WO2019077258A1

WO2019077258A1 - Oil-in-water emulsion based on essential oils, and formulated without surfactant

Info

Publication number: WO2019077258A1
Application number: PCT/FR2018/052569
Authority: WO
Inventors: Isabelle Desjardins-Lavisse
Original assignee: Genialis Biotech
Priority date: 2017-10-16
Filing date: 2018-10-16
Publication date: 2019-04-25
Also published as: FR3072290A1; EP3697371A1; FR3072280A1; FR3072290B1

Abstract

The present invention relates to the field of oil-in-water emulsions and more particularly to oil-in-water emulsions containing essential oils and formulated without a surfactant or any other substitute substance.

Description

OIL-IN-WATER EMULSION BASED ON ESSENTIAL OILS AND

FORMULATED WITHOUT SURFACTANTS

The present invention relates to the field of oil-in-water emulsions and more particularly proposes oil-in-water emulsions based on essential oils formulated without surfactant or any other substitute substance.

PRIOR ART The preparation of emulsions without surfactant has been a subject of interest in the fields of cosmetics and pharmacopoeia for many years. Most of the solutions proposed to date concern the use of particular substances, not classified as surfactants, but whose role in the formulation is to compensate for their absence. US Pat. No. 6,416,748 proposes, for example, the use of a crosslinked polymer of at least one ethylenically unsaturated monomer, while the patent FR2750327 proposes to use a crosslinked and neutralized poly (2-acrylamido-2-methylpropane sulfonic acid). . These solutions are thus based on the use of large molecules, which stabilize the emulsion by structuring that they impose on their environment. The patents FR27221 16 and FR2720644 propose, for their part, examples of use of solid particles which ensure the dispersion of one of the two phases in the other. These particles also have the advantage of offering product textures that are more advantageous for the consumer. Other solutions are proposed by patents CA2295533 and FR2771293, which respectively describe the use of a cationic gel and a lipophilic agent whose HLB (hydrophilic / lipophilic balance) is less than 3. The stability of the preparations made is then ensured by the structuring that allow these compounds at the hydrophilic / lipophilic interface.

Concerning preparations of essential oils in particular, there are today three galenic forms potentially without surfactants in order to vectorize them:

Dispersions or emulsions containing alcohol;

Dispersions in oils;

- Emulsions containing soaps. Direct dispersion in water or any other aqueous solution is not possible without having particular technologies.

ADVANTAGES OF THE INVENTION

It appears from the state of the prior art that there are currently no proposals for the preparation of emulsified products containing no substance, of any kind, to ensure stability. In addition, the texture of products containing essential oils proposed so far is not satisfactory. It would be interesting to propose a new galenic, allowing to have products with the texture more pleasant, without greasy sticky effect with the application, with a soft touch and which dry quickly on the skin.

Thus, the invention relates to very simple compositions, consisting of an emulsion of an essential oil in an aqueous solution, this aqueous solution preferably being a hydrosol. Remarkably, these compositions are stable in the absence of any surfactant molecule and pleasant to use. These compositions containing only essential oils and an aqueous phase constitute a new and innovative galenic.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to novel short and single galenical formulations of essential oils (HE) for use in aromatherapy. These formulations constitute stable emulsions of HE in an aqueous solution without addition of surfactant. Such emulsions can be obtained for example using the method using high frequency ultrasound, as described in the patent application WO2010 / 149668. This preparation process makes it possible in particular to prepare a stable oil-in-water emulsion. This method combines a lipid phase with an aqueous phase by subjecting the mixture to vibratory energy, in a closed container, by applying a transducer operating in a frequency range between 900 kHz and 3 MHz. In a preferred embodiment, the transducer operates at a higher frequency or equal to 1 MHz. A first subject of the invention therefore relates to an oil-in-water emulsion composition comprising an aqueous solution and at least one HE, this composition not containing a surfactant and being obtained by an ultrasonic treatment whose vibration frequency is greater or equal to 1 MHz.

For the purposes of the invention, the compositions do not contain surfactant, emulsifier or any other substance or particle intended to stabilize the preparation with respect to phase separation.

The nature of the aqueous solution used to prepare the emulsion can be diverse. It is preferably an aqueous solution containing plant extracts, in particular a hydrosol, an infusion or a maceration of plants, or a fruit water. In a preferred embodiment, the aqueous solution is a hydrolate, pure or diluted, or a mixture of hydrolates.

The quantity of HE contained in the compositions must be adapted so that the finished products can be used directly, for example in topical application, without presenting a risk for the users (irritations, itching, or even burns caused by HE in overdose). Thus, the proportion of HE contained in the compositions is generally less than 3%, for example 1%, 1, 5%, 2% or 2.5%. Preferably, the amount of HE will be 2%.

In the compositions of the invention, the oily phase is provided solely by the HE, to the exclusion of any other vegetable oil.

In a particular embodiment, the invention relates to compositions consisting of an emulsion of one or more HE in one or more aqueous solutions, in particular in one or more hydrosols.

In another particular embodiment, the composition contains a hydrolate and an HE from the same plant. This embodiment is particularly interesting because it makes it possible to propose an integral plant preparation comprising all the components extracted from the plant. Indeed, during the distillation of a plant on the one hand ΙΉΕ and on the other hand the hydrolate (or distillation water) whose compositions are different, beyond the fact that ΙΉΕ is a very concentrated extract relative to the hydrolate.

By way of example, there may be mentioned a composition comprising:

an EO of pink and a hydrosol of rose, preferably 2% of EO of pink.

a peppermint EO and peppermint hydrosol, preferably 2% peppermint EO

an HE of lavender and a hydrosol of lavender, preferably 2% of lavender

a tea tree HE and a tea tree hydrosol, preferably 2% of tea tree HE.

In these compositions, the hydrolate and ΙΉΕ may be the only ingredients.

In other embodiments, emulsions can be obtained from a mixture of aqueous solutions and / or a mixture of HE or from emulsions mixed with each other.

Emulsions containing aqueous solution and HEs, excluding any texturizing agent, are liquid. So as to facilitate handling and use, gelling agents may be added without this denatures the emulsion, including its properties.

Thus, the compositions according to the invention may contain gelling agents, preferably of natural origin, such as xanthan gum or alginates. The addition of gelling agents respects the naturalness and purity of the product and makes it possible to obtain a creamier and more pleasant texture when applied to the skin. The texture of the composition will depend on the amount of gelling agent added.

In order to obtain a liquid-type composition of the lotion type, the proportion of gelling agent will generally be less than 0.1%, preferably absent from the composition. In order to obtain a milk-type composition that has a flowable but non-sprayable appearance, the proportion of gelling agent will generally be between 0.1% and 0.8% of the composition. In order to obtain a gel composition of non-flowing appearance, the proportion of gelling agent will generally be between 0.8% and 2% of the composition.

To obtain a poultice-like composition or mask, of thick and creamy appearance, the proportion of gelling agent will generally be between 2% and 5% of the composition.

Since the texture is temperature dependent, these indications correspond to the appearance of the compositions at room temperature, ie at a temperature of about 20 ° C., and generally between 15 ° C. and 27 ° C.

The gelling agents are added after emulsification according to the desired texture.

On the other hand, moisturizing agents, preferably of natural origin can be added to the composition, for example glycerin.

When moisturizing agents are added, their proportion is generally between 2% and 10% of the composition. In general, the moisturizing agents may be added before or after emulsification; however, if the agents are hydrophobic, they will be added before emulsification.

It is also possible to add, if necessary, an acidity corrector to adjust the pH of the composition closer to that of the skin. This acidity corrector can be added either during the process or at the end of the process. It should be noted that the compositions according to the invention do not contain a preservative. They are protected from microbial growth because of the presence of HE in the composition. The advantages of the compositions of the invention are numerous.

Because of their simple formulation, these compositions are natural and healthy and they have less allergenic risk. The compositions can be 100% organic. They also have other very interesting properties. The inventors have indeed shown that the activity of the active ingredients is preserved in the emulsified compositions without surfactant and that the effectiveness of the compositions (without surfactant) is higher than that of the products with surfactants, in proportion to equivalent active ingredients.

Finally, these compositions are stable. Their stability is ensured by the method, in particular and preferably by an ultrasound treatment whose vibration frequency is greater than or equal to 1 MHz, as described in the patent WO2010 / 149668. Their stability at room temperature is observed for at least 3 months and up to more than 12 months.

The compositions according to the invention are compositions for topical use that can be used in humans or animals.

In a particular embodiment, the aqueous solution of the composition is water and is a mixture of katafray HE, camphor rosemary HE, lemon eucalyptus HE and juniper EO. common. An example of such a composition is described in Example 1; it has the effect of causing heating after topical application. Such a composition is in the form of a lotion preparatory to the muscular effort.

Thus, a second object of the invention relates to the use of a composition containing an oil-in-water emulsion based on a mixture of katafray HE, camphor rosemary, lemon eucalyptus and common juniper. as a preparation lotion for muscular effort. FIGURES

FIGURE 1: presents a comparison of heating on skin with the application of the composition A (without surfactant, curve marked with the squares) with the composition A-TS (with surfactant, curve marked with circles).

EXAMPLES

EXAMPLE 1 Characteristics of an Oil-in-Water Emulsion Product Product Comprising Essential Oils and Without Surfactant a. Composition of the product "preparation for the effort": composition A

Composition A is prepared using the method described in Application WO2010 / 149668 and defined below:

Table 1: Ingredients of the composition "preparation for the effort" An A-TS composition was prepared using the same method and using the same ingredients as for Composition A, with the difference that 1% Twin 80 is added as a surfactant. b. Measurement of the heating effect of the product "preparation for the effort"

In order to evaluate the heating effect of composition A, it was applied to the arm of healthy subjects. The test was performed as follows:

1) A defined area of the subject's arm was spotted and cleaned (with soap, then rinsed and dried). The application surface is about 9 cm ² , a square of 3 cm side).

2) The temperature on the marked area was measured using an infrared thermometer.

3) 10mg of the product to be tested were applied to the area.

4) The temperature was measured immediately, then again at regular intervals (at least every minute) for 15min.

The protocol was repeated on three people and the data was averaged. The result is shown in Figure 1 (curve A).

The graph shows a rise in temperature during the first 5 minutes after application, to reach a maximum corresponding to a temperature increase of 2.2 ° C. The temperature then decreases gradually, remaining still one degree higher than the temperature of the zone before application.

These results show the effectiveness of the composition A to induce a heating in the skin and thus also the muscle underlying the area tested. Such a composition can therefore be used as a preparation product for muscular effort, by topical application to the muscles that will be stressed. c. Comparison of the effectiveness of composition A with that of a composition

A-TS containing surfactants In order to evaluate the effectiveness of the formulation without surfactant, a comparative study was carried out using in parallel a product having the same components as composition A and prepared with the same process but to which surfactants were added; this composition is called A-TS composition.

FIG. 1 represents the temperature increase obtained after topical application of these two compositions. While the composition A allows a temperature increase of more than 2 ° C. (as described in the previous paragraph), the composition A-TS (curve A-TS) induces a very limited rise in temperature, generally less than 0.5 ° C.

These results clearly show that the composition A formulated without surfactant is more effective to cause heating, the composition A-TS comprising a surfactant, while these two compositions have the same proportion of active ingredients. There is therefore a better activity of the active ingredients in a formulation without surfactant compared to the same dose of active ingredients in the presence of surfactant. This observation highlights the fact that a formulation without surfactant allows a better bioavailability of the active ingredients.

EXAMPLE 2 Formulation of an Integral Peppermint Gel

An integral peppermint gel preparation according to the invention can be obtained from the following ingredients:

Table 2: Composition of an integral gel of peppermint

Both ingredients are emulsified under high frequency vibration, as described in patent application WO2010 / 149668. The pH of the preparation is then adjusted to 7, if necessary. A texturizer may optionally be added to the emulsion so as to obtain a texture that is less liquid and easier to apply. It is also possible to add to this composition, without modifying the properties of interest, a preservative and an antioxidant in respective proportions to ensure the non-degradation of the product over time.

Remarkably and similar to the observations of Example 1, a stable equivalent product (prepared without high frequency vibration treatment) can not be obtained without the addition of surfactant. In addition, a product prepared with the same protocol but containing in addition a surfactant will be less effective.

The product according to the invention can be used directly for conventional applications of peppermint essential oil (headaches, digestion, etc.). In topical use, it does not require additional dilution. In particular, no dilution in an oil is necessary. The touch of the product is completely aqueous and its application therefore leaves no unpleasant feeling of stickiness and fat.

EXAMPLE 3 Formulation of an Integral Lavender Gel

An integral lavender gel preparation according to the invention can be obtained from the following ingredients:

Table 3: composition of an integral lavender gel

Both ingredients are emulsified under high frequency vibration, as described in patent application WO2010 / 149668. The pH of the preparation is then adjusted to 7, if necessary. A texturizer may optionally be added to the emulsion so as to obtain a texture that is less liquid and easier to apply. It is also possible to add to this formula, without changing its properties of interest, a preservative and an antioxidant in respective proportions to ensure the non-degradation of the product over time.

Remarkably and similar to the observations of the previous Examples, a stable equivalent product (prepared without high frequency vibration processing) can not be obtained without the addition of surfactant. In addition, a product prepared with the same protocol but containing in addition a surfactant will be less effective.

The product according to the invention can be used directly for conventional applications of essential oil of lavender aspic (burns, insect bites, etc.). In topical use, it does not require additional dilution. In particular, no dilution in an oil is necessary. The touch of the product is completely aqueous and its application therefore leaves no unpleasant feeling of stickiness and fat. EXAMPLE 4: Formulation of an integral tea tree gel

A tea tree integral gel preparation according to the invention can be obtained from the following ingredients:

Table 4: Composition of an integral tea tree gel

Both ingredients are emulsified under high frequency vibration, as described in patent application WO2010 / 149668. The pH of the preparation is then adjusted to 7, if necessary. A texturizer may optionally be added to the emulsion so as to obtain a texture that is less liquid and easier to apply. It is also possible to add to this formula, without modifying the properties of interest, a preservative and an antioxidant in respective proportions to ensure the non-degradation of the product over time. Remarkably and similar to the observations of the previous examples, a stable equivalent product (prepared without high frequency vibration processing) can not be obtained without the addition of surfactant. In addition, a product prepared with the same protocol but containing in addition a surfactant will be less effective.

The product according to the invention can be used directly for conventional applications of tea tree essential oil (sore throat, acne, antiseptic, etc.). In topical use, it does not require additional dilution. In particular, no dilution in an oil is necessary. The touch of the product is completely aqueous and its application therefore leaves no unpleasant feeling of stickiness and fat.

Claims

1. Oil-in-water emulsion type composition comprising an aqueous solution and at least one essential oil, characterized in that this composition contains no surfactant and is obtained by an ultrasonic treatment whose vibration frequency is greater than or equal to at 1 MHz.

2. Composition according to claim 1, wherein said aqueous solution is a hydrosol, a plant infusion or a fruit water.

3. Composition according to claim 2, wherein the hydrosol and the essential oil are from the same plant.

4. Composition according to one of the preceding claims, further comprising a gelling agent.

5. Composition according to one of the preceding claims wherein the aqueous solution is water and the essential oils are a mixture of katafray HE, camphor rosemary, lemon eucalyptus and common juniper.

6. Use of a composition according to claim 5 for heating the muscles before exercise.

7. Composition according to one of claims 1 to 4 comprising between 1 and 2.5% of essential oil and a hydrosol.

8. Composition according to one of claims 1 to 4 or 7 comprising peppermint essential oil and a peppermint hydrosol.

9. Composition according to one of claims 1 to 4 or 7 comprising lavender essential oil and a lavender hydrosol.

10. Composition according to one of claims 1 to 4 or 7 comprising tea tree essential oil and a tea tree hydrosol.