Dry pediculicidal composition

Abstract

Present invention relates to a dry shampoo for use in treatment of infection by lice and / or lice ova, said dry shampoo comprising a film forming polymer, wherein said film forming polymer is an vinyl acetate polymer. Present invention further relates to a method of treating infection by lice and / or lice ova.

Description

[0001] DRY PEDICULICIDAL COMPOSITION

[0002] FIELD OF THE INVENTION

[0003] The invention to which this application relates is to a product or formulation for a dry shampoo that has any one or any combination of head lice deterrent, repellent and / or insecticidal (including ovicidal and / or adulticidal) properties.

[0004] In particular, the technology relates to a novel formulation concept for the control of head lice using a polymer whose addition surprisingly makes current dry shampoos 100% effective in controlling head lice.

[0005] BACKGROUND

[0006] As shown in table 1 the current marketed dry shampoo formulations do not kill head lice, they appear to coat the external cuticle of the louse with an ineffective layer of starch.

[0007] The practice of using silicones to control head lice has become common in modern society and frequently, infestations are treated using a conventional silicone lotion However, such products have significant drawbacks as they are slippery, drip, there is increasing resistance, and they are notoriously difficult to remove from the hair once the recommended exposure time is completed.

[0008] Other innovations are required to address these key issues and therefore create an effective product formulation for the control of head lice

[0009] For example, in the control of head lice, silicones have been used for over 10 years, these products have become outdated, ineffective, and still maintain their limitations due to resistance, slipperiness, wash off, residue and overall feel on the hair.

[0010] New products for daily hair care include new formulation concepts which do not require rinsing off with either water or shampoo. These are becoming increasingly popular in the hair care sector and may provide a technological answer.

[0011] One such concept is the use of dry shampoos which do not contain silicones, do not need washing out, and are quick and easy to use. These factors can save time and provide added convenience since no rinsing with water or shampoo is needed; rather, removal of the dry shampoo can be done by simply brushing or blotting it from the scalp once the exposure time is completed.

[0012] Therefore, the use of dry shampoos may provide an alternative or complementary method for controlling arthropods such as lice or other insects.

[0013] It should be noted that the use of commercially available preformulated dry shampoos currently on the market do not work as a way to control arthropods to achieve insect control.

[0014] Commercially available dry shampoos have various characteristics, which in their present formulations, make them unsuitable for use against arthropods.

[0015] Traditional dry shampoo powders absorb some of the excess oil on the hair, they can have a heavy feel, and have a tendency to form clumps of particles which when used against arthropods coat the insect unsatisfactorily leaving uncoated areas and resulting in no arthropod elimination.

[0016] There is therefore a need for new dry shampoo compositions that remain liquid for sufficient time to coat the arthropod with a suitable polymer and control it as an alternative to conventional head louse products.

[0017] SUMMARY OF THE INVENTION

[0018] The present invention and embodiments thereof serve to provide a solution to one or more of above-mentioned disadvantages. The present technology is related generally to novel dry shampoo compositions that can control arthropods where previous dry shampoo compositions could not. To this end, the present invention relates to a dry shampoo according to claim 1. Preferred embodiments are described in claims 2 to 14. In one embodiment of the present technology, for example, a dry shampoo composition incorporates a carboxylated vinyl acetate terpolymer in combination with a starch. This is not limited to this terpolymer and includes other terpolymers.

[0019] According to another aspect, the present technology provides a product comprising a novel non-clumping dry shampoo composition incorporating the present technology in an aerosol to deliver the novel composition as a powdered wet spray. In another aspect, the present technology provides a method of controlling head lice, which comprises applying the novel non-clumping dry shampoo composition of the present technology to the scalp and hair.

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention concerns a pediculicidal dry shampoo composition.

[0022] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0023] As used herein, the following terms have the following meanings:

[0024] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0025] "About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

[0026] "Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0027] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0028] The expression "% by weight", "weight percent", "%wt" or "wt%", here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation. The weight of the formulation refers to the entire weight of the composition or dry shampoo, including solvent or carrier unless otherwise specified.

[0029] Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.

[0030] As used herein, the term "volatile solvent" refers to a compound that exhibits a vapor pressure of at least 5 kPa at 20 °C and a boiling point below 90 °C at atmospheric pressure. Such solvents evaporate rapidly upon application, leaving behind minimal or no residue. Preferred volatile solvents include ethanol, isopropyl alcohol, and ethyl acetate. These compounds enable fast drying and contribute to the dry, non-greasy feel of the formulation.

[0031] In contrast, the term "non-volatile solvent" refers to a compound with a vapor pressure less than 3 kPa at 20 °C and / or a boiling point greater than 90 °C, which typically evaporates slowly or incompletely, resulting in a moist, tacky or oily residue. Examples include water, polyethylene glycols, and certain fatty alcohols. Preferably, the amount of non-volatile solvents in present composition is limited, and more preferably, contains less than 10 wt.% water, more preferably less than 5 wt.% water, more preferably less than 3 wt.% water, most preferably less than 1 wt.% water. The term "propellant" refers to a pressurized or liquefied gas which functions to expel the composition. Typically from a pressurized container in the form of an aerosol. A propellant as used herein has a vapor pressure greater than 100 kPa at 20 °C and a boiling point below 45°C at 1 atm, allowing for instantaneous evaporation after application. Propellants act to disperse and deliver the composition, preferably as an aerosol. Suitable propellants include dimethyl ether (DME), propane, n-butane, and isobutane. A preferred propellant is dimethyl ether (DME), which is non-oily, pharmaceutically acceptable, relatively environmental friendly and rapidly evaporates, leaving a dry, powdery film.

[0032] For clarity, the term "in-can formulation weight" or "weight of the dry shampoo" refers to the total weight of the formulation as present in the pressurized container, including all components: film-forming polymer, absorbent powders, volatile solvents, non-volatile solvents, and propellant. When not specified, or specified as relative to the weight of the dry shampoo, any "wt.%" herein is relative to the incan formulation weight.

[0033] The term "aerosol formulation weight" refers to the total weight of the formulation excluding the propellant only. This includes the dry matter, such as film-forming polymer, absorbent powders and further constituents, as well as and both volatile and non-volatile solvents.

[0034] The term "non-volatile residue weight" refers to the total weight of the components remaining on the hair or scalp after complete evaporation of the volatile phase, and comprises the film-forming polymer, absorbent powder(s), and any non-volatile solvent(s).

[0035] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention.

[0036] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0037] "copolymer of vinyl acetate and vinyl ester" or "vinyl acetate vinyl ester copolymer" as used herein is a copolymer comprising both vinyl acetate and vinyl ester monomers. This is not restricted to polymers only consisting of vinyl acetate and vinyl ester monomers; but may also be a terpolymer or copolymer comprising additional monomers. Preferably, the copolymer of vinyl acetate and vinyl ester is a statistical copolymer, that is to say both monomers are distributed statistically rather than deterministically, such as alternating copolymers or block copolymers.

[0038] In a first aspect, the invention relates to a dry shampoo comprising a film forming polymer. In a preferred embodiment, the film-forming polymer is an vinyl acetate polymer. The inventor surprisingly found that the addition of an vinyl acetate polymer significantly increased the effectiveness of dry shampoos in the treatment of infection by arthropods.

[0039] Film-forming polymer

[0040] In a first aspect, the invention relates to a dry shampoo comprising a film forming polymer. More preferably, said film forming polymer is an vinyl acetate polymer or copolymer. The inventors found that vinyl acetate copolymers are well suited to treat lice in dry shampoo compositions, without leaving oily residues, requiring rinsing with water or interfering with the adsorbent properties typically desired and expected in dry shampoos. This is believed to be achieved by vinyl acetate copolymers having good film-forming ability from solid dispersion; through natural spreading and coalescence of the polymer chains thereby forming a coherent film. In a further preferred embodiment, said film forming polymer is a carboxylated vinyl acetate polymer. More preferably, said film forming polymer is an vinyl acetate vinyl ester copolymer. Preferably said vinyl ester is a long-chain vinyl ester, such as a C5 to C12 vinyl ester. More preferably, said vinyl ester is selected from the list of: vinyl laurate, vinyl stearate, vinyl palmitate, vinyl oleate, vinyl ethylhexanoate, vinyl versatate, vinyl neodecanoate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl nonanoate and mixtures thereof. Even more preferably, said vinyl ester is vinyl neodecanoate.

[0041] In a further preferred embodiment, said film forming polymer is a copolymer of vinyl acetate and crotonic acid and I or esters of crotonic acid, more preferably a terpolymer of vinyl acetate, a long-chain vinyl ester and crotonic acid and I or esters of crotonic acid. Preferably, crotonic acid is partially neutralized either through esterification or reaction with alkali or aminohydroxy compounds, thereby forming crotonates. Preferably, the crotonic acid monomers are partially neutralized by inclusion of sodium hydroxide or aminohydroxy compounds preferably AMP (2- amino-2-methyl-l-propanol), thereby resulting in "crotonates". The inclusion of crotonatic acid I crotonates improves its adhesive and rheologic properties, which was found to be beneficial for the efficacy in the treatment of lice.

[0042] In a preferred embodiment, the dry shampoo comprises said film-forming polymer, most preferably a terpolymer of vinyl acetate, vinyl ester and crotonates in an amount of at least 0.01 wt.%, more preferably at least 0.05 wt.%, more preferably at least 0.10 wt.%, more preferably at least 0.15 wt.%, more preferably at least 0.20 wt.%, more preferably at least 0.25 wt.%, more preferably at least 0.30 wt.%, more preferably at least 0.35 wt.%, more preferably at least 0.40 wt.%, more preferably at least 0.45 wt.%, more preferably at least 0.50 wt.%. In a preferred embodiment, the dry shampoo comprises said film-forming polymer in an amount of at most 2.0 wt.%, more preferably at most 1.9 wt.%, more preferably at most 1.8 wt.%, more preferably at most 1.7 wt.%, more preferably at most 1.6 wt.%, more preferably at most 1.5 wt.%, more preferably at most 1.4 wt.%, more preferably at most 1.3 wt.%, more preferably at most 1.2 wt.%, more preferably at most 1.1 wt.%, more preferably at most 1.0 wt.%, more preferably at most 0.9 wt.%, more preferably at most 0.8 wt.%, more preferably at most 0.7 wt.%, more preferably at most 0.6 wt.%, more preferably at most 0.5 wt.%. All percentages are by weight relative to the weight of the dry shampoo. In shampoos and lotions in the art, which are aqueous or solvent-based compositions used in combination with water, silicones and to a lesser extent other film-forming polymers are known for the treatment of lice. Without wishing to be bound by theory, their method of action is believed to be the suffocation and immobilization of arthropods, particularly lice by coating said arthropods and particularly the spiracles leading to suffocation thereof.

[0043] However, it has been found difficult to produce a dry shampoo with high efficacy for the treatment of lice, while simultaneously fulfilling the cosmetic functions of a dry shampoo, particularly removing excess oil and fattiness from the hair and lacking substantial amounts of solvent. Both these factors are believed to interfere with the formation of a uniform film over all lice, resulting in lackluster efficacy in the treatment of lice. This is evidenced by the dry shampoo compositions on the market having low efficiency in the treatment of lice, as evidenced herein.

[0044] Dry shampoo composition

[0045] The composition of the present invention preferably comprises at least one absorbent powder. This is preferred for achieving the desired combination of pediculicidal efficacy and cosmetic performance. The absorbent powder facilitates the deposition and uniform distribution of the film-forming polymer, aids in adherence of the active components to the hair and scalp, and contributes to the physical mode of action by promoting contact between the active film and the cuticle of lice and their ova. Furthermore, the absorbent powder enhances the tactile finish of the formulation, leaving a dry, powdery residue that is perceived as clean and non-greasy by the user.

[0046] In a preferred embodiment, the absorbent powder is selected from starches and starch derivatives, clays, silicates, diatomaceous earth, and mixtures thereof. More preferably, the absorbent powder comprises a starch or a starch derivative, optionally in combination with one or more other absorbent materials. Suitable starches include corn starch, rice starch, potato starch, and tapioca starch. Preferred starch derivatives is aluminium starch octenylsuccinate, which has been found to offer superior oil absorption, excellent flowability, and reduced residue visibility on dark hair. In a further preferred embodiment, said starch and starch derivatives are corn starch. Corn starch, also known as maize starch, is an unmodified, natural starch that is extracted from corn kernels. It is a natural, biodegradable, sustainable and non-irritating substance. It possesses anti-inflammatory properties and is capable of soothing itchy skin and scalp. When incorporated into compositions according to the present technology, corn starch has been found to provide a unique powdery-dry, smooth after-feel, to control immediate and residual shine and oiliness, and to reduce any perceivable tackiness and stickiness leaving the hair looking smooth and silky.

[0047] In a preferred embodiment, the dry shampoo comprises aluminium starch. More preferably, the dry shampoo comprises aluminium starch octenyl succinate. Aluminum starch octenyl succinate offers superior oil absorption, reduced residue visibility, and enhanced flowability compared to regular starch and other starch derivatives, making it particularly effective in dry shampoos. Its fine particle size ensures smooth application, while its chemical stability and compatibility with other ingredients contribute to a more effective and user-friendly product, especially for those with darker hair or sensitive skin.

[0048] In a further preferred embodiment, the dry shampoo comprises starch or a starch derivative, preferably aluminium starch octenyl succinate, in an amount of at least 0.5 wt.% relative to the weight of the dry shampoo, more preferably in an amount of at least 0.10 wt.%, more preferably in an amount of at least 0.50 wt.%, more preferably in an amount of at least 1.00 wt.%, more preferably in an amount of at least 1.50 wt.%, more preferably in an amount of at least 2.00 wt.%, more preferably in an amount of at least 2.50 wt.%, more preferably in an amount of at least 3.00 wt.%, more preferably in an amount of at least 3.50 wt.%, more preferably in an amount of at least 4.00 wt.%. In a preferred embodiment, the dry shampoo comprises starch or a starch derivative, preferably aluminium starch octenyl succinate, in an amount of at most 15.0 wt.% relative to the weight of the dry shampoo, more preferably in an amount of at most 10.0 wt.%, more preferably in an amount of at most 9.0 wt.%, more preferably in an amount of at most 8.0 wt.%, more preferably in an amount of at most 7.0 wt.%, more preferably in an amount of at most 6.0 wt.%, more preferably in an amount of at most 5.0 wt.%, more preferably in an amount of at most 4.0 wt.%, relative to the weight of the incan formulation. In a preferred embodiment, the dry shampoo comprises an anti-caking agent. More preferably, the dry shampoo comprises magnesium stearate. While magnesium stearate is most preferred, other anti-caking or flow-enhancing excipients may be used in combination or as alternatives. Suitable alternatives include zinc stearate, calcium stearate, talc, colloidal silica (e.g., fumed silica), aluminium silicate, and tricalcium phosphate, provided they are compatible with the aerosol formulation and do not interfere with the spreading or sensory performance of the polymer-powder matrix. Magnesium stearate advantageously prevents clumping and coalescence of the granular material in the dry shampoo. This both benefits the feel of the product when applied to scalp and hair, and improves the treatment of lice. In addition, magnesium stearate has a texturizing effect on hair and scalp. Without wishing to be bound by theory, it is believed magnesium stareate aids in ensuring the filmforming polymer is dispersed throughout the hair and scalp. The inventors found the inclusion of magnesium stearate improved the effectiveness of the composition on lice in vitro.

[0049] In a more preferred embodiment, the dry shampoo comprises magnesium stearate in an amount of at least 0.01 wt.% relative to the weight of the dry shampoo, more preferably at least 0.05 wt.%, more preferably at least 0.10 wt.%, more preferably at least 0.20 wt.%, more preferably at least 0.25 wt.%, more preferably at least 0.40 wt.%, more preferably at least 0.40 wt.%, more preferably at least 0.50 wt.%, more preferably at least 0.60 wt.%, more preferably at least 0.75 wt.%. In a preferred embodiment, the dry shampoo comprises magnesium stearate in an amount of at most 5 wt.% relative to the weight of the dry shampoo, more preferably at most 4 wt.%, more preferably at most 3 wt.%, more preferably at most 2 wt.%, more preferably at most 1 wt.%. These amounts were found to be well suited to achieve the desired anti-caking and texturizing effects of magnesium, while also positively impacting the effectiveness of the dry shampoo on lice and their ova.

[0050] Solvents and propellants

[0051] In a preferred embodiment, the dry shampoo comprises a solvent. More preferably, said solvent is an organic solvent. More preferably, said solvent is a pharmaceutically acceptable, volatile organic solvent. More preferably, said solvent is selected from the list of : ethanol, isopropyl alcohol, ethyl acetate, dimethyl ether and mixtures thereof. Most preferably, said solvent is dimethyl ether (DME), ethanol or mixtures thereof. In an embodiment, the composition comprises a propellant, wherein said propellant is chosen from the list of: dimethyl ether (DME), propane, n-butane, isobutane, compressed air, nitrogen, carbon dioxide (CO2), and mixtures thereof. In a further embodiment, the composition comprises a propellant selected from DME, propane, n-butane, isobutane, and mixtures thereof. In a further embodiment, the composition comprises a propellant selected from DME and mixtures of DME with one or more of propane, n-butane, and isobutane. In a further embodiment, the composition comprises DME as the sole propellant.

[0052] Dimethyl ether is preferred for particular reasons. As a minimum requirement is it acceptable in terms of health, cost and environment. It dries quickly, having a fast evaporation rate with minimal odor which is important in cosmetic products. DME is non-oily and evaporates quickly, leaving behind a clean, non-greasy finish on the hair and scalp. It has a low GWP and no ODP, and can be produced renewably (i.e. Bio-DME) making it environmentally friendly. These properties make dimethyl ether is particularly suitable as propellant.

[0053] Ethanol has a fast evaporation rate, without leaving wet or sticky residue when used at moderate levels. However, when present at relatively high concentrations in the composition, it was observed to leave a comparatively greasy or heavy feel on the hair. Due to its fast evaporation rate, ethanol provides a slight cooling effect upon application. This gives the use of the dry shampoo a functional and refreshing feel. Ethanol advantageously has mild preservative properties which help extend shelf life. Ethanol is particularly suitable as volatile solvent.

[0054] In a further preferred embodiment, wherein said dry shampoo comprises at least two solvents, each in an amount of at least 25 wt.%, wherein both solvents are independently selected from the list of : ethanol, isopropyl alcohol, ethyl acetate and dimethyl ether (DME). More preferably said two solvents are ethanol and dimethyl ether (DME). More preferably, said two solvents are ethanol (as a volatile solvent) and dimethyl ether (as a propellant). In a further preferred embodiment, both solvents are included in an amount of at least 20 wt.% each, more preferably at least 25 wt.%, more preferably at least 30 wt.%, more preferably at least 35 wt.%, more preferably at least 40 wt.%, more preferably at least 45 wt.%. These weight ratios are for each solvent, measured separately. In a more preferably, dry shampoo comprises dimethyl ether (DME) and ethanol (EtOH) in a ratio of 1: 1 to 10: 1, more preferably in a ratio of 2: 1 to 8: 1, more preferably in a ratio of 5:2 to 7: 1, more preferably in a ratio of 5:2 to 6: 1.. The combination of these solvents resulted in fast drying without leaving the hair wet or sticky or greasy, a mild cooling effect, suitable solubilization of the film-forming polymer, and limited odor. While dimethyl ether (DME) is referred to herein as a solvent and a propellant, it may exhibit limited solvent-like behaviour while in its liquefied state under pressure within the gas canister. In this state, DME can contribute to the uniform solubilisation or dispersion of the polymer and other formulation components. However, upon actuation of the aerosol valve and release to atmospheric pressure, DME instantly volatilises and performs the role of a true propellant, expelling and atomising the formulation into a fine spray. As it evaporates almost immediately on contact with air, DME does not remain on the scalp or hair, nor does it act as a solvent under use conditions. The function of DME in the present invention is therefore that of a volatile propellant, not a carrier solvent, and it does not contribute to the non-volatile residue or tactile properties of the dried formulation.

[0055] In a further preferred embodiment, the dry shampoo comprises a high proportion of propellant and a reduced proportion of volatile solvent, thereby achieving a particularly dry, powdery finish with minimal residual wetness or tackiness. In this context, the propellant-to-volatile solvent weight ratio is preferably greater than 2: 1, more preferably greater than 3: 1, more preferably greater than 4: 1, and most preferably at least 5: 1.

[0056] Expressed differently, the volatile solvent is preferably present in an amount of at least 5 wt.%, more preferably at least 8 wt.%, more preferably at least 10 wt.%, more preferably at least 12 wt.% relative to the in-can formulation weight. The volatile solvent is preferably present in an amount of less than 55 wt.%, more preferably less than 40 wt.%, more preferably less than 35 wt.%, more preferably less than 30 wt.%, more preferably less than 25 wt.%, more preferably less than 20 wt.%, and most preferably less than 15 wt.% of the in-can weight. The volatile solvent is preferably selected from ethanol, isopropanol, or ethyl acetate, and most preferably consists essentially of ethanol. Levels of solvent, particularly ethanol above about 40 wt.%, were found to be associated with a perceptibly greasier and wetter after-feel compared to formulations with lower ethanol content.

[0057] The propellant, preferably dimethyl ether (DME), is present in an amount of at least 35 wt.%, more preferably at least 40 wt.%, more preferably at least 45 wt.%, more preferably at least 50 wt.%, more preferably at least 55 wt.%, more preferably at least 60 wt.%, more preferably at least 65 wt.%, more preferably at least 70 wt.%, and more preferably at least 75 wt.% relative to the in-can formulation weight. In a particularly preferred embodiment, the propellant is present in an amount of about 80 wt.%. This high propellant level ensures rapid evaporation and fine dispersion of the formulation, contributing to a dry, powdery deposition and uniform distribution of the polymer-powder mixture.

[0058] In a particularly preferred embodiment, the dry shampoo composition comprises a combination of (i) a film-forming polymer, (ii) at least one absorbent powder, preferably a starch or starch derivative, and (iii) a limited amount of one or more non-volatile solvents. This specific combination was found to be critical to achieve the desired properties of a dry shampoo: namely, the ability to be sprayed and deposited as a thin, rapidly drying film that leaves behind no appreciable greasiness, stickiness or moisture, while still exerting high efficacy against lice and their ova.

[0059] It was found that low levels of non-volatile solvent are essential to maintain the dry, powdery character of the formulation. In preferred embodiments, the non-volatile solvent is present in an amount of less than 30 wt.%, more preferably less than 25 wt.%, more preferably less than 20 wt.%, more preferably less than 15 wt.%, more preferably less than 10 wt.%, more preferably less than 7 wt.%, more preferably less than 5 wt.%, more preferably less than 3 wt.%, and most preferably less than 1 wt.%, relative to the aerosol formulation weight. In terms of the non-volatile residue, the non-volatile solvent is preferably present in an amount of less than 60 wt.%, more preferably less than 50 wt.%, more preferably less than 40 wt.%, more preferably less than 35 wt.%, more preferably less than 30 wt.%, more preferably less than 25 wt.%, more preferably less than 20 wt.%, more preferably less than 15 wt.%, more preferably less than 12 wt.%, and most preferably less than 10 wt.%, relative to the non-volatile residue weight. The present invention thus provides an anhydrous or substantially anhydrous aerosol composition with a high proportion of volatile components, a solid-phase polymer-powder network, and only minimal nonvolatile solvent content, which together yield a dry, clean, and effective pediculicidal performance upon application.

[0060] The inclusion of a non-volatile solvent in small quantities was found to aid in the spreading, deposition and physical distribution of the film-forming polymer across the hair, scalp, and target organisms. Without wishing to be bound by theory, this improves the overall contact between the polymer film and the cuticle of lice and their ova, thereby increasing pediculicidal and ovicidal efficacy. However, the use of non-volatile solvents involves a notable trade-off: even modest levels can lead to a wet, greasy, or sticky feel, which undermines the essential cosmetic function of a dry shampoo.

[0061] The non-volatile solvent is preferably not water. Water was found to be particularly undesirable due to its negative impact on the sensory performance of the composition. Even in small quantities, water results in a wet, moist, or sticky feel upon application, which is incompatible with the objectives of a dry shampoo. Accordingly, the composition preferably contains less than 10 wt.%, more preferably 5 wt.%, more preferably less than 4 wt.%, more preferably less than 3 wt.%, more preferably less than 2 wt.%, more preferably less than 1.5 wt.%, more preferably less than 1.0 wt.%, more preferably less than 0.8 wt.%, more preferably less than 0.5 wt.%, more preferably less than 0.3 wt.%, more preferably less than 0.2 wt.%, more preferably less than 0.1 wt.%, relative to the in-can weight. In a further preferred embodiment, the composition preferably contains less than 10 wt.%, more preferably 5 wt.%, more preferably less than 4 wt.%, more preferably less than 3 wt.%, more preferably less than 2 wt.%, more preferably less than 1.5 wt.%, more preferably less than 1.0 wt.%, more preferably less than 0.8 wt.%, more preferably less than 0.5 wt.%, more preferably less than 0.3 wt.%, more preferably less than 0.2 wt.%, more preferably less than 0.1 wt.%, relative to the aerosol formulation weight. In terms of the non-volatile residue, the water content is preferably less than 40 wt.%, more preferably less than 35 wt.%, more preferably less than 30 wt.%, more preferably less than 25 wt.%, more preferably less than 20 wt.%, more preferably less than 15 wt.%, more preferably less than 10 wt.%, more preferably less than 8 wt.%, more preferably less than 5 wt.%, more preferably less than 3 wt.%, and most preferably less than 1 wt.% of the non-volatile residue.

[0062] In a preferred embodiment, said dry shampoo further comprises a fatty alcohol. More preferably, said fatty alcohol is selected from the list of : 1-hexanol, 1-heptanol, 1- octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1- tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol and mixtures thereof. More preferably, said fatty alcohol is selected from : 1-octanol, 1- nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol and mixtures thereof. More preferably, said fatty alcohol is selected from: 1-decanol, 1- undecanol, 1-dodecanol. Most preferably, said fatty alcohol is 1-dodecanol. The combination of a film-forming polymer and a fatty alcohol was found to significantly improve the effectiveness of the dry shampoo in the treatment of lice and their eggs or ova. These fatty alcohols can be considered a non-volatile solvent in the context of present application. In a preferred embodiment, the non-volatile solvent is a fatty alcohol, more preferably a C10-C14 primary alcohol, and most preferably 1- dodecanol. These non-volatile alcohols provide beneficial spreading and structural properties without imparting a wet sensory impression. When used at limited levels in combination with the film-forming polymer and absorbent powder, the fatty alcohol enhances deposition and contributes to the efficacy of the dry shampoo, while maintaining a dry, non-greasy feel.

[0063] In a further preferred embodiment, the dry shampoo comprises said fatty alcohol in an amount of at least 0.01 wt.% relative to the weight of the dry shampoo, more preferably at least 0.05 wt.%, more preferably at least 0.10 wt.%, more preferably at least 0.20 wt.%, more preferably at least 0.25 wt.%, more preferably at least 0.30 wt.%, more preferably at least 0.40 wt.%, more preferably at least 0.50 wt.%, more preferably at least 0.60 wt.%, more preferably at least 0.70 wt.%, more preferably at least 0.75 wt.%, more preferably at least 0.80 wt.%, more preferably at least 0.90 wt.%, more preferably at least 1.00 wt.%. In a further preferred embodiment, the dry shampoo comprises said fatty alcohol in an amount of at most 10.0 wt.% relative to the weight of the dry shampoo, more preferably at most 9.0 wt.%, more preferably at most 8.0 wt.%, more preferably at most 7.0 wt.%, more preferably at most 6.0 wt.%, more preferably at most 5.0 wt.%, more preferably at most 4.0 wt.%, more preferably at most 3.0 wt.%, more preferably at most 2.0 wt.%, more preferably at most 1.5 wt.%, relative to the in-can weight.

[0064] In a further preferred embodiment, the dry shampoo composition comprises both a film-forming polymer and a fatty alcohol, wherein the ratio of film-forming polymer to fatty alcohol by weight is between 1 : 10 and 1: 1, more preferably between 1:5 and 1: 1, more preferably between 1:4 and 1 : 1, more preferably between 1:4 and 1:3, most preferably about 1:2. The inventors found that a film-forming polymer and a fatty alcohol, particularly in the abovementioned ratios, are synergistic for the treatment of lice, without hampering or impairing the function as dry shampoo.

[0065] In a preferred embodiment, said composition is devoid of polydimethylsiloxane (PDMS), more preferably devoid of silicone oils, most preferably devoid of silicones. Silicone oils particularly PDMS are known in the art of wet shampoos and lotions as a film-forming oil for the treatment of lice. However, silicone oils leave an oily or fatty feel to the hair and scalp after treatment with the dry shampoo, in particular when it is not intensively rinsed off with water or other solvents. Consequently, the dry shampoo function of reducing excess oil and sebum is not fulfilled.

[0066] In a particular preferred embodiment, said dry shampoo comprises, more preferably essentially consists of:

[0067] A) a film forming polymer, preferably in an amount of 0.05 to 2 wt.% relative to the weight of the dry shampoo;

[0068] B) a fatty alcohol, preferably in an amount of 0.05 to 5.0 wt.% relative to the weight of the dry shampoo;

[0069] C) starch or a starch derivative, preferably in an amount of 1 to 10 wt.% relative to the weight of the dry shampoo; and

[0070] D) a solvent, preferably in an amount of at least 25 wt.%, more preferably at least 50 wt.%.

[0071] More preferably, said dry shampoo comprises, more preferably essentially consists of : wherein said dry shampoo comprises:

[0072] A) a film forming polymer, wherein said film-forming polymer is an vinyl ester copolymer, preferably in an amount of 0.05 to 2 wt.% relative to the weight of the dry shampoo;

[0073] B) a fatty alcohol, wherein said fatty acid is selected from the list of: 1-octanol, 1- nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, preferably in an amount of 0.05 to 5.0 wt.% relative to the weight of the dry shampoo;

[0074] C) starch or a starch derivative, preferably in an amount of 1.0 to 10.0 wt.% relative to the weight of the dry shampoo; and

[0075] D) a solvent, said solvent is chosen from the list of : ethanol, isopropyl alcohol, ethyl acetate and dimethyl ether (DME) and mixtures thereof, preferably in an amount of at least 25 wt.%, more preferably at least 50 wt.%.

[0076] More preferably, said dry shampoo comprises, and more preferably essentially consists of:

[0077] A) a film-forming polymer, wherein said polymer is a vinyl acetate-vinyl ester copolymer, preferably in an amount of 0.05 to 2.0 wt.% relative to the in-can formulation weight; B) a fatty alcohol, selected from the group consisting of 1-octanol, 1-nonanol, 1- decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, and 1-tetradecanol, preferably in an amount of 0.05 to 5.0 wt.% relative to the in-can formulation weight;

[0078] C) starch or a starch derivative, preferably aluminium starch octenylsuccinate, in an amount of 1.0 to 10.0 wt.% relative to the in-can formulation weight;

[0079] D) a volatile solvent, preferably ethanol, present in an amount of at least 5 wt.%, more preferably at least 10 wt.%, and more preferably less than 55 wt.%, relative to the in-can formulation weight; and

[0080] E) a propellant, preferably dimethyl ether (DME), preferably present in an amount of at least 40 wt.%, more preferably at least 60 wt.%, more preferably at least 70 wt.% relative to the in-can formulation weight. In this embodiment, the composition preferably comprises less than 10 wt.% of a non-volatile solvent, more preferably less than 8 wt.%. Further more preferably the composition comprises less than 5 wt.% water, more preferably less than 3 wt.% water, relative to the in-can formulation weight. The composition is formulated as a pressurised aerosol dry shampoo, delivering a fine, uniform spray which dries rapidly and leaves a powdery, clean finish on the scalp and hair. This composition provides superior cosmetic properties while maintaining high efficacy against lice and their ova, including resistant strains, without the need for post-treatment washing.

[0081] These compositions were found to have these combined properties: highly effective against lice and their ova, even during relatively short treatment periods; non-clumping; fast drying on hair and scalp, without leaving a wet, oily or greasy feel or touch; effective in absorbing oil and sebum, resulting in a clean, refreshed look without requiring rinsing or washing with water; limited odor due to solvent or propellant; allowing both neutral (odorless) and scented formulations; smooth finish and pleasant texture of the hair after use; lightweight feeling, that is to say it does not weigh down the hair nor does the film-forming polymer result in a stiff hair feeling or restricted movement of the hair;

[0082] No visible residue nor discoloration on any hair type; long shelf life. In a further embodiment, the present invention relates to a liquid non-aerosol dry shampoo, wherein the composition is identical in active structure to the aerosol formulation, but lacks a propellant and is delivered as a liquid, for example, by pump spray, dropper, or manual application. The composition preferably comprises, and more preferably essentially consists of:

[0083] A) a film-forming polymer, wherein said polymer is a vinyl acetate-vinyl ester copolymer, preferably in an amount of 0.05 to 5.0 wt.%, more preferably about 2.50 wt.%, relative to the total composition weight;

[0084] B) a fatty alcohol, selected from the group consisting of 1-octanol, 1-nonanol, 1- decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, and 1-tetradecanol, preferably 1- dodecanol, and preferably in an amount of 0.05 to 5.0 wt.%, more preferably about 5.00 wt.%;

[0085] C) starch or a starch derivative, preferably aluminium starch octenylsuccinate, in an amount of 1.0 to 20.0 wt.%, more preferably about 20.00 wt.%;

[0086] D) a volatile solvent, preferably ethanol, present in an amount of at least 5 wt.%, more preferably at least 10 wt.%, more preferably at least 50 wt.%, and most preferably about 68.30 wt.%, relative to the total weight of the composition;

[0087] E) optionally, a base or neutralising agent, such as sodium hydroxide, preferably in an amount of about 0.45 wt.%, and optionally an anti-caking agent, preferably magnesium stearate, preferably in an amount of at least 1 wt.% and at most 5 wt.%. In this embodiment, the composition is free of propellant and is preferably applied in liquid form, for example using a mechanical spray pump or other non-pressurised dispenser, with a high content of volatile solvent. Upon application, the volatile solvent evaporates rapidly, leaving behind a dry, powder-coated film containing the film-forming polymer and absorbent powder. The formulation preferably comprises less than 10 wt.% of a non-volatile solvent, more preferably less than 8 wt.%, and further more preferably less than 5 wt.% water, more preferably less than 3 wt.%, relative to the total composition weight. This composition delivers a dry tactile finish with high efficacy against lice and their ova, including resistant strains. Although applied as a liquid, the absence of water and the predominance of volatile solvent ensure that the composition dries quickly, does not require rinsing, and retains the cosmetic and therapeutic benefits of a dry shampoo, making it suitable for nonaerosol delivery formats.

[0088] In another embodiment, the present invention relates to a powder-only dry shampoo composition, which is applied directly in particulate form without the use of a volatile solvent or propellant. The composition is particularly suited for direct dusting, brushing, or mechanical application to the scalp and hair, and is designed to deliver both pediculicidal efficacy and oil absorption, while leaving a dry, non-greasy finish. The composition preferably comprises, and more preferably essentially consists of:

[0089] A) a film-forming polymer, preferably a vinyl acetate-vinyl ester copolymer, such as PVP / VA copolymer, in an amount of 2.0 to 20.0 wt.%, more preferably 3.0 to 15.0 wt.%, more preferably 5.0 to 10.0 wt.%;

[0090] B) starch or a starch derivative, preferably aluminium starch octenylsuccinate, in an amount of 40.0 to 80.0 wt.%, more preferably 50.0 to 70.0 wt.%;

[0091] C) a fatty alcohol, selected from the group consisting of 1-octanol, 1-nonanol, 1- decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, and 1-tetradecanol, preferably 1- dodecanol, preferably 1-dodecanol, in an amount of 5.0 to 20.0 wt.%,

[0092] D) optionally a base or pH adjusting agent, such as sodium hydroxide (NaOH), preferably in an amount of 0.5 to 3.0 wt.%; and

[0093] E) optionally an anti-caking agent, preferably magnesium stearate, in an amount of 5.0 to 20.0 wt.%, more preferably 10.0 to 15.0 wt.%.

[0094] This composition is free of both volatile solvents and propellants. Upon application, the powder adheres to the hair and scalp, where the fatty alcohol and film-forming polymer promote adhesion and contact with lice and ova. The absorbent starch component removes sebum and moisture, while the magnesium stearate prevents agglomeration and supports even distribution. The resulting powder deposit leaves a dry tactile finish and has demonstrated high efficacy against lice and their ova, including resistant forms, without the need for washing or solvent-based removal.

[0095] The dry shampoo composition of the present invention may be formulated and applied in any of three delivery formats: (i) as a pressurised aerosol spray, (ii) as a liquid non-aerosol formulation, or (iii) as a powder-only composition. In all three formats, the active, non-volatile components remain substantially the same, and only the physical form and mode of delivery differ. The invention thus provides a unified compositional platform delivering consistent efficacy across application modes. In a particularly preferred embodiment, the non-volatile residue— defined as the total weight of solids and any non-volatile solvent remaining after complete evaporation of volatile solvents (if any) as defined herein; comprises, and more preferably essentially consists of:

[0096] A) a film-forming polymer, preferably a vinyl acetate-vinyl ester copolymer, such as PVP / VA copolymer, in an amount of 2.0 to 20.0 wt.%, more preferably 3.0 to 15.0 wt.%, more preferably 5.0 to 10.0 wt.%, relative to the non-volatile residue weight; B) starch or a starch derivative, preferably aluminium starch octenylsuccinate, in an amount of 40.0 to 80.0 wt.%, more preferably 50.0 to 70.0 wt.%, relative to the non-volatile residue weight;

[0097] C) a fatty alcohol, selected from the group consisting of 1-octanol, 1-nonanol, 1- decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, and 1-tetradecanol, preferably 1- dodecanol, in an amount of 5.0 to 20.0 wt.%, relative to the non-volatile residue weight;

[0098] D) optionally, a base or pH adjusting agent, such as sodium hydroxide, preferably in an amount of 0.5 to 3.0 wt.%, relative to the non-volatile residue weight; and

[0099] E) optionally, an anti-caking agent, preferably magnesium stearate, in an amount of 5.0 to 20.0 wt.%, more preferably 10.0 to 15.0 wt.%, relative to the non-volatile residue weight.

[0100] In other words, in a preferred embodiment, the invention relates to a dry shampoo composition comprising: a non-volatile residue; optionally a volatile solvent, preferably ethanol; and optionally a propellant, preferably DME; wherein said nonvolatile residue comprises, preferably essentially consists of components A-E outlined earlier this paragraph. The preferred ratio's, weights or components for the volatile solvent and propellant have been described in detail in the previous paragraphs. These weight ratios define the functional phase of the dry shampoo across all formats. The interaction between the polymer, powder, and fatty alcohol promotes even coverage and strong physical adhesion to lice and ova. The composition leaves a dry, non-greasy finish, does not require rinsing, and provides high efficacy against lice and their ova, including resistant forms.

[0101] In a preferred embodiment, said composition is free of insecticides. In a further preferred embodiment, said composition is free of insecticides selected from : pyrethrins and pyrethroids such as permethrin, organophosphate insecticides such as malathion, organochlorine insecticides such as lindane and mixtures thereof. Insecticides have several disadvantages, such as skin irritation, itching, allergic reactions and health implications. These are amplified as the dry shampoo composition does not have to be rinsed off after the treatment. In addition, lice known as "treatment resistant lice" or "super lice" have developed resistance against insecticides, particularly pyrethrins and pyrethroids. As present composition utilizes a different method of action, inclusion of insecticides is neither necessary nor desirable.

[0102] In a preferred embodiment, said dry shampoo composition is substantially free of water. In a preferred embodiment, said dry shampoo comprises water in an amount of at most 10 wt.%, more preferably at most 5 wt.%, more preferably at most 4 wt.%, more preferably at most 3 wt.%, more preferably at most 2 wt.%, more preferably at most 1 wt.%, more preferably at most 0.8 wt.%, more preferably at most 0.6 wt.%, more preferably at most 0.5 wt.%, more preferably at most 0.4 wt.%, more preferably at most 0.3 wt.%, more preferably at most 0.2 wt.%, more preferably at most 0.1 wt.%, more preferably at most 0.05 wt.%, more preferably essentially free of free water, most preferably free of free water. The moisture content is preferably measured by Karl Fischer titration, more preferably in accordance with ISO 760: 1978. Low water content is advantageous for a number of reasons. It improves the reducing the need for preservatives particularly against bacteria, mold and yeasts which thrive in aqueous media; reducing coalescence of particles in dry powder formulations; improving spray consistency in aerosol or sprayed formulations; and reducing drying time on the hair and scalp.

[0103] In addition, present dry shampoo has high efficiency against lice and their ova; and good consumer acceptance with respect to hair greasiness and feel when used as a dry treatment even without subsequently rinsing off or rinsing out the dry shampoo with water. Commercial dry shampoo formulations often required rinsing off or rinsing out the formulation with water, preferably at an elevated temperature such as between 30 and 38 degrees to reduce hair greasiness and I or improve effectiveness of the treatment against lice.

[0104] Treatment

[0105] The dry shampoo as described herein is particularly designed to be an effective treatment of infestation of arthropods. Consequently, present invention relates to a dry shampoo for use in treatment or prevention of infection by arthropods. In a preferred embodiment, arthropods as described herein are lice. In a more preferred embodiment, the dry shampoo is for use in treatment or prevention of infection by lice in humans. In a preferred embodiment, said lice are selected from: Pediculus humanus capitis; Pediculus humanus corporis and Pthirus pubis. These are the main types of lice which infest humans.

[0106] More preferably, said lice are Pediculus humanus capitis (head lice). Head lice are the most common species of lice in human. Furthermore, the dry shampoo composition as described herein has shown high efficacy on head lice. In a further preferred embodiment, said head lice are "resistant head lice", "super lice" or "drug resistant" head lice. Head lice are commonly resistant to insecticidebased treatments, particularly to pyrethrin and permethrin insecticides. The dry shampoo as described herein has shown high efficacy against resistant head lice.

[0107] In a further preferred embodiment, the dry shampoo as described herein is effective against both lice and their ova. Treatment with the dry shampoo compositions disclosed herein reduces the viability of the ova of lice. This results in a significant increase in treatment efficiency, as the treatment does not need to be repeated regularly over an extended period to ensure all lice and ova are eradicated.

[0108] In another embodiment, the present invention relates to the use of the dry shampoo composition in the treatment or prevention of infestation by arthropods in animals, particularly in veterinary applications. The dry shampoo is especially well suited for leave-on topical application, as it is easy to apply, does not require rinsing, and can be administered without the need for bathing or wetting the animal. The formulation is free of conventional insecticides and acts through a mechanical mode of action, including physical coating and occlusion, which reduces the risk of resistance development and avoids systemic toxicity. This makes the composition highly suitable for repeated use and for animals that may be sensitive to pharmacological insecticides. In a preferred embodiment, the dry shampoo is used in the treatment or prevention of lice infestation in domestic or farm animals, including but not limited to: dogs, cats, rabbits, guinea pigs, ferrets, sheep, goats, horses, donkeys, cattle, pigs, poultry, and exotic pets such as rodents and birds. In a more preferred embodiment, said lice are selected from: Trichodectes canis (canine biting louse), Felicola subrostratus (feline louse), Gliricola porcelli and Gyropus ovalis (guinea pig lice), Bovicola ovis (sheep biting louse), Bovicola bovis (cattle biting louse), Haematopinus suis (pig louse), Bovicola equi (horse louse), Menopon species such as Menopon gallinae (poultry louse), and Menacanthus species such as Menacanthus stramineus (poultry louse). These lice species are known ectoparasites affecting the hair, fur or feathers of animals, often causing irritation, scratching, hair loss, and reduced health or productivity. The dry shampoo as described herein is therefore particularly well adapted for veterinary field use, where water may not be readily available, and where ease of handling, rapid application, and a non-invasive, non- systemic mode of action are essential. The powdery dry finish and absence of greasy residues further enhance compliance and comfort for both animals and caretakers. In a further aspect, present invention relates to a method for the treatment of infection by lice and lice ova, said method comprising:

[0109] - applying an effective amount of the composition according to the first aspect to hair and the scalp;

[0110] - optionally working the composition according to the present invention in contact with the hair and scalp, especially to the region behind the ears and the hairline at the back of the head,

[0111] - optionally leaving the composition according to the present invention on the hair for a suitable period of time to allow killing to occur,

[0112] - preferably without rinsing or washing said hair and scalp with water within an hour from said application.

[0113] In a preferred embodiment, the use of the composition for treating hair for instance comprises the steps of: (a) applying an effective amount of the composition according to the present invention to the wet or preferably dry hair and the scalp, (b) working the composition according to the present invention in contact with the hair and scalp, especially to the region behind the ears and the hairline at the back of the head, (c) leaving the composition according to the present invention on the hair for a suitable period of time to allow killing to occur.

[0114] Advantageously, the dry shampoo composition does not need to be rinsed or washed out. The dry shampoo leaves a fresh, clean look and removes excess grease and sebum from the hair for a long duration removing the need for rinsing or washing. This is particularly advantageous for repeated fast treatments, which are commonly required when lice infect schools, workplaces and other social environments, as it is a quick and efficient treatment.

[0115] Optionally, excess dry shampoo may be removed by dry techniques such as combing and I or blotting of the hair and scalp. Advantageously this is often much faster and convenient as compared to fully washing hair, particularly for long hair.

[0116] The composition according to the present invention is left into contact with the hair, e.g. for about 5 or 10 minutes. Short treatment times suffice to kill both lice and achieve high efficacy against their ova.

[0117] In another embodiment, the dry shampoo is left in contact with the hair for at least 1 hour, more preferably at least 2 hours, more preferably at least 4 hours, more preferably at least 6 hours, more preferably at least 8 hours, more preferably at least 10 hours, more preferably at least 12 hours, more preferably at least 20 hours, most preferably about 24 hours. As the composition does not need to be washed or rinsed out, and aids in providing a fresh, clean look and feel to the hair and scalp, the composition may be left throughout an extended period of time. It is noted that the solvent in the composition will quickly evaporate, and only the non-volatile components will remain for these prolonged periods. Additionally, near full efficacy against ova is achieved by utilizing the dry shampoo as leave-on formulation.

[0118] The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended to, nor should they be interpreted to, limit the scope of the invention.

[0119] The present invention will be now described in more details, referring to examples that are not limitative.

[0120] EXAMPLES AND / OR DESCRIPTION OF FIGURES

[0121] Materials

[0122] Head lice, Pediculus capitis, were obtained from volunteer children according to ethical approval from the Research Ethics Committee (REC reference Number 06 / Q010640). The lice were combed from the volunteer's heads in accordance with Insect R&D Limited Standard Operating Procedure CT.LLI.COM.1 Edition No. 1.0. As a result, lice used in the tests were obtained from different sources. This ensured an accurate representation of the normal variation of head lice likely to be encountered in the community, and any variation of response was, therefore, representative of the range of response likely to be encountered in consumer use.

[0123] Lice were counted into batches of approximately 20 and provided with squares of open meshed nylon gauze, as a substrate upon which to stand. Each batch was allocated to a marked 90-millimetre plastic Petri dish.

[0124] Direct Spray

[0125] Each square of lice and gauze (4cm2) was sprayed through a sieve with a ten second spray held 10 cm from sieve. After the lice have been exposed to the test formulations for 20-minutes, they were rinsed using a 1 : 14 solution of frequent wash shampoo and water.

[0126] The gauze was then rinsed three times using 250 milliliters of warm (34°C Celsius) tap water poured through and over the gauze squares. These were blotted dry using medical wipe tissue and incubated under normal maintenance conditions in clean plastic Petri dishes until the results were recorded.

[0127] After the treatments had been washed off, the lice were observed for signs of recovery or degeneration. During these readings' lice were categorized as 'Immobile', 'Moribund' and 'Alive'. 'Immobile' refers to a state of no movement, 'Moribund' describes slight uncoordinated movement and 'Alive' is used to describe lice with full movement.

[0128] Example 1 and comparative examples 2-3

[0129] Example 1 consists of 0.5 wt.% of a copolymer of vinyl acetate, vinyl neodecanoate and crotonic acid; 1 wt.% lauryl alcohol (1-dodecanol), 0.09 wt.% Natrium hydroxide, 4 wt.% of aluminium starch octenyl succinate and 0.75 wt.% of magnesium stearate dissolved in a mixture of 43.66 wt.% denaturized ethanol and 50 wt.% dimethyl ether. Natrium hydroxide was included to partially neutralize free acid groups within the copolymer.

[0130] Comparative examples 2 and 3 were commercial dry shampoo products available on the market.

[0131] Each of these products were sprayed directly. In addition, a negative control (water) was included.

[0132] The results shown in Table 1 demonstrates that example 1 is 100% effective at killing lice with a 20 minute exposure when compared to a control, and two commercially available dry shampoos. There was a high level of mortality in the controls of 58.3% so Abbotts Correction was applied.

[0133] This gave 100% efficacy for example 1 and a negative efficacy of -59.9% for C. ex. 2, and 12.7% for C. ex. 3. Further readings were not taken as the level of control mortality was high. Table 1: Adulticidal effects of Ex. 1, C. Ex 2 and 3 and a negative control

[0134] Examples 4-7

[0135] In examples 4 to 6, the materials and methods of example 1 were repeated with different dry shampoo compositions. The composition of each example is shown in table 2.

[0136] Polymer A is the same copolymer of vinyl acetate, vinyl neodecanoate and crotonic acid as utilized in example 1. Al. Starch is the same aluminium starch as example 1. Consequently, the composition of Ex. 5 and Ex. 1 are identical.

[0137] In addition to the adulticidal efficacy on lice, the ovicidal efficacy was tested. Again, water was included as a negative control.

[0138] Ovicidal efficacy utilized the same direct spray protocol onto the ova and subsequently rinsed to limit treatment time to 10 minutes. After 7-10 days, each ova was investigated. Compl. indicates complete hatching, indicating treatment was ineffective. Incompl. indicates the ova did not fully hatch, a sign of limited viability. No hatch indicates the ova did not hatch, indicating treatment was effective.

[0139] The adulticidal effects are shown in table 3. The ovicidal effects are shown in table 4. The ovicidal effects are measured in a similar

[0140] From table 3, we can see that the solvent system itself compromises to a low extent the viability of adult lice.

[0141] Inclusion of polymer A into the solvent system improves the efficacy of the composition against adult lice and their ova.

[0142] Addition of aluminium starch octenyl succinate and magnesium stearate significantly increases the efficacy of the composition against adult lice. Without wishing to be bound by theory, it is believed this synergistic effect is achieved by improved dispersion of the polymer-solvent system when sprayed as a dry shampoo. This shows the difficulty of translating wet shampoo and lotion compositions known in the art to dry shampoo compositions which are applied and dispersed very differently. However, the efficacy against ova remained limited.

[0143] The addition of lauryl alcohol resulted in full mortality of the lice. Furthermore, it significantly improved the ovicidal activity.

[0144] Table 3 : Adulticidal effects (Knockdown and mortality, [%])

[0145] Table 4 : Ovicidal effects

[0146] Example 8

[0147] A dry shampoo was formulated as a pressurised aerosol composition comprising:

[0148] 0.5 wt.% vinyl acetate-vinyl ester-crotonic acid terpolymer (film-forming polymer)

[0149] 1.0 wt.% lauryl alcohol (1-dodecanol)

[0150] 4.0 wt.% aluminium starch octenylsuccinate

[0151] 0.75 wt.% magnesium stearate

[0152] 23.66 wt.% ethanol (volatile solvent)

[0153] 70.0 wt.% dimethyl ether (propellant)

[0154] 0.09 wt.% sodium hydroxide (neutralising agent)

[0155] This composition was found to be highly effective against lice and their ova, and exhibited a dry, powdery feel upon application.

[0156] Example 9

[0157] A dry shampoo was formulated as a pressurised aerosol composition comprising:

[0158] 0.5 wt.% vinyl acetate-vinyl ester-crotonic acid terpolymer (film-forming polymer)

[0159] 1.0 wt.% lauryl alcohol (1-dodecanol) 4.0 wt.% aluminium starch octenylsuccinate

[0160] 0.75 wt.% magnesium stearate

[0161] 13.66 wt.% ethanol (volatile solvent)

[0162] 80.0 wt.% dimethyl ether (propellant)

[0163] 0.09 wt.% sodium hydroxide (neutralising agent)

[0164] This composition performed nearly identical to example 8. The composition was found to be highly effective against lice and their ova, and exhibited a dry, powdery feel upon application.

[0165] Example 10

[0166] A dry shampoo was formulated as a liquid, non-aerosol spray composition, comprising:

[0167] - 2.5 wt.% vinyl acetate-vinyl ester copolymer (PVP / VA)

[0168] - 5.0 wt.% lauryl alcohol (1-dodecanol)

[0169] - 20.0 wt.% aluminium starch octenylsuccinate

[0170] - 3.75 wt.% magnesium stearate

[0171] - 0.45 wt.% sodium hydroxide

[0172] - 68.3 wt.% ethanol (volatile solvent)

[0173] This composition was applied topically without rinsing and was found to be effective against lice and their ova. Upon evaporation of the ethanol, the composition left a dry, greasy residue.

[0174] Example 11

[0175] An aerosol dry shampoo composition was prepared with increased ethanol and reduced propellant, comprising:

[0176] - 0.5 wt.% film-forming polymer

[0177] 1.0 wt.% lauryl alcohol

[0178] - 4.0 wt.% aluminium starch octenylsuccinate

[0179] - 0.75 wt.% magnesium stearate

[0180] - 43.66 wt.% ethanol (volatile solvent)

[0181] - 50.0 wt.% dimethyl ether (propellant)

[0182] - 0.09 wt.% sodium hydroxide

[0183] This formulation was effective against lice and their ova, but left a perceptibly wetter and more greasy feel on the hair, relative to examples 8 to 11.

[0184] Example 12 An aerosol dry shampoo composition was prepared comprising:

[0185] - 0.5 wt.% film-forming polymer

[0186] 1.0 wt.% lauryl alcohol

[0187] - 4.0 wt.% aluminium starch octenylsuccinate - 0.75 wt.% magnesium stearate

[0188] 13.66 wt.% ethanol

[0189] - 5.0 wt.% water

[0190] - 75.0 wt.% dimethyl ether

[0191] - 0.09 wt.% sodium hydroxide The composition showed broad efficacy against lice and their ova, but left a wet and moist sensory profile. The inclusion of water, even at relatively slow amounts, negatively affected the drying time and the perceived cosmetic dryness of the product. Comparing examples 8 and 9, the inclusion of a modest amount of nonvolatile solvent, particularly water, had a pronounced effect on the wet feeling of the applied composition relative to a larger increase in the amount of volatile solvent.

Claims

CLAIMS1. A dry shampoo for use in treatment of infection by lice, said dry shampoo comprising a film forming polymer, wherein said film forming polymer is an vinyl acetate polymer; and starch or a starch derivative.

2. Dry shampoo for use according to claim 1, wherein said dry shampoo does not comprise non-volatile solvents with a boiling point greater than 90 °C in an amount greater than 5 wt.% relative to the weight of the dry shampoo.

3. Dry shampoo for use according to any one of claims 1-2, wherein said dry shampoo comprises aluminium starch.

4. Dry shampoo for use according to any one of claims 1-3, wherein said film forming polymer is a carboxylated vinyl acetate polymer.

5. Dry shampoo for use according to any one of claims 1-4, wherein said film forming polymer is a copolymer of vinyl acetate and a vinyl ester, preferably said vinyl ester is a long-chain vinyl ester.

6. Dry shampoo for use according to any one of claims 1-5, wherein said film forming polymer is a copolymer of vinyl acetate and a vinyl ester, wherein said vinyl ester is selected from the list of : vinyl laurate, vinyl stearate, vinyl palmitate, vinyl oleate, vinyl ethylhexanoate, vinyl versatate, vinyl neodecanoate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl nonanoate and mixtures thereof.

7. Dry shampoo for use according to any one of claims 1-6, wherein said film forming is a copolymer of vinyl acetate and a vinyl ester, wherein said vinyl ester is vinyl neodecanoate.

8. Dry shampoo for use according to any one of claims 1-7, wherein said dry shampoo is devoid of polydimethylsiloxane (PDMS), preferably devoid of silicones.

9. Dry shampoo for use according to any one of claims 1-8, wherein said dry shampoo comprises water in an amount lower than 1 wt.%.

10. Dry shampoo for use according to any one of claims 1-9, wherein said dry shampoo comprises a solvent in an amount of at least 30 wt.%, preferably said solvent is chosen from the list of : ethanol, isopropyl alcohol, ethyl acetate and dimethyl ether (DME) and mixtures thereof.

11. Dry shampoo for use according to any one of claims 1-10, wherein said dry shampoo comprises at least two solvents, each in an amount of at least 25 wt.%, wherein both solvents are independently selected from the list of : ethanol, isopropyl alcohol, ethyl acetate and dimethyl ether (DME); preferably said two solvents are ethanol and dimethyl ether (DME).

12. Dry shampoo for use according to any one of claims 1-11, wherein said dry shampoo further comprises a fatty alcohol, preferably said fatty alcohol is selected from the list of : 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1- decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1- pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol and mixtures thereof.

13. Dry shampoo for use according to any one of claims 1-12, wherein said dry shampoo comprises:A) a film forming polymer, preferably in an amount of 0.05 to 2 wt.% relative to the weight of the dry shampoo;B) a fatty alcohol, preferably in an amount of 0.05 to 5 wt.% relative to the weight of the dry shampoo;C) starch or a starch derivative, preferably in an amount of 1 to 10 wt.% relative to the weight of the dry shampoo; andD) a solvent, preferably in an amount of at least 25 wt.%, more preferably at least 50 wt.%.

14. Dry shampoo for use according to any one of claims 1-13, the dry shampoo composition comprising: (i) a non-volatile residue; (ii) optionally a volatile solvent; and (iii) optionally a propellant; wherein said non-volatile phase comprises, preferably essentially consists of:A) a film-forming polymer, wherein said film-forming polymer is a vinyl acetate polymer, in an amount of 2.0 to 20.0 wt.%, more preferably 3.0to 15.0 wt.%, more preferably 5.0 to 10.0 wt.%, relative to the nonvolatile residue weight;B) a fatty alcohol, selected from the group consisting of 1-octanol, 1- nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, and 1- tetradecanol, preferably 1-dodecanol, in an amount of 5.0 to 20.0 wt.%, relative to the non-volatile residue weight;C) starch or a starch derivative, preferably aluminium starch octenylsuccinate, in an amount of 40.0 to 80.0 wt.%, more preferably 50.0 to 70.0 wt.%, relative to the non-volatile residue weight;D) optionally, a base or pH adjusting agent, such as sodium hydroxide, preferably in an amount of 0.5 to 3.0 wt.%, relative to the non-volatile residue weight; andE) optionally, an anti-caking agent, preferably magnesium stearate, in an amount of 5.0 to 20.0 wt.%, more preferably 10.0 to 15.0 wt.%, relative to the non-volatile residue weight.

15. Method for the treatment of infection by lice and lice ova, said method comprising:Applying an effective amount of the composition according to any one of claims 1-14 to hair and the scalp; optionally working the composition according to the present invention in contact with the hair and scalp, especially to the region behind the ears and the hairline at the back of the head, optionally leaving the composition according to the present invention on the hair for a suitable period of time to allow killing to occur, preferably without rinsing or washing said hair and scalp with water within an hour from said application.

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