WO2024261099A1 - Method for formulating a liquid or semi-liquid composition, compositions obtained by such a method, and corresponding uses - Google Patents

Abstract

The present invention relates to the production of a liquid or semi-liquid composition containing at least one active substance or active ingredient. This composition can be used for formulating biocidal compositions, phytosanitary compositions or cosmetic compositions.

Description

DESCRIPTION

TITLE: Process for formulating a liquid or semi-liquid composition, compositions obtained by such a process, and corresponding uses.

Field of invention

The invention relates to the field of the formulation of liquid or semi-liquid compositions containing at least one active substance or active principle. The invention finds its application in particular in the field of the formulation of compositions for the control of pests such as biocidal, veterinary and physical barrier products, phytosanitary compositions or even cosmetic compositions.

More specifically, the invention relates to a process for formulating a liquid or semi-liquid composition containing at least one active substance, as well as the compositions obtained by such a process, and corresponding uses.

Prior art

Many formulations of liquid or semi-liquid compositions containing one or more active substances use water. Water has the combined advantages of being economical and having no effect on human and environmental toxicity.

Such liquid or semi-liquid compositions may in particular be ready-to-use compositions but also compositions concentrated in active substance(s) intended to be diluted extemporaneously with water.

However, the use of water in formulations can lead to the hydrolysis of the active substances contained in them, leading to a reduction in their effectiveness.

In order to protect the active substances from such action of water, formulation processes leading to the encapsulation of the active substances are known. Such processes make it possible to obtain capsules inside which the active substances are protected from water and therefore cannot be hydrolyzed.

However, in the field of biocides, the compounds used to form such capsules, such as polyurea and formaldehydes ¹¹¹¹²¹ , are compounds derived from petrochemicals whose use poses problems, particularly with regard to the environment. In particular, the encapsulations present on the market based on polyurea or Formaldehyde has the disadvantage of generating microplastics and using raw materials classified as harmful to humans and the environment such as isocyanates.

In addition, most biocides are dispersed in the environment in liquid form, and after evaporation, they deposit traces of active substances with which harmful organisms come into contact when passing through the treated area. However, the active substance degrades in the environment at a more or less significant speed under the action of natural oxidation or under the influence of UV radiation, thus reducing its long-term effectiveness.

Furthermore, in the field of insecticides, some galenics have an extremely high wetting power so as to improve the penetration of the active substance on insects. However, the inventors have noticed that approximately 30% of the active substance can be absorbed by the support and therefore not be available to act on insects.

Compositions containing film-forming compounds, such as silanes, siloxanes, aminosiloxanes, polysiloxanes or fluorinated compounds, have thus been developed in order to limit the absorption of the active substance by the supports on which the compositions are applied. However, the effectiveness of the compositions is reduced by the presence of these film-forming raw materials. This effect could be explained by the fact that the film-forming raw materials can have a harmful activity on the active substance by creating a network causing the imprisonment of the active substance.

Since many active substances are lipophilic and therefore immiscible in water, it is necessary to produce emulsions to bind the aqueous phase and the phase containing the lipophilic active substance, and therefore to use surfactant compounds to stabilize such emulsions. Thus, European patent application EP 2047838 A1 specifically provides for the use of a surfactant in a cosmetic composition to form wax-based microcapsules in which the active substance is enclosed and protected. Furthermore, American patent application US 2012/0164204 teaches an emulsification process for obtaining an emulsifier free of biopolymers and composed of "core-shell" capsules comprising a hydrophobic liquid core and capable of housing active substances that dissolve little in a wax. However, it remains necessary to add surfactants so that the emulsifier obtained is sufficiently stable and effective. The interactions between the surfactant and the active substance create intermolecular bonds, which are either steric or electrostatic depending on the nature of the surfactants involved. The interactions modify the three-dimensional mobility of the active substance by forming a new surfactant-active substance system generally designated by the acronym "TA-SA". This new TA-SA system has the disadvantage of a loss of specificity of the neurotoxic chemical message. Indeed, the insertion of the substance on its active site would be made more difficult by the TA-SA system.

Another disadvantage of the TA-SA complex is that it interacts with non-target proteins and also with the cell membrane and its phospholipids. These non-specific interactions result in disrupting the permeability of cell membranes ¹³¹ , but also in decreasing the specificity of the neurotoxic chemical message.

In the presence of surfactants, the active substance no longer focuses on its receptor because the TA-SA complex binds to other sites. In other words, the TA-SA system acts sparsely on the cell and not on the insecticide receptor. The chemical message is therefore no longer as specific and the active substance loses its effectiveness.

For example, a widely used surfactant in biocide formulations is a nonionic surfactant called polysorbate 80. However, it is known to those skilled in the art that polysorbate 80 ^[4] has the disadvantage of penetrating into the intercellular regions of organisms. One of the negative consequences of the penetration of the complex is the separation of membrane phospholipids which has the effect of increasing the fluidity of the cell membranes. A second negative consequence of this penetration of the TA-SA complex is the binding of the polysorbate with keratin filaments which disrupts the integrity of the surrounding corneocytes.

Furthermore, a method for microencapsulating active ingredients is known to those skilled in the art, as described in patent application EP 2894978 A1, which consists in heating a fatty phase comprising a wax and at least one active ingredient to be encapsulated, at a reaction temperature higher than the melting temperature of the wax. However, the method described in this patent application results in a solid substance being obtained. The latter cannot therefore be sprayed onto surfaces to be treated, and its effectiveness still needs to be improved. Objectives of the invention

In order to overcome the aforementioned drawbacks, the inventors have developed a method for formulating a liquid or semi-liquid composition containing at least one active substance and having the following properties: the specificity of the composition is improved compared to compositions obtained by prior art formulation methods, or the active substance content can be reduced compared to compositions obtained by prior art formulation methods which have substantially the same effectiveness, in particular for applications in the phytosanitary field and the biocide field, or the composition makes it possible to obtain compositions in which the toxicity is reduced, compared to compositions obtained by prior art formulation methods, or the composition makes it possible to increase its mobility and availability compared to compositions obtained by prior art formulation methods having substantially the same effectiveness, or the composition makes it possible to improve the protection against water molecules and ultraviolet radiation of the active substance compared to compositions obtained by prior art formulation methods and having substantially the same effectiveness, and above all the composition does not require the addition of a surfactant compound in the composition.

In the context of cosmetic use, an active substance will be understood to mean an active principle (term generally used in this field).

Description of the invention

The inventors have put forward a process which makes it possible to obtain a composition containing an aqueous phase and a particularly stable oily phase, without having to include a surfactant compound in the composition, since its oily phase is designed to act as a protective film, thus preserving the active substance which it contains, while allowing the interaction of the active substance with its site of action. The present invention therefore aims to provide a method for formulating a liquid or semi-liquid composition comprising at least one active substance, said method comprising the following steps: producing an apolar fatty phase comprising o at least one active substance (or active ingredient) present at a rate of 0.01% to 90% by weight relative to the total weight of the apolar fatty phase, o at least one wax present at a rate of 5% to 60% by weight relative to the total weight of the apolar fatty phase, o at least one solvent capable of solubilizing the wax, said solvent being an acetal, present at a rate of 5% to 94.99% by weight relative to the total weight of the apolar fatty phase, producing a polar aqueous phase comprising o water present at a rate of more than 90% by weight relative to the total weight of the polar aqueous phase, o at least one gelling agent present at a rate of 0.01% to 1% by weight relative to the total weight of the apolar fatty phase, total mass of the aqueous phase, heating the apolar fatty phase to a first temperature Tl and heating the polar aqueous phase to a second temperature T2, said first temperature Tl and the second temperature T2 being higher than the melting temperature of the wax, the first Tl and second temperature T2 have a temperature difference between them of at most 5°C and being preferably equal; mixing the entire polar aqueous phase heated to the second temperature T2 with 1 to 20% by mass of the apolar fatty phase heated to the first temperature Tl relative to the total mass of the mixture.

Unlike compositions comprising surfactants or film-forming agents, obtained by the formulation processes of the prior art, the compositions obtained by the process according to the invention do not create networks likely to cause the imprisonment of the active substance and to hinder its access to its site of action. Indeed, the compositions thus obtained have a film-forming effect having no negative action of immobilization or imprisonment of the active substance. Thus, the active substance included in the liquid or semi-liquid compositions obtained with the method according to the invention has improved mobility and can access its active site more easily. The method according to the invention therefore offers the possibility of reducing the amount of active substance present in the liquid or semi-liquid composition, while maintaining an effectiveness of the active substance contained therein at least equivalent to that obtained with the formulation methods of the prior art using surfactant compounds or film-forming agents. In addition, the composition obtained with the method according to the invention allows the active substance to interact more specifically on its site of action, that is to say without causing unwanted interaction with the phospholipids of cell membranes.

Furthermore, the method according to the invention makes it possible to obtain a composition in which the active substance is protected by means of double encapsulation.

Thus, in the method according to the invention, the first step of producing a non-polar fatty phase makes it possible to obtain a first liquid-liquid encapsulation of the active substance, which leads to the formation of so-called liquid-liquid capsules. This first encapsulation also makes it possible, in particular thanks to the use of wax, to protect the active substance from reactions of water, present in the aqueous phase but also once the composition is distributed on its application site, from reactions with external elements such as oxygen, ultraviolet rays, etc.

Then a second encapsulation is carried out when mixing the product preparation by the user. When diluting the concentrate, part of the gelling agent surrounds the liquid-liquid capsules, so as to form a plurality of capsules. Each of these capsules thus comprises a liquid matrix comprising the wax, the solvent and the active substance, and a membrane of a solid polymer, encompassing the matrix, consisting of gelling agent. The capsules are suspended in water, thus creating overprotection of the active substance.

Nonpolar fatty phase

The apolar fatty phase comprises an active substance present at a rate of 0.01% to 90% by mass relative to the total mass of the apolar fatty phase. Preferably, the active substance may be present at a rate of 0.01% to 70% by mass relative to the total mass of the apolar fatty phase. Any lipophilic active substance can be used as an active substance.

The apolar fatty phase also comprises at least one wax present at a rate of 5% to 60% by mass relative to the total mass of said apolar fatty phase.

Advantageously, a vegetable wax, preferably rapeseed wax, can be used as wax.

The wax content makes it possible to modulate the persistence of the active substance, the persistence increasing with a higher percentage of wax. For the purposes of the present invention, persistence means the duration during which the active substance continues to exert its action on a surface. The presence of wax used in the composition according to the invention also makes it possible to obtain an increased effectiveness over time compared to the solutions of the prior art. Thus, it is possible to reduce the amount of active substance present in the compositions to obtain an effect at least equivalent to the compositions of the prior art.

The apolar fatty phase also comprises a solvent capable of solubilizing said wax, which is an acetal present at a rate of 5% to 94.99% by mass relative to the total mass of said apolar fatty phase.

Advantageously, the solvent capable of solubilizing the wax can be present at a rate of 5% to 50% by mass relative to the total mass of the apolar fatty phase.

Advantageously, the apolar fatty phase may further comprise a synergist, i.e. a compound making it possible to increase the effectiveness of the active substance.

Polar aqueous phase

The polar aqueous phase comprises, in addition to water, at least one gelling agent present at a rate of 0.01% to 1% by mass relative to the total mass of said aqueous phase.

Advantageously, the gelling agent may be present at a rate of 0.2% to 0.5% by mass relative to the total mass of the polar aqueous phase.

As a gelling agent, synthetic or natural gelling agents may be used in the context of the present invention, and for example a crosslinked polyacrylic acid polymer of formula -[CH2CH(COOH)] _n - may be used as a gelling agent. Advantageously, the polar aqueous phase may further comprise at least one additive chosen from a neutralizer, a preservative, a colorant. Preferably, the composition obtained by the process according to the invention may be free of surfactant. By surfactant-free composition is meant, within the meaning of the present invention, a composition comprising no surfactant or comprising one or more surfactants in an amount of less than 0.5% by mass relative to the total mass of the composition.

The present invention also relates to finished liquid or semi-liquid compositions capable of being obtained by the formulation process according to the invention.

Preferably, such compositions are characterized in that they comprise: A dispersed phase comprising: o at least one active substance present at a rate of 0.001% to 10% by mass relative to the total mass of the composition, o at least one wax, present at a rate of 0.01% to 1% by mass relative to the total mass of the composition, and o at least one solvent capable of solubilizing the wax, preferably an acetal, present at a rate of 0.01% to 5% by mass relative to the total mass of the composition,

A continuous phase comprising: o water in a content greater than or equal to 85% by mass relative to the total mass of the composition, and o at least one gelling agent present at a rate of 0.01% to 1% by mass relative to the total mass of the composition, the solvent being an acetal present at a rate of 0.01% to 5% by mass relative to the total mass of the composition.

The active substance (or active principle), the solvent, the wax, and the gelling agent are as defined above.

The present invention also relates to the use of a composition as described above in a preparation intended for cosmetic use.

The present invention also relates to the use of a composition as described above in a preparation intended for phytosanitary use. The present invention also relates to the use of a composition as described above in a preparation intended to combat pests such as insecticides, veterinary products and physical barriers.

The features and advantages of the invention will become more apparent upon reading the examples described.

EXAMPLES

Products and raw materials active substances: o cypermethrin, o pyrethrum, o sesame oil, o argan oil, wax: rapeseed vegetable wax solvent: acetal network water gelling agent: cross-linked polyacrylic acid polymer marketed under the brand CARBOPOL® EZ3 from the company Lubrizol, preservative: Acticide MBS

Other additive: neutralizer

Example 1 - Production of insecticide compositions C2 to C4 free of surfactant

A first step of the formulation process 1 consists of producing an apolar fatty phase, which constitutes a first liquid-liquid encapsulation.

For this purpose, the active insecticide substance, the wax and the acetal are mixed in the same container.

A second step is to create a polar aqueous phase. To do this, the gelling agent and water are mixed in a second container.

The apolar fatty phase is then heated to a temperature Tl between 60°C and 70°C (depending on the nature of the wax and therefore its melting point), while the polar aqueous phase is heated separately to a temperature T2 between 60°C and 70°C depending on the nature of the wax and therefore its melting point). The temperatures Tl and T2 are higher than the melting temperature of the wax, so that the wax can be completely liquefied. The temperatures Tl and T2 are preferably identical, but a temperature difference of 5°C is tolerated.

Subsequently, during a mixing step with stirring using a rotor/stator system, part of the apolar fatty phase is taken in order to integrate it into the polar aqueous phase in order to obtain a homogeneous composition comprising less than 10% by mass of active substance relative to the total mass of the composition.

The process implemented makes it possible to obtain a composition C2 in accordance with the invention, which comprises a dispersed phase comprising the active substance, the acetal and the wax, and a continuous phase comprising the gelling agent and the water.

Similarly, compositions C3 and C4 are prepared according to the same procedure as C2, but comprise respectively three times and five times higher wax contents than composition C2. The different compositions C2 to C4 are presented in Table 1 below:

[Table 1]

These surfactant-free compositions C2 to C4 are compared to a prior art formulation C1 with surfactant and having the same active substance at the same concentration as compositions C2 to C4. In Table 1, X can vary between 0.01 and 1% by mass relative to the total mass of the composition, and Y can vary between 0.01 and 5% by mass relative to the total mass of the composition.

Efficacy and persistence tests

Tests were carried out to evaluate the insecticidal efficacy of compositions C2, C3 and C4 on the one hand and of composition Cl of the prior art containing the same quantity of active substance but containing surfactants.

This efficacy was determined by spraying each of the insecticide compositions C1, C2, C3 and C4 onto supports, on which insects were subsequently placed. The insect mortality rate was then determined by counting the insects that died on these supports after different periods of time.

The persistence of the insecticide efficacy on the supports was also studied by depositing new insects on these supports after a certain time and measuring their mortality rate after different periods of time. The efficacy tests were carried out in accordance with the method described in the English document "Guidance on the Biocidal Products Regulation". More precisely, a group of insects (group 1) was exposed to the different compositions Cl, C2, C3 and C4 for a period of 4 hours and 24 hours on the first day of testing (initial T). The dead insects were counted a first time after the 4-hour period. A new count of the dead insects was carried out after the 24-hour period.

A new group of insects (group 2) was introduced onto the surfaces treated with the different compositions four weeks after the first application (T=4 weeks) of the compositions on the surfaces. Dead insects were counted after 24 hours of exposure on the treated surface.

Similarly, a new group of insects (group 3) was introduced onto the surfaces treated with the different compositions eight weeks (T=8 weeks) after the first application of the compositions on the surfaces. Dead insects were counted after 24 hours of exposure on the treated surface.

The different counts made it possible to determine the effectiveness of the different compositions comprising the insecticide. The effectiveness of each of the compositions is expressed as a percentage of dead insects in Table 2. [Table 21

It is clear from the results of this table that the initial efficacies after 4 hours of exposure (initial T) of compositions C2, C3 and C4 are significantly higher than the efficacy of composition Cl according to the prior art, and have respective efficacies of 100%, 100% and 83%, while Cl shows an efficacy of 39% after 4 hours.

It should also be noted that composition C2 has a higher efficiency than compositions C3 and C4. Thus, a high percentage of wax can decrease the efficiency.

The results of this table show that composition C2 has a 24-hour efficacy significantly higher than the efficacy of Cl four weeks after the first application and eight weeks after the first application. However, it should be noted that a high wax content reduces the efficacy of the composition.

Thus, a composition according to the invention has a higher long-term efficacy than a composition according to the prior art. This improved efficacy can in particular be explained by better accessibility of the active site of the active substance, thus making the active substance more available.

Example 2 - Preparation of a composition based on cypermethrin intended for use in a biocidal preparation

A cypermethrin-based composition intended for biocidal use is prepared in accordance with the process according to the invention.

The quantities of each ingredient are shown in Table 3 below. To do this, the active substance (cypermethrin), the acetal and the wax are weighed and then mixed for about 30 minutes in a container until a homogeneous phase is obtained at temperature. This phase constitutes the apolar fatty phase.

In the same way, the gelling agent (CARBOPOL EZ3), the tap water, and the preservative (Acticide MBS) are weighed and then mixed for about 30 minutes in a container until a homogeneous phase is obtained at temperature. This phase constitutes the polar aqueous phase.

Once the two phases are homogeneous, a determined quantity of the apolar fatty phase is taken and added to the tank of the aqueous phase. The mixture is then stirred for 5 minutes, then a neutralizer is added to the mixture. The stirring speed is then increased.

Exemple 3 - Réalisation d'une composition à base de pyrèthre destinée à être utilisée dans une préparation phytosanitaire Finally, the mixture is stirred for at least one hour at a temperature between 60 and 70°C depending on the nature of the wax. [Table 3]

Example 3 - Production of a pyrethrum-based composition intended for use in a phytosanitary preparation

A pyrethrum-based composition intended for phytosanitary use is prepared in accordance with the process according to the invention, in the same manner as in Example 2. The quantities of raw materials to be taken are indicated in Table 4 below.

In this example, the apolar fatty phase consists of pyrethrum, acetal, rapeseed wax and a synergist. The polar aqueous phase consists of tap water, the gelling agent Carbopol EZ3 and an Acticide MBS preservative.

The addition of synergist in the apolar fatty phase was made to improve the effectiveness of the product.

Exemple 4 - Réalisation d'une composition à base d'huile de sésame et d'huile d'argan destinée à être utilisée dans une préparation cosmétique [Table 4]

Example 4 - Production of a composition based on sesame oil and argan oil intended to be used in a cosmetic preparation

A composition based on sesame oil and argan oil intended for cosmetic use is prepared in accordance with the process according to the invention, in the same manner as in Examples 2 and 3. The quantities of the different ingredients are indicated in Table 5 below.

The interest of this composition is to avoid the toxicity of surfactants on skin cells. [Table 51

References [1] Lemaire J., (2016). Formaldehyde, a possible environmental pollutant of the atmosphere in work offices: assessment of the knowledge and professional practices of French occupational physicians on this ubiquitous irritant and carcinogen in our indoor air.

[2] Afsset, (2009). Health risks linked to the presence of formaldehyde. Air and chemical agents.

[3] Lemery E., (2015). Structure and physicochemistry of surfactants, their impacts on skin toxicity and barrier function.

[4] Nokhodchi A., Shokri J., Dashbolaghi A., Hassan-Zadeh D., Ghafourian T. and Barzegar-Jalali M., (2003). The enhancement effect of surfactants on the penetration of lorazepam through rat skin. Int. J. Pharm.

Claims

1. A method of formulating a liquid or semi-liquid composition comprising at least one active substance, said method comprising the following steps: producing an apolar fatty phase comprising: o said active substance present at a rate of 0.01% to 90% by weight relative to the total weight of said apolar fatty phase, o at least one wax present at a rate of 5% to 60% by weight relative to the total weight of said apolar fatty phase, and o at least one solvent capable of solubilizing said wax, said solvent being an acetal, present at a rate of 5% to 94.99% by weight relative to the total weight of said apolar fatty phase; producing a polar aqueous phase comprising: o water present at a rate of more than 90% by weight relative to the total weight of said polar aqueous phase, and o at least one gelling agent present at a rate of 0.01% to 1% by weight relative to the total weight of said aqueous phase; heating said apolar fatty phase to a first temperature Tl and heating said polar aqueous phase to a second temperature T2, said first temperature Tl and said second temperature T2 being higher than the melting temperature of said wax, said first Tl and second temperatures T2 having between them a temperature difference of at most 5°C and being preferably equal; mixing all of said polar aqueous phase heated to said second temperature T2 with 1 to 20% by mass of said apolar fatty phase heated to said first temperature Tl relative to the total mass of said mixture. 2. Formulation process according to claim 1, according to which said active substance is present at a rate of 0.01% to 70% by mass relative to the total mass of said apolar fatty phase. 3. Formulation process according to any one of claims 1 and 2, wherein said solvent capable of solubilizing said wax is present at a rate of 5% to 50% by mass relative to the total mass of said apolar fatty phase. 4. Formulation process according to any one of claims 1 to 3, according to which said gelling agent is present at a rate of 0.2% to 0.5% by mass relative to the total mass of said polar aqueous phase. 5. Formulation process according to any one of claims 1 to 4, according to which said wax is a vegetable wax, preferably a rapeseed wax. 6. Formulation process according to any one of claims 1 to 5, according to which said gelling agent is a crosslinked polyacrylic acid polymer of formula - [CH ₂ CH(COOH)] _n -. 7. Formulation process according to any one of claims 1 to 6, according to which said apolar fatty phase further comprises at least one synergist. 8. Formulation process according to any one of claims 1 to 7, according to which said polar aqueous phase further comprises at least one additive chosen from a neutralizer, a preservative, a colorant. 9. Formulation process according to any one of claims 1 to 8, according to which said composition is free of surfactant. 10. Liquid or semi-liquid composition (1) obtainable by a formulation process according to any one of claims 1 to 9 comprising: A dispersed phase comprising: o at least one active substance present at a rate of 0.001% to 10% by mass relative to the total mass of the composition, o at least one wax present at a rate of 0.01% to 1% by mass relative to the total mass of the composition, o at least one solvent for said at least one wax, A continuous phase comprising: o water in a content greater than or equal to 85% by mass relative to the total mass of the composition, and o at least one gelling agent present at a rate of 0.01% to 1% by mass relative to the total mass of the composition, characterized in that said solvent is an acetal present at a rate of 0.01% to 5% by mass relative to the total mass of the composition. 11. Use of a composition as defined according to claim 10 in a preparation intended for cosmetic use. 12. Use of a composition as defined according to claim 10 in a preparation intended for phytosanitary use. 13. Use of a composition as defined according to claim 10 in a preparation intended to combat pests such as insecticides, veterinary products and physical barriers.