FORMULATIONS FOR TOPICAL USE CONTAINING LACTOFERRIN, THEIR PREPARATION AND USE

Field of the invention

The present invention relates to formulations for topical administration of active principles, in particular lactoferrin.

Prior art

Lactoferrin (hereinafter referred to by the acronym LF) is a monomeric glycoprotein of molecular weight approximately 80 KDa belonging to the lactoferrin group, which glycoprotein is composed of a single polypeptide chain subdivided into two globular lobes, each of which is capable of binding to an iron atom. It is present in the human body under normal conditions and plays an important role, both in iron metabolism and the immune response, and in the defence mechanisms of the host to various pathogens. Its therapeutic use, via the oral route and topically, has been described in the scientific literature.

A small number of patents that already been filed claim the use of LF - by means of various products and formulated principally for oral use - in various areas of therapeutics, cosmetics and nutrition; in a few cases its topical application has also been claimed.

However, like all proteins which play an active role in cell metabolism, LF can undergo degradation and therefore a loss of activity through the action of various factors, among which the presence of water proves crucial. It has been demonstrated that, in aqueous solution, LF breaks down rapidly in only a few days, rendering the product unusable. Conversely, water has proved useful for allowing solubilisation, and thus for enabling the activity of LF.

It is therefore considered extremely important to have available formulations which minimise the intervention of degradation factors (in particular, the presence of water) and in which LF therefore retains its physicochemical integrity in such a way as to guarantee its ability to express the desired activity, and therefore to enable its topical use in the treatment of pathological conditions (or in cosmetic treatments) where the benefits of its presence have been demonstrated. Summary of the invention

Formulations for topical use containing lactoferrin have been described, in which said lactoferrin is maintained in a totally anhydrous environment at least up to the moment of use.

Detailed description of the invention

The present invention enables the above-mentioned problem to be overcome thanks to formulations for topical use containing lactoferrin, in which said lactoferrin is maintained in a totally anhydrous environment, at least until the moment of use.

According to a first embodiment of the invention, the formulations for topical application consist of a solid phase comprising LF in powder form, and a liquid or semi-solid phase (such as that defined below) in which said lactoferrin is dissolved only at the moment of use by the patient.

The formulations such as those mentioned above are packaged into vials (ampoules or small bottles) with a breakable stopper. The solid phase containing the LF is inserted into the sealed portion of the stopper, which is applied to a vial containing the liquid or semi-solid phase. At the moment of use, the powder really has to be made to drop into the liquid or semi-solid phase (by pressing the stopper, causing the partition to break) and to agitate until solubilisation of the solid phase is achieved.

In place of the vial with breakable stopper, the solid phase containing the LF may be contained in a separate bottle or in a bag/sachet (for example in a paper/aluminium/PE bag) to be mixed and solubilised at the moment of use in an appropriately selected solvent phase supplied in a separate container, or possibly simply in water. This is in accordance with the system routinely used for extemporaneous preparations, for example, syrups or granulates for oral use.

The liquid used for the liquid or semi-solid phase normally consists of water; however, in view of the use for which the formulation is intended (topical application), it is preferable for the end product (that is, that obtained at the moment of use by mixing the liquid/semi-solid phase and the solid phase as described above) to have a viscosity enabling it to be applied topically. The formulations will therefore preferably comprise humectants and/or viscosifiers and/or gelling agents, as well as thickeners to give the end product a viscosity such as to confer a consistency suitable for topical application.

Among humectants that are useful for the invention we may cite: sorbitol, glycerin, propylene glycol, macrogols, maltodextrin, and wheat extracts.

The viscosifiers and gelling agents are, for example: hydroxyethyl cellulose and other celluloses, sodium croscaramellose, carbopol, starch gel, carrageenin, pectins and other polysaccharides.

The said agents - the list of which indicated above should be considered non- exhaustive in view of the broad spectrum of components which exert the same function in an equivalent manner in the preparation of pharmaceutically acceptable products - may be present, as preferred or as necessary, both directly in the liquid phase (which will consequently be of an advantageous viscosity and thus semisolid according to the definition used in the present invention) and in the solid phase of the formulation, i.e., mixed with the LF; in the second case, the semisolid phase will be formed at the moment of dissolution of the solid phase in the liquid phase.

Normally, the proportion of lactoferrin in the formulations according to the invention are within the range from 0.1% to 20%, calculated as weight by total weight of the final formulation.

The proportion of each humectant, viscosifier and gelling agents will, as a guideline, be within the range from 0 to 50%, calculated as weight by total weight of the final formulation; this percentage is a function of the physicochemical nature of the agent and of its function in the environment of the final product.

The presence of the above-mentioned agents will, however, be such as to guarantee the formulation for topical application a viscosity tending to be less than 250,000 mPa-s, preferably within the range from 100 to 50,000 mPa-s.

The formulations according to the invention will moreover obviously also be able to comprise the usual preserving agents, to guarantee the microbiological stability of the liquid phase up to the moment of reconstitution of the final product, as well as to confer more prolonged storage stability (within the span of the following hours) of the reconstituted product; and furthermore, the formulations may possibly contain other active principles if considered useful or complementary to the development of the desired activities, in combination with LF.

All the above-mentioned components (preferably soluble or dispersible in water, with a view to obtaining a homogenous end product), may be present in a solid phase or already dissolved in the liquid or semi-solid phase.

With regard to the materials of which the container (containing the liquid or semisolid phase) is composed, and to the stopper or container (containing the solid phase), these must be selected by verifying compatibility with the content, and relative stability. Any device capable of preserving integrity of the product over time may be applied to the system. An advantageous application system may be attached to the packaging containing the product, for example, a dose-metering dispenser, a teat, a nebuliser etc, to facilitate application thereof.

In the light of the above, the formulations according to the invention may be composed, for example, of:

a) Solid phase:

Lactoferrin 0.1 to 20%

Hydroxyethyl cellulose: 0 - 3%

Maltodextrin: 0 - 20%

b) Liquid phase

Phenoxyethanol: 0 - 2%

Wheat extract: 0 - 20%

Sorbitol: 0 - 20%

Glycerin: 0 - 50%

Benzalconium chloride: 0 - 50 mg/100g

Water q.s. ad 100 and not less than 25% by volume, to enable correct solubilisation of the lactoferrin.

According to a further particular embodiment of the invention, the formulations are composed of a totally anhydrous cream or gel or ointment or paste or dispersion. The absence of water favours the physicochemical integrity, and therefore the activity of the LF. In this case the formulation will consist of LF and anhydrous components selected, for example, from thickeners and/or emollients such as: macrogols of various molecular weight, vaseline oil or viscous vaseline, triglycerides of higher fatty acids; this list should be considered non-exhaustive in view of the broad spectrum of anhydrous ingredients performing the same function in an equivalent manner for preparation of pharmaceutically acceptable products. The concentration of each of the ingredients indicated above (apart from LF) will be a function of the obtained quantity of variously solid finished products corresponding to the specific use (cream, spray, pastes, lotions, dispersions) and will normally be below 50% [within the indicative interval mentioned above], calculated as weight by total weight of the final formulation. This percentage is a function of the physicochemical nature of the agent and of its function in the context of the end product.

The titre of lactoferrin within the formulations will preferably be variable between 0.1 and 20% by weight.

Antibacterial protection of the preparations can be achieved by having recourse to the substances normally used for this purpose (methyl, propyl, butyl parahydroxybenzoates, phenoxyethanol, sorbates, benzoates, other preservatives).

The formulations according to the invention can be used for the treatment of disorders- varying in type and extension - of the skin, the mucosae (oral, vaginal, anal) and of the eyes; this is due to the anti-inflammatory, anti-infective, cicatrising, antimicrobial, antibacterial, antioxidant and anti-free radical action of lactoferrin, as well as to Its chelating capacity in respect of Fe ions and its coadjuvant effect in regard to a number of antibiotics.

The formulations can therefore prove useful in: inflammations, infections, irritations, allergies, acne, rosacea, skin blemishes, rashes, dryness, ulcers, bedsores, delayed scar formation, psoriasis, eczema, dermatitis, burns, sunburn, cosmetic treatments.

The formulations may also be used to support orally-administered lactoferrin therapy. By way of example, we present below an example of a liquid/solid formulation and an example of a formulation in ointment according to the invention.

Example 1

The formulation for a system with a breakable stopper applied to the bottle is composed of:

a) Solid phase:

Lactoferrin 150 mg;

Hydroxyethyl cellulose (viscosifier) 12 mg;

Maltodextrin (humectant) 48 mg

b) Liquid phase:

Phenoxyethanol (preservative) 12.6 mg;

Wheat extract (soothing humectant) 120 mg;

Sorbitol (hydrating humectant) 120 mg;

Glycerin (humectant) 120 mg;

Benzalconium chloride (preservative) 0.075 mg;

water (vehicle) q.s. ad 3 ml.

Once the two phase have been mixed, the final formulation will contain LF in a concentration of 5% in 3 ml of solution.

Small bottles made of PET are used to contain the liquid phase; the stopper containing the solid phase is composed of PE.

The solid phase is charged into the breakable stopper, and the liquid phase into the bottle, using the normal methods and equipment for the preparation of this type of bottle. Example 2

100 g of product in ointment form contains:

No. Component Grams / 100 grams

1 Macrogol 400 61.8 (47.8 + 14)

2 Macrogol 1500 33

3 Methyl parahydroxybenzoate 0.150 4 Propyl parahydroxybenzoate 0.050

5 Lactoferrin (LF) 5

The ointment is prepared using the techniques normally employed for preparing products for topical use.

For example, a base is prepared by melting components 1-2-3-4 at 50-60°C, leaving aside an aliquot part (14 g) of the macrogol 400, and then cooled with agitation to a temperature of 20-30°C.

The LF, which may be advantageously micronised to promote its dispersion, is dispersed in the fatty phase, in the aliquot part of macrogol 400 kept to one side (14 g).

Finally, the suspension of LF thus obtained is added to the base previously obtained, and mixed until completely homogenous.