WO2020216676A1

WO2020216676A1 - Emulsion comprising piroctone olamine

Info

Publication number: WO2020216676A1
Application number: PCT/EP2020/060772
Authority: WO
Inventors: Jesus Pitarch Lopez; Jochen KLEINBLOTEKAMP; Thierry Muller
Original assignee: Clariant International Ltd
Priority date: 2019-04-26
Filing date: 2020-04-16
Publication date: 2020-10-29
Also published as: EP3958822A1

Abstract

According to the invention, an emulsion of the type P/S is provided, wherein P refers to the dispersed phase, which is immiscible with oil, S refers to the continuous oil phase and wherein: - dispersed phase P comprises more than 80%wt of polyol; - continuous phase S comprises a silicone oil; and - the emulsion comprises a first emulsifier and piroctone olamine.

Description

EMULSION COMPRISING PIROCTONE OLAMINE

DESCRIPTION

The present invention relates to emulsions comprising piroctone olamine, to personal care products comprising the emulsion and to methods of making the emulsions.

With reference to DE 2 234 009 A1 and DE 1 795 270 A1 , 1-Hydroxy-4-methyl-6- (2,4,4-trimethyl)-pentyl-2(1 H)-pyridone, 2-aminoethanol salt, also known as piroctone ethanolamine or piroctone olamine, is an anti-fungal active agent which may be effective against the causes of dandruff.

It is known, for example from the above-mentioned documents, to include piroctone olamine in personal care products, such as shampoos, conditioners and skin care products. In shampoos and conditioners, piroctone olamine may act as an anti-dandruff active agent. On skin piroctone olamine may have a variety of effects, for example with reference to EP 0 801 947 A1 , as a skin depigmentation agent.

Polyol-in-oil emulsions are known, for example from EP 2 875 803 A1. Such non- aqueous emulsions have been proposed as a delivery form for active ingredients which react with or are degraded by water. Similar considerations apply to

US 2001/0007653 A1.

In order to be as effective as possible, it is important that the piroctone olamine is deposited on and remains on hair or skin in order to have the desired activity. An aspect of piroctone olamine which may be disadvantageous in this regard is its relatively high solubility in aqueous solutions. Personal care products comprising piroctone olamine are frequently formulated as aqueous emulsions with the piroctone olamine residing in the aqueous phase. In use, for example in the shower, the piroctone olamine is exposed to the surfactants cleansing the hair or skin and may be washed off the hair or skin reducing the product’s effectiveness in achieving the desired activity. It would be desirable to ensure that the piroctone olamine remains on the hair or skin to which it is applied, so that as much of it as possible remains there, even in environments such as a shower.

It is with this background that the present invention has been devised.

As used herein and unless otherwise stated:

All percentages are by weight (w/w) of the total composition;

All ratios used herein are weight ratios.

“%wt” means percentage by weight.

All ranges used herein are inclusive and combinable.

The number of significant digits conveys neither a limitation on the indicated amounts nor on the accuracy of the measurements.

All numerical amounts are understood to be modified by the word“about”. All measurements are understood to be made at 23°C and at ambient conditions, where“ambient conditions” means at 1 atmosphere (atm) of pressure and at 50% relative humidity.“Relative humidity” refers to the ratio (stated as a percent) of the moisture content of air compared to the saturated moisture level at the same temperature and pressure. Relative humidity can be measured with a hygrometer, in particular with a probe hygrometer from VWR^® International.

The term“min” means“minute” or“minutes”.

The term“mol” means mole.

The term“g” following a number means“gram” or“grams” and“kg” means “kilogram” or“kilograms”.

The terms“molecular weight” or“M.Wt.” or“MW’ and grammatical equivalents mean the number average molecular weight.

The word "comprising" means that other steps and other ingredients can be in addition.

Embodiments and aspects described herein may comprise or be

combinable with elements, features or components of other embodiments and/or aspects despite not being expressly exemplified in combination, unless an incompatibility is stated.“In at least one embodiment” means that one or more embodiments, optionally all embodiments or a large subset of embodiments, of the present invention has/have the subsequently described feature.

The term“water-soluble” refers to any material that is sufficiently soluble in water to form a clear solution to the naked eye at a concentration of 0.1 % by weight of the material in water at 25°C. The term“water-insoluble” refers to any material that is not“water-soluble”.

The term“monomer” means a discrete, non-polymerised chemical moiety capable of undergoing polymerisation in the presence of an initiator or any suitable reaction that creates a macromolecule e.g. such as

polycondensation, polyaddition, anionic or cationic polymerization.“Unit” means a monomer that has already been polymerised i.e. is part of a polymer.

"Polymer" means a chemical formed from the polymerisation of two or more monomers. The term "polymer" includes all materials made by the polymerisation of monomers as well as natural polymers. Polymers made from only one type of monomer are called homopolymers. Herein, a polymer comprises at least two monomers. Polymers made from two or more different types of monomers are called copolymers. The distribution of the different monomers can be random, alternating or block-wise (i.e. block copolymer). The term“polymer” used herein includes any type of polymer including homopolymers and copolymers.

According to a first aspect of the invention, an emulsion of the type P/S is provided, wherein P refers to the dispersed phase, which is immiscible with oil, S refers to the continuous oil phase and wherein:

dispersed phase P comprises more than 80%wt of polyol;

continuous phase S comprises a silicone oil; and

the emulsion comprises a first emulsifier and piroctone olamine.

Without wishing to be bound by theory, the inventors consider that incorporation of the active agent, piroctone olamine, in a delivery system comprising a solution of the piroctone olamine in a solvent, which is emulsified in a continuous phase having a high affinity for scalp and hair, reduces the amount of active agent which is washed and rinsed off during washing and showering. Since the piroctone olamine is not present in the aqueous phase, it is to some extent protected from the surfactants used to cleanse hair and skin.

In one embodiment, the P/S emulsion of the first aspect of the invention may comprise from 2%wt to 90%wt of dispersed phase P, so it may in some cases be a high internal phase emulsion (HIPE). Preferably the emulsion of the first aspect of the invention comprises from 5%wt to 80%wt of dispersed phase P.

In one embodiment, the P/S emulsion of the first aspect of the invention may comprise from 1wt% to 20wt% of piroctone olamine. Piroctone olamine may be soluble to some extent in both the dispersed phase, P, and the continuous phase, S, depending upon the constituents of those phases and the emulsifiers used. Preferably the emulsion comprises from 2wt% to 16wt%, more preferably from 4wt% to 10wt% of piroctone olamine.

In one embodiment according to the first aspect of the invention, the polyol is selected from the group consisting of propylene glycol, butylene glycol,

1 ,5-pentane glycol, 1 ,2-hexanediol, polyalkylene glycol, glycerine, polyglycerine and mixtures thereof. Advantageously, the polyol comprises and preferably consists of propylene glycol, due to the high solubility of piroctone olamine in propylene glycol.

In one embodiment according to the first aspect of the invention, the dispersed phase P comprises less than 100%wt of polyol.

In one embodiment according to the first aspect of the invention, the dispersed phase P comprises more than 90%wt of polyol. Advantageously, the dispersed phase P consists of one or more polyols and more advantageously still, the dispersed phase P consists of propylene glycol. In one embodiment according to the first aspect of the invention, the continuous phase S comprises an oil selected from the group consisting of mineral oil, silicone oil, vegetable oil and mixtures thereof. In one embodiment, the continuous phase S consists of silicones including silicone oil. In one embodiment, the continuous phase S consists of silicone oil.

In one embodiment, the silicone oil is selected from the group consisting of dimethicone, cyclomethicone, phenyl trimethicone, trimethyl pentaphenyl trisiloxane, dimethicone copolyol and mixtures thereof. Advantageously, the continuous phase S consists of dimethicone.

Suitable silicone oils include those which have a viscosity, as measured at 25°C, of less than 10,000 cSt, preferably from 1 cSt to 1000 cSt, more preferably from 1 cSt to 100 cSt. Examples of such oils include Dow Coming’s 200 Series polydimethylsilixane fluids, which are available in range of kinematic viscosities from 50 to 1000 Centistoke.

In one embodiment of the first aspect of the invention, the P/S emulsion may additionally comprise a thickener. Suitable thickeners may be selected from the group consisting of silicones, waxes, clays, silicas, salts, natural and synthetic esters, fatty alcohols, and mixtures thereof. Advantageously, the thickener may be a silicone. Suitable silicones include alkyl siloxane gellants, silicone elastomers, high molecular weight dimethicones (fluids greater than 1000 cSt), and high molecular weight alkyl, hydroxyl, carboxyl, amino, and/or fluoro-substituted dimethicones (fluids greater than 1000 cSt). The thickener may be present in an amount from 0.2% to 20%, preferably from 0.4% to 15% of the P/S/W emulsion. In an advantageous embodiment, the P/S emulsion does not comprise any salt, such as sodium chloride, to thicken or stabilize the emulsion.

According to an advantageous embodiment of the first aspect of the invention, the emulsion is a polyol-in-silicone emulsion. The nature of an emulsifier/surfactant can be represented by the hydrophilic- lipophilic balance (HLB) of the molecule. The degree of this hydrophilic-lipophilic balance can be determined by calculating values for the different regions of the molecule, as described by Griffin in 1949 and 1954. Griffin's method has been primarily developed for non-ionic surfactants as described in 1954 works as follows

HLB = 10*Mh/M where Mh is the molecular mass of the hydrophilic portion of the molecule, and M is the molecular mass of the whole molecule, giving a result on a scale of 0 to 20. An HLB value of 0 corresponds to a completely lipophilic molecule, and a value of 20 corresponds to a completely hydrophilic molecule.

The term“HLB” as used in this specification for nonionic surfactants is calculated by the above formula. The method of Griffin is published, for example, in Journal of the Society of Cosmetic Chemists, 5 (4), 249-256 (1954). The term“HLB” as used in this specification for anionic, cationic or amphoteric surfactants is calculated by the method of Davies. This method is published, for example, in Gas/Liquid and Liquid/Liquid Interfaces. Proceedings of 2nd Inter-national Congress Surface Activity, pp. 426-438, Butterworths, London 1957.

According to one embodiment of the first aspect of the invention, the first emulsifier has an HLB value of less than 8, preferably from 2 to 6. Emulsifiers of this type are known to the skilled person and include glyceryl stearate (HLB of 3.8), polyglyceryl-4-oleate (HLB of 4-6), sorbitan oleate (HLB of 4.3), sorbitan stearate (HLB of 4.7), steareth-2 (HLB of 4.9). Furthermore, silicone polyethers including polyether end-capped dimethicone and silicone polyether/dimethicone co-polymers having an appropriate HLB-value may advantageously be used. An example of such a material is dimethicone and PEG/PPG-18/18 dimethicone, which is available from Dow Corning as DOWSIL ES-5226 DM (HLB of 2) in a 2cST dimethicone carrier or as DOWSIL ES-5227 DM in a 5cST dimethicone carrier. Advantageously, the first emulsifier comprises a silicone polyether emulsifier with an HLB-value of 2-6.

According to a second aspect of the invention, a multiple emulsion of the type P/S/A is provided, comprising a P/S emulsion according to the first aspect of the invention dispersed in an aqueous phase, A, wherein the P/S emulsion is stabilized in the aqueous phase A by a second emulsifier or wherein the P/S emulsion is stabilized in the aqueous phase A by particulates as a Pickering Emulsion.

According to one embodiment, the aqueous phase may comprise water, water soluble components and materials which are miscible with water, such as lower monoalcohols having 1 -5 carbon atoms (including ethanol and isopropanol); glycols having 2-8 carbon atoms, such as glycerine, propylene glycol, ethylene glycol, 1 ,3-butylene glycol, dipropylene glycol; C3-C4 ketones, and C2-C4 aldehydes. Advantageously, the aqueous phase comprises more than 50%wt, preferably more than 80%wt, more preferably more than 90%wt water. In some cases, the aqueous phase may comprise more than 95%wt water, and it may consist of water.

According to one embodiment, the second emulsifier has an HLB value from 8 to 18. Emulsifiers of this type are known to the skilled person and may include ionic or nonionic surfactants. Suitable examples of nonionic surfactants include trideceth-10 (HLB of 13.9), trideceth-12 (HLB of 14.5), polysorbates, such as polysorbate-20 (HLB of 16.7) and polysorbate-60 (HLB of 14.9) and ceteareth-20 (HLB of 15.3). Suitable examples of anionic surfactants include sodium dodecane 1 -sulfonate (HLB of 12.3) and sodium oleate (HLB of 18).

According to one embodiment, the particulates which stabilize the Pickering Emulsion may be synthetic or natural clays, surface-modified silica particles, cellulose nanocrystals or other types of particulates known to stabilize such emulsions. According to one embodiment of the second aspect of the invention, the P/S/W emulsion may additionally comprise a polymer comprising at least one monomeric unit selected from (meth)acrylate and meth(acrylamide) types containing at least one fatty acid chain containing from 8 to 30 carbon atoms. An example of such a monomer is lauryl methacrylate, which may be polymerized to form

poly(laurylmethacrylate) and stearyl methacrylate, which may be polymerized to form poly(stearylmethacrylate). Without wishing to be bound by theory, it is believed that such polymers, which are lipophilic in nature, dissolve in the silicone oil, may assist in maintaining the integrity of the droplet of P/S and in deposition and attachment of the P/S emulsion droplets to hair and skin.

According to one embodiment, the polymer may be present in an amount from 0.1 wt% to 10wt% of the P/S/A emulsion.

Advantageously, the multiple emulsion of the second aspect of the invention is a polyol-in-silicone-in-water emulsion, preferably a propylene glycol-in-silicone-in- water emulsion.

According to a third aspect of the invention, a method of making an emulsion of the type P/S is provided, wherein P refers to the dispersed phase, which is immiscible with oil, S refers to the continuous oil phase and wherein:

dispersed phase P comprises more than 80%wt of polyol;

continuous phase S comprises a silicone oil; and

the emulsion comprises a first emulsifier and piroctone olamine

the method comprising dissolving the piroctone olamine in phase P, mixing the first emulsifier into phase S, adding phase P to phase S under continuous stirring to form a homogenous dispersion of dispersed phase P within continuous phase S.

According to one embodiment of the third aspect of the invention, the piroctone olamine is dissolved in phase P at a temperature from 40 degrees Celsius to 55 degrees Celsius. According to one embodiment of the third aspect of the invention, mixing the first emulsifier into phase S, adding phase P to phase S under continuous stirring to form a homogenous dispersion of dispersed phase P within continuous phase S takes place at a temperature from 20 degrees Celsius to 40 degrees Celsius.

According to one embodiment of the third aspect of the invention, the method comprises adding a thickener to the P/S emulsion after formation. Suitable thickeners may be selected from the group consisting of silicones, waxes, clays, silicas, salts, natural and synthetic esters, fatty alcohols, and mixtures thereof. Advantageously, the thickener may be a silicone. Suitable silicones include alkyl siloxane gellants, silicone elastomers, high molecular weight dimethicones (fluids greater than 1000 cSt), and high molecular weight alkyl, hydroxyl, carboxyl, amino, and/or fluoro-substituted dimethicones (fluids greater than 1000 cSt). The thickener may be present in an amount from 0.2% to 20%, preferably from 0.4% to 15% of the P/S/W emulsion. The thickener may be mixed into the P/S emulsion_at a temperature from 20 degrees Celsius to 30 degrees Celsius in order to thicken the P/S emulsion.

According to a fourth aspect of the invention, a method of making a multiple emulsion of the type P/S/A is provided, comprising:

taking a P/S emulsion made according to the third aspect of the invention; mixing a second emulsifier into the P/S emulsion;

forming an aqueous phase A;

mixing the P/S emulsion with the aqueous phase A to form a homogenous dispersion of droplets of the P/S emulsion within aqueous phase A.

According to one embodiment of the fourth aspect of the invention may

additionally comprise:

prior to mixing the P/S emulsion with the aqueous phase A, mixing the P/S emulsion with monomers selected from (meth)acrylate and

meth(acrylamide) types containing at least one fatty acid chain containing from 8 to 30 carbon atoms;

after mixing the P/S emulsion with the aqueous phase A, polymerising the monomers to form a polymer.

According to this embodiment, the monomer, which is hydrophobic, is miscible with the continuous phase, S. Polymerisation may be performed in ways known to the skilled person. The resulting polymer may stabilise the dispersed droplets and assist them in maintaining their integrity, for example when subjected to shear during dispersion in aqueous phase, A.

According to a fifth aspect of the invention, a personal care product is provided comprising an emulsion according to any preceding claim. The personal care product of the fifth aspect of the invention may be in the form of a skin care product or a hair care product. If it is a hair care product, then it may

advantageously be a shampoo or a conditioner. Such products are typically O/W emulsions. Emulsification of a P/S emulsion as described herein within the water phase of such an O/W emulsion will effectively give rise to a P/S/W emulsion as also described herein.

A personal care product according to the invention may additionally comprise one or more ingredients common in the field of cosmetology, pharmacy, and dermatology. Such additional ingredients may include oils, petrolatum, fatty alcohols, silicones, waxes, emulsifiers, co-emulsifiers, cationic polymers, film- formers, superfatting agents, stabilizers, polyols, preservatives, pearlizing agents, opacifiers, dyes, fragrances, solvents, protein derivatives such as gelatin, collagen hydrolysates, natural or synthetic-based polypeptides, egg yolk, lecithin, lanolin and lanolin derivatives and mixtures thereof.

The invention will now be further described with reference to the accompanying Figure 1 which illustrates a particle of polyol-in-silicone emulsion, itself dispersed in an aqueous phase. EXAMPLES

Examples 1 -4; polyol-in-oil emulsions

¹Octopirox is piroctone olamine, manufactured by Clariant.

²Dowsil ES 5226 DM: 37.5% dispersion of PEG/PPG-18/18 Dimethicone in a low viscosity, volatile dimethicone fluid; manufactured by Dow Chemical.

³Dowsil ES 5227 DM: 25% dispersion of silicone polyether in a low viscosity, non- volatile dimethicone fluid; manufactured by Dow Chemical.

⁴Abil EM 97s: bis-PEG/PPG-14/14 Dimethicone (and) Dimethicone; manufactured by Evonik.

Method: the emulsifiers and silicone oil were mixed together. The piroctone olamine was dissolved in propylene glycol at a temperature from 40 degrees

Celsius to 55 degrees Celsius and this solution was added carefully to the mixture of emulsifiers and silicone oil at a temperature from 20 degrees Celsius to

30 degrees Celsius under continuous stirring, resulting in bluish, semi-translucent high viscosity fluid, which may be diluted with further silicone fluid. Examples 5 and 6; polyol-in-oil-in-water emulsions

⁵Hoesch T12 90% is aqueous Trideceth 12 (Tridecethethoxylate 12 EO) 90% active, manufactured by Julius Hoesch GmbH

Method: if additional oil is to be added (as in the case of Example 5), then this is done first - the oil is mixed with the propylene glycol-in-silicone emulsion of Example 4 at room temperature to dilute it. Hoesch T12 90% is added to the propylene glycol-in-silicone emulsion at a temperature from 20 degrees Celsius to 30 degrees Celsius under stirring and further diluted with water to achieve the desired concentration of P/S/W emulsions.

Example 7: polyol-in-oil-in-water emulsions comprising high viscous silicone polymer thickener

Method: the first five ingredients were combined to make a P/S emulsion, in the fashion described in relation to Examples 1 -4. The 60,000 cSt PDMS was then mixed into the P/S emulsion at a temperature from 20 degrees Celsius to 30 degrees Celsius to thicken it. The P/S/W emulsion was then made as described in relation to Examples 5 and 6.

Examples 8 and 9: polyol-in-oil-in-water emulsions comprising polymer

Method: A P/S emulsion was prepared as described in relation to Examples 1 -4. The monomer was then added to the P/S emulsion, so that it dissolved in the silicone oil continuous phase. The Hoesch T12 was mixed with water and the monomer-containing P/S emulsion was added to the Hoesch T12/water mixture. All the steps were performed at a temperature from 20 degrees Celsius to 30 degrees Celsius. The mixture was then heated to 70 degrees Celsius under nitrogen. After it had reached a temperature of 70 degrees Celsius an aqueous solution of Luparox TBH 70 (70% 1 ,1 -dimethylethyl hydroperoxide solution in water) and ascorbic acid were added in 2 portions. Polymerization was complete after 2 hours.

Figure 1 illustrates a particle of polyol-in-silicone emulsion, itself dispersed in an aqueous phase, the P/S/A emulsion comprising the formulation of Example 8. Within the particle of silicone oil, smaller particles of propylene glycol can be distinguished.

Formulation Examples

Method: A 1 %wt P/S emulsion according to Example 1 , above, was added to the Shampoo A1 and stirred for 30 seconds to 2 min at room temperature with a lab stirrer until homogeneous incorporation was achieved.

Method: A 1 %wt P/S/W emulsion according to Example 5, above, was added to the Shampoo A2 and stirred for 30 seconds to 2 min at room temperature with a lab stirrer until homogeneous incorporation was achieved.

Claims

Patent claims

1. An emulsion of the type P/S, wherein P refers to the dispersed phase, which is immiscible with oil, S refers to the continuous oil phase and wherein: dispersed phase P comprises more than 80%wt of polyol;

continuous phase S comprises a silicone oil; and

the emulsion comprises a first emulsifier and piroctone olamine.

2. The emulsion of claim 1 comprising from 2%wt to 90%wt, preferably from 5%wt to 80%wt of dispersed phase P.

3. The emulsion of claim 1 or 2, comprising from 1wt% to 20wt%, preferably from 2wt% to 16wt%, more preferably from 4wt% to 10wt% of piroctone olamine.

4. The emulsion of any preceding claim, wherein the polyol is selected from the group consisting of propylene glycol, butylene glycol, 1 ,5-pentane glycol, 1 ,2-hexanediol, polyalkylene glycol, glycerine, polyglycerine and mixtures thereof.

5. The emulsion of claim any preceding claim, wherein dispersed phase P comprises more than 90%wt of polyol, preferably consists of one or more polyols and more preferably consists of propylene glycol.

6. The emulsion of any preceding claim, wherein continuous phase S comprises an oil selected from the group consisting of mineral oil, silicone oil, vegetable oil and mixtures thereof.

7. The emulsion of any preceding claim, additionally comprising a thickener, preferably a silicone thickener, more preferably a silicone having a viscosity of greater than 1000 cSt.

8. The emulsion of any preceding claim, wherein continuous phase S comprises silicone oil selected from the group consisting of dimethicone, cyclomethicone, phenyl trimethicone, trimethyl pentaphenyl trisiloxane, dimethicone copolyol and mixtures thereof and wherein the continuous phase S preferably comprises dimethicone.

9. The emulsion of any preceding claim, wherein continuous phase S consists of silicone.

10. The emulsion of any preceding claim, wherein the emulsion is a polyol-in- silicone emulsion.

11. The emulsion of any preceding claim, wherein the first emulsifier has an HLB value of less than 8, preferably from 2 to 6.

12. The emulsion of any preceding claim, wherein the first emulsifier comprises a silicone polyether emulsifier with an HLB value from 2 to 6.

13. A multiple emulsion of the type P/S/A comprising a P/S emulsion according to any preceding claim dispersed in an aqueous phase, A, wherein the P/S emulsion is stabilized in the aqueous phase A by a second emulsifier or wherein the P/S emulsion is stabilized in the aqueous phase A by particulates as a

Pickering Emulsion.

14. The multiple emulsion of claim 13, wherein the second emulsifier has an HLB value from 8 to 18.

15. The multiple emulsion of claim 13 or 14, additionally comprising a polymer comprising at least one monomeric unit selected from (meth)acrylate and meth(acrylamide) types containing at least one fatty acid chain containing from 8 to 30 carbon atoms.

16. The multiple emulsion of any of claims 13 to 15, wherein the emulsion is a polyol-in-silicone-in-water emulsion, preferably a propylene glycol-in-silicone-in- water emulsion.

17. A method of making an emulsion of the type P/S, wherein P refers to the dispersed phase, which is immiscible with oil, S refers to the continuous oil phase and wherein:

dispersed phase P comprises more than 80%wt of polyol;

continuous phase S comprises a silicone oil; and

the emulsion comprises a first emulsifier and piroctone olamine

18. A method of making a multiple emulsion of the type P/S/A, comprising: taking a P/S emulsion made according to the method of claim 17;

mixing a second emulsifier into the P/S emulsion;

forming an aqueous phase, A;

mixing the P/S emulsion with the aqueous phase, A, to form a homogenous dispersion of droplets of the P/S emulsion within aqueous phase A.

19. The method of claim 18, comprising:

20. A personal care product comprising an emulsion according to any of claims 1 to 12 or a multiple emulsion according to any of claims 13 to 16.

21. The personal care product of claim 20 which is in the form of a skin care product.

22. The personal care product of claim 20, which is in the form of a hair care product, preferably a shampoo or a conditioner.

5