DERIVATIVE OF VITAMIN E, ITS PREPARATION AND USE

Field of the invention

The present invention relates to derivatives of Vitamin E and to their use in combination with textile fibres. State of the art

Fabrics and garments, such as T-shirts, capable of releasing substances, for example anti-bacterial or deodorant substances, are known.

In particular, T-shirts comprising or composed of particular fibres capable of releasing Vitamin C simply by rubbing against the skin have been produced for some years.

However, studies are being conducted to improve or widen the sphere of substances made to adhere to textile fibres and which can be assimilated through the skin taking account of the various problems that this implies.

In fact, these studies concentrate on finding a way to make the desired substance adhere to the textile fibre so that it is then gradually released and absorbed through the skin of the user, but is also capable of remaining on the fibre for at least a moderate number of wash cycles to which the garment will be subjected.

In particular, as it is known, Vitamin E is an oily compound, insoluble in water and soluble in apolar solvents. Vitamin E is known for its anti-oxidant power in particular for its action to prevent oxidation of polyunsaturated fatty acids limiting the formation of free radicals and thus plays an essential role in protecting cellular structures against early and marked aging.

Detailed description of the invention The present invention responds to the aforesaid requirements through a derivative of Vitamin E that allows easy and stable fastening of the Vitamin E to the textile fibres (natural and artificial) and at the same time permits their slow release and adsorption through the skin of the user.

The invention also relates to textile fibres, fabrics and garments to which, or to part of which, said derivative has been applied.

In particular, among the garments according to the invention there are preferred those commonly worn in contact with the skin, such as scarves, T-shirts, vests, shirts, underwear, etc..

In particular, in the case of garments according to the invention these can obviously be made up with fabrics already comprising Vitamin E according to the invention or can be subjected to the process of loading with Vitamin E after having been made up with conventional fabrics.

According to the invention the derivative of Vitamin E is a product of formula (I):

(I) in which R is a hexose or a pentose

According to the invention, sugar is intended as a hexose or pentose such as: glucose, mannose, ribose, arabinose, galactose, etc... Glucose is preferred, according to the invention.

According to the invention, a product of formula (I) particularly preferred is racemic α-tocopheryl-β-o-glucopyranoside.

The product according to the invention can be produced according to known synthesis techniques.

For example, a preparation process provides for the reaction of the sugar, the OH groups of which have been previously protected, with pure α-tocopherol followed by purification, if required, and finally deprotection of the groups previously protected and neutralization and elimination of the solvent. Protection of the OH groups is implemented with easily hydrolyzable groups such as acyl and acetyl groups, the acetyl group being preferred according to the invention.

Protection is implemented according to known methods, for example with sodium acetate and acetic anhydride.

Preferably equimolar quantities of protected sugar and α-tocopherol are utilized, using boron trifluoride as catalyst. The reaction is preferably conducted in an organic solvent such as dichloromethane at the temperature of 18 ° - 25 °C.

If purification of the product obtained is necessary, it can be implemented by flash chromatography, for example with SILICA GEL 60 (200-400 mesh).

Deprotection is preferably implemented in an alkaline environment, for example using sodium methylate methoxide and subsequently neutralizing the solution obtained, for example with an ion exchange resin such as AMBERLITE IR 120 H ⁺ .

If preferred, instead of pure α-tocopherol it is possible to start with α-tocopherol- acetate (product available on the market) which will in this case be previously deacetylated and analogously start with sugar and proceed with protection of the OH groups using the preferred protector group and then proceed as indicated above.

The product thus obtained (racemic α-tocopheryl-β-o-glucopyranoside) is then applied to the desired fabric, or to the textile fibres, by immersion thereof in an aqueous solution containing suitable known emulsifiers, capable of emulsifying the product, which per se is insoluble in water.

Product/fibre fastening takes place through the presence of OH groups of the cellulose forming the fibres and of the glucose; moreover the structural analogy between the compound and the fibres facilitates superimposition and consequently reciprocal bonding. Examples of possible emulsifiers according to the invention are oxo alcohols containing ethylene oxide (e.g. Lialet 123-3 ^® (Chimica Augusta, Italy) or Neopal

Ma 8).

Natural and artificial fibres or fabrics can be used, for example cotton, viscose, linen, hemp, jute, etc. According to a particular embodiment of the invention the fibres or fabrics can be treated directly with a stable derivative of Vitamin E and sugar syrup, suitably emulsified.

Among the stable derivatives of Vitamin E particularly preferred is acetate.

The sugar syrup is obtained by dissolving the sugar in water (normally in a quantity equivalent to 40% in weight) and utilizing the same emulsifiers indicated above. Also in this case glucose is preferred as sugar.

Normally, the molar ratio between sugar and Vitamin E acetate utilized is between

0.3 and 1.

To better clarify the invention some examples are set forth below.

Example 1 Preparation of racemic α-tocopheryl-β-o- glucopyranoside

Glycosylation

150 cc of dichloromethane is poured into a round-bottomed flask, 4.3g of all-rac α tocopherol is then added, stirring for 5 min. and then adding 3.9 g of β- pentaacetyl glucose. This is stirred for a further 5 min. and 3 cc of BF3 ethyl etherate is added, continuing to stir for 45 minutes at ambient temperature in the dark; this is then cooled with ice and the excess BF3 is eliminated with sodium bicarbonate; finally the solvent is evaporated.

Purification The product obtained above is purified with flash chromatography on a column of

SILICA GEL 60 (200-400 mesh), using dichloromethane-acetone as elution solvent.

Deacetylation and neutralization

The purified product is dissolved in methanol and sodium methylate methoxide is added, drop-wise, to a pH of 8.

The product obtained is neutralized with a column containing AMBERLITE 120H+, filtered and concentrated to obtain a very thick yellowish syrup, composed of racemic α-tocopheryl-β-o-glucopyranoside.

Example 2 Preparation of the glucose/Vitamin E acetate mixture

896 g of water is placed in a mixer with propeller stirrer, 24 g of Lialet 123-3© and

40 g of NEOPAL MA 8© are added, mixing for approximately 10 minutes.

5 g of glucose syrup at 38% is then added, mixing for a further 10 minutes and subsequently adding 5 g of Vitamin E acetate and continuing to mix for a further

30 minutes.

30 g of MORBIREX MIC-HP ^® (a silicone micro-emulsion at 42% that gives a soft handle and increases the resistance of the vitamin to washing) is added and mixing is continued for a further 10 minutes, if necessary adjusting the pH to 6 - 7.

The product thus obtained is ready to be applied to the product.

Example 3

Application to the fabric A 100% cotton Jersey knitted fabric, purged and ready for dyeing, is treated with the mixture obtained in example 2 using a padder.

The mixture obtained according to the previous example is then poured into the container of the padder and the fabric is impregnated, the squeeze ratio (intended as percentage of bath absorbed by the fabric in relation to its weight) is 90%. The fabric is then dried at 140 °C.

When analyzed the fabric presents 4.027 mg of Vitamin E per 1000 g of fabric and therefore almost all the Vitamin E used has adhered to the treated fabric.

Example 4

Wash test A sample of fabric treated as above is subjected to 5 wash cycles performed according to the standard ISO 6330 cycle 6A (40° C).

After said wash cycles the quantity of Vitamin E found on the fabric is equivalent to

2.450 mg per 1000 g of fabric, equivalent to approximately 60% of the vitamin initially adhering to the fabric. Example 5

Transfer during wear test

With part of the fabric treated according to example 3, a ladies T-shirt is made up and is worn in direct contact with the skin for 79 hours (equivalent to almost 10 days of wear, 8 hours a day). At the end of the test, analysis shows a residue of Vitamin E on the garment equivalent to 3.005 mg per kg of T-shirt which proves transfer of Vitamin E to the skin of approximately 25% with respect to the initial quantity.

Obviously, by increasing the quantity of Vitamin E acetate used to prepare the sugary mixture to be applied to the fabric it is possible to load the fabrics with larger quantities of Vitamin E, thus dosing their presence on the fabric as desired.