WO2018099931A1

WO2018099931A1 - Anti-perspirant composition comprising chitosan

Info

Publication number: WO2018099931A1
Application number: PCT/EP2017/080728
Authority: WO
Inventors: Ian Christopher Chandler; Mark John Berry; Karl John Hunter; Jason Richard Williams; Huanjun ZHOU; Shuqi ZHU
Original assignee: Unilever NV; Conopco Inc
Current assignee: Unilever NV; Conopco Inc
Priority date: 2016-12-01
Filing date: 2017-11-28
Publication date: 2018-06-07
Anticipated expiration: 2019-06-01

Abstract

An anti-perspirant composition comprising chitosan or a salt thereof, with a weight average molecular weight of from 250 to 650 kDa.

Description

ANTI-PERSPIRANT COMPOSITION COMPRISING CHITOSAN

Field of the invention The invention relates to an anti-perspirant composition that contains chitosan or a salt thereof.

Background of the invention Current anti-perspirant ingredients are based on aluminium, but inorganic salts have the effect of leaving white patches on clothes. The current approach is to reduce the amount of aluminium in antiperspirants or to use additional metal salts such as those of zirconium. However, this approach tends to lower the efficacy of the formulation and hence prove more expensive. Zirconium-based antiperspirants tend to leave yellow patches on clothes.

US 2009/0016978 A1 (Courtois et al.) describes an antiperspirant composition comprising a carrier substance and a water-soluble or water-dispersible thiolated polymer. The prior art inventors believe that the thiol groups of the thiomer enable or enhance the polymer's ability to act as a mucoadhesive and that this ability enables or enhances the antiperspirant activity of the thiomer. "Mucoadhesives" are materials that can attach to mucin in a biological surface. The prior art inventors further believe that the antiperspirant activity results, at least in part, from the ability of the thiomers to act as pore blockers. The thiomers, when swollen by water, are thought to serve to as plugs that may, at least in part, block the exit of sweat from eccrine sweat glands. It is essential for the invention that the thiomer is water-soluble or water-dispersible in order for it to dissolve or disperse in eccrine sweat.

WO 03/042251 (The Procter & Gamble Company) discloses compositions comprising chitosan in the form of a network of nano-sized fibres. Traditional chitosan is usually semi-crystalline and only soluble in acidic medium, typically in a pH range of from 1 to 5 limiting homogeneous formulation. A process for producing the network of nano- sized fibres is described involving the steps of forming an aqueous solution, neutralising the chitosan just to the point of precipitation, and homogenising the resulting suspension. It was observed that the minimum concentration of chitosan to inhibit Malassezia furfur (yeast implicated in dandruff) was lower than expected. This document also discloses an anti-dandruff composition comprising from about 0.01 % to about 5 %, preferably from about 0.5 % to about 2 % of chitosan by weight of the composition as the active anti-dandruff agent. The chitosan can be used in different applications, such as hair care, skin care, personal cleansing, odour control, wound care, blood management, oral care, film formation, controlled release of hydrophobic or hydrophilic materials, hard surface, fabric treatment, plant care, seed, grain, fruit and food protection, water purification and drug delivery. The chitosan compositions provide hair care benefits when formulated into products such as shampoos, conditioners, hairsprays, styling mousses and gels, hair tonics and hair colorants, especially anti-dandruff benefits and reduction of hair damage caused by the process of hair bleaching, permanent waving or coloration. Additionally, the compositions provide scalp benefits and conditioning properties such as softening, manageability and stylising of the hair. Specific examples are a shampoo, a conditioner, a dentifrice, a mouthwash, a non-abrasive gel, a chewing gum and a plant care composition.

WO 2006/040092 (Beiersdorf AG) discloses an aerosol formulation comprising one or more anti-perspirants and/or deodorising substances and chitosan having a degree of deacetylation of 75 to 98 %, a viscosity of 5 to 10 mPas, a weight average molecular weight distribution of less than 300 000 Da and a number average molecular weight distribution of less than 100 000 Da. It appears that the disclosed chitosan preserves the skin flora rather than acting purely as a bacteriocide. In particular, the chitosan appears to bind to the bacteria preventing microbial decomposition of sweat leading to odour. Anti-perspirants reduce sweat formation with the aid of astringent compounds in them, which are predominantly aluminium salts, such as aluminium hydrochloride, activated aluminium chlorohydrate or aluminium zirconium. It is customary to combine astringents with antimicrobials in the same composition. Aerosol products generally contain active anti-perspirant substances in the form of solids, which are suspended in an oil phase. Conventional active deodorant substances include ethyl hexyl glycerol, methyl phenyl butanol and polyglyceryl-2-caprate. One aim of the invention described in WO 2006/040092 is to reduce whiteness on skin or clothes. The formulation comprises 0.001 -2, preferably 0.01 -1 , especially 0.015-0.3 % w/w chitosan. The formulation comprises 1-35, preferably 1 -25, especially 1 -20 % w/w anti-perspirant component. The formulation comprises preferably 0.01-10, especially 0.05-5 % w/w deodorant component. Examples disclosed are anhydrous compositions. WO

2006/040092 further discloses that the pressure container used for the aerosol can be made of a metal, protected glass, non-shatter glass or some other glass, or else of a plastic. The propellant gas is preferably chosen from a long list of suitable gases.

US 2003/0133891 (Cognis Corporation) discloses a deodorising preparation containing nanoscale chitosans and/or chitosan derivatives with a particle diameter in the range from 10 to 300 nm. Chitosans have a bacteriostatic effect and a synergistic deodorising effect with esterase inhibitors and aluminium chlorohydrates. It is disclosed that absorption of nanoscale chitosans and/or chitosan derivatives by the Stratum Corneum is increased leading to long-lasting deodorising effect. The chitosan is normally used at levels of 0.01 -5, preferably 0.1 -1 , more particularly 0.2-0.6 % w/w. The document provides long lists of anti-perspirants based on salts of aluminium, zirconium or zinc, and deodorants. The preparations may contain 1 -50, preferably 5-30, particularly 10- 25 % w/w anti-perspirants. Specific examples of anhydrous anti-perspirant or deodorant suspension sticks and soft solids, deodorant cream emulsions, and oil-in- water roll-on and sprayable anti-perspirants / deodorants are provided. In particular a composition (composition 2 in table 2) is disclosed comprising the nanoscale chitosan, distearyl ether and dioctyl carbonate.

WO 03/072610 (Cognis Deutschland GmbH & Co. KG) discloses transparent cosmetic preparations containing chitosan and having a pH of below 6, comprising a) chitosan and/or chitosan derivatives, b) at least one anionic surfactant, c) at least one alkyl oligoglycoside, and d) water. Chitosans are valuable raw materials for use in cosmetics, because they have film-forming and moisturizing properties. They are also known to inhibit the activity of esterase-producing bacteria, so they are often incorporated into deodorants as well. Previously, it had been difficult to use them simultaneously with anionic surfactants, owing to the positive charge on them, leading to precipitation, which made the resulting preparation turbid. The document provides lists of anti-perspirants and esterase inhibitors. The preparations may contain 1 -50, preferably 5-30, particularly 10-25 % w/w anti-perspirants. Transparent anti- perspirants are claimed in claim 9. Examples of water-based clear cosmetic preparations containing chitosan and anionic surfactants are provided. US 5 968 488 (Henkel KgA) discloses deodorizing preparations containing cationic biopolymers, aluminium chlorohydrate and esterase inhibitors. It has surprisingly been found that cationic biopolymers, preferably of the chitosan type, inhibit the activity of esterase-producing bacteria and that a synergistic deodorizing effect is obtained in conjunction with the two components mentioned above. The biopolymers have a bacteriostatic effect. At the same time, the use of the cationic biopolymers leads to an improvement in the dermatological compatibility of the products. Examples of water- based compositions are provided. US 5 968 488 further discloses use of propellant gases for spray applications. The formulations are preferably marketed as rollers (roll- on emulsion), sticks, deodorant sprays or pump sprays.

WO 2015/058935 discloses the use of chitosan or a salt thereof as the sole anti- perspirant ingredient in an anti-perspirant composition. The chitosans had a high molecular weight of greater than 1000 kDa or low molecular weight of less than 100 kDa.

Further improvements in this area would be desirable. Summary of the invention

The present inventors have found that medium molecular weight chitosans or salts thereof provide a surprisingly superior anti-perspirant effect than either smaller or larger molecular weight chitosans. Without wishing to be bound by theory, it is believed that the lower molecular weights do not form large enough gel structures to enable efficient pore blocking. It is also believed that the large molecular weights form large gel structures but only on the outside of the capillaries of the width typical of a human sweat gland. However it is believed that the medium molecular weights form gel particles which fit comfortably within the sweat glands of a human and thus have a significantly better antiperspirancy effect. Thus in a first aspect, the present invention relates to an anti-perspirant composition comprising chitosan or a salt thereof, with a weight average molecular weight of from 250 to 650 kDa. Preferably the chitosan has a weight average molecular weight of from 300 to 550 kDa.

The methods and uses of the present invention should be understood to be non- therapeutic in nature, typically achieved by the topical application of one or more cosmetic compositions. The methods and uses may be termed "cosmetic". The methods lead to reduction in perspiration or sweating, which can enhance an individual's comfort, appearance, and/or confidence.

Preferably the composition comprises less than 3 wt% of aluminium salt. Preferably the anti-perspirant composition comprises less than 2 wt% aluminium salt, preferably less than 1 wt%, and most preferably is substantially or completely free of aluminium salt.

In a second aspect, the invention relates to a method of reducing perspiration from the surface of the human body comprising the topical application of a composition as described herein.

In a third aspect, the invention relates to the use of a composition described herein, in an anti-perspirant composition as an anti-perspirant ingredient.

For the purposes of this specification, the term "anti-perspirant composition" means a composition which prevents or reduces the appearance of perspiration or sweat in humans. In a preferred embodiment, the composition will be packaged in a form which indicates to the consumer that the composition has an anti-perspirant effect, and in particular may contain the wording "antiperspirant" on the packaging. For the purposes of this specification, the term "anti-perspirant ingredient" means an ingredient which prevents or reduces the appearance of perspiration or sweat in humans. For the purpose of this specification, the degree of acetylation is as measured using the dye-binding method (Gummow et al., Makromol. Chem., 186, 1239-1244 (1985)).

For the purposes of this specification the weight average molecular weight of chitosan may be determined by size exclusion chromatography. An example method involves dissolving 20 mg of chitosan in 1 % v/v aqueous formic acid. Polysaccharide reference standards are dissolved in the same diluent. Samples and standards are left to stand overnight to allow complete dissolution. Samples are prepared in duplicate. The analysis may be carried out on an Agilent 1200 series HPLC equipped with an ELSD detector. The chromatographic separation is achieved on an Agilent PL aquagel-OH MIXED H, 300 x 7.5 mm ID, 8 mm particle size GPC column, using a buffer of 0.01 M aqueous ammonium formate (0.1 % formic acid) at pH 3.1 as mobile phase, at a flow rate of 1.0 ml.min-1. Chitosan is a partially deacetylated form of the arthropod shell material chitin and is soluble in water at a pH of no more than 6.0. As well as from arthropods, chitosan and its precursor, chitin, are produced by fungi and bacteria, thus potentially providing a non-animal source for chitosan from a by-product of the fermentation industry. Without being bound by theory, it is thought that when chitosan or a salt thereof is applied to the skin, it can diffuse into pores where it comes into contact with sweat, which has a pH of approximately 6.2 to 7.7, and precipitates forming a gel blocking the pores and reducing sweat flow. The gel formed is not permanent as it is hydrolysed over time.

Preferably the chitosan or salt thereof has a degree of acetylation of 0-40 %.

Preferred salts of chitosan are selected from the group consisting of acetate, chloride, citrate, formate, fumarate, gluconate, glycolate, lactate, maleate, malate, phosphate, propionate, succinate, sulphate, tartrate and mixtures thereof, preferably selected from the group consisting of formate, glycolate, lactate and mixtures thereof.

Preferably the anti-perspirant composition comprises 1 to 5 wt%, preferably 2 to 4 wt%, chitosan or chitosan salt. The chitosan or salt thereof is preferably either in an anhydrous form or dissolved in water at a pH of no more than 6.0, preferably no more than 5.5, most preferably no more than 5.0. The chitosan or salt thereof can be dissolved in water at a pH of at least 3.5, preferably at least 4.0, more preferably 4.5.

Preferably a 0.5% wt/vol aqueous solution of the chitosan or salt thereof has an apparent viscosity of greater than 6.0, more preferably greater than 10.0 most preferably greater than 15.0 mPas at a shear rate of 100s^"1 at room temperature. The viscosity was measured by using an Anton Paar MCR501 rheometer with a cone and plate configuration, a cone tip diameter of 50mm and a gap distance of 0.049mm.

The composition may additionally comprise auxiliary ingredients selected from the group consisting of a fragrance, a bactericidal agent, a bacteriostatic agent, a perspiration absorber, an esterase inhibitor, a surfactant, a thickener, a chelator and a preservative.

The composition preferably is an aqueous composition with a pH of from 3.0 to 6.0, preferably from 3.0 to 4.5, more preferably from 3.5 to 4.5. In certain preferred embodiments, the composition comprises at least 50% water, preferably at least 70% water, more preferably at least 80% water, still more preferably at least 90% water.

Suitable bactericides include chlorinated aromatics such as biguanide derivatives of which triclosan (e.g. Irgasan DP300 or Triclorban), and chlorhexidine warrant specific mention. Another class of effective bactericide comprises polyaminopropyl biguanide salts such as are available under the trade mark Cosmosil.

Chelators that can sequester iron retard bacterial growth and thereby inhibit malodour formation. Examples include aminopolycarboxylates such as ethylenediamine tetraacetic acid (EDTA) or higher homologues such as diethylenetriamine pentaacetic acid (DTPA).

Bactericides and chelators are commonly employed at a concentration of from 0.1 to 5, and particularly 0.1 to 2 % w/w. The composition can be in the form of a gel, or suitable for spray application, or suitable for application by aerosol, or suitable for application with a stick applicator. The method for their manufacture is well known to those skilled in the art. One preferred format is that the anti-perspirant composition is an aerosol composition comprising a volatile propellant.

As the composition is intended for use as an anti-perspirant composition, it is a leave- on composition, which means that the product is applied to the body without washing off with water at the time of application so that it is left on the body surface for a substantial period of time of e.g. a few or several hours at least.

The composition typically comprises less than 10 wt% surfactant and preferably less than 5 wt% surfactant. If any surfactant is present then it is preferably only of the non- ionic type and is substantially free of any other types of surfactants.

Preferably the composition comprises less than 10 wt% dipropyleneglycol, preferably less than 5 wt%. Preferably the composition comprises less than 10 wt% triglycerides, preferably less than 5 wt%. Such materials can provide the composition with an oily nature, which is undesirable in an anti-perspirant leave-on composition which is often in contact with clothing of a user.

In a preferred embodiment the composition comprises a lamellar phase stabilised oil- in-water emulsion.

Lamellar phase stabilised oil-in-water emulsions as used in the present invention may be called oleosome dispersions. Typically, they comprise dispersed droplets of oil surrounded by multiple layers of liquid crystalline lamellar phase comprised of one or more surfactants, non-ionic surfactants being preferred.

The average particle size of the lamellar phase stabilised oil-in-water emulsion is preferably at least 4 microns. Such measurements may be made using optical microscopy. Using oleosome dispersions of lower average particle size can lead to reduced performance. The oil of the oleosome dispersions should preferably remain in a liquid state at temperatures as low as 20°C or even 15°C. For this reasons, typical oils have melting point from their solid state of less than 20°C, preferably less than 15°C, and more preferably less than 10°C.

Preferred oils should be relatively fluid, having a kinematic viscosity of less than 100 cSt (mm²/s) and preferably less than 50 cSt (mm²/s) at 20°C.

Suitable oils include hydrocarbon oils and ester oils, particularly triglyceride oils, such as sunflower seed oil. Other particular oils that might be used in the oleosomes are

C-12-15 alkyl benzoate esters, hydrogenated polybutene, PPG-14 butyl ether, triethyl citrate, isopropyl palmitate, and isopropylmyristate.

The lamellar phase of the oleosome dispersion is typically comprised of two non-ionic surfactants, one having a relatively low HLB (less than 8 and preferably less than 5) and one having a relatively high HLB (more than 12 and preferably more than 15). The ratio high HLB surfactant to low HLB surfactant is chosen so as to give a stable oleosome dispersion, typically ratios being from 1 :1 to 1 :6 by weight, respectively. A blend of steareth-2 and steareth-20 has been found to be suitable, particularly when used in combination with sunflower oil. Steareth-2 and steareth-20 are best used at a ratio of from 1 :4 to 1 :5 by weight.

The oleosome dispersions have an oil content that typically makes up from 1 to 30%, preferably from 1 to 20%, and more preferably from 1 to 10% by weight of the total composition. The surfactant content typically makes up from 1 to 30%, preferably from 1 to 20%, and more preferably from 1 to 10% by weight of the composition. The ratio of oil to surfactant is typically from 1 :3 to 3:1 and preferably from 1 :2 to 2:1 .

The invention will now be illustrated with reference to the following figures, in which:

Figure 1 is a schematic representation of testing apparatus.

Figure 2 is an image of the results of testing by using the apparatus shown in figure 1 . Examples

Testing on narrow capillaries An experiment was arranged using a device with an arrangement as shown in figure 1 . The device had a 20^*20 μηη channel and the inner surface was modified further with mucin coating (porcine gastric derived). Before use, the channel was filled with model ionic sweat (pH6.9) (comprising chloride salts, lactic acid, urea and water). Throughout the experiment, the sweat was kept still. A solution comprising chitosan was placed on the top of the channel. Three chitosans were chosen for investigation as Chitopharm™ from Chitinor, with peak molecular weight values of 222 kDa (Chitopharm S™), 430 kDa (Chitopharm M™) & 699 kDa (Chitopharm L™).

To start the reaction between active and sweat, a droplet of chitosan formula was applied over the outer area of the channel. The whole reaction process was monitored under inverted microscope (NIKON Ti-Eclipse).

Figure 2 shows an inverted confocal microscopy image when Chitopharm M™ is placed onto the capillary opening (Nikon Eclipse Ti), Reflection mode (no fluorescent dye), 100^* oil lens, Z-direction, 1 ^m/layer, total depth 27μη-ι.

Gelation happened after 15mins, mainly outside the channel. It was noticed that something formed in the inside of channel wall (believed to be gel). This is not seen with Chitopharm L™, but is observed with aluminium-containing antiperspirants.

Testing on wider capillaries

The break pressure, as a measure of the gel strength of chitosan in a pore, was measured for 1.5% 222 kDa (Chitopharm S™), 1.5% 430 kDa (Chitopharm M™) and 1 .5% 699 kDa (Chitopharm L™) respectively on wider capillaries. The chitosan sample compositions were as noted in Table 1 below, with either Chitopharm S, M or L included at 1 .5 w/w%. Artificial sweat was drawn into a glass capillary (141 μηη diameter). The capillary was then placed in the test solution for one hour to allow diffusion into the capillary. The capillary was then removed from the solution and allowed to dry for 60 minutes before measuring the break pressure. The capillary was inserted into a water-filled tube attached to a syringe pump which was in turn connected to a digital pressure sensor (Omega Engineering). Hydrostatic pressure was applied to the capillary at a rate of 0.05 ml/min until sweat was seen to emerge from the tip of the capillary. The pressure at which this occurred was noted.

The figures obtained were tabulated below. Artificial sweat was prepared as an aqueous solution (pH 7.7) consisting of: 160mg/L Potassium chloride, 1 180mg/L Sodium bicarbonate, 840mg/L sodium chloride, 212 mg/L Ammonium chloride, 892 mg/L L-(+)-lactic acid, 540mg/L L-methionine, 52mg/L Mucic acid and 180mg/L urea. The pH of this solution (typically 6.0-6.2) was then adjusted to the desired pH by the dropwise addition of 0.01 M sodium hydroxide to raise the pH to 7.7.

Higher pressure denotes to more capillary blocking and by inference, sweat duct blocking. Chitopharm S is seen inferior to Chitopharm M and L.

Test on viscosity

In addition to capillary blocking, the viscosity of the chitosan solution is also tested. More viscous solution denotes to slower diffusion into the sweat duct, thus a less dynamic gel plugging for the sweat duct.

Viscosity of 1 .5% 222 kDa (Chitopharm S™), 1.5% 430 kDa (Chitopharm M™) and 1 .5% 699 kDa (Chitopharm L™) was measured respectively. The relative viscosity was determined by the time taken for a 3mm diameter stainless steel ball to fall to a depth of 95mm in a solution of the chitosan dissolved in 1 M acetic acid. Experiments were carried out at room temperature (22°C) and results are given in table below. Chitopharm S Chitopharm M Chitopharm L

Relative viscosity 0.03 1.00 16.00

of a 1.5%solution

Chitopharm L is much more viscous than Chitopharm M and S. Human Subject Testing

A single product application is performed to each underarm by a member of the study staff on 3 consecutive days (designated day 1 , day 2 and day 3) and the amount applied is recorded. For aerosols this is a 2 second spray (-15 cm from the underarm), 2-3 pumps for a pump spray and a 300mg (+/- 25mg) target dose for contact applicators such as sticks and roll-ons. All aerosol/pump spray products are applied in a ventilated air booth.

Hot Room sittings are performed under standard conditions of 40 °C and 40% RH within the operating limits stated above. Subjects may sit for up to 80 minutes (40 minute warm up + 1 x 20 minute sweat collection period or 40 minute warm-up + 2 x 20 minute sweat collection) - the standard protocol comprises a 40 minute warm up and a single 20 minute sweat collection period. During a sweat collection period the sweat produced in each underarm is collected in absorbent cotton pads.

After the 40 minute warm-up subjects come out of the Hot Room in the order that they entered. Each axilla is wiped with a tissue which is then discarded as clinical waste (separate tissues ensure that there is no cross contamination). A collection pad is then placed under each axilla such that the folded edge is in contact with the axillary fold (surface area in contact with the skin is 10cm x 7cm). Subjects then re-enter the Hot Room and the timer is set for the 20 minute sweat collection period. During this period subjects are not permitted to carry out any activity in the Hot Room which involves more movement of one arm than the other (e.g. writing). Subjects must sit upright with legs uncrossed to minimise any variations in the data. After 20 minutes the subjects come out of the Hot Room in order of entry. Pads are collected, placed in the appropriate pots and the lids secured. Pots are subsequently weighed. A further 20 minute sweat collection period may be implemented immediately after the first collection period.

Test 1

Hot Room studies were carried out on 31 female subjects.

The test subjects were given an underarm composition which was either (a) a chitosan prototype solution comprising Chitopharm L™ at 1.5 wt% in a roll-on format, or (b) an Impulse™ Hint of Musk deodorant spray, acting as a control.

The chitosan prototype formulation was as shown in table 1 :

Table 1

The compositions were applied three times, at once per day. The study was balanced and randomised. This gave a mean sweat reduction of 6% with a reduction of from -6 to 16% in the 95% confidence range with a p-value of 0.3127.

It could therefore not be concluded that there was a statistically significant

improvement over the control.

Test 2 Hot Room studies were carried out on 31 female subjects.

The test subjects were given an underarm composition which was either (a) an emulsion roll-on formulation (with no Al AP active and pH adjusted to approx.. 3.7 to 4.0 with lactic acid) comprising Chitopharm L™ at 1.5 wt% in a roll-on format, or (b) an Impulse™ Hint of Musk deodorant spray, acting as a control.

The chitosan formulation was as shown in table 2:

Table 2

The compositions were applied three times, at once per day. The study was balanced and randomised.

This gave a mean sweat reduction of 9% with a reduction of from 1 to 16% in the 95% confidence range with a p-value of 0.024

It can therefore be concluded that the composition containing 1 .5 wt% of the

Chitopharm L™ had a statistically significant AP effect over the control.

Hot Room studies were carried out on 29 female subjects. The test subjects were given an underarm composition which was either (a) a chitosan prototype solution comprising Chitopharm M™ at 3 wt% in a roll-on format, or (b) an Impulse™ Hint of Musk deodorant spray, acting as a control. The chitosan prototype formulation was as shown in table 3:

Table 3

This gave a mean sweat reduction of 22% with a reduction of from 17 to 27% in the 95% confidence range with a p-value of <0.0001 .

It could therefore be concluded that there was a statistically significant improvement over the control. Furthermore, a sweat reduction effect of 22% in human subjects demonstrates a significant antiperspirant effect.

Claims

1. An aqueous anti-perspirant composition comprising chitosan or a salt thereof, with a weight average molecular weight of from 250 to 650 kDa, determined by size exclusion chromatography, and having a pH of from 3.0 to 6.0, preferably from 3.0 to 4.5, more preferably from 3.5 to 4.5.

2. An anti-perspirant composition according to claim 1 , wherein the chitosan or a salt thereof has a weight average molecular weight of from 300 to 550 kDa.

3. An anti-perspirant composition according to claim 1 or claim 2, which comprises less than 3 wt% of aluminium salt, preferably less than 2 wt%, more preferably less than 1 wt%, and most preferably is substantially or completely free of aluminium salt.

4. An anti-perspirant composition according to any one of the claim, wherein the chitosan or salt thereof has a degree of acetylation of 0-40 %.

5. An anti-perspirant composition according to any one of the preceding claims, wherein a 0.5% wt vol aqueous solution of the chitosan or salt thereof has an apparent viscosity of greater than 6.0, more preferably greater than 10.0 most preferably greater than 15.0 mPas at a shear rate of 100s^"1 at room

temperature, using an Anton Paar MCR501 rheometer with a cone and plate configuration, a cone tip diameter of 50mm and a gap distance of 0.049mm.

6. An anti-perspirant composition according to any one of the preceding claims, wherein the salt of chitosan is selected from the group consisting of acetate, chloride, citrate, formate, fumarate, gluconate, glycolate, lactate, maleate, malate, phosphate, propionate, succinate, sulphate, tartrate and mixtures thereof, preferably selected from the group consisting of formate, glycolate, lactate and mixtures thereof. An anti-perspirant composition according to any one of the preceding claims, which comprises 1 to 5 wt%, preferably 2 to 4 wt%, chitosan or chitosan salt.

An anti-perspirant composition according to any one of the preceding claims, wherein the composition is an aerosol composition comprising a volatile propellant.

An anti-perspirant composition according to any one of the preceding claims, packaged in a form which indicates to the consumer that the composition has an anti-perspirant effect

An anti-perspirant composition according to any one of the preceding claims, which comprises less than 10 wt% surfactant.

An anti-perspirant composition according to any one of the preceding claims, comprising a lamellar phase stabilised oil-in-water emulsion.

A cosmetic method of reducing perspiration from the surface of the human body comprising the topical application of a composition according to any one of the preceding claims.

The use of a composition according to any one of claims 1 to 1 1 , in an anti- perspirant composition as an anti-perspirant ingredient.