Field of the Invention

The present invention relates to multilamellar vesicles and to the use of these vesicles in ocular and nasal care.

Background of the invention

Vehicles for delivering pharmaceutical and cosmetic compounds have been described and are typically phospholipid-based, frequently lecithin-based. Lecithin-based liposomes have been widely used for transdermal application of pharmaceutically active ingredients, such as alkaloids, contraceptives, insulin and salicylic acid derivatives. The cosmetic industry has applied the findings of the pharmaceutical industry, and used it for topical delivery of cosmetically active substances, such as moisturisers, botanicals, vitamins and ceramides. The size of the liposomes may vary from 20 nm to 1000 nm. Because of their size they are able to pass the stratum corneum of the skin and deliver the active compound. In practice this can be done until the first subcutaneous membrane is reached. W094/01089 discloses an eye spray comprising lecithin-based liposomes.

One drawback of lecithin -based liposomes is that the presence of other surface active agents, such as emulsifiers, solubilisers or wash-active ingredients, will destabilise the liposome, since the additional surface active agents will impart in the liposomal structures. Consequently liposomes cannot be applied in traditional emulsions and wash-active preparations.

Another drawback of lecithin-based liposomes is that the liposomes are usually characterised by a relatively low degree of loading. Loading capacity may be high enough for pharmaceutical preparations, but is in most cases insufficient for cosmetic ingredients.

Another drawback of lecithin -based liposomes is the fact that the molecule needs to be unsaturated to produce liposomes. Theoretically it is possible to prepare lecithin-based liposomes on the basis of hydrogenated phosphatidylcholine, but it is difficult and does not allow for targeted controlled release. In practice therefore unsaturated phosphatidylcholine is required to prepare liposomes that enable targeted controlled release. Unsaturation, easily leads to peroxide formation and the formation of malondialdehyde, the typical odour of rancid oils and fats. This is a very sincere limitation for using lecithin-based liposomes. Another drawback of lecithin-based liposomes is their size, frequently in the range of 500-800 nm. This does not allow for sterile filtration to avoid contamination with micro organisms. Therefore, preservatives need to be added to lecithin-based liposome

formulations. Their large size also makes it impossible to prepare transparent formulations.

The drawbacks of lecithin -based liposomes are very much limiting their use.

It would be desirable to have an alternative which does not have the drawbacks of the lecithin based liposomes.

Detailed description of the invention

The present invention relates to a multilamellar vesicle comprising neutralised hydrogenated polymerised fatty acids, wherein the fatty acids are obtained from a feedstock comprising C18 unsaturated fatty acids.

The multilamellar vesicles according to the invention have several advantages. One advantage is their stability. Unlike lecithin-based liposomes, the multilamellar vesicles according to the invention are insensitive to surface agents and therefore ideal for a wide variety of formulations. The multilamellar vesicles according to the invention may be applied in emulsions and wash-active products.

Another advantage is that the multilamellar vesicles according to the invention may be fully hydrogenated and thereby become insensitive to oxidation. This avoids the problem of the formation of peroxide and malondialdehyde, leading to the typical odour of rancid oils and fats.

Another advantage is that the vesicles are smaller than most lecithin-based liposomes, which frequently have a size in the range of 500-800 nm. The multilamellar vesicles according to the invention have a flexible width of 100 to 400 nm, which allows them to pass a 200 nanometer filter or opening. Therefore, use of the vesicles according to the invention enables the production of preservative-free spray formulations, since products according to the invention allow for sterile filtration. In one embodiment, a spray comprising multilamellar vesicles according to the invention is sterilized on leaving the spray bottle nozzle which is provided with a 200 nm opening.

Another advantage is the relatively simple and uncomplicated production process of the multilamellar vesicles according to the invention. Starting from hydrogenated polymerised unsaturated fatty acids, the process for preparing the multilamellar vesicles involves neutralization and addition of energy. No spacers or linker molecules are required to obtain the vesicles, making the production process more economical and practical.

Another advantage is that the loading capacity of the multilamellar vesicles according to the invention is higher than the loading capacity of lecithin-based liposomes. In the context of the present invention, the term "lecithin-based liposomes" refers to phospholipid-based liposomes wherein the phospholipid comprises a phosphatidylcholine or phosphatidylcholine- derivative in the polar head group.

Yet another advantage is that transparent compositions may be prepared using the multilamellar vesicles according to the invention.

The vesicles are prepared from hydrogenated polymerised unsaturated fatty acids. The unsaturated fatty acids for polymerization may be obtained from any feedstock comprising mono- unsaturated or poly-unsaturated fatty acids. Suitable examples include linseed oil, olive oil, palm oil and rape seed oil. However, since the application of the product is in personal care, medical devices or pharmaceutical products, preferably soy-based feedstock is used. In one embodiment, soy bean oil comprising a mixture of mono-unsaturated and poly unsaturated fatty acids is used as the feedstock. In one embodiment, the unsaturated fatty acids are ethylenically unsaturated C12-C30 fatty acids. In another embodiment, the unsaturated fatty acids are ethylenically unsaturated 18 fatty acids, such as oleic acid and linoleic acid.

Several methods for polymerisation of unsaturated fatty acids are known in the art, see for example from US 2,955,121, US 3,632,822 or US 4,776,983. The polymerisation process of unsaturated fatty acids typically involves heating under pressure, such as 300-380 DEG C at 0.5-2.8 MPa or mixing unsaturated fatty acids for 1-8 hours at a temperature in the range of 200 to300 DEG C with 1-20 weight % of clay and 1-5 weight % of water under agitation. The use of a catalyst allows for lower temperatures to be used. Suitable catalysts for

polymerization of unsaturated fatty acids include acid or alkaline clays and strong Lewis acids. A suitable example of a strong Lewis acid is lithium carbonate. The catalyst may be positioned on a carrier, for example on a silica support. In one embodiment, the polymerized fatty acid product is prepared by polymerisation of soy bean feedstock at a temperature in the range of 200 to 300 DEG C using lithium carbonate on a silica support as a catalyst. The polymerised product comprises a mixture of polymerized fatty acids, which for example may be acyclic, monocyclic, bicyclic or aromatic. The mixture may comprise isomers, including structural isomers, such as positional isomers, and stereoisomers, such as cis-trans isomers. Dimerised fatty acids, 36 carbon dibasic acids, are the major component in the mixture, but monomers, trimers, higher fatty acid polymers or isostearic acids may also be present after

polymerization. The ratio of these different polymers will depend on the feedstock used. Preferably the mixture comprises at least 95% w/w or at least 98% w/w dimer acids, C36 dimer acids, preferably from dimerized C18 soy fatty acids.

The polymerised product is hydrogenated to remove all or part of the unsaturated bonds. In one embodiment, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95% of the unsaturated bonds are removed. Hydrogenation may be carried out using methods known in the art, typically by using hydrogen at a temperature in the range of 200 DEG C to 400 DEG C at elevated pressure in the presence of a catalyst, for example as described in GB 999 732 resulting in a viscous and virtually colourless liquid at ambient temperature.

Polymerised fatty acids or hydrogenated polymerised fatty acids may be obtained commercially. Any commercially obtainable mixture of (hydrogenated) polymerized unsaturated fatty acids which contains polymers of C12-C30 fatty acids may be used.

Preferably, a hydrogenated polymerised fatty acid composition comprises at least 95% w/w or at least 98% w/w hydrogenated dimer acids, hydrogenated C36 dimer acids, preferably from dimerised C18 soy fatty acids, is used. Preferably, a hydrogenated polymerized fatty acid composition is used which has an acid value in the range of 194-198 (mg KOH/g), an iodine value below 15 (g/100 g), preferably 10 (g/100 g) or less or more preferably 0.5 (g/100 g) or less and a dicarboxylic acid content of at least 95%w/w, preferably more than 98%w/w. A suitable example of a commercially available hydrogenised polymerized fatty acid mixture is Pripol 1009 (Uniqema Nederland BV, Gouda, The Netherlands).

The different products in the polymerization product may be separated from each other. In one embodiment, dimers are separated from monomers, trimer and higher polymers which are present in the mixture after polymerization. Separation may be performed using methods known in the art, for example methods including distillation. In another embodiment, there is no separation of the polymerized products in the mixture before or after

hydrogenation is carried out.

The hydrogenated polymerised fatty acid mixture itself does not form vesicles. The vesicles are only obtained after neutralization of the hydrogenated polymerised fatty acids and addition of energy, preferably mechanical energy. A method for preparing a composition comprising multilamellar vesicles according to the invention is another aspect of the present invention.

In one embodiment, a method for preparing a composition comprising multilamellar vesicles according to the invention comprises:

- providing a composition comprising hydrogenated polymerised fatty acids;

- adding a neutralisation agent to the hydrogenated polymerised fatty acids;

- adding energy to the neutralisation agent and the hydrogenated polymerised fatty acids until multilamellar vesicles are obtained.

In one embodiment, the hydrogenated polymerised fatty acids are neutralized with a base. Suitable bases for neutralization include 2-amino-ethanol (MEA), triethanolamine (TEA), 2-amino-2-methylpropan-l-ol (AMP), 2-amino-2-methyl-l, 3-propanediol (AMPD) and 2-amino- 2-hydroxymethyl-propane-l,3- diol (Tris). In one embodiment, Tris is the preferred neutralising agent because Tris does not lead to irritation of the mucosa of the eye or the nose. In one embodiment, the ratio hydrogenated polymerised fatty acids: neutralisation agent is in the range from 2.0: 1 up to 2.3:1. In another embodiment, the ratio is 2.22:1.

Depending on the neutralisation agent and the pH, the neutralised hydrogenated polymerised fatty acids may be present in salt form, acid form or anion form. In one embodiment, the neutralised hydrogenated polymerised fatty acids are present in salt form.

For neutralisation a solvent may be used. The solvent is preferably a diol compound, such as 1,3-propanediol (1, 3-dihydroxypropane), 1,3 propylene glycol, 1,2 propylene glycol, glycerol (1,2,3-trihydroxypropane), trimethylolpropane, dimethyl isosorbide or 2-methyl-l,3- propylene glycol. In one embodiment, 1,3-propanediol is used as the solvent, since it does not cause skin or eye irritation, nor does it lead to sensitisation. Suitable concentrations of the solvent are from 1% to 60%, from 20% to 50% or from 40% to 55% by weight of composition.

Addition of energy is required to obtain the multilamellar vesicles. Energy may be added by methods known in the art, such as by homogenization, high speed mixing or sonication. In one embodiment, neutralised hydrogenated polymerized fatty acids are converted to multilamellar vesicles by high speed mixing for a period of 10 to 60 minutes at a speed of 7000 to 10 000 rpm, for example for a period of 20 to 40 minutes at 8000 rpm. In another embodiment, neutralised hydrogenated polymerized fatty acids are converted to multilamellar vesicles by sonication. After addition of sufficient energy, multilamellar vesicles, comprising multiple bilayers, such as two, three or more, concentrically stacked one upon each other, like the layers of an onion, are formed. In one embodiment, multilamellar vesicles according to the invention comprise at least two, at least three, at least four or at least five bilayers, for example 2-12 bilayers, 4-12 or 5-8 bilayers.

The multilamellar vesicles comprising dehydrogenated fatty acids may be applied as such or may encapsulate other components. Suitable examples of components which may be encapsulated include drug molecules, such as anti-inflammatory compounds or nursing and maintaining compounds, including anti-inflammatory agents, anti-oxidants, anti-microbial agents, lipids, vitamins and plant extracts. In one embodiment, carbohydrates or carbohydrate derivatives, such as monosaccharide, sugars and polysaccharides, or derivatives thereof are encapsulated. Suitable examples include a-glucanes, b-glucanes, N-acetylglucosamine, sialic acid, glycosaminoglycans polysaccharides and anti-microbial polysaccharides derivable from Aloe vera. Both hydrophilic and lipophilic components may be encapsulated.

In one embodiment, the encapsulated compound is a sulfated glycosaminoglycan, preferably selected from the group consisting of chondroitin sulfates, keratan sulfate, chitin, hyaluronic acid and heparin, or salts or derivatives of these components. In one embodiment, hyaluronic acid is encapsulated. Hyaluronic acid is preferably used in the form of the sodium salt, i.e. sodium hyaluronate. Preferred hyaluronic compounds have a molecular weight of at least 10 kDa and at most 100,000 kDa. In one embodiment, the molecular weight of the hyaluronic compound is 2,000 kDa. The encapsulated compound is used at an effective level.

In one embodiment, the amount of encapsulated compound is from 0.01% to 10%, more preferably from 0.1% to 4%, most preferably 0.2 tol.5% by weight of the composition comprising the multilamellar vesicles.

For encapsulation of an active compound, the active compound is added before addition of energy. In another embodiment according to the invention, active compound, the same or another, is also added after the addition of energy. As a result, the active is both encapsulated and non-encapsulated. This allows for both immediate release and controlled release of active from the multilamellar vesicle according to the invention. Therefore the beneficial effect of the active component may be immediate, for example within 5-10 seconds, and may be maintained for at least two to four hours due to the controlled release.

Formation of multilamellar vesicles may be confirmed by examination by means known in the art, for example by microscopy, such as light or electron microscopy. In one embodiment, multilamellar vesicles are detected by freeze fracture electron microscopy. Multilamellar vesicles may be distinguished from micelles, which comprise a monolayer of surfactant material, while multilamellar vesicles comprise concentric bilayers. Concentric bi layers can easily be detected using the microscope and polarised light.

The multilamellar vesicles according to the invention are similar to liposomes, because both comprise several bilayers surrounding an aqueous core. However, where liposomes comprise phospholipid bilayers, the multilamellar vesicles according to the invention comprise bilayers of neutralised hydrogenated polymerized fatty acids. Multiple bilayers, such as two, three or more bilayers, are concentrically stacked one upon each other, like the layers of an onion, to form the multilamellar vesicles according to the invention. The bilayers form the walls of the multilamellar vesicle and comprise neutralised hydrogenated polymerized fatty acids as the wall-forming material. Between the layers there are hydrophilic domains in which water- soluble substrates may be introduced and hydrophobic domains in which oil-soluble substrates may be introduced. The multilamellar vesicles according to the invention offer a longer term depot of wetting compounds. In one embodiment, the Sauter mean diameter of the vesicles is in the range from 100 nm up to 400 nm, such as from 100 nm up to 350 nm, from 110 nm up to 250 or from 110 nm up to 200 nm, as determined by a particle sizer machine from AccuSizer 780 AD, Particle Sizing Systems, Santa Barbara, USA, equipped with an auto-dilution system.

In another aspect, the present invention relates to a composition comprising multilamellar vesicles according to the invention. In one embodiment, the composition comprises multilamellar vesicles, which vesicles comprise bilayers of neutralised hydrogenated polymerised fatty acids, whereby the unsaturated fatty acids were obtained from soy feedstock. In one embodiment, the composition is a milky white, non-transparent, odourless aqueous dispersion of multilamellar vesicles according to the invention. The hydrogenated polymerised fatty acids may constitute from 0.01 to 20%, from 0.01 to 10% or from 0.10 to 5% by weight of the composition. In one embodiment, the composition comprises from 0.01 to 20% hydrogenated polymerised fatty acids and 0.30% of an active, such as sodium

hyaluronate, by weight of the composition.

In yet another embodiment, the composition comprises 50.200% demineralised water, 48.775% 1,3-propandiol, 0.500% hydrogenated polymerised fatty acids, 0.300% sodium hyaluronate and 0.225% tromethamine by weight of the composition.

The pH of the composition is or is adjusted to a pH in the range of pH 7.0 to pH 7.6, preferably in the range of pH 7.2 to pH 7.6. In one embodiment, the pH of the composition is 7.4. This allows for the application of the composition in personal care, medical devices or pharmaceutical products.

The viscosity of the composition is in the range of 300 to 500 mPas, determined at 19- 20 degrees C using using a Viscometer & Model Brookfield DV-II+ Programmable at spindle 2.

The osmolarity of the composition is may be in the range of 200 to 1500 mOsmol/kg, such as 200 to 1400 mOsmol/kg or 600 to 1400 mOsmol/kg . In one preferred embodiment, the osmolarity is in the range of 200 to 400 mOsmol/kg, for example in the range of 275 to 300 mOsmol/kg.

The density of the composition may be about 1.0105 g/cubic cm.

Excipients or additives, such as buffers, stabilisers or thickeners may be added to the composition, as long as care is taken to maintain a pH in the range of pH 7.0 to pH 7.6, preferably in the range of pH 7.2 to pH 7.6.

If there is a desire to do so, the composition may be perfumed. In contrast to lecithin- based liposomes, the multilamellar vesicles according to the invention are resistant to and remain stable in the presence of perfume compounds which are often excellent solvents. In one embodiment, the composition is not perfumed.

The composition may be a non-sterile or sterile composition. The composition preferably comprises max.10 CFU/g and pathogens and spores are absent. The compositions according to the invention allow for in use sterilisation by filtration, due to the size of the multilamellar vesicles. Therefore, there is no need to add preservatives and preservatives such as chlorohexidine, organic acids, such as benzoic acid, formic acid, lactic acid, levulinic acid and sorbic acid or parabens, such as propyl paraben, butyl paraben, are preferably not added. If a preservative is used, which is not necessary because the composition may be sterilized by filtration, preferably a non-ionic preservative which is compatible with a pH in the range of pH 7.0 to pH 7.6 is used. A sterile composition without preservatives, and a method for obtaining such a composition, is also part of the invention.

In one embodiment, the composition is used in personal care, as a medical device or in a pharmaceutical product, for example as a moisturizer, as a carrier or in a sun screen. The composition is preferably used in applications in the range of pH 7.0 to 7.6. Therefore, the composition may advantageously be applied to the eye or nose, for example to the ocular or nasal mucosa. In another embodiment, the composition is for use in a method for the prevention or treatment of ocular or nasal conditions. In yet another embodiment, the composition is for use in a method for ocular or nasal care. In yet another embodiment, the composition is for application to dry eyes or dry nose.

The composition according to the invention may be used to alleviate, treat or prevent dry eye problems such as in dry eye syndrome. The dry eye problem may be light, moderate or severe. Use of the composition according to the invention may lead to improvements in eye problems, for example to improvement in subjective comfort (more), eye redness (less), eye irritation or burning (less), tear film deficiencies (corrected) or tear break-up time (TBUT, minimally 15 seconds). Depending on the formulation used, the composition may be applied to the closed eye lid (spray) or to the inner side of the lower eye lid (drops). The drops may then be introduced into the eye by movement of the eye lid. The composition may advantageously be used by contact lens wearers, people with allergy and people over 40, which groups more frequently than other people experience dry eye problems or problems of burning or itching eyes.

The composition according to the invention may be used to alleviate, treat or prevent dry nose problems. The dry nose problem may be light, moderate or severe. Use of the composition according to the invention may lead to improvement in subjective comfort (more) or to a more moisturised nasal mucosa. The nasal spray may for example be formulated into a spray in a pump bottle or in a pressurized bottle.

The composition may advantageously be used by people with allergy, people with a cold, people on certain medication or with certain medical conditions and people who smoke. These groups more frequently than other people experience dry nose problems.

The composition may be formulated into a suitable application form such as spray, lotion, gel, drops, nasal plug or wipes, which may be applied in any convenient way, such as by spray bottle, pump bottle, pressurized bottle, sponge, bandage or dosing system with pipette. The dosing system may be a monodose system or multidose systems.

In one embodiment, a composition of multilamellar vesicles loaded with 0.3% hyaluronate by weight of the vesicles is used in an eye spray to reach a final concentration of hyaluronate in the range of 0.015% to 0.040%, preferably in the range of 0.020% to 0.030% by weight of the spray composition. In another embodiment, a composition of multilamellar vesicles loaded with 0.3% hyaluronate by weigth of the vesicles are used in an eye drop composition to reach a final concentration of hyaluronate in the range of 0.08% to 0.2% by weight of the eye drop composition. In a preferred embodiment, the composition is formulated into a spray, for example an eye spray or a nasal spray. In one embodiment for application as an eye spray, two puffs or three puffs are applied from about 10 cm in the direction of the closed upper eyelid, immediately followed by forced blinking 3 to 5 times. The eye spray reliefs dryness and redness of the eye, which effect is immediate and maintained for at least four hours or at least six hours.

In one embodiment for application as a nasal spray in a pressurized bottle with tip, the tip is inserted careful and gently in one nostril, while the other nostril is closed with a finger. The head is preferably held upright and before the spray is used nasal passages are preferably cleared by gently blowing of the nose. The bottle is squeezed while slowly breathing in through the nose. Then the bottle is removed and the spray is applied to the other nostril. The effect is immediate and last for several hours.

The multilamellar vesicles in the composition may encapsulate an active compound, as indicated above. In one embodiment according to the invention, the composition comprises an encapsulated active and non-encapsulated active. This allows for a combination of direct release and controlled release of the active. In one embodiment, an eye spray is applied comprising multilamellar vesicles comprising both encapsulated and non-encapsulated hyaluronic acid. In this spray, hyaluronic acid is preferably used in a concentration of at least 0.015% and not more than 0.03% by weight of the composition.

The formulation may be a non-sterile or sterile formulation. In one embodiment, the formulation is a sterile formulation. A suitable method for preparing a sterile formulation is by sterile filtration of a composition according to the invention. In one embodiment, the composition according to the invention is sterilised by filtration through a 200 nanometer filter or opening. The filter or opening may be part of a spray bottle. In one embodiment, the composition is a spray formulation in a spray bottle with spray nozzle and is sterilized while it passes the filter or opening in the spray nozzle.

The skilled person will understand that the above-mentioned embodiments may be combined to form new embodiments. Embodiments and preferred embodiments mentioned for the method of preparing the composition comprising multilamellar vesicles may also be applied to the vesicles, to the composition and to the use of the composition, and vice versa.

EXAMPLES Materials & Methods

Particle size and particle size distribution was determined using a particle sizer machine (AccuSizer 780 AD, Particle Sizing Systems, Santa Barbara, USA), equipped with an auto-dilution system.

Viscosity was determined at 19-20 degrees C using using a Viscometer & Model

Brookfield DV-II+ Programmable, at spindle 2.

Example 1 Preparation of vesicles

For the preparation of the hydrogenated fatty acid vesicles, 0.075 kg sodium hyaluronate (Proturon TM, MV-C, FMC Biopolymer, Philadelphia, USA) was dissolved in 12.5243 kg of demineralised water, while mixing at high speed with a Silverson mixer (Silverson Machines Inc., USA) for 10 min. While mixing, the sodium hyaluronate was added to the steep wall of the vortex created by the mixing. Next, mixing was continued for another 30 min using a Typhoon mixer (Typhoon Roertechniek BV, Raamsdonkveer, The Netherlands) until a clear viscous solution free from particles was obtained. This was solution A. For encapsulation of the hyaluronate, 12.1938 kg 1,3-propanediol (Zemea, DuPont, Tate & Lyle), 0.0563 kg Tris Amino and 0.125 kg Pripol 1009 were added to 80% of the prepared solution A, while stirring at a speed of at least 8000 rpm for 30 min with the Silverstone mixer. During preparation, the temperature increased to 60 to 70 DEG C. After 30 minutes mixing, the other 20% of the solution was added, while stirring at a lower speed using the Typhoon mixer. A milky white non-transparent, odourless liquid with a viscosity of 400 mPas was obtained. The pH was adjusted to 7.4 using a 50% citric acid. Microscopic evaluation using polarised light showed the presence of Maltese crosses which confirmed that the liquid comprised vesicles. This composition allowed for both direct and controlled release of the active compound. The composition comprised less than 10 CFU/g and pathogens and spores were absent.

Example 2 Particle size and particle size distribution

Particle size and particle size distribution of the dispersion prepared in Example 1 were determined using a particle sizer machine (AccuSizer 780 AD, Particle Sizing Systems, Santa Barbara, USA), equipped with an auto-dilution system, before and after sterilization for 15 minutes at 115 deg C and 1.5 bar pressure,. The results obtained are shown in Table 1. The measurements show a bimodal Gauss curve. Table 1

The residue value was 0%, which means that there are no aggregates larger than 500 nm present, which would be indicative of aggregates of insufficiently dissolved sodium

hyaluronate. The vesicles have a flexible width with a compression factor of 2.0 at 100 kPa. Therefore, vesicles of up to 400 nm will still be able to pass through a 200 nm opening.

Therefore both fractions will be able to pass a bacterial filter. The Example also shows that sterilisation does not affect the particle size distribution. Example 3 Spray

The composition prepared in Example 1 was used in a spray formulation in a concentration of 10%. Spray containers with a 200 nanometer filter integrated in the spray nozzle were filled with the spray formulation and tested on individuals suffering from moderate dry eye syndrome. Two puffs were applied from about 10 cm in the direction of the closed upper eyelid, immediately followed by forced blinking 3 to 5 times. The users indicated that the vesicles really provided relief of dryness and redness. Users mentioned that the relief was still noticeable after more than four hours.

Example 4 physical- chemical parameters before and after filtration

A hydrogenated fatty acid vesicle composition was prepared as described in Example 1. The composition was adjusted to different pH values using citric acid. These pH values represent pH values of the different production steps or pH values of different physiological conditions in the body.The composition was analysed for physical- chemical parameter before and after filtration using European Pharmacopoeia standard methods as indicated. The composition was filtered through a 32mm Syringe Filter with 0.8/0.2 pm polyethersulfone Supor ^® Membran (Pall Life Sciences, Ml, USA). Appearance, pH and osmolarity were measured according to European pharmacopeia standard methods. Odour was determined organoleptically. Results are presented in Table 2. The pH, a critical physical-chemical parameter, was not affected by filtration. The solution remained a transparent -opaque odourless and colourless solution.

Example 5 Oxidative stability

A multilamellar vesicle composition according to the invention was prepared according to Example 1, and additionally contained 5% w/w betaine and 30% w/w Aloe vera high molecular negatively charged polysaccharides. To analyze the oxidative stability of the multilamellar vesicles formed, two approaches were investigated.

Table 2

a) Stability data after storage of multilamellar vesicles according to the invention in a semi-permeable container-closure system

First, the stability of multilamellar vesicles according to the invention was analyzed after storage of the product in a semi-permeable container-closure system for 3 months at different temperatures. Appearance, pH, osmolarity, viscosity and density were measured according to European pharmacopeia standard methods. Odour was determined organoleptically. Results are presented in Table 3. The multilamellar vesicles according to the invention showed no alteration in physical-chemical parameter after storage at 25°C/60%rH for 3 month. Even under elevated conditions (40°C/75%rH) the product was relatively stable for 3 months. Table 3

b) Treatment of multilamellar vesicles according to the invention with air and storage at room temperature and at elevated temperature

Secondly, in order to increase the exposure of the product to air, the product was treated with 10ml air via a 32mm Syringe Filter with 0.8/0.2 pm polyethersulfone Supor ^® Membran (Pall Life Sciences, Ml, USA) and a cannula and stored at 25°C/60%rH or 40°C/75%rH for 13 days.

Appearance, pH and osmolarity were measured according to European pharmacopeia standard methods. Odour was determined organoleptically. Results are presented in Table 4. Even under this extreme exposure to air the physical-chemical parameters persisted unchanged in the multilamellar vesicles according to the invention.

Table 4