FR2649318A1 - Dehydrated pharmaceutical dosage forms for dermatological and cosmetic use - Google Patents

Abstract

Dehydrated pharmaceutical dosage forms for dermatological or cosmetic use, which take the form of pre-emulsions; dehydrated pharmaceutical dosage forms consisting of solid vehicles combined with the aforementioned pre-emulsions, and process for obtaining them.

Description

 The present invention relates to new dosage forms, derived from t emulsions and suitable for dermatological or cosmetic use, and to solid supports associated with said preparations.

 Emulsions are widely used in the pharmaceutical and cosmetic industries. Indeed, these forms are of great interest, because they make it possible to combine substances with different properties, such as hydrophilic substances and lipophilic substances, and, which is particularly advantageous when it comes to products intended for be applied to the skin, to ensure a homogeneous distribution of the substances contained in these products, and possibly to control their penetration.

 The emulsions also have organoleptic properties which make them forms particularly appreciated by users.

 However, emulsions have certain drawbacks which lie mainly in the problems posed by preservation and storage.

 Indeed, the products in emulsified form and in particular the emulsions in aqueous phase are particularly sensitive to bacterial and fungal attacks and to oxidation reactions, including redox reactions.

 To remedy this drawback, antiseptic or antioxidant preservatives are commonly added to the dispersing phase.

 The use of preservatives is itself a significant difficulty. Indeed, these preservatives are sometimes poorly tolerated and can even cause allergies.

 This risk is increased by the fact that different preservatives are most often combined, mixed.

 In addition, emulsions are thermodynamically unstable forms, this being due to coalescence phenomena, by which the particles constituting the emulsion tend to gather to reconstitute the separate elementary phases.

 The inventor therefore set himself the goal of providing a solution to these conservation problems, by developing products which allow the user to benefit from the advantages of emulsions, but do not have the disadvantages of these. ci and, in particular, not requiring the addition of preservatives.

 The present invention relates to new dosage forms suitable for dermatological or cosmetic use, characterized in that they are in the form of preemulsions. For the purposes of the present invention, the term “pre-emulsion” means a dehydrated preparation allowing an oil / water emulsion to be obtained by simple addition of the aqueous phase, without stirring.

 The structure of the preemulsions used in the present invention is that of an oil / water emulsion, in which the aqueous phase would be replaced by a gas, a mixture of gases or vacuum. This structure therefore consists of solid particles based on lipophilic substances. The interstices between these particles may possibly contain non-volatile hydrophilic substances.

 The particles based on lipophilic substances, as well as the interstitial hydrophilic substances must be solid at storage and use temperature of the products in accordance with the invention.

 According to a preferred embodiment of the present invention, the lipophilic substances contained in the preemulsion have a minimum melting point of 40 ° C.

 The products in accordance with the present invention can be prepared from emulsions in the aqueous phase by evaporation of the said aqueous phase.

 This evaporation can be carried out from a fluid or thick emulsion, by lyophilization of the emulsion, or alternatively, from a fluid emulsion, by spraying the emulsion under vacuum, with simultaneous evaporation.

 The products according to the present invention are dehydrated, which makes it possible to avoid any bacterial or fungal development. These products can therefore be stored for a long time, without the need to add preservatives; the pre-emulsified form thus allows excellent conservation of fragile active principles, whether they are liposoluble substances, or water-soluble substances present in dehydrated form in the interstices of the preemulsion.

 From the products according to the present invention, it is also possible to instantly reconstitute, if desired, an emulsion by simple addition of water, or a hydrophilic liquid. In this case, the dosage of the quantity of liquid makes it possible to obtain an emulsion having the desired texture; it is advantageous, for this purpose to use single-dose packages, or else any suitable packaging, containing, on the one hand, a pre-emulsion according to the present invention, and on the other hand, - a device making it possible to dose the liquid.

 The products according to the present invention can also be used as such, without reconstitution of the emulsion. The very fine and solid structure of these products gives them very specific properties, which find their application in particular in the field of make-up. These products allow an excellent distribution of pigments on the skin, (which is difficult to obtain with conventional emulsified products, such as foundations), while retaining the advantages of emulsions.

 The products according to the present invention therefore make it possible to prepare preparations which are not only very pleasant to use, but also which give a color rendering much superior to the other cosmetic forms used up to now.

 In addition, as the products according to the present invention do not contain a preservative, their tolerance is excellent, which is particularly advantageous in making up very sensitive areas such as the eye area.

 The inventor further noted that it was particularly advantageous to use the preemulsions in accordance with the present invention, as well as other products resulting from the dehydration of dispersions in the aqueous phase, such as colloidal suspensions, in combination with solid supports, for the preparation of dosage forms which are particularly convenient to use in dermatology and cosmetics.

 As a variant, the present invention comprises dosage forms for dermatological or cosmetic use, characterized in that these consist of solid supports of porous or fibrous material, covered and / or impregnated with a preemulsion as defined above and / or a product resulting from the dehydration of a colloidal suspension.

 These supports are, for example wadding, papers, woven or non-woven textiles, sponge supports with communicating or non-communicating pores, etc.

 The supports can be based on cellulose, or on different polymers.

 The present invention further relates to a process for the preparation of dosage forms as defined above, characterized in that in a first step the solid support is covered and / or impregnated with an emulsion, and / or a suspension colloidal, and in a second step the impregnated support is subjected to dehydration.

 According to a preferred embodiment of the method according to the present invention, in the first step the impregnation is carried out under vacuum.

 According to another preferred embodiment of the process according to the present invention, the dehydration is carried out by lyophilization.

 The solid supports treated according to the process according to the present invention have very varied uses.

 They can for example be used dry. In this case, they allow particularly practical applications of the pre-emulsified products in accordance with the present invention, for example in the field of make-up, where they make it possible to package products in individual doses, easy to transport and use; or, in the medical field, for the manufacture of dressings.

 The solid supports in accordance with the present invention can be moistened before use, to reconstitute the emulsion, and thus serve for the application of make-up removing or treating products. For this purpose, they can be moistened with water or hydrophilic substances, but also with lipophilic bodies, or with emulsions, which makes it possible to produce treatment products combining several actions. The liquid intended to moisten the solid supports can be supplied at the same time as these, for example in single-dose packaging, or in a container optionally provided with a dosing system.

 The invention will be better understood with the aid of the additional description which follows, which refers to examples of the preparation of products in accordance with the present invention.

 It should be understood, however, that these examples are given solely by way of illustration of the subject of the invention, of which they do not in any way constitute a limitation.

EXAMPLE 1 TREATMENT PREEMULSION IN THE GAS PHASE (NITROGEN)
A) Manufacture of the emulsion
Formula 1) . Stearic Acid ............................... Stearic 14 g. Isopropyl palmitate 1.5 g. Sorbitan 60 monostearate ............... 2 g. Polyoxyethylated Sorbitan monostearate 60 1.5 g 2). Water .................................... Water 65 g 3). Water ..................................... Water 15.5 g. Ascorbic Acid 0.5 g
Protocol 1 - Melt the components of 1) at 80-C and mix 2 - Gradually add 65 g 2) heated beforehand to
at 80 C 3 - Stir with a turbine for 10 '4 - Cool while continuing to stir until 25 * C 5 - Finally add the mixture 3) at 25 C.

B) Lyophilization
Freezing -20 * C - evaporation under vacuum 10-2 m bar
C) Conditioning under inert gas (nitrogen) in closed container
D) Use
The pre-emulsion is reconstituted extemporaneously by
addition of 80.5 g of water.

EXAMPLE 2: PRE-EMULSION CLEANER IN THE GASEOUS PHASE (AIR)
ON SUPPORT CONSISTING OF A COTTON DISC
HYDROPHIL
A) Manufacture of the emulsion
Formula
Lanette wax (mixture of cetyl and stearyl alcohols sulfated at 10% ......................... 108 15 g
Myristic Alcohol 3 g
Water 82 g
Protocol 1 - Heat Lanette's wax and Myristic alcohol to 75 ° C
and mix them.

2 - Gradually add the water heated beforehand to 75 ° C.

3 - Agitate with a turbine at 75C for 10 '4 - Cool while continuing to agitate until 25 * C
B) Impregnation of the hydrophilic cotton disc
This impregnation can be carried out under pressure
atmospheric or vacuum to accelerate penetration.

C) Lyophilization
Freezing is carried out at -20-C, and the evaporation of
water under vacuum of 10-2 mbar.

D) Use
For use, just moisten the cotton wool
with water, the cleansing emulsion is instantly
reconstructed.

EXAMPLE 3: PRE-EMULSION FOR MAKEUP (AIR) ON SUPPORT
CONSISTS OF AN ER COTTON OR SYNTHETIC FIBER DISC
A) Manufacture of the emulsion
Formula . Stearic Acid ............................... Stearic 14 g. Isopropyl palmitate 0.7 g. Sorbitan monostearate ............................. Sorbitan 2.5 g. Polyoxyetylenated Sorbitan monostearate 1.2 g. Pigments (Titanium dioxide) (Talc Iron oxide) ... 12 g. Water .................... Water qs100 g
Protocol 1 - Heat stearic acid, Isopropyl Palmitate,
Sorbitan Monostearate and Sorbitan Monostearate
polyoxyetylenated at 80 ° C and mix.

2 - Disperse the pigments in this fatty phase -at 80-C
Shake for 10 '3 - Add the water previously heated to 80C and shake
for 15 '
- cool while continuing to stir until 25 C 4 - Switch to the homogenizer.

B) Impregnation of the cotton or synthetic disc
This impregnation can be carried out under vacuum to
accelerate penetration.

C) Lyophilization
Freezing at -20-C - evaporation under vacuum 10-2.D)
D) Use
The pre-emulsion is used without prior hydration,
by contacting the skin with the impregnated disc.

EXAMPLE 4 SUSPENSION OF ZINC OXIDE IN A GASEOUS MEDIUM (AIR)
ON A DRESSING TAPE SUPPORT
A) Obtaining suspense
Formula . Methyl Cellulose ...................... Cellulose 2 to 3. Wetting agent ............................... wetting agent 0.05. Zinc oxide .................................... Zinc 10. Water ...................................... Water qs 100 g
Protocol 1 - Dissolution of the wetting agent in water 2 - Cold preparation of the suspension of Methyl Cellulose
in water with the wetting agent.

3 - Cold incorporation by dispersion of Zinc Oxide
in the suspension of Methyl Cellulose.

B) Impregnation of the strip under vacuum
C) Lyophilization
Freezing -20iC - Evaporation at 10-2
As is apparent from the above, the invention is in no way limited to those of its modes of implementation, embodiment and application which have just been described more explicitly; on the contrary, it embraces all the variants which may come to the mind of the technician in the matter, without departing from the scope or the scope of the present invention.

Claims (9)

 1 ') Dehydrated dosage forms for dermatological or cosmetic use, characterized in that they are in the form of preemulsions, the structure of which consists of solid particles based on lipophilic substances, the interstices between said particles possibly containing substances non-volatile hydrophilic, said structure being that of an oil / water emulsion in which the aqueous phase would be replaced by a gas, a mixture of gases, or vacuum.  2 ') Dosage forms for dermatological or cosmetic use, according to Claim 1, characterized in that they contain lipophilic substances whose melting point is greater than 40'C.  3 *) Dehydrated dosage forms for dermatological or cosmetic use, characterized in that they consist of solid supports made of spongy or fibrous material, covered and / or impregnated with a preemulsion according to any one of Claims 1 or 2 and / or a product resulting from the dehydration of a colloidal suspension.  4 ') Dosage forms according to Claim 3, characterized in that the solid support consists of a fibrous material, woven or nonwoven.  5-) Dosage forms according to Claim 3, characterized in that the solid support is a spongy support with communicating pores.  6 *) Process for the preparation of dosage forms according to any one of Claims 3 to 5, characterized in that in a first step the solid support is covered and / or impregnated with an emulsion and / or a colloidal suspension, and in a second step the impregnated support is subjected to dehydration.  7 ') Method according to Claim 6, characterized in that, in a first step, the impregnation is carried out under vacuum. Claims 6 or 7, characterized in that in the second step dehydration is carried out by lyophilization.  8 ') Method according to any one of  9 ') Products for dermatological or cosmetic use reconstituted by mixing separate constituents, which products are characterized in that at least one of said constituents is a dehydrated dosage form according to any one of Claims 1 to 5, and in that that another of said constituents is a suitable liquid.