Ophthalmic composition useful particularly for the administration of active ingredients that are poorly water-soluble or unstable in water.

Abstract

The present invention relates to an ophthalmic composition comprising a non-ionic oil-in-water emulsion with: an aqueous phase Aq, a lipid phase L in the form of droplets dispersed in the aqueous phase, an interface between said lipid phase L and said aqueous phase Aq, and a particulate surfactant for stabilizing the emulsion, located at the interface between the lipid phase and the aqueous phase, said surfactant comprising or consisting of organic particles with an average size of 1 µm or less, said composition being free of non-particulate surfactants and advantageously preservative-free. These compositions are useful as a medicinal product, particularly for administration by ocular instillation. The invention also relates to a method for preparing said compositions. Figure for the abstract: [Fig. 1]

Description

Title of the invention: Ophthalmic composition useful in particular for the administration of active ingredients which are not very water-soluble or not very stable in water. FIELD OF THE INVENTION

[0001] The invention relates to ophthalmic compositions comprising a non-ionic oil-in-water emulsion, and optionally a poorly water-soluble active ingredient, of BCS class II or IV. STATE OF THE ART

[0002] The administration of active substances by ophthalmic route aims to achieve a therapeutic concentration and maintain it over time. However, the various eye protection mechanisms run counter to these treatment objectives.

[0003] In the case of ophthalmic administration, the first challenge is to be able to maintain a sufficiently long residence time at the administration site to guarantee absorption of the active ingredient. Indeed, blinking of the eyelids and the significant clearance of the tear film contribute to rapid evacuation of the administered liquids. When blinking, the eyelid allows better spreading of the tear film on the corneal surface, but also promotes its flow. The volume of the tear fluid, approximately 7 pL, is completely renewed every 5 minutes, leading to rapid elimination of the administered active ingredients.

[0004] Thus, an isotonic formula with a pH close to that of the tear fluid (pH of approximately 7.4) will be better tolerated on the ocular surface and less likely to be eliminated by tears. Similarly, a viscous formula will be eliminated more slowly. Although diluted in the tear film during administration, the formulation can therefore play a role in tear clearance.

[0005] The second challenge is to ensure good ocular bioavailability of the active ingredient. Indeed, while increasing the residence time on the surface of the eye allows for a wider window of time available for absorption of the active ingredient, this is not enough. The active ingredient still has to cross the various barriers.

[0006] In the case of anterior pathologies of the eye, it is the cornea. The cornea is composed of 5 layers:

[0007] 1. the corneal epithelium, which is a non-keratinized stratified squamous epithelium rich in in lipids representing approximately 10% of the thickness of the cornea. The cells are linked by tight junctions, conferring the role of barrier to the diffusion of the epithelium;

[0008] 2. Bowman's layer, located under the basal lamina of the epithelium, is a layer dense stromal derivative consisting of collagen fibers with random organization;

[0009] 3. the stroma, which constitutes almost 90% of the thickness of the cornea. It is made up keratocytes producing collagen fibers with regular orientation and ground substance rich in water and glycoproteins;

[0010] 4. Descement's membrane, which is the basal lamina of the endothelium, rich in type IV collagen fibers, the thickness of which increases with age;

[0011] 5. finally the endothelium, composed of a monolayer of hexagonal cells derived neural crests. Active ion transport by the endothelium allows the transfer of water from the stroma and maintains stromal transparency.

[0012] All the layers of the cornea, by their different structures and properties, are therefore obstacles to the absorption of active ingredients. Thus, it has been estimated that during the administration of a conventional ophthalmic solution less than 10% of the active ingredient is absorbed.

[0013] In addition to these problems common to all active ingredients, the formulation of active ingredients that are poorly soluble or unstable in water poses particular challenges. To illustrate this, we will take the example of formulations based on prostaglandins or their analogues (PGA), useful in the treatment of glaucoma, and more particularly in the treatment of open-angle glaucoma.

[0014] Indeed, it has been reported that approximately 25% of patients were not compliant with their treatment (non-compliance defined by the withdrawal of at least one administration per week or the patient's inability to describe their dosing schedule precisely), mainly due to forgetfulness but also the occurrence of adverse effects.

[0015] Local adverse effects restrict the use of PGAs even though it has been demonstrated that their hypotensive effect is the most important among anti-glaucomatous treatments.

[0016] This can be explained by the fact that in the relatively wide range of pharmaceutical formulations of PGA, most contain preservatives and / or solubilizing agents such as benzalkonium chloride (BAK), or non-particulate surfactants such as macrogolyglycerol hydroxystearate (MGHS).

[0017] However, the use of preservatives, particularly BAK, in ophthalmic eye drops is problematic. Numerous studies comparing formulas with BAK versus preservative-free formulas have been carried out, whether for latanoprost, travoprost or bimatoprost. All have concluded that BAK has a harmful effect.

[0018] Furthermore, most preservative-free PGA formulations use MGHS as a solubilizing and stabilizing agent. However, the in vitro cytotoxicity of MGHS has recently been highlighted. MGHS has also been shown in vitro to significantly induce necrosis and activation of the P2X7 receptor, a receptor linked to various cellular effects ranging from inflammation and oxidative stress to apoptosis. In addition, studies report the deleterious effects of MGHS, among other surfactants, on the ocular surface.

[0019] There is therefore still, at present, a need for formulations for molecules of this pharmacological class.

[0020] Faced with this problem, alternative aqueous formulations have been developed. These include: • surfactant-based formulations, such as micellar solutions, liposomes and niosomes. Examples of such formulations in which non-ionic surfactants (PS80, also noted Tween 80) make it possible to solubilize a prostaglandin derivative are described in particular in Alviset et al. Pharmaceutics 2022, 14, 453; • formulations based on cyclodextrins; • hydrogel-based formulations; • formulations based on polymeric nanoparticles.

[0021] Oil-in-water (O / W) emulsions are also common for solubilizing and stabilizing active ingredients that are poorly soluble or unstable in water. With a sufficiently high partition coefficient of the active ingredient between oil and water, solubilizing a sensitive active ingredient in oil droplets can protect it. This phenomenon has been demonstrated by several teams for latanoprost in particular.

[0022] Another advantage of O / W emulsions, specific to ocular administration, is the interaction with the tear film. One example is Santen pharmaceutical's Novasorb® technology, based on eye drops comprising a cationic O / W emulsion. The positive charges of the emulsion allow for close interaction with the negatively charged mucin layer covering the cornea, while the lipophilic part of the emulsion can spread over the surface and simulate the lipid layer of the tear film. This mechanical action has enabled the commercialization of the product Cationorm®, artificial tears for treating dry eye. DE-130A, or Ca-tioprost®, a preservative-free cationic emulsion containing latanoprost, for treating glaucoma while protecting the ocular surface, is currently under development (phase III trials started in 2019 and marketing authorization application filed).

[0023] International application WO2021 / 113637 also describes cationic emulsions, intended for ophthalmic administration, in particular for the treatment of presbyopia.

[0024] In these cationic emulsions, it is noted that the active ingredient can be coated by various substances in order to modify the release kinetics of the latter. These emulsions may contain nanoparticles, but only silica is given as an example of nanoparticles. However, silica is irritating to the cornea and non-biodegradable, which does not seem compatible with ocular administration. In addition, the use of benzalkonium chloride as a cationic agent is being considered.

[0025] O / W nanoemulsions of travoprost at 1% w / v oil phase, stabilized by PS80 at 2% w / w, have also been described (Ismail et al. Int. J. Pharm. 2020, 583, 119402). The ocular bioavailability of travoprost was increased twofold with this formulation. This effect was attributed to the small size of the nanodroplets and their oily nature increasing their residence time on the corneal surface as well as to the presence of PS80 which can act as an absorption promoter. Nevertheless, the stability of the product (three months at 25°C under a relative humidity of 60%) proved to be largely insufficient for storage at room temperature.

[0026] Thus, a need remains for new aqueous formulations, essentially free of preservatives that irritate the cornea, particularly during repeated applications, and avoiding the use of solubilizers or non-particulate surfactants - even non-ionic ones - while remaining stable at room temperature over periods of several months. Optionally, the formulations comprise an active ingredient, particularly one that is not soluble or not very stable in water, and improve its stability and / or bioavailability during ocular administration. BRIEF STATEMENT OF THE INVENTION

[0027] To respond to this, the inventors propose new ophthalmic compositions, comprising a Pickering emulsion (also called Ramsden emulsion) stabilized using organic particles having particular properties.

[0028] Thus, according to a first aspect, the invention relates to an ophthalmic composition, comprising an oil-in-water emulsion with: • an aqueous phase Aq, • a lipid phase L, in the form of droplets dispersed in the aqueous phase, • an interface between said lipid phase L and said aqueous phase Aq, and • a particulate surfactant to stabilize the emulsion, located at the interface between the lipid phase and the aqueous phase,

[0029] said surfactant comprising or consisting of organic particles of average size (in intensity) less than or equal to 1 pm, preferably less than or equal to 500 nm

[0030] said composition being free of non-particulate surfactant, and preferably free of preservative,

[0031] said lipid phase L optionally comprising at least one active ingredient li- posoluble.

[0032] The ophthalmic compositions of the invention are stable at room temperature, and this over periods of several months.

[0033] The ophthalmic compositions of the invention make it possible to dispense with the use of (non-particulate) surfactants. Thus, they also have improved tolerance compared to the compositions of the prior art, in particular when they must be administered repeatedly. In addition, the lipid globules help to reconstitute the lubricating lipid films protecting the eye, which improves tolerance, and extends the residence time of the active ingredient on the eye.

[0034] Thus, where appropriate, the ophthalmic compositions of the invention also improve the adsorption of the active ingredient because the lipid globules disintegrate rapidly on contact with the eye and biological fluids.

[0035] According to another aspect, the invention relates to said composition for its use as a medicament, in particular for administration by ocular instillation.

[0036] According to another aspect, the invention relates to a method of preparing the emulsion.

[0037] According to a particular aspect of the invention, the active ingredient is chosen from prostaglandins. These particular compositions are useful as medicaments, in particular in the treatment or prevention of glaucoma, such as open-angle glaucoma.

[0038] According to another particular aspect of the invention, the active ingredient is chosen from steroids. These particular compositions are useful as medicaments, in particular for preventing, relieving or treating ocular inflammations. DETAILED DESCRIPTION OF THE INVENTION Ophthalmic compositions

[0039] In the present invention, the term "pharmaceutical acceptable" is intended to mean that which is generally safe, non-toxic, neither biologically nor otherwise undesirable, and which is acceptable for veterinary or human pharmaceutical use, in particular by ocular administration.

[0040] In the present invention, the term "pharmaceutical composition" is intended to mean a composition which is generally safe, non-toxic and neither biologically nor otherwise undesirable, and which is acceptable for veterinary or human pharmaceutical use, in particular by ocular administration.

[0041] By "ocular administration" is meant a topical application to the eye. Thus, the composition can be applied to the eye and more particularly to the cornea, in particular by ocular instillation. The instillation can take place in different sites of the eye, more particularly at the level of the cornea, the conjunctiva, and in particular at the level of the conjunctival sac.

[0042] For the purposes of the present invention, the term “ophthalmic composition” means a pharmaceutical composition for ocular administration, such as eye drops. Such compositions are formulated so as to respect: good tolerance (in particular acceptable pH) and physiological osmolarity. It is also preferable that the compositions are sterile and formulated so as to avoid bacterial contamination during use. Galenic formulations for ocular administration include in particular: • Eye drops: in the form of a sterile emulsion, containing one or more active ingredients. Eye drops can be packaged in multi-dose or single-dose packaging. • Eye ointments, which are semi-solid, sterile preparations intended to be applied to the conjunctiva, containing one or more active ingredients and suitable excipients (petroleum jelly, liquid paraffin). • Ophthalmic gels, i.e. sterile, semi-solid preparations intended to be applied to the conjunctiva, containing one or more active ingredients and suitable excipients. The excipient is advantageously a hydrophilic polymer which gels in the presence of water, such as hyaluronic acid or a hyaluronate salt such as sodium hyaluronate, a cellulose derivative, a gellan gum, a xanthan gum, or a synthetic polymer such as a carbomer, carbopol®, polyacrylic acid or one of its derivatives. The cellulose derivative is preferably chosen from hydroxyethylcellulose (for example NATROSOL 250M®, NATROSOL 250G®) and / or hydroxypropylmethylcellulose. • Ophthalmic inserts, i.e. sterile solid or semi-solid preparations, intended to be inserted into the conjunctival sac. They generally consist of a reservoir of active ingredient embedded in a matrix surrounded by a membrane to control the release. The active ingredient is released gradually.

[0043] Eye drops will be used preferably because it is easier for a patient to administer such a composition by instilling 1 or 2 drops of the solution, suspension, emulsion, semi-solid gel into the affected eye. However, the composition may also be a suspension, a viscous or semi-viscous gel or other types of solid or semi-solid compositions.

[0044] The ophthalmic composition is free of non-particulate surfactants. Such compositions in fact have better tolerance on the ophthalmic mucosa, because non-particulate surfactants (particularly ionic) generate problems of cellular toxicity as indicated above. Surfactants are well known to those skilled in the art: they are a molecule or a salt capable of modifying the surface tension of the emulsion, particularly at the level of the interface between the lipid L and aqueous Aq phases. Non-particulate surfactants are distinguished from particulate surfactants in that they do not comprise particles, whether solid or semi-solid. There are three categories of non-particulate surfactants: anionic surfactants, cationic surfactants, and non-ionic surfactants.

[0045] For the purposes of the invention, a “composition free of non-particulate surfactants” means a composition comprising approximately 0% by weight, relative to the total weight of the composition, of surfactant, whether ionic or non-ionic. In other words, no surfactant is added to the composition. Indeed, even non-ionic surfactants are problematic for ocular tolerance, because just like ionic surfactants, they destabilize biological membranes. Their use must therefore be particularly limited in ophthalmic compositions, particularly in terms of concentrations.The composition is in particular free of surfactants chosen from the group consisting of BAK, MGHS 15, MGHS 35, MGHS 40, glycerol monostearate, hydrogenated polyoxyethylene stearate, PEG-PPG copolymers, nonoxynol-9, octoxynol-40, poloxamer 188, poloxamer 407, polysorbate 20, polysorbate 80, polyoxylethylene stearate (in particular 40), tyloxapol, and mixtures thereof.

[0046] Preferably, the ophthalmic composition is sterile, that is to say that it is devoid or essentially devoid of any form of life, such as in particular bacteria or microorganisms such as yeast and mold.

[0047] Advantageously, the ophthalmic composition is free of preservatives with antimicrobial or microstatic properties, and preferably free of cyclodextrin.

[0048] As used herein, a "preservative" or "preservative agent" exhibits microbicidal or microstatic properties in the composition, i.e., a microbicidal agent is an agent that kills microbes, while a microstatic agent only inhibits the growth of microbes. Preservatives with antimicrobial (i.e., microbicidal or microstatic) properties should be distinguished from auxiliary agents involved in maintaining the physicochemical characteristics of the active compound or solution: examples of such auxiliary agents include, but are not limited to, EDTA and vitamin E. Furthermore, some preservatives have surface-active properties.

[0049] The ophthalmic composition is advantageously free of surfactant preservatives. Certain preservatives (non-surfactants) may nevertheless be present in the composition of the invention.

[0050] Preferably, the composition is therefore free of surface-active preservative agents, in particular auxiliary agents involved in maintaining the characteristics physicochemical characteristics of the active compound or solution. Thus, the composition will advantageously comprise 0% of auxiliary agent such as: sorbic acid and its salts, and quaternary ammonium halides, in particular quaternary ammonium chloride and bromide such as, for example, BAK, benzododecinium halides (such as, for example, benzododecinium bromide), benzethonium halides (such as, for example, benzethonium chloride), lauralkonium halides (such as, for example, lauralkonium chloride), cetrimide, hexadecyltrimethylammonium halide halides (such as, for example, hexadecyltrimethylammonium bromide), tetradecyltrimethylammonium halides (such as, for example, tetradecyltrimethylammonium bromide), do-decyltrimethylammonium halides (such as, for example, dodecyltrimethylammonium bromide), halides cetrimonium, behenalkonium halides,cetalkonium halides (such as, for example, cetalkonium chloride), cetethyldimonium halides, cetylpyridinium halides, benzododecinium halides, chlorallyl methenamine halides, myristalkonium halides, stearalkonium halides and parabens.

[0051] In this particular embodiment, the composition may comprise at most 0.01% by weight, relative to the total weight of the composition, of a microbicidal and / or microstatic agent (non-surfactant), in particular selected from the group consisting of antioxidant agents, boric acid and its salts, benzoic derivatives, a salt thereof, or a mixture thereof.

[0052] According to another particular embodiment, the composition is free of preservatives, surfactant or non-surfactant, that is to say that it comprises at most 0.001% by weight of preservative, and advantageously at most 0.0001% by weight of preservatives, relative to the total weight of the composition. Non-ionic oil-in-water emulsion

[0053] The composition comprises an oil-in-water emulsion, also referred to as O / W. Thus, the aqueous phase Aq forms the continuous phase of the O / W emulsion, while the lipid phase L (also called the oily phase) forms the discontinuous phase of the O / W emulsion. More precisely, the lipid phase is in the form of droplets dispersed in the aqueous phase.

[0054] Advantageously, the lipid phase is present at a content of between 0.1% and 5%, in particular between 0.5 and 2%, for example 1%, by volume relative to the total volume of the composition. Lipid Phase L

[0055] The lipid phase preferably comprises, or is essentially composed of, glycerol esters of the following formula (I):

[0056] [Chem.l] ^0¾ [--0¾ --0¾ (I)

[0057] in which Rb R2 and R3, independently of each other represent H, a -(O=C)-CrCi8 alkyl group or a -(O=C)-C2-Ci8 alkenyl group, it being understood that at least one of Rb R2 and R3 is different from H.

[0058] For the purposes of the present invention, the term “(CrCi8) alkyl” means a saturated, linear or branched monovalent hydrocarbon chain comprising 1 to 18 carbon atoms. For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl or hexyl groups may be mentioned.

[0059] For the purposes of the present invention, the term “(C2-C18) alkenyl” group means a monovalent, linear or branched hydrocarbon chain comprising at least one double bond and comprising 2 to 18 carbon atoms. For example, linoleyl groups may be mentioned.

[0060] Preferably, Rb R2 and R3, independently of each other represent H, a -(O=C)-C6-C18 alkyl group or a -(O=C)-C6-C18 alkenyl group, it being understood that at least one of Rb R2 and R3 is different from H.

[0061] According to a particular embodiment, one of Rb, R2 and R3 represents a linoleyl group, and the other two residues among Rh, R2 and R3 represent H. Advantageously, it is glycerol monolinoleate.

[0062] According to another particular embodiment, the lipid phase comprises or is essentially constituted of triglycerides. According to this embodiment, RB R2 and R3, independently of one another, represent a -(O=C)-Cr-Ci8 alkyl group or a -(O=C)-C2-Ci8 alkenyl group. Advantageously, RB R2 and R3, independently of one another, represent a -(O=C)-C6-Ci8 alkyl group.

[0063] According to a particular embodiment, the lipid phase comprises or is essentially constituted of triglycerides and / or glycerol monolinoleate.

[0064] The oily phase may also comprise agents acting on the penetration of the active ingredient. The penetration agents which may be used are for example:

[0065] - certain heterocyclic amine amide compounds,

[0066] - glycols, such as for example propylene glycol;

[0067] - propylene carbonates; or

[0068] As indicated above, the emulsion is a Pickering emulsion: it is stabilized by a particulate surfactant - that is to say comprising organic particles capable of modifying the surface tension of the emulsion - and not by non-particulate surfactants.

[0069] Advantageously, the particulate surfactant / lipid phase mass ratio is between 0.1% and 2%. Those skilled in the art will be able to adapt this ratio according to the size and number of droplets desired to stabilize the emulsion while maintaining good absorption of the active ingredient where appropriate.

[0070] Preferably, the O / W emulsion is free of non-particulate surfactants, whether these are ionic or non-ionic. According to one variant, the emulsion is free of benzalkonium chloride, macrogolyglycerol hydroxystearate and PS80 (also called Tween 80).

[0071] The emulsion is characterized by its volume average diameter and the Span value.

[0072] The volume average diameter - noted Dl4>3J - is given by equation (1):

[0073] Eq. (1): Dl4>3J =(E n^4) / (E n^3)

[0074] in which n; represents the number of particles denoted i with diameters d;.

[0075] The polydispersity of the droplet size distribution is expressed by the value of the “Span”, defined by equation (2):

[0076] Eq. (2): Span = (D90-D10) / D50

[0077] Wherein Dio, D50 and D9o represent the diameter of the droplets below which are 10%, 50% and 90% of the sample, respectively.

[0078] The values ​​of Dl4j3J, Di0, D50 and D90 can be measured by LASER diffraction.

[0079] Thus, the droplets typically have a volume average diameter of less than or equal to 100 μm, preferably between 10 and 80 μm, in particular between 20 and 70 μm. Advantageously, the droplets have an average diameter of 60 μm. Indeed, droplets with average diameters that are too high can slow down diffusion, and therefore the release of the liposoluble active ingredient.

[0080] Furthermore, the droplets advantageously have a Span value of between 1 and 3, in particular between 1.5 and 2. Span values ​​of less than or equal to 3 will be preferred, since too great a dispersion can harm the bioavailability of the active ingredient. Furthermore, emulsions with large dispersions are generally difficult to obtain in a reproducible manner. Aqueous phase Aq

[0081] The compositions may also contain conventional, pharmaceutically acceptable additives, as listed below.

[0082] Optionally, the ophthalmic composition may contain other ingredients such as, but not limited to, osmolarity influencing agents, buffers, or viscosity increasing agents.

[0083] Various osmolarity-influencing compounds may be used to adjust the osmolarity of a solution to approximate the composition of natural tears. For example, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, dextrose, and / or mannitol may be used. in order to approach physiological osmolarity (generally in the order of 150-450 mOsm and preferably 250-350 mOsm).

[0084] Viscosity-acting agents (also called viscosifying agents) that may be used in the ophthalmic formulations of the present invention may be, but are not limited to, xanthan gum, gellan gum, monomeric polyols, povidone, hydroxypropylmethyl cellulose, poloxamers, carboxymethyl cellulose, carbomers or hydroxyethylcellulose, dextrans such as dextran 70, water-soluble proteins such as gelatin, hyaluronic acid or sodium hyaluronate. Preferably, it is hyaluronic acid or sodium hyaluronate.

[0085] The pH of the aqueous phase is typically between 5.5 and 7.5, for example between 5.8 and 6.5, in particular equal to 6.

[0086] According to a first variant, the aqueous phase Aq is essentially composed of water and buffers. It may in particular be water for injections (WFI water), mixed with a buffer, and optionally an osmolarity modifying agent and / or a viscosifying agent, in particular as indicated previously.

[0087] The buffer typically comprises acids and / or bases. For example, sodium hydroxide (NaOH), sodium citrate and / or acetic acid may be used as a buffer.

[0088] According to a second variant, the aqueous phase is preferably in the form of an aqueous gel.

[0089] The aqueous gel is advantageously obtained by gelling an aqueous solution comprising pharmaceutically acceptable viscosifying agents, such as those listed above, and preferably xanthan gum, gellan gum, hyaluronic acid and / or sodium hyaluronate, all cellulose derivatives (HPMC, HEC, EC, etc.) or xanthan gum.

[0090] Advantageously, the viscosifying agent is present in an amount sufficient to achieve a dynamic viscosity at rest typically between 3000 and 3500 mPa.s, advantageously between 3200 and 3300 mPa.s. Preferably, the viscosifying agent is also present in an amount sufficient to achieve a loss factor tan(δ) at rest of less than 1, preferably between 0.8 and 0.15. Those skilled in the art know how to determine the gelling agent content to achieve the targeted dynamic viscosity and loss factor tan(δ) ranges, a content which depends on the nature but also on the molecular weight of the gelling agent.

[0091] The loss factor tan(ô) at rest of the emulsion is generally measured at 20°C by performing an amplitude sweep in oscillation using a rotary rheometer MCR102 (Anton Paar GmbH, Graz, Austria) equipped with a cone-plate geometry of diameter 50 mm and angle 1°. The shear strain is varied from 0.4 to 100%. The loss factor tan(ô) at rest corresponds to the value obtained in the linearity domain viscoelastic.

[0092] The dynamic viscosity at rest is measured after dilution in artificial tears adjusted to pH 7.4 at a ratio of 30:7 (Emulsion:Artificial Tears), in order to simulate the dilution during administration in the eye. The flow curves are obtained using a rotational rheometer, such as an MCR102 rheometer (Anton Paar GmbH, Graz, Austria) with a cone-plate geometry of diameter 50 mm and angle 1° and a Peltier plane to control the sample temperature at 20 °C. The shear gradient is varied from 0.1 to 1000 s-1 with an acquisition time of 10 to 1 s per point. The value retained is the initial dynamic viscosity of the flow curve. Artificial tears typically have the following compositions:

[0093] [Tables 1] Mass per 100 mL CaCl2.H2O 8 mg MgCl2 5 mg KC1 138 mg NaCl 670 mg NaHCO3 200 mg Water ppi QSP 100 mL

[0094] In this second variant, the aqueous gel further increases the stabilization of the emulsion by avoiding or slowing down creaming.

[0095] Creaming is a phenomenon of gravitational separation of the phases due to the difference in gravity of the phases: the dispersed lipid phase, less dense than the aqueous phase, migrates upwards, generating a vertical concentration gradient. Creaming is a reversible phenomenon, however, it is preferable to avoid it because it promotes flocculation, prior to the coalescence of the droplets, which increases their size irreversibly.

[0096] According to this second variant, the aqueous gel typically comprises a buffer, typically comprising acids and / or bases. For example, sodium hydroxide (NaOH), sodium citrate and / or acetic acid may be used as a buffer. Particulate surfactant

[0097] The particulate surfactant comprises or consists of organic polymer particles.

[0098] Particles are defined by their average size in intensity and their polydispersity index.

[0099] By "mean size in intensity" corresponds to the harmonic mean diameter, and is denoted Z-av. The intensity-averaged size can be expressed as the harmonic mean based on the intensity (2,3) and is illustrated by the equation below:

[0100] [Math.l]

[0101] where S; is the scattered intensity of particle i and D; is the diameter of particle i. The value of the average size Z is calculated by cumulant methods (see in particular J. Chem. Phys 57 (11), pp 4814-4820, 1972.). It is based on measurements carried out by dynamic light scattering (DLS).

[0102] By "polydispersity index" is meant a measure of the heterogeneity of a sample as a function of its size. Polydispersity can be due to the size distribution in a sample. Thus, in the case of a peak, the polydispersity index is 1, in the case of a Gaussian, the index can be greater than 3. The polydispersity index is generally measured by DLS.

[0103] The organic particles typically have an average intensity size (Z-Av) less than or equal to 500 nm, in particular between 100 and 300 nm, preferably between 150 and 250 nm. Particles of 500 nm or less are preferred, because they are distributed on the surface of the droplets and provide sufficient stability to the emulsion.

[0104] The organic particles typically have a polydispersity index less than or equal to 0.3, preferably between 0.05 and 0.2, in particular between 0.1 and 0.15.

[0105] According to an advantageous variant, the particulate surfactant does not play the role of vector of an active principle: thus, the solid particles of the particulate surfactant are devoid of active principle.

[0106] Advantageously, the surfactant comprises or consists of particles of a mucoadhesive polymer, preferably chosen from hyaluronic acid, chitosan, PLA-PEG ((polylactic acid)-polyethylene glycol), PLGA (poly(lactic-co-glycolic acid)), PLGA-PEG (poly(lactic-co-glycolic acid)-polyethylene glycol), PVP (Polyvinylpyrrolidone), PVP-PEG (Polyvinylpyrrolidone-polyethylene glycol), PCL (Polycaprolactone), PCL-PEG (Polycaprolactone-polyethylene glycol), and mixtures thereof.

[0107] Advantageously, these are chitosan particles. Indeed, such particles have mucoadhesive properties, beneficial for improving the residence time of the composition on the ocular mucosa, and therefore the bioavailability of the active ingredient.

[0108] The chitosan particles are obtained by coprecipitation with an organic acid salt. For the purposes of the present invention, an “organic acid” means an organic molecule comprising at least one carboxylic acid function -COOH, and whose pKa is between 3 and 5. It may in particular be an acid of formula R-COOH, in which R represents a C1-C6 alkyl (preferably C1-C4) optionally substituted by one to three substituents chosen from -OH, -COOH. Examples of organic acids according to the invention are acetic acid, lactic acid, citric acid. The organic acid is pharmaceutically acceptable, and suitable for ophthalmic applications. Alternatively, it may be tripolyphosphate (CAS No. 14127-68-5).

[0109] For the purposes of the present invention, the term "organic acid salt" means the pharmaceutically acceptable base addition salts formed when an acid proton present in the organic acid is either replaced by a metal ion, for example an alkali metal ion, an alkaline earth metal ion or an aluminum ion; or coordinated with a pharmaceutically acceptable organic or inorganic base. Acceptable organic bases include diethanolamine, ethanolamine, N-methylglucamine, triethanolamine, tromethamine and the like. Acceptable inorganic bases include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate and sodium hydroxide. Preferably, it will be a sodium salt.

[0110] Preferably, the organic acid salt is sodium hyaluronate or sodium citrate. In a particular embodiment of the invention, the surfactant comprises or consists of particles obtained by coprecipitation between chitosan and sodium citrate.

[0111] Concerning the protocol for forming the particles of the surfactant, the chitosan is dissolved in water, then the solution is optionally filtered. The acid salt is added (with stirring) either in solid form or in solution form, then the pH of the solution is raised to approximately 6 by adding a base, preferably mineral and if necessary with a cation identical to that of the weak acid salt, such as sodium hydroxide. The formation of nanoparticles is then observed. Active ingredient

[0112] According to one embodiment, the composition comprises at least one active ingredient.

[0113] The active ingredient may be liposoluble or hydrosoluble.

[0114] For the purposes of the invention, the term “water-soluble active ingredient” means an active ingredient having high solubility in water, within the meaning of the biopharmaceutical classification system “BCS” (cited above). More specifically, reference is made to active ingredients of class I or III within the meaning of the BCS. Thus, an active ingredient is water-soluble when the entire highest therapeutic dose of the active ingredient considered is soluble in 250 mL of a buffered aqueous solution over a pH range of 1 to 6.8 at 37°C±1°C.

[0115] According to one embodiment, the ophthalmic compositions of the invention contain an effective amount of water-soluble active ingredient.

[0116] Examples of water-soluble active ingredients are beta-blockers chosen in particular from timolol, levobunolol, dorzolamide and / or brinzolamide, preferably timolol.

[0117] In this embodiment, the water-soluble active ingredient is advantageously included in the aqueous phase Aq, or is adsorbed on the surface of the organic particles. However, the active ingredient does not form a covalent bond with the organic particles. The formulation of Pickering emulsions with a water-soluble active ingredient is well known to those skilled in the art.

[0118] According to one embodiment of the invention, the composition, and more particularly the lipid phase L, comprises at least one liposoluble active ingredient.

[0119] By “liposoluble active ingredient” is meant an active ingredient having low solubility in water, within the meaning of the biopharmaceutical classification system “BCS”, as defined in particular in the document “M9 Biopharmaceutics Classification SystemBased Biowaivers - Guidance for Industry” published in May 2019 by the American “Food and Drug Administration” (FDA), or the document “ich-m9-biopharmaceutics-classification-system-based-biowaivers-step-5” officially published by the European Medicines Agency (EMA) on 07 / 30 / 2020, and available online at: https: / / www.ema.europa.eu / documents / scientific-guideline / ich-m9-biopharmaceutics-classification-system-based-biowaivers-step-5_en.pdf. More specifically, we are referring to active ingredients of class II or IV within the meaning of the BCS. Thus, an active ingredient is considered fat-soluble when less than 85% by weight of the highest therapeutic dose is soluble in 250 mL of a buffered aqueous solution over a pH range of 1 to 6.8 at 37°C±1°C.

[0120] The ophthalmic compositions contain an effective amount of fat-soluble active ingredient. Generally, the compositions described in the present invention will contain between 5 pg / mL and 10 mg / mL of fat-soluble active ingredient.

[0121] Examples of fat-soluble active ingredients include prostaglandins and steroids.

[0122] By "prostaglandins" is meant compounds of the prostaglandin family, their derivatives and / or analogues, whether of natural or synthetic origin, such as prostamides. Prostaglandins have a cyclopentyl substituted in position 1 and 4 by oxygen atoms (i.e. by two hydroxyl groups, or carrying a ketone function C=O in position 1 and substituted by a hydroxyl group in position 4), and in position 2 and 3 by two identical or different monovalent hydrocarbon chains, saturated or unsaturated (i.e. comprising at least one C=C double bond), linear or branched, comprising 1 to 12 carbon atoms. The chain in position 3 generally comprises an ester or amide function. Prostaglandins can be of series H, D, E, F, Alpha or I and of class 1, 2 or 3.

[0123] Advantageously, prostaglandins having therapeutic indications for the treatment or prevention of ophthalmic diseases or conditions will be chosen. In particular, the prostaglandins are selected from the group consisting of latanoprost, travoprost, bimatoprost and tafluprost.

[0124] When the liposoluble active ingredient is a prostaglandin, the compositions of the invention will typically contain between 5 pg / mL and 500 pg / mL, in particular from 20 to 400 pg / mL, for example from 40 to 300 pg / mL, of liposoluble active ingredient.

[0125] Preferably, for Latanoprost or Travoprost, the composition comprises between 10 and 100 pg / mL, in particular between 20 and 75 pg / mL, for example 50 pg / ml or 40 pg / ml of liposoluble active ingredient.

[0126] Preferably, for Latanoprost, the composition comprises between 10 and 100 pg / mL, in particular between 20 and 75 pg / mL, for example 50 pg / ml of liposoluble active ingredient.

[0127] Advantageously, for Bimatoprost, the composition comprises between 10 and 100 pg / mL, in particular between 50 and 400 pg / mL, for example between 100 and 300 pg / ml of liposoluble active ingredient.

[0128] By "steroids" is meant a compound comprising a partially or fully hydrogenated hydrophobic cyclopentanophenanthrenic (sterane) nucleus or derived therefrom. Steroids include in particular sterols characterized by the presence of a hydroxyl group on the C3 carbon (for example, cholesterol).

[0129] Steroids are or behave like hormones. They can be grouped into five categories according to their receptors: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestins. Vitamin D derivatives form a sixth hormonal system. • Glucocorticoids: cortisol, dexamethazone • Mineralocorticoids: aldosterone, fludrocortisone • Androgens: testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, dihydrotestosterone (DHT) • Estrogens: estradiol, estrone, estriol • Progestins: progesterone

[0130] Advantageously, a steroid chosen from among the anti-inflammatory steroids will be chosen. roids, such as hydrocortisone, prednisone, prednisolone, methylprednisolone, betamethasone, dexamethasone, triamcinolone, estradiol, estrone, estriol, progesterone, and mixtures thereof.

[0131] When the liposoluble active ingredient is a corticosteroid, the compositions of the invention will typically contain between 0.01 mg / mL and 10 mg / mL, in particular from 0.05 to 7.5 mg / mL, for example from 0.1 to 5 mL, of liposoluble active ingredient.

[0132] Advantageously, for dexamethasone, the composition comprises between 0.1 and 2 mg / mL, for example 1 mg / ml of liposoluble active ingredient.

[0133] In a particular embodiment, the composition comprises at least one liposoluble active ingredient and optionally a water-soluble active ingredient. For example, in a particular embodiment of the invention, the composition comprises both a liposoluble active ingredient, such as a prostagalandin (PGA) derivative or a steroid derivative, and a water-soluble active ingredient such as a [3-blocking agent.

[0134] According to a particular embodiment, the composition comprises one or more protaglandin(s) in combination with a beta-blocker chosen from timolol, ε-vobunolol, dorzolamide and / or brinzolamide, preferably timolol. In this embodiment, the prostaglandin is advantageously included in the lipid phase, while the β-blocker is advantageously included in the aqueous phase. Particular embodiments

[0135] According to one embodiment, the ophthalmic composition comprises a non-ionic oil-in-water emulsion with: • an aqueous phase Aq, • a lipid phase L, in the form of droplets dispersed in the aqueous phase, • an interface between said lipid phase L and said aqueous phase Aq, and • a surfactant to stabilize the emulsion, located at the interface between the lipid phase and aqueous phase,

[0136] said lipid phase L comprising at least one liposoluble active ingredient,

[0137] said surfactant being particulate, in the form of organic particles of average size in intensity between 100 and 300 nm, preferably between 150 and 250 nm, and

[0138] with a polydispersity index typically less than or equal to 0.3, preferably between 0.05 and 0.2, in particular between 0.1 and 0.15.

[0139] According to this embodiment, the lipid phase is present at a content of between 0.1% and 5%, in particular between 0.5 and 2%, for example 1%, by volume relative to the total volume of the composition. The droplets of the emulsion advantageously have a volume average diameter of less than or equal to 100 μm, preferably between 10 and approximately 80 pm, in particular between 20 and 70 pm, and a Span value between 1 and 3, in particular between 1.5 and 2.

[0140] Typically, the lipid phase preferably comprises, or consists essentially of, glycerol esters of formula (I):

[0141] [Chem.l] p-CM -0¾ --0¾ (I)

[0142] in which Rb R2 and R3, independently of each other represent H, a -(O=C)-CrCi8 alkyl group or a -(O=C)-C2-Ci8 alkenyl group, it being understood that at least one of Rb R2 and R3 is different from H,

[0143] and may also include penetrating agents.

[0144] Preferably, the surfactant comprises or consists of chitosan particles.

[0145] Advantageously, the particulate surfactant / lipid phase mass ratio is between 0.1% and 2%.

[0146] Typically, the pH of the aqueous phase is typically between 5.5 and 7.5, for example between 5.8 and 6.5, and the aqueous phase is preferably in the form of an aqueous gel.

[0147] The aqueous gel is for example obtained by gelling an aqueous solution comprising pharmaceutically acceptable viscosifying agents, such as xanthan gum, gellan gum, hyaluronic acid and / or sodium hyaluronate, cellulose derivatives, xanthan gum and alginate. The viscosifying agent is present in an amount sufficient to achieve a dynamic viscosity at rest typically between 3000 and 3500 mPa.s, advantageously between 3200 and 3300 mPa.s. Preferably, the viscosifying agent is also present in an amount sufficient to achieve a loss factor tan(δ) at rest of less than 1, preferably between 0.8 and 0.15.

[0148] Preferably, the active ingredient is chosen from prostaglandins (such as la-tanoprost, travoprost, bimatoprost and tafluprost), optionally in admixture with timolodol, levobunolol, dorzolamide and / or brinzolamide, and steroids (such as hydrocortisone, prednisone, prednisolone, methylprednisolone, beta-methasone, dexamethasone, triamcinolone, and mixtures thereof), at a concentration of between 5 pg / mL and 10 mg / mL of prostaglandins. Process for preparing the emulsion

[0149] The composition is prepared according to methods known to those skilled in the art.

[0150] The composition of the invention, which comprises: • an aqueous phase Aq, • a lipid phase L, in the form of droplets dispersed in the aqueous phase, comprising at least one liposoluble active ingredient, • an interface between said lipid phase L and said aqueous phase Aq, and • a particulate surfactant, in the form of organic particles of average size in intensity less than or equal to 500 nm to stabilize the emulsion, located at the interface between the lipid phase and the aqueous phase,

[0151] is advantageously prepared according to the following steps: a. Suspending the particulate surfactant in the aqueous phase, b. Dissolving the active ingredient in an oil to form the lipid phase, c. Addition of the lipid phase to the suspension obtained in step a), d. Emulsification, so as to obtain an emulsion.

[0152] The droplets of the emulsion obtained at the end of step d) typically have a volume average diameter less than or equal to 100 μm, preferably between 10 and approximately 80 μm, in particular between 20 and 70 μm.

[0153] Furthermore, the droplets advantageously have a Span value of between 1 and 3, in particular between 1.5 and 2.

[0154] Preferably, the emulsification step d) is carried out using a high shear mixer, such as a rotor / stator mixer, or a high pressure homogenizer. The emulsification is preferably carried out without heating, and / or at room temperature. When the mixer is a rotor / stator, it typically operates at a stirring speed greater than 10,000 rpm, for example between 10,000 and 20,000 rpm.

[0155] During step c) of adding the lipid phase to the aqueous phase, the lipid phase preferably represents between 0.1% and 5%, in particular between 0.5 and 2%, for example 1%, by volume relative to the total volume of the composition. Step c) can be carried out in a conventional manner for those skilled in the art. Step c) is typically carried out at room temperature.

[0156] The oil used in step b) of dissolving the active ingredient in an oil to form the lipid phase is as described previously in the lipid phase L section, and comprises, or consists essentially of, glycerol esters of formula (I) as defined above, and optionally penetrating agents. Step b) is typically carried out at room temperature.

[0157] The aqueous phase comprises or consists essentially of water (in particular WFI water), and optionally of agents influencing osmolarity, buffers, and / or viscosifying agents, as defined above.

[0158] The aqueous phase used in step a) is preferably gelled. In this case, the process comprises a prior step of gelling an aqueous solution, said gelling step comprising:

[0159] al) dissolving a gelling agent in water, typically with stirring and preferably heating to a temperature between 50 and 80°C then cooling to room temperature,

[0160] a2) optionally adding agents influencing osmolarity, buffers, and / or agents viscosifiers in solution in water,

[0161] a3) homogenization of the gelled aqueous solution to form the aqueous phase.

[0162] The quantities of water gelling agent, and where appropriate other additives op tionals are chosen so as to achieve a dynamic viscosity at rest typically between 3000 and 3500 mPa.s, advantageously between 3200 and 3300 mPa.s and preferably a loss factor tan(ô) at rest of less than 1, preferably between 0.8 and 0.15. Therapeutic Applications

[0163] The ophthalmic compositions of the invention are useful as medicaments, in particular for administration by ocular instillation.

[0164] According to a first variant, the composition is useful for the treatment of dry eye. In this case, the composition does not necessarily contain an active ingredient, the oily phase and, where appropriate, the gelling agent (in particular sodium hyaluronate) being sufficient in itself to combat dry eye.

[0165] According to a second variant, the composition comprises a liposoluble active ingredient.

[0166] According to one embodiment, the active ingredient is chosen from steroids. These Particular compositions are useful as a medicament, in particular for preventing, relieving or treating ocular inflammations. Alternatively, the invention relates to a method for preventing, relieving or treating ocular inflammations, comprising the ocular administration of an effective amount of the ophthalmic composition to a patient in need thereof, the active ingredient being chosen from steroids.

[0167] Ocular inflammation can cause, in particular, a breakdown of the barriers that isolate the eye from the general circulation, allowing the entry of proteins and cells that participate in the inflammatory process and have an impact on healing. Inflammation can affect the cornea and sclera on the surface of the eye; the uvea, which is composed of the iris, ciliary body, and choroid; and the origin of the optic nerve, the retina and the optic disc. For example, ocular inflammation affects the sclera on the surface of the eye; the uvea, which is composed of the iris, ciliary body, and choroid; and the origin of the optic nerve, the retina and the optic disc. This ocular inflammation can be responsible for opacities and lesions of the cornea (keratitis); lesions of the sclera (scleritis and episcleritis); uveitis with the complication of clouding of the lens (cataract); adhesions of the iris to the lens (synechiae); macular edema; retinal detachment; ocular hypertension and degeneration of the optic nerve caused by glaucoma. the formation of new vessels (neovascularization); etc.

[0168] According to another embodiment, the active ingredient is chosen from prostaglandins, optionally in admixture with timolodol, levobunolol, dorzolamide and / or brinzolamide. These particular compositions are useful as medicaments, in particular in the treatment or prevention of intraocular hypertension, and / or glaucoma, such as open-angle glaucoma. Alternatively, the invention relates to a method for preventing or treating intraocular hypertension, and / or glaucoma, such as open-angle glaucoma, comprising the ocular administration of an effective amount of the ophthalmic composition, the active ingredient being chosen from prostaglandins, optionally in admixture with timolodol, levobunolol, dorzolamide and / or brinzolamide.

[0169] For the purposes of the present invention, an "effective amount" refers to the level or amount of active ingredient targeted, without causing significant negative or undesirable side effects on the target, (1) delaying or preventing the onset of the disease or condition; (2) slowing or stopping the progression, aggravation, or deterioration of one or more symptoms of the disease or condition; (3) causing improvements in the symptoms of the disease or condition; (4) reducing the severity or incidence of the disease or condition; or (5) curing the disease or condition. An effective amount may be administered before the onset of the disease or condition, for prophylactic or preventive action. Alternatively or in addition, the effective amount may be administered after the initiation of the disease or condition, for therapeutic action.

[0170] The patient may be a mammal, preferably a human. FIGURES

[0171] [Fig.l] [Fig.l] schematically illustrates the structure of the three emulsions NP-E, GE and NP-GE of Example 3. The spheres represent the droplets of the lipid phase, while the network represents the gel form of the gelled aqueous phase.

[0172] [Fig.2] Rheological characterization of the emulsions of interest. A) Flow curves representing the dynamic viscosity as a function of the shear gradient. B) Plot of the shear stress as a function of the shear gradient. C) Blink simulation test over 10 cycles of 1 min. D) Observation

[0173] visual of creaming after 8 weeks.

[0174] [Fig.3] Particle size measurements of emulsions obtained by laser diffraction. A) Volume distributions for the three emulsions studied, NP-E, GE, and NP-GE at the initial time. B) Evolution of Dl4j3J over time after storage at room temperature. The results are represented by the mean and standard deviation of the measurements of 3 independent samples (n = 3).

[0175] [Fig.4] Travoprost release profiles for Travatan® (- -), NP-E simple Pickering emulsion (-), GE emulsion / gel (-) and Pickering emulsion in the NP-GE gel (-).

[0176] [Fig.5] Relative cell viability of the three emulsions selected in comparison with commercial Travatan®. BAK: Benzalkonium Chloride. **p-value < 0.01 in a t-test with Welch correction. EXAMPLES ABBREVIATIONS

[0177] ACN acetonitrile

[0178] rpm rotation per minute

[0179] Tamb Ambient temperature

[0180] PPI For Injectable Preparations

[0181] v / v volume / volume

[0182] m / v mass / volume

[0183] DLS analysis by LASER diffraction (in English "Dynamic Light Scattering")

[0184] Z-Avg Average size in intensity

[0185] PDI Polydispersity Index

[0186] PS80 PolySorbate 80

[0187] NaHA Sodium Hyaluronate

[0188] Cs Chitosan

[0189] Qsp Quantity sufficient for MATERIALS AND METHODS

[0190] Three types of Cs (Chitoclear®) with 1% w / v solution viscosities of 10, 12, and 90 mPa.s (supplier's information) and respective degrees of deacetylation of 95, 74, and 95% (supplier's information) were supplied by Primex (Siglufjôrôur, Iceland). Glacial acetic acid grade AnalaR® NORMAPUR® was purchased from VWR Chemicals (Radnor, PA, USA). 2N sodium hydroxide was supplied by LCH Chimie (Les Aires, France). Pharmaceutical excipient grade sodium hyaluronate (NaHA) with intrinsic viscosity of 2.5 m3 / kg was supplied by Shiseido CO., LTD. (Kakegawa-shi, Japan). Sodium citrate dihydrate (molar mass 294.1 g / mol) was supplied by Caesar & Loretz GmbH (Hilden, Germany). Gellan gum (Kelcogel® CG-LA) was supplied by CP Kelco (Atlanta, GA, USA). Lipophilic Labrafac™ WL 1349 (Medium Chain Triglycerides, MCT) was supplied by Gattefossé (Lyon, France).Travoprost was provided by Sanofi Chinoin (Budapest, Hungary). Pyrene of 98% purity was provided by Acros Organics (Illkirch, France). Rhodamine-grafted Cs (Cs-Rhodamine), with a molecular weight of 5 kDa and a degree of deacetylation of 95%, and a molar substitution of 1%, was provided by HAworks LLC (Bridgewater, NJ, USA). Sodium chloride (NaCl), calcium chloride dihydrate (CaCl2-2H2O), and . Magnesium chloride (MgCl2), potassium chloride (KCl), sodium bicarbonate (NaHCO3), ACN, and porcine mucin type II were purchased from Sigma-Aldrich (St. Louis, MO, USA). The commercial product Travatan® was supplied by Alcon® (Hünenberg, Switzerland). Lavoisier water for injection (WFI) was supplied by CDM Lavoisier Laboratories (Paris, France). Granulometric analyses by laser diffraction

[0191] The colloidal stability of the emulsions over time after storage at room temperature was evaluated by laser diffraction. After morphological observation under a transmission optical microscope, the Dl4 3J of the globules was measured by laser diffraction using a MasterSizer 3000 equipped with a cell for the Hydro SM liquid channel (Malvern Panalytical Ltd., Malvern, United Kingdom). The measurements were carried out under mechanical stirring of 2500 rpm at an obscuration between 10 and 15%. For the processing of the acquired data, the type of particle chosen was spherical, with a refractive index of 1.47 and an absorption index of 0.002 as previously determined by the optical properties optimizer of the MasterSizer software Version 3.62 (Malvern Panalytical Ltd., Malvern, United Kingdom).The result for a sample consists of the average of 6 measurements of 10 s spaced 30 s apart, ensuring compliance with the variability criteria of the European Pharmacopoeia (< 10% for D50 and < 15% for D10 and D90). Observation by fluorescence microscopy

[0192] The probes used are pyrene for the lipid phase, and Cs-rhodamine of similar molecular weight and degree of deacetylation for the solid nanoparticles.

[0193] For the purposes of the measurements, samples are formed as follows: pyrene is dissolved in the lipid phase to obtain a concentration of 4 mg / mL prior to emulsification, and 1% of the mass of Cs used to formulate the NPs is substituted with Cs-rhodamine of similar molecular weight and degree of deacetylation.

[0194] Transmission and fluorescence observations were performed using an Axiophot fluorescence microscope (Zeiss, Oberkochen, Germany) equipped with an X-Cite® 120Q light source (Excelitas Technologies, Waltham, MA, USA). Image acquisition was performed using a Qlmaging® Retiga-2000R digital camera (Teledyne Photometrics, Tucson, AZ, USA) and QCapture Pro software version 6.0.0.605 (Teledyne Photometrics, Tucson, AZ, USA). The filters used to view pyrene and Cs-rhodamine were exc. BP 365 / 12 em. LP 397 and exc. 546 / 12 em. LP 590, respectively.

[0195] The exploitation of the obtained images was carried out using the Image! software version 1.53s from the National Institutes of Health (Madison, WI, USA). USP4 release studies

[0196] The release of travoprost from the compositions is evaluated using a USP4 CE7 Smart dissolution apparatus coupled to a CP7 pump (Sotax, Aesch, Switzerland). Cells with a diameter of 22.6 mm are used. A 5 mm ruby ​​bead is placed at the bottom of the cells, then covered by 1 mm diameter glass beads. This arrangement ensures a laminar flow of the dissolution medium at the cell level. Artificial tears adjusted to a pH of 7.4 are used as the dissolution medium, adding a concentration of 0.1% v / v of PS80 to satisfy the closed-circuit sink conditions. The volume of dissolution medium is set at 50 mL, with a pulsatile flow rate of 16 mL / min. The temperature of the dissolution medium is regulated at +35 ± 0.5 °C by the water bath of the CE7 Smart device in order to mimic the temperature conditions of the ocular surface.

[0197] The test sample of the emulsions is 2 mL (equivalent to a dose of 80 pg of travoprost). At each time point, 1 mL of the dissolution medium was taken before adding 1 mL of new medium. The samples are immediately stored in the freezer (20 °C) for one week before carrying out the travoprost assay by the HPLC-UV method described in 1.7.3 below. Gompertz modeling is applied to the dissolution profiles of the emulsions from the initial time up to a release of 85% using the DDsolver software. Travoprost assay by HPLC-UV

[0198] Sample preparation before assay consists of a half-fold dilution in ACN, followed by centrifugation for 20 minutes at 10,000 rpm. The supernatant is recovered, and 10 μL were injected for analysis. Chromatographic separation is performed with an UltiMate 3000 HPLC system (Thermo Fisher Scientific, Waltham, MA, USA) equipped with a Kinetex column of Cl8 grafted silica with dimensions of 150 x 4.6 mm and particle size of 5 μm (Phenomenex, Torrance, CA, USA) set at 40 °C. The mobile phase flow rate is set at 1 mL / min. The ACN / 10 mM phosphate buffer pH 3 content of the mobile phase is varied according to the following gradient: • from 0 to 26 minutes of analysis: linear gradient of ACN / Phosphate buffer ranging from 38 / 62 v / v to 50 / 50 v / v, • then, from 26 to 29 minutes of analysis: isocratic phase at an ACN / Phosphate buffer ratio of 50 / 50 v / v, • finally, 29 to 40 minutes of analysis: linear gradient of ACN / Phosphate buffer ranging from 50 / 50 v / v to 38 / 62 v / v.

[0199] Detection of travoprost is carried out by a UV detector at a wavelength of 200 nm. The chromatograms obtained were analyzed using Chromeleon™ 7.3.1 software (Thermo Fisher Scientific, Waltham, MA, USA). The calibration curve ranged from 5 to 25 pg / mL for the determination of eye drops (finished product) and from 0.082 to 2.5 pg / mL for the determination in dissolution samples. Linearity was confirmed by a coefficient of determination R2 > 0.995 and a bias recalculated for each point of the standard line of less than 5%. The accuracy of the method was verified by its precision, located between 98 and 102% as estimated from the recovery of control samples at the target concentration (20 μg / mL) and its precision, confirmed by a coefficient of variation less than 3% for the control samples. Finally, the injection repeatability was less than 0.4%. Cell viability assessment

[0200] The evaluation is carried out on human corneal epithelium cells (immortalized HCE-T line). The cells are cultured under standard conditions (humid atmosphere, 5% CO2 at 37 °C) in Dulbecco's Minimum Essential Medium (DMEM) supplemented with 2.5% fetal calf serum (FCS), 2 mM L-glutamine, 50 IU / mL penicillin and 50 IU / mL streptomycin. The culture medium is changed every 3 days. When the cells are confluent, they are trypsinized and then reintroduced into 96-well plates (200 pL per well) at a density of 110,000 cells / mL. Cultures are kept for 24 hours at 37°C before exposure to the compositions to allow the cells to adhere to the microplate and reach confluency.

[0201] Before incubation, the cells were washed with 200 pL of phosphate buffer saline (Phosphate Buffer Saline, PBS), then the compositions were incubated pure (100 pL / well) for 30 minutes on the cells.

[0202] After incubation, the composition is removed and the cells are washed again with 200 μL of PBS, then incubated with DMEM culture medium supplemented with 2.5% FCS for 24 hours. An AlamarBlue™ dye solution (200 μL) is added to each well for a 6-hour incubation at 37°C. The AlamarBlue™ dye solution is pre-diluted to 0.09 mg / mL in the culture medium supplemented with 2.5% FCS. The fluorescence of the AlamarBlue™ (Xex = 535 nm; / .cm = 600 nm) is measured using a cytofluorometer (Safire, Tecan Group Ltd., Mannedorf, Switzerland) adapted to microplates. The fluorescence intensity results obtained are expressed as a percentage of viable cells relative to the control.

[0203] 0.01% B AK is used as a positive control. The results presented are the mean and standard deviation of 3 independent manipulations. EXPERIMENTAL PART

[0204] Example 1a - Preparation of Chitosan Nanoparticles - sodium hyaluronate (NaHA)

[0205] Cs was dissolved in a 0.1% v / v acetic acid solution under magnetic stirring at 350 rpm for at least 12 h before being filtered on a Clearline® polyethersulfone (PES) membrane with a porosity of 0.45 pm (Dutscher, Bemolsheim, France). On the other hand, NaHA was dissolved in WFI water under magnetic stirring at 600 rpm for at least 6 h. Both solutions were left to stand overnight. 2N NaOH was added to the NaHA solution so as to obtain a pH of 6.0 at the end of the process.

[0206] The NaHA solution was then gradually added into the Cs solution, by a continuous flow under stirring.

[0207] The nanoparticles thus obtained have a Z-Avg of 190 nm and a PDI of 0.159.

[0208] Example 1b - Preparation of Chitosan Nanoparticles - Citrate

[0209] Chitosan with a viscosity in solution at 1% m / v of 10 mPa.s and a degree of 95% deacetylation and sodium citrate.

[0210] Chitosan is dissolved in a 0.1% v / v acetic acid solution to reach a concentration of 0.04% w / v (12 h of magnetic stirring at room temperature at 350 rpm). The resulting solution is filtered through a 0.45 pm polyethersulfone (PES) filter before neutralizing the pH to 6.0 with 0.4 N NaOH. Sodium citrate is dissolved in the filtered solution to reach a concentration of 2.94% w / v. Acetic acid is then added from a 5% v / v solution under magnetic stirring at 500 rpm until a pH of 6.0 is reached. The resulting nanoparticles have a Z-avg of 193 nm and a PDI of 0.1.

[0211] For variations in concentration of chitosan and sodium citrate between 0.025 and 0.04% w / v and 2.5 and 3.0% w / v respectively, the nanoparticles obtained have a Z-Avg which can vary from 180 to 200 nm and a PDI of 0.10 to 0.15 as determined by DLS measurements.

[0212] Compared to the nanoparticles of example 1a, the size of the nanoparticles obtained is not significantly different but the PDI is clearly improved, which can be attributed to the fact of having replaced a polymer of large molar mass (NaHA) by a molecule of small size (citrate).

[0213] Example 2 - Preparation of an emulsion according to the invention with Solid Chitosan Nanoparticles obtained according to Example 1

[0214] Preparation of the lipid phase

[0215] The oily phase of the emulsion corresponds to a 0.4% w / v solution of travoprost in medium-chain triglycerides (consisting of compounds of general formula (I) as defined above, with substituents Rb R2 and R3 chosen from C6-Ci8 alkyls). Dissolution is carried out at room temperature with magnetic stirring at 250 rpm for 2 h.

[0216] Preparation of a gelled aqueous phase

[0217] The aqueous phase of the emulsion comprises the nanoparticles obtained in Example 1 and a weak gel of gellan gum and sodium hyaluronate. The gel is obtained by first dissolving the gellan gum in WFI water in a water bath at 80°C with magnetic stirring at 700 rpm (gellan gum concentration of 0.6% w / v). Once dissolved, the solution is allowed to cool to room temperature. The sodium hyaluronate and the remainder of the WFI water are added so as to obtain a gellan gum and sodium hyaluronate concentration of 0.3 and 0.2% w / v respectively. The solution is homogenized for 5 h at room temperature with magnetic stirring at 700 rpm.

[0218] Suspension of nanoparticles

[0219] The suspension of nanoparticles of example 1a or 1b and the aqueous phase - preferably gelled - are mixed in equal volume to obtain the final aqueous phase of the emulsion (1 h at 1,400 rpm).

[0220] Emulsification

[0221] The final emulsion is obtained by adding 1% v / v of oil phase into the aqueous phase under magnetic stirring at 1,400 rpm to homogenize and stirring with a rotor-stator at 15,000 rpm for 3 minutes to emulsify the oil phase. The emulsification parameters can vary from 10,000 to 20,000 rpm and from 2 to 5 minutes without significant impact on the final size distribution of the emulsion obtained.

[0222] Results obtained for Pickering emulsions with Cs-NaHA nanoparticles (example 1a):

[0223] Several concentrations of 1 to 4% v / v of oil were explored.

[0224] We obtain a volume average diameter D4 3 varying from 32 pm to 96 pm and a Span value varying from 1.3 to 2.6 depending on the concentration of the lipid phase concentration.

[0225] Size measurements by laser diffraction after emulsification showed that the oil concentration impacted the Dl43J of the emulsions obtained. Indeed, for a higher concentration (4% vs 1% v / v) the Dl4>3J of the emulsions was three times larger and the size distribution wider than for a lower oil concentration.

[0226] This observation indicates that the Cs - NaHA NPs are not in excess compared to the oil.

[0227] Coalescence is observed for the 4% emulsion. Creaming is also observed for the 2% emulsion as well as flocculation. Flocculation is also observed after 48 hours of standing for the emulsion containing 1% v / v of triglycerides (lipid phase).

[0228] A first attempt consisted of increasing the NP / oil ratio by reducing the concentration of triglycerides to 0.25% v / v. This appears to have reduced flocculation, which nevertheless persists.

[0229] Results obtained for Pickering emulsions with Cs-citrate nanoparticles (example 1b):

[0230] A volume average diameter D43 of approximately 60 pm and a Span value of approximately 1.9 are obtained.

[0231] Furthermore, the organization of NPs around the oil droplets was visualized by fluorescence microscopy, confirming their involvement in the stabilization of the emulsion.

[0232] The absence of significance of the impacts of the different factors studied (time and speed of homogenization) on the values ​​of Dl4>3J and Span made it possible to conclude that the process was robust.

[0233] Despite the stability of the emulsion, a creaming phenomenon was observed. Although this creaming is reversible and the flocculation problem previously encountered with the nanoparticles of example 1a does not occur, creaming can promote coalescence over time. Thus, the rheology of the aqueous phase was optimized by gelation using gellan gum, which makes it possible to obtain weak gels in the presence of cations, introduced here with sodium citrate.

[0234] The evaluation of the different gels was carried out by combining a visual bottle test with rheology measurements to visually evaluate the creaming by observing the accumulation of oil at the meniscus of the emulsion. A 0.05% w / v gellan gel seems sufficient to stabilize the emulsion against creaming without excessively increasing the dynamic viscosity of the medium. However, a syneresis phenomenon is observed. The addition of NaHA, a hygroscopic polymer, makes it possible to retain water in the gel and limit this phenomenon. The optimal gel is composed of 0.15% w / v gellan gum in association with 0.1% w / v NaHA. Example 3: comparative study

[0235] For the continuation of the work 3 emulsions were retained and compared ([Fig.l]): 1. a Pickering emulsion according to the invention, designated NP-E, not containing gelling polymers in the aqueous phase, 2. a comparative emulsion stabilized only by a weak gel present in the aqueous phase, designated by GE, 3. a Pickering emulsion according to the invention obtained with a gelled aqueous phase, noted NP-GE.

[0236] These three emulsions were compared on the basis of their colloidal stability, their rheological properties, and their in vitro dissolution profiles. 1. Colloidal stability

[0237] The colloidal stability of the emulsions at room temperature was evaluated by laser diffraction, the results are presented in [Fig.3]. For the 3 emulsions obtained the particle size distribution (Figure 2A) can be considered as monodisperse (Span < 2) with respective spans of 1.6, 1.8 and 1.9 for the NP-E, GE and NP-GE emulsions.

[0238] The evolution of Dl4j3J over time (Figure 3B) shows that despite some variations the size of the oil droplets is stabilized by the Cs-Citrate NPs and / or by the freezing of the aqueous phase. 2. Rheology

[0239] A rheological characterization was carried out on the different emulsions ([Fig.2]). The flow curves (Figure 32A) show a shear-thinning behavior of the 3 formulas through the decrease in dynamic viscosity as a function of the shear gradient. It is possible to distinguish the simple Pickering emulsion, NP-E, from the GE and NP-GE emulsions containing the weak gel providing a higher dynamic viscosity. Although they all have a shear-thinning character, another notable difference can be highlighted by this rheological characterization. Indeed, by representing the shear stress as a function of the shear gradient (Figure 2B), it is possible to evaluate the flow threshold of the formulas, which is determined by the ordinate at the origin of the graph. The GE and NP-GE emulsions are again distinguished from the NP-E emulsion by their shear stress at the origin being 35 times greater.This is visually reflected by creaming of the oil droplets for the NP-E emulsion while this phenomenon is inhibited for emulsions presenting the gel in its aqueous phase (Figure 2D).

[0240] Finally, a rheological characterization, linked to the thixotropy of the formulas, was carried out in order to evaluate their behavior once instilled in the eye. The evolution of the dynamic viscosity during 10 cycles mimicking the eyelid blink is shown in Figure 2D. For the three emulsions studied, a decrease in the dynamic viscosity is observed over time, which testifies to their rheofluidifying and thixotropic character. On this criterion, it is the emulsions containing NP, NP-E and NP-GE, which are distinguished from the GE formula by higher recovery indices (RI), of 66 and 60% against 49%. 3. In vitro dissolution

[0241] The travoprost release profiles obtained after the in vitro dissolution tests are shown [Fig.4], as well as the Gompertz modeling parameters. The profile of the NP-E emulsion (without gel) is similar to that of the commercial comparator, Travatan®. Indeed, more than 90% of the dose is released after 5 minutes without control of the kinetics. In addition, the release profiles of the gel emulsions (GE and NP-GE) demonstrate control of the kinetics by the latter. The application of Gompertz modeling makes it possible to assess two quantities describing the dissolution profile. Firstly, parameter a, giving the proportion of undissolved travoprost in the release medium after 1 h, and parameter 13, evaluating the dissolution rate and dictating the shape of the profile. For the two parameters studied, there is no significant difference between the GE and NP-GE emulsions. Indeed, parameter a indicates that 13 and 16% of undissolved travoprost remain respectively after one hour, and parameter 13 is equivalent in both cases, at 1.4. NPs therefore do not seem to have an impact on the travoprost release profiles. 4. Assessment of cell viability

[0242] The results of the cell viability study after exposure to the 3 emulsions in comparison with commercial Travatan® are presented in [Fig.5]. The positive and negative controls reinforce the reliability of the test. Only 0.01% B AK induces a significant decrease in relative cell viability according to a t-test with Welch correction. These results seem to show an equivalence between the emulsions and travatan®, preserved with polyquatemium-1, from the point of view of cell viability after a punctual exposure to the different formulas. 5. Conclusions

[0243] From the point of view of colloidal stability, although the NP-E emulsion exhibits creaming, laser diffraction measurements demonstrate effective stabilization of the emulsion by the Cs-Citrate NPs over a period of 6 months at room temperature. The GE and NP-GE emulsions are also stable over this period, with the gel also preventing creaming of the emulsion.

[0244] For all 3 emulsions, a shear-thinning behavior is observed, which is in agreement with the usual rheology of polymeric emulsions. In addition, the threshold fluid character obtained by the gellan gum and NaHA gel was preserved when adding the Cs-Citrate NPs (GE vs. NP-GE), which explains the satisfactory stabilization against creaming of the emulsion.

[0245] In in vitro dissolution tests, the GE and NP-GE formulations were able to slow down the release kinetics of travoprost, compared to Travatan® ophthalmic solution. However, this slowing down of the release of Travoprost® is not necessarily an advantage for the ocular route when the residence time of the eye drops on the eye is short.

[0246] A repeated blink simulation test was therefore carried out in order to evaluate the evolution of the dynamic viscosity of the different emulsions when they are subjected to strong cyclic stresses. This method made it possible to demonstrate that The NP-GE emulsion was more resistant to this type of stimulation, with a higher dynamic viscosity than the NP-E and GE emulsions at the end of the test.

[0247] In vitro cell viability tests have shown equivalence between the three emulsions and the commercial Travatan® formula. However, this test is based on a single 30-minute exposure. This allows us to conclude for the moment that the formulas are relatively well tolerated at the time of their administration. CONCLUSIONS

[0248] Compositions according to the invention have been prepared, with travoprost as the liposoluble active ingredient. They make it possible to dispense with the use of non-particulate surfactants, which guarantees good tolerance as demonstrated by cytotoxicity tests, without compromising the stability of the emulsions at room temperature.

Claims

Claims

1. Ophthalmic composition, comprising an oil-in-water emulsion with: • an aqueous phase Aq, • a lipid phase L, in the form of droplets dispersed in the aqueous phase, • an interface between said lipid phase L and said aqueous phase Aq, and • a particulate surfactant for stabilizing the emulsion, located at the interface between the lipid phase and the aqueous phase, said surfactant comprising or consisting of organic particles of average size less than or equal to Ipm, said composition being free of non-particulate surfactant, and advantageously free of preservative.

2. Composition according to claim 1, characterized in that the droplets have a volume average diameter less than or equal to 100 pm, preferably between 10 and approximately 80 pm, in particular between 20 and 70 pm, and advantageously have a Span value of between 1 and 3, in particular between 1.5 and 2.

3. Composition according to claim 1 or 2, characterized in that the lipid phase is present at a content of between 0.1% and 5%, in particular between 0.5 and 2%, for example 1%, by volume relative to the total volume of the composition.

4. Composition according to any one of claims 1 to 3, characterized in that the organic particles have an average intensity size less than or equal to 500 nm, in particular between 100 and 300 nm, preferably between 150 and 250 nm, and a polydispersity index typically less than or equal to 0.3, preferably between 0.05 and 0.2, in particular between 0.1 and 0.

15.

5. Composition according to any one of claims 1 to 4, characterized in that the surfactant comprises or consists of chitosan particles.

6. Composition according to claim 5, characterized in that the surfactant comprises or consists of particles of chitosan co-precipitated with an organic acid salt, in particular sodium citrate.

7. Composition according to any one of claims 1 to 6, characterized in that the mass ratio of particulate surfactant / lipid phase L is between 0.1 and 2%.

8. Composition according to any one of claims 1 to 7, characterized in that the aqueous phase Aq is in the form of a gel.

9. Composition according to claim 8, characterized in that the aqueous gel is obtained by gelling an aqueous solution comprising pharmaceutically acceptable viscosifying agents, such as xanthan gum, gellan gum, hyaluronic acid and / or sodium hyaluronate.

10. Composition according to any one of claims 1 to 9, characterized in that said composition comprises at least one active ingredient.

11. Composition according to any one of claims 1 to 9, characterized in that the active ingredient is chosen from • prostaglandins, such as latanoprost, travoprost, bi-matoprost and tafluprost, optionally mixed with timolol, levobunolol, dorzolamide and / or brinzolamide, and • steroids, such as hydrocortisone, prednisone, prednisolone, methylprednisolone, betamethasone, dexamethasone, triamcinolone, estradiol, estrone, estriol, progesterone, and mixtures thereof.

12. An ophthalmic composition according to any one of claims 1 to 11 for use as a medicament.

13. Composition for use according to claim 12 for administration by ocular instillation.

14. Composition for its use according to any one of claims 12 and 13, characterized in that: • the composition is useful for the treatment of dry eye, and / or • the liposoluble active ingredient is chosen from prosta glandins, optionally in admixture with timolodol, levobunolol, dorzolamide and / or brinzolamide, and the com- position is useful for the treatment or prevention of intraocular hypertension, and / or glaucoma, such as open-angle glaucoma, or • the fat-soluble active ingredient is chosen from steroids, and the composition is useful for preventing, relieving or treating eye inflammations.

15. A process for preparing the composition according to any one of claims 1 to 10, said process comprising the following steps: a. Suspending the particulate surfactant in the aqueous phase Aq, b. Dissolution of the liposoluble active ingredient in an oil to form the lipid phase L, c. Addition of the lipid phase L to the suspension obtained in step a), d. Emulsification, so as to obtain an emulsion.

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