric acid, lactic acid, which generally maintain the pH of the conditioner at about 4 to 6; (vii) thermal protectors, usually heat-absorbing polymers, which shield the hair against excessive heat, e.g. caused by blow-drying or curling irons or hot rollers such as for instance those sold by Croda as Mirustyle™ MFP (quaternized starch); and
(viii) UV protection agents, to protect hair or formulation components from degradation by UV light, such as those sold by Croda as Crodasorb™ UV-HPP. In one embodiment, the anti-dandruff composition of the invention is in the form of an emulsion (or dispersion), such as an oil-in-water or water-in-oil emulsion, particularly an oil-in-water emulsion.
The oil phase of the emulsion will preferably be mainly an emollient oil of the type used in personal care or cosmetic products. The emollient can and usually will be an oily material which is preferably liquid at ambient temperature. Alternatively, it can be solid at ambient temperature, in which case in bulk it will usually be a waxy solid, provided it is liquid at an elevated temperature at which it can be included in and emulsified in the composition.
Suitable normally liquid emollient oils include non-polar oils, for example mineral or paraffin, especially isoparaffin, oils, such as that sold by Croda as Arlamol™ HD; or medium polarity oils, for example vegetable ester oils such as jojoba oil, vegetable glyceride oils, animal glyceride oils, such as that sold by Croda as Crodamol™ GTCC (caprylic/capric triglyceride), synthetic oils, for example synthetic ester oils, such as isopropyl palmitate and those sold by Croda as Estol™ 1512, ether oils, particularly of two fatty e.g. C8 to C18 alkyl residues, such as that sold by Cognis as Cetiol OE (dicaprylether), guerbet alcohols such as that sold by Cognis as Eutanol G (octyl dodecanol), or silicone oils, such as dimethicione oil such as those sold by Dow Corning as DC200, cyclomethicone oil, or silicones having polyoxyalkylene side chains to improve their hydrophilicity; or highly polar oils including alkoxylate emollients for example fatty alcohol propoxylates such as that sold by Croda as Arlamol™ E (propoxylated stearyl alcohol).
The concentration of the oil phase may vary widely. The amount of the oil phase in the emulsion is preferably in the range from 0.5% to 80%, more preferably 1 % to 30%, particularly 1 .5% to 15%, and especially 2% to 10%, by weight based on the total weight of the emulsion. The amount of the aqueous phase in the emulsion is preferably in the range from 20% to 99.5%, more preferably 70% to 99%, particularly 85% to 98.5%, and especially 90% to 98%, by weight based on the total weight of the emulsion. A wide range of emulsifiers may be employed, particularly one or more cationic emulsifier(s). The specific nature of the emulsifier surfactant used in any particular instance depends on the type of emulsion being made, particularly the amount and nature of the oil being emulsified and the total desired level of emulsifier. The concentration of emulsifier in the emulsion is preferably in the range from 0.1 % to 20%, more preferably 0.5% to 15%, particularly 1 % to 10%, and especially 2% to 7%, by weight based on the total weight of the emulsion.
The emulsion suitably comprises in the range from 0.01 % to 10%, preferably 0.5% to 5%, more preferably 0.1 % to 4%, particularly 0.2% to 2%, and especially 0.3% to 1 % by weight of the unsaturated dicarboxylic acid mixture based on the total weight of the emulsion.
Many other components that may be used in hair care compositions or end-use products may also be included in the anti-dandruff composition according to the present invention. These components may be oil soluble, water soluble or non- soluble. Examples of such materials include:
(i) preservatives such as those based on parabens (alkyl esters of 4- hydroxybenzoic acid), phenoxyethanol, substituted ureas and hydantoin derivatives, e.g. those sold commercially under the trade names Germaben II Nipaguard BPX and Nipaguard DMDMH, when used usually in a concentration in the range from 0.5% to 2% by weight based on the total weight of the composition;
(ii) perfumes, when used typically at a concentration in the range from 0.1 % to 10% more usually up to about 5% and particularly up to about 2%, by weight based on the total weight of the composition;
(iii) humectants or solvents such as alcohols, polyols such as glycerol and polyethylene glycols, when used typically at a concentration in the range from 1 % to 10% by weight based on the total weight of the composition;
(iv) alpha hydroxy acids such as glycolic, citric, lactic, malic, tartaric acids and their esters; self-tanning agents such as dihydroxyacetone; (v) vitamins and their precursors including: (a) Vitamin A, e.g. as retinyl palmitate and other tretinoin precursor molecules, (b) Vitamin B, e.g. as panthenol and its derivatives, (c) Vitamin C, e.g. as ascorbic acid and its derivatives, (d) Vitamin E, e.g. as tocopheryl acetate, (e) Vitamin F, e.g. as polyunsaturated fatty acid esters such as gamma-linolenic acid esters;
(vi) skin care agents such as ceramides either as natural materials or functional mimics of natural ceramides;
(vii) natural phospholipids, e.g. lecithin;
(viii) vesicle-containing formulations;
(ix) botanical extracts with beneficial skin care properties;
(x) skin whiteners such as kojic acid, arbutin and similar materials;
(xi) skin repair compounds actives such as Allantoin and similar series;
(xii) caffeine and similar compounds;
(xiii) cooling additives such as menthol or camphor;
(xiv) insect repellents such as N,N-diethyl-3-methylbenzamide (DEET) and citrus or eucalyptus oils;
(xv) essential oils; and
(xvi) pigments, including microfine pigments, particularly oxides and silicates, e.g. iron oxide, particularly coated iron oxides, and/or titanium dioxide, and ceramic materials such as boron nitride, or other solid components, such as are used in make up and cosmetics, to give suspoemulsions, typically used in an amount in the range from 1 % to 15%, but usually at least 5% and particularly about 10% by weight based on the total weight of the composition. Application of the anti-dandruff composition, particularly a shampoo, to the hair typically includes working the composition through the hair. One preferred method for providing anti-dandruff efficacy comprises the steps of (i) wetting the hair with water, (ii) applying an effective amount of the anti-dandruff composition to the hair, and (iii) rinsing the anti-dandruff composition from the hair using water. These steps may be repeated, in order to obtain the desired cleansing, and/or
conditioning, and anti-dandruff effect sought.
An alternative method comprises the steps of (i) wetting the hair with water, (ii) applying an effective amount of the anti-dandruff shampoo composition, (iii) rinsing the shampoo composition from the hair using water; (iv) applying an effective amount of a conditioner composition optionally containing the unsaturated dicarboxylic acid mixture defined herein; (v) rinsing the conditioner composition from the hair using water. A preferred embodiment of the method is when both the shampoo composition and the conditioner composition comprise the unsaturated dicarboxylic acid mixture defined herein.
In this specification the following test methods have been used:
(i) Iodine Value
The iodine value of the unsaturated dicarboxylic acid mixture was determined by the Wijs method (A.O.C.S. Official Method Tg 1 -64 (1993)) and expressed as the number of grams of iodine absorbed by 100 grams of sample under the defined test conditions.
(ii) Acid Value
The acid value of the unsaturated dicarboxylic acid mixture was measured using the A.O.C.S. Official method Te 1 a-64 (Reapproved 1997), and expressed as the number of milligrams of potassium hydroxide required to neutralise the free fatty acids in one gram of sample.
(iii) Saponification Value
The saponification value of the unsaturated dicarboxylic acid mixture was determined using the A.O.C.S. Official method Tl 1 a-64 (1997) and defined as the number of milligrams of potassium hydroxide which reacts with one gram of sample under the prescribed conditions.
(iv) Fatty Acid Composition
The fatty acid composition of the unsaturated dicarboxylic acid mixture was determined by gas chromatography (GC). Prior to the GC analysis, the sample was methylated using the Combipal system. 8 mg of the fatty acid composition was dissolved in 100 μΙ of methanol. 0.5 ml BF3 catalyst, 20% in methanol was added, agitated and heated to 80 °C for 4 minutes. After cooling to room temperature, 600 μΙ heptane and 600 μΙ water were added. The two phase system was agitated for 2 minutes, and the upper (heptane) layer was transferred into a new sample vial, ready for analysis.
Instrumentation and gas chromatographic conditions were as follows:
Column : CP-FFAP CB, length : 25 m, ID : 0.32 mm, film thickness : 0.30 mm. Temperature : 120 Ό increased e^/min to 250 °C (6.25 minutes).
Carrier gas : Hydrogen.
Flow : 120 ml/min.
Injection : Split/1 μΙ.
Detection : F.I.D.
Pressure : 9 psi.
Run time : 22.5 minutes.
(v) Trans/Cis Isomer Composition
The methylated sample produced in (iv) above wase also used for the trans/cis isomer measurements using GC. The standard trans/cis isomer method for monomethylesters is not suitable for dimethyl esters. Therefore the isothermic oven temperature was increased from 160 °C to 210 ^ and the run time was 15 minutes. Results of the trans/cis isomer determinations were based on comparison with an all cis standard fatty acid composition.
Instrumentation and gas chromatographic conditions were as follows:
Column : CP Sil 88, length : 25 m, ID : 0.32 mm, film thickness : 0.20 μηι.
Temperature : 21 C (15 minutes).
Carrier gas : Hydrogen.
Flow : 1 .39 ml/min.
Injection : Split (split ratio 1 :100).
Detection : F.I.D.
Pressure : 5.6 psi.
Run time : 15 minutes.
The invention is illustrated by the following non-limiting examples. Example 1
50 grams of methyl oleate of more than 90% of purity, stabilized using 100 ppm of tert-butylhydroquinone antioxidant, was heated to 100°C under nitrogen. 200 ppm of titanium isopropoxide as a catalyst enhancer was added under stirring. 5 ppm of the catalyst (Umicore M73 SIMES (a Ruthenium based complex catalyst) in 100 μΙ tetrahydrofuran) was then added. After approximately 5 minutes the theoretical equilibrium was reached. 2 g of activated bentonite was then added to the reaction mixture to entrap the catalyst and enhancer. The mixture was then filtered through a cellulose filter to remove the catalyst and the filtrate was recovered.
The catalyst-free product was then purified using fractional distillation at 1 -10 mbar vacuum, firstly distilling off the 9-octadecene and methyl oleate (unreacted starting material), and then collecting dimethyl octadecenedioate in the temperature range of 210-220 °C. Gas chromatography analysis indicated a purity of greater than 85%. The dimethyl octadecenedioate fraction was then hydrolyzed by saponification (in a KOH/water/methanol mixture at 70 °C under reflux) and subsequently cooled to 55 °C. During progressive acidification with phosphoric acid, under stirring, precipitation of the product occurred. Solids were filtered off, washed with water until the filtrate had a neutral pH, and dried under vacuum (approx. 10 mbar, 60°C) resulting in 9-octadecene- 1 ,18-dicarboxylic acid, which was further purified by molecular distillation at 180°C and 0.001 mbar. The final product was a white solid which was subjected to the test procedures described herein. The results are given in Table 1 .
Table 1
Parameter Value
Acid value 345 mg KOH/g
Saponification value 347 mg KOH/g
Iodine value 80 g 1/100 g
Melting point 90-95 °C
9-octadecene- 1 ,18-dicarboxylic acid 94.4 wt.%
Monocarboxylic acids 0.3 wt.%
Di and tri unsaturated dicarboxylic 2.9 wt.%
acids
Saturated dicarboxylic acids 2 wt.%
Trans isomer of 9-octadecene-1 ,18- 77 wt.%
dicarboxylic acid
Cis isomer of 9-octadecene-1 ,18- 17.4 wt.%
dicarboxylic acid Example 2
The anti-dandruff effect of the unsaturated dicarboxylic acid mixture produced in Example 1 was shown by using concentrations of 0.1 %, 1 % and/or 2% by weight in DMSO to inhibit the growth of Malassezia furfur or Malassezia globosa. Yeast concentrations of 10 5 to 10 8 cell/ml in solid medium and 10 6 cell/ml in liquid medium were employed. Modified Dixon's Medium was used as culture medium. The growth was monitored over several days and visual observation was used on culture dishes and cell count used in liquid medium. ln-vitro inhibition of the reproduction of Malassezia micro-organisms has been shown to result in a statistically significant reduction in the severity of dandruff.
Example 3
An anti-dandruff cleansing conditioner formulation was made of the following composition;
PRODUCT % INCI NAME
Phase A
H 2 0 Qsp 100 Water
Potassium Sorbate qs Potassium Sorbate
IINCROMIDE™ OXIDE 2.0 Cocamidopropylamine Oxide & Water
C-LQ-MH (ex Croda)
LUSTREPLEX™ LQ-MH 1 .5 Polyquaternium-70 & Dipropylene Glycol
(ex Croda)
Phase B
CRODAZOQUAT™ 1 .5 Behentrimonium Methosulfate & Cetearyl
MCC-PA-MH (ex Croda) Alcohol & Quaternium-86
CRODACOL™ CS-PA- 3.0 Cetearyl Alcohol
RB (ex Croda)
Product of Example 1 1 .0 Phase C
Glycerin 3.0 Glycerin
CROVOL™ A70-LQ-RB 1 .0 PEG-60 Almond Glycerides
(ex Croda)
Phenoxyethanol qs Phenoxyethanol
Phase D
Fragrance 0.1 Fragrance
Procedure:
Phase A components were mixed and heated at 85 °C in a water bath. Phase B components were mixed and heated at 85 °C in a water bath. Phase C components were mixed and homogenized. Phase C was added to Phase A under normal Staro agitation (v=30%). Phase B was added to Phase A+C under rapid Staro stirring (v=50%). The mixture was cooled to 35°C and Phase D added under Staro stirring (v=20%) and mixed well. Example 4
An anti-dandruff oil formulation was made of the following composition;
PRODUCT % INCI NAME
Phase A
BRB CM 56 Qsp 100 Cyclopentasiloxane & Cyclohexasiloxane
XIAMETER PMX 200 5cs 6.0 Dimethicone
BRB PTM 20 2.0 Phenyltrimethicone
CRODAMOL™ DA-LQ-RB 10.0 Diisopropyl Adipate
ARLAMOL™ HD-LQ-RB 5.0 Isohexadecane
CRODAMOL™ TN-EU-LQ-JP 5.0 Isotridecyl Isononanoate
Product of Example 1 3.0
Phase B
Phenoxyethanol qs Phenoxyethanol
Fragrance 0.2 Fragrance
Ethanol (96°) 5.0 Alcohol Procedure:
Phase A components were mixed and stirred using a propeller (v=300 rpm). Phase B components were mixed and homogenized. Phase B was added to Phase A under propeller stirring (v=300 rpm) and mixed well. A clear and colourless oil was obtained.
Example 5
An anti-dandruff leave-on formulation was made of the following composition;
Procedure:
Xanthan gum was sprinkled under rapid stirring into a mixture of the other Phase A components and left for 30 minutes. Phase A was heated at 75 °C in a water bath. Phase B components were mixed and heated at 75 °C in a water bath. Phase A was added to Phase B and mixed well. Phase C components were mixed well below 35^. Phase C was added to Phase A+B under staro stirring (v=1000 rpm) and mixed well. Phase D was added slowly to Phase A+B+C and mixed well. Example 6
Anti-dandruff shampoo formulations were made of the following compositions; Procedure:
Phase A components were mixed and stirred using a propeller (v=200 rpm). Phase B components were mixed and homogenized. Phase B was added to Phase A under propeller stirring. Phase C components were mixed and homogenized. Phase C was added to Phase A+B under propeller stirring (v=300 rpm). Phase
A+B+C were heated at 85 °C in a water bath. Phase C components were mixed and heated at 85 °C in a water bath. Phase D was added to Phase A+B+C under slow Staro stirring (v=1000 rpm) and homogenized well. The mixture was cooled to 35 °C, and Phase E added, under slow Staro stirring (v=600 rpm). Phase F was added and homogenized well.
The above examples illustrate the improved properties of an anti-dandruff composition according to the present invention.
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