EP3634510A1

EP3634510A1 - Sterile injectable composition containing cross-linked hyaluronic acid and articaine

Info

Publication number: EP3634510A1
Application number: EP18711386.5A
Authority: EP
Inventors: Samuel Gavard Molliard; Bénédicte Vincente TAUZIN
Original assignee: Kh Medtech Sarl
Current assignee: Kh Medtech Sarl
Priority date: 2017-05-29
Filing date: 2018-03-02
Publication date: 2020-04-15
Also published as: CN111132705A; WO2018220283A1; WO2018220288A1

Abstract

The present invention relates to a sterile injectable composition in the form of a hydrogel containing cross-linked hyaluronic acid, or a salt thereof, and articaine, or a salt thereof, to a method for preparing said sterile injectable composition, to the use of said sterile injectable composition in the fields of aesthetics and medicine, and to a method for treatment by injection of said sterile injectable composition in the fields of aesthetics and medicine.

Description

STERILE INJECTABLE COMPOSITION CONTAINING RETICULATED HYALURONIC ACID AND ARTICAN

The subject of the present invention is: a sterile injectable composition in the form of a hydrogel containing crosslinked hyaluronic acid, or one of its salts, and articaine, or one of its salts

a process for the preparation of said sterile injectable composition

the use of said sterile injectable composition in the fields of aesthetics and medicine

a method of treatment by injection of said sterile injectable composition in the fields of aesthetics and medicine

Hyaluronic acid is a polysaccharide formed by the repetition of a disaccharide unit composed of D-glucuronic acid and N-acetylglucosamine. Its structure is linear and without species specificity. Hyaluronic acid is widely distributed in human and animal living organisms, in which it plays many biological functions such as the control of the hydration rate or the maintenance of the viscoelasticity of fluids or tissues. It is found especially in high concentration in the synovial fluid, the vitreous body of the eye and in the dermis. A 70 kg human has about 15 g of hyaluronic acid, half of which is contained in the skin and this quantity decreases with aging.

Hyaluronic acid hydrogels are known and used in broad areas of aesthetics and medicine for many years. These gels are, in particular, commonly injected: in the eyes, during ophthalmological surgeries, in order to maintain the intraocular space and protect the tissues of the eye

in the joints, in case of osteoarthritis, to supplement the deficient synovial fluid and temporarily restore the chondroprotective properties of said biological liquid in or under the skin, to fill wrinkles or increase the volume of certain areas of the face or body Hyaluronic acid has a low half-life in living organisms (less than 1 week).

In many applications in aesthetics and medicine, it is injected in patients in its native form, that is to say, it is not crosslinked and / or chemically modified. For other applications, it is administered to patients in a stabilized form by crosslinking. Cross-linking makes it possible to considerably increase the life (also known as remanence) of hyaluronic acid in vivo, but it also makes it possible to modify its mechanical and rheological properties, in particular by making it more elastic, which then makes it possible to increase its capacity. to create volume once injected into the desired tissues. Thus, thanks to this modification by crosslinking, a hydrogel based on crosslinked hyaluronic acid has for example the ability to fill wrinkles over a period of several months.

Cross-linked hyaluronic acid injections are generally accompanied by a sensation of pain in the patient being treated during the practitioner's administration of the product. In fact, the fact of injecting a hydrogel with a high viscosity into the tissues (dermis, subcutaneous tissues, ...) or into body fluids (synovial fluid, aqueous humor, etc.) induces most of the time pain from a low to moderate level during the injection procedure and within minutes of this procedure. In order to limit this pain, and particularly in the context of cosmetic procedures, most injectable products containing cross-linked hyaluronic acid (JUVEDERM ^® , RESTYLANE ^® , BELOTERO ^® , etc.) for filling wrinkles now possess lidocaine (a local anesthetic), and more specifically lidocaine hydrochloride at a concentration of 0.3% (3 mg / ml). As demonstrated in various clinical studies over the last 10 years, the addition of lidocaine in cross-linked hyaluronic acid-based gels has significantly improved the comfort of treated patients (pain reduction) compared to non-allergenic products. containing no lidocaine, making it incontestably today the reference solution in the market of aesthetic filling products.

In view of the key role played by cross-linked hyaluronic acid in the fields of aesthetics and medicine (several million injections made each year worldwide), one skilled in the art constantly seeks to improve safety and performance of injectables based on crosslinked hyaluronic acid. Those skilled in the art also seek to provide sterile injectable products stable over time and it is well known that the addition of an anesthetic active ingredient such as lidocaine in an injectable composition. based on hyaluronic acid has instabilities relating to the active ingredient. These instabilities are observed during the process for preparing the sterile injectable composition but also during the shelf life of this composition; instabilities that must be contained in order to make the composition manageable in humans. The present invention aims precisely to propose:

a composition in the form of a sterile injectable hydrogel based on hyaluronic acid, or one of its salts, and a local anesthetic, articaine, or one of its salts, in order to significantly improve the safety (to minimize undesirable effects) but also performance (to maximize effectiveness) compared to current injectables based on crosslinked hyaluronic acid containing lidocaine, for uses in the fields of aesthetics and of medicine.

a sterile injectable composition in which the anesthetic agent articaine, or one of its salts, is stable during the process for preparing the composition and throughout its shelf life, that is to say in general for a duration equal to or greater than 24 months at room temperature, in order to meet the safety requirements of the product but also to be able to legally register this product in all the desired countries for its commercialization.

Thus, in this context, the present invention discloses a solution making it possible to significantly improve the level of safety of injectable products based on hyaluronic acid crosslinked with anesthetic by proposing a stable composition involving, under the specific conditions of the invention, of articaine, instead of lidocaine, a local anesthetic with a toxicological profile significantly more interesting than that of lidocaine (anesthetic faster metabolized by the body in comparison with lidocaine, no metabolite with high toxicity as in the case of lidocaine, ...), but also allowing to offer a composition with a better clinical performance (time necessary to benefit from the beginning of the shorter anesthetic effect, power and action time of the anesthetic superior to that of lidocaine, ...). These major advantages, as well as many others highlighted and demonstrated in this description, make this new sterile injectable composition a solution of choice to allow injections of cross-linked hyaluronic acid with anesthetic having a better performance but also a better level. safety for the millions of patients treated each year with this type of product. Thus, the present invention relates, according to a first aspect, to a new sterile injectable aqueous composition in the form of a stable yoghel with time, containing at least crosslinked hyaluronic acid, or one of its salts, and a local anesthetic, articaine, or one of its salts. According to the invention, the composition contains hyaluronic acid or one of its salts, and in particular its physiologically acceptable salts, such as the sodium, calcium, zinc and potassium salts, advantageously salt. sodium. Hyaluronic acid can be of animal origin or obtained by bacterial fermentation. It may have a molecular weight of a few daltons to several million daltons, preferably about 0.01 to 5 million daltons, more preferably about 0.1 to 3.5 million daltons.

According to one aspect of the invention, the composition may be based on a derivative of hyaluronic acid, that is to say based on a molecule obtained by modifying chemically, or by any other route, the molecule of hyaluronic acid.

According to the invention, the total concentration of hyaluronic acid, or one of its salts, is between 0.001 and 70 mg / ml, between 0.01 and 50 mg / ml, between 1 and 40 mg / ml, between 5 and 35 mg / ml, between 8 and 33 mg / ml, between 9 and 30 mg / ml, between 10 and 29 mg / ml, between 11 and 28 mg / ml, between 12 and 27 mg / ml, between 13 and 26.5 mg / ml, ml, advantageously between 14 and 26 mg / ml.

According to the invention, the hyaluronic acid contained in the composition is crosslinked, totally or partially, preferentially according to the crosslinking techniques described in the prior art. The crosslinking agent (s) involved in the crosslinking may be identical or different. These are generally bi- or poly-functional crosslinking agents of different types and they may for example be selected from divinylsulfone, bi- or poly-functional epoxies, carbodiimides and formaldehyde. The agents of the bi- or polyfunctional epoxy family are preferably chosen, in particular 1,4-butanedioldiglycidyl ether (BDDE), diepoxy-octane or 1,2-bis (2,3-epoxypropyl) -2. , 3-ethylene. It is particularly preferred to use BDDE. The crosslinking temperatures are generally between about 15 ° C. and 60 ° C. and the crosslinking times are generally several hours, advantageously more than 1 hour until about 24 hours.

It is important to note that the crosslinking agent used for bridging the hyaluronic acid chains is a molecule generally possessing. a significant level of toxicity. The residual crosslinker after crosslinking (that has not reacted with HA) must be eliminated during the purification of the hydrogel (generally by dialysis in physiological solution). so as to have an injectable composition having the highest possible level of safety for the patient. In the case of the BDDE mentioned above, in a completely surprising manner, it has been shown in the context of the studies carried out by the inventors that the content of residual BDDE in the finished product, after sterilization, must be less than or equal to 10 ppm, preferably less than or equal to 5 ppm, more preferably less than or equal to 2 ppm, to minimize the degradation of articaine during the preparation process of the sterile injectable composition. Thus, in the case of a sterile injectable product based on hyaluronic acid crosslinked with BDDE according to the invention, the residual concentration of BDDE must be less than or equal to 10 ppm, preferably less than or equal to 5 ppm, more preferably lower than or equal to 2 ppm, to obtain a stable composition with a maximum level of safety.

According to the invention, the hyaluronic acid is totally or partially crosslinked. Thus, the composition according to the invention advantageously comprises more than 80% by weight of hyaluronic acid in the crosslinked form and less than 20% by weight of hyaluronic acid in the non-crosslinked form. Preferably, the mass fraction of hyaluronic acid in the non-crosslinked form is less than or equal to 15% of the total mass of hyaluronic acid in the finished product.

According to the invention, the composition has water as the main ingredient, hence the term aqueous composition or hydrogel for the novel composition according to the invention. The mass of water in the composition according to the invention is greater than 51% of the total mass, advantageously greater than 60% of the total mass, advantageously greater than 70% of the total mass, advantageously greater than 75% of the total mass. advantageously greater than 80% of the total mass, advantageously greater than 85% of the total mass. A buffer solution is advantageously used in particular to better control the pH and osmolarity of the formulation throughout its shelf life. For example, use may be made of a buffer based on sodium chloride and phosphate ions.

According to the invention, the sterile injectable composition advantageously has a physiological osmolarity, that is to say an osmolarity of between 200 and 400 mOsm / kg.

It is important to specify that the studies of the inventors have demonstrated that the pH of the hydrogel according to the invention is a very important element of the composition. Indeed, it has been shown that, for a pH below 6.0, a significant degradation of the biophysical properties of the hydrogel (case of the elasticity of the gel with the elastic modulus G ') is observed during the test. sterilization of the product. On the other hand, it has also been shown that, for a pH greater than 7.9, white particles are observed in the finished product whereas none of these particles (identified as being articaine) is observed for a pH less than or equal to 7.9. Thus, in the case of the present invention, a pH greater than or equal to 6.0 and less than or equal to 7.9 is required in order to have a stable product with the highest level of safety and performance. Advantageously, the pH of the sterile injectable composition according to the invention is greater than or equal to 6.2 and less than or equal to 7.8.

According to the invention, the composition contains the local anesthetic articaine, or one of its salts, whatever the enantiomeric form. Advantageously, articaine hydrochloride is the form used, in particular because of its good solubility in water and therefore in the aqueous composition according to the invention.

According to the invention, the concentration of articaine is homogeneous within the hydrogel and it is between 0.1 and 50 mg / ml (ie between 0.01% and 5% by weight), preferably between 1 and 50 mg / ml (either between 0.1% and 5% by weight), more preferably between 2 and 45 mg / ml (ie between 0.2% and 4.5% by weight). In the case of injections for aesthetic applications, it is advantageously fixed at 3 mg / ml (ie 0.3% by weight), that is to say at a concentration equal to the concentration of anesthetic set for injectables based on cross-linked hyaluronic acid containing lidocaine. In the case of medical applications, for example in the case of dental surgery, it can advantageously be fixed at 4% (ie 40 mg / ml). The studies of the inventors have made it possible to demonstrate that, just as in the case of lidocaine in a cross-linked hyaluronic acid hydrogel, articaine is in the free state in the sterile injectable composition according to the invention. that is, the molecule of articaine is not covalently bound to hyaluronic acid) and that this local anesthetic is able to be released rapidly from the hydrogel (= kinetics of release equivalent to that of the lidocaine, which is surprising because the higher liposolubility of articaine compared to lidocaine should induce a slower release of the molecule) to act as quickly as possible at the level of the surrounding tissues at the implantation site, after injection at the treated patient.

According to the invention, the composition is sterile. It is sterilized according to the techniques described in the prior art. It is advantageously sterilized with heat, preferably with moist heat (also called steam autoclaving).

Preferably, the wet heat sterilization is carried out at a temperature greater than 100 ° C., advantageously greater than 110 ° C., advantageously greater than 1 ° C. In general, the sterilization time can range from a few seconds to several minutes. For example, the following wet heat sterilization cycles may be mentioned: 121 ° C for 20 minutes or 125 ° C for 7 minutes or 127 ° C for 4 minutes or 130 ° C for 3 minutes. It is important to note that the heat sterilization is advantageously selected because it gives a high level of sterility to the chosen composition, which makes it possible to aim for a high level of safety for the treated patient.

The studies of the inventors have made it possible to demonstrate that the articaine molecule is stable and therefore not thermally degraded during the heat sterilization process of the composition according to the invention since:

the residual crosslinking concentration is low in the product. In the case of BDDE, it has been proved in these studies that the residual concentration of BDDE after sterilization must be less than or equal to 10 ppm to strongly limit the degradation of articaine in the sterile injectable composition according to the invention. the pH of the composition must be greater than or equal to 6.0. Indeed, as described above, a pH below 6.0 induces a significant degradation of the biophysical properties of the crosslinked hyaluronic acid hydrogel and moreover, a pH below this value catalyzes a degradation of the articaine during the process. sterilizing the composition; undesirable catalysis that continues during storage during the shelf life of the product and therefore generates a product that is not stable over time.

Without wishing to be bound to an explanation, pH very probably plays a major role in the molecular interactions between hyaluronic acid and articaine within the composition under the specific conditions of the invention, in particular by impacting the dense network of hydrogen bonds which exist between these 2 molecules and which ensure their stability during the preparation process of the sterile injectable composition according to the invention but also during the shelf life of the composition.

In this context, it should be noted that the studies of the inventors have shown that the sterile injectable composition, under the conditions of the invention, is stable during storage of the composition at room temperature. Thus, the stability of the key parameters of the sterile injectable composition according to the invention shows that the composition is entirely compatible with a shelf-life of 18 to 36 months, that is to say a duration equivalent to that of cross-linked hyaluronic acid products containing lidocaine anesthetic.

According to the invention, the composition is injectable. It is preferably packaged in a syringe or in a vial, so that it can be easily administered through a needle or cannula.

According to the invention, the injectable sterile composition based on crosslinked hyaluronic acid is preferably in the form of a so-called monophasic hydrogel rather than in the form of a so-called biphasic hydrogel.

According to the invention, the injectable sterile composition based on crosslinked hyaluronic acid has an elasticity G 'at 0.7 Hz advantageously between 10 Pa and 880 Pa, preferably between 20 Pa and 700 Pa, preferably between 30 Pa and 500 Pa, still preferably, between 50 Pa and 400 Pa. The viscoelastic properties of a gel based on hyaluronic acid are indeed essential for the safety and efficacy produced for both aesthetic and medical uses. In the case of the present invention, the sterile injectable composition must not have a G 'elasticity at 0.7 Hz of less than 10 Pa, because in this particular case, it is not able to effectively fill tissue and the gel. spread / diffuse too much at the level of the treated area. The sterile injectable composition according to the invention, in the form of a viscoelastic gel, must also not have a G 'elasticity at 0.7 Hz greater than 880 Pa, since in this case, it can be seen that: the gel is difficult to extrude at through a fine needle (it is necessary to push hard on the plunger of the syringe to extrude the gel) and the injection is irregular with potential needle clogging because of a significant heterogeneity of the composition.

- The gel has a hard appearance, unsuited to the surrounding soft tissues, which makes it particularly palpable in the tissues. A composition with such characteristics (G 'at 0.7 Hz less than 10 Pa or greater than 880 Pa) is therefore not able to meet the high level of safety and desired performance for the injectable composition according to the invention, and it is therefore excluded from the scope of the invention.

According to one aspect of the invention, the composition according to the invention does not contain any water-soluble organic product other than hyaluronic acid, or one of its salts, and articaine, or one of its salts. So, in this case, the sterile injectable composition can not contain additional water-soluble organic molecule such as polyol, in addition to hyaluronic acid and articaine.

According to one aspect of the invention, the composition according to the invention contains one or more active substances of natural or synthetic origin with or without pharmacological action, such as, for example, anti-inflammatories, antiseptics, antibacterials, antifungals, anticancer, proteins, hormones, fatty acids, biologically acceptable lipids, alone or in combination. These active substances are either dispersed in the hydrogel, or grafted to one or more of the hydrogel polymers, or contained / encapsulated in liposomes / niosomes dispersed in the hydrogel, or contained / encapsulated in another material itself. dispersed within the hydrogel.

According to one aspect of the invention, the composition according to the invention contains one or more compounds of biological origin such as cells, enriched platelets, genes, DNA fragments or growth factors. These compounds are preferentially dispersed in the hydrogel, but they can also be grafted to one or more of the hydrogel polymers or contained / encapsulated in liposomes / niosomes dispersed in the hydrogel or contained / encapsulated in another material itself. even dispersed within the hydrogel.

According to one aspect of the invention, the composition according to the invention contains polymers which are dispersed within the crosslinked matrix of the hydrogel. Examples that may be mentioned include polymers of the family of polysaccharides, polyesters, polyanhydrides, polyphosphazenes, poly-ε-caprolactones, polylactic acids and their derivatives, polyvinyl acids, polyacrylamides, N-vinyl pyrrolidone and acrylic polymers and biologically acceptable derivatives.

According to one aspect of the invention, the composition according to the invention contains mineral substances which are dispersed within the crosslinked matrix of the hydrogel. For example, hydroxyapatite or tricalcium phosphates such as β-tricalcium phosphate may be mentioned.

According to one aspect of the invention, the composition according to the invention is mixed with one or more other substances, preferably sterile, likely to bring a benefit to the body, just before its administration to the patient. The mixing is then carried out by the end user, that is to say by a practitioner or by authorized personnel, according to an appropriate method using one or more mixing devices to achieve a satisfactory mixture and maintain sterility. For example, the mixture can be cited by the end user of the hydrogel according to the invention and of one or more compounds such as fatty acids, lipids, active substances, biologicals or mineral substances: by going back and forth between two containers (one filled with hydrogel according to the invention and the other filled with the compound to be dispersed in the hydrogel), these containers being for example syringes

simultaneously extruding the contents of two containers (one filled with the hydrogel according to the invention and the other filled with the compound to be dispersed in the hydrogel) to join the different compounds and / or mix them in another container before administration in the patient

The novel sterile and stable injectable composition disclosed in the present invention aims to significantly improve the safety and performance / clinical efficacy of injectable products based on cross-linked hyaluronic acid with local anesthetic by providing, in particular, the following benefits around the desired anesthetic effect: articaine has an ability to anesthetize faster and higher potency than lidocaine. This is explained by the lower pKa of articaine (pKa = 7.8) compared to lidocaine (pKa = 7.9), but also by a higher liposolubility of articaine (49.5%) compared with lidocaine ( 2.9%) (explained in particular by the presence of a thiophene group on the molecule of articaine and the capacity to make more intermolecular hydrogen bonds). This is a considerable advantage to improve patient comfort during the treatment procedure. Indeed, on a procedure of injection of a cross-linked hyaluronic acid lasting approximately 10 to 20 minutes in general, it is key for the patient as for his practitioner to benefit from the anesthetic effect at the earliest during the injection, so that the act occurs in the best possible conditions articaine has a lower level of cytotoxicity than lidocaine (key for better safety at both local and general levels) as this is for example described in the publication of Malet et al., The Comparative Cytotoxic Effects of Different Local Anesthetics on Human Neuroblastoma Cell Line, Anesth analg, 120 (3). -589-96, 2015 articaine is more rapidly metabolized (= shorter elimination time) by the body probably due to the presence of an ester bond at the molecule level. This property is major vis-à-vis the safety profile of the product because it reduces the risk of systemic toxicity of articaine in the treated patient

Articaine has no toxic metabolites and this characteristic is a significant advantage over lidocaine. Indeed, lidocaine has a metabolite (which is also a synthetic impurity of lidoca raw material). consequently found naturally in the final product based on crosslinked hyaluronic acid containing the anesthetic), 2,6-dimethylaniline (DMA), having a significant toxicity vis-à-vis the body (carcinogenic molecule). Not having a toxic metabolite like DMA but also having a shorter elimination time in the body represent absolutely considerable safety benefits in favor of articaine by compared to lidocaine. These factors largely explain why articaine is currently injected at 4% for local anesthesia requiring a significant reduction in pain (dental surgeries), while lidocaine is generally not recommended and used. at a concentration greater than 2% for the same clinical applications. These benefits can for example allow:

- or reduce the amount of anesthetic articaine needed compared to lidocaine to have the same anesthetic effect (and thus reduce the potential side effects of the anesthetic such as less redness after injection)

- to increase the clinical efficacy of articaine anesthesia in comparison with lidocaine if the same concentration / anesthetic dose is used for the 2 active ingredients

articaine is also considered to be a molecule with a longer duration of action compared to lidocaine, as shown by the higher protein binding ratio of articaine (95%) compared to lidocaine (65%) . This advantage is relevant to aesthetic and medical indications so that the effect on pain reduction will continue over a longer post injection period compared to the current solution with the products based on hyaluronic acid using lidocaine

On the other hand, the studies carried out by the inventors made it possible to show the various surprising elements according to the sterile injectable composition according to the invention:

during the autoclave heat sterilization of articaine, the molecule is more stable in the composition based on crosslinked hyaluronic acid according to the invention than in a physiological solution. This advantage is key because it is imperative to have the best possible stability for an active ingredient such as articaine, for reasons of product safety, but also for reasons related to the regulatory requirements of products containing this type of substance. pharmaceutical. Without wishing to be bound to an explanation, one can suppose hyaluronic acid plays a role of stabilizer for articaine by creating with the active principle a dense network of hydrogen bonds, which participates in particular to stabilize the ester bond of the molecule (= the most fragile bond of the molecule articaine in the aqueous environment of the composition according to the invention) - as previously discussed, the pH of the composition according to the invention plays a major role both on the stability (and solubility) of articaine and on the stability of the cross-linked hyaluronic acid, whether during the preparation process (and more particularly during the sterilization process) than during storage of the composition at room temperature

- the crosslinking agent used to bridge the hyaluronic acid chains must be in the form of minute traces in the sterile finished product (less than 10 ppm in the case of BDDE) - without wishing to be bound to an explanation, it is assumed that the epoxide functions of the residual BDDE in the gel react with the reactive functions of articaine thus inducing instability of the active ingredient), which implies removing it as much as possible before sterilization, so as not to catalyze a deterioration of articaine during of the heat sterilization process but also during storage at ambient temperature of the composition according to the invention

the addition of articaine in a cross-linked hyaluronic acid gel has a negligible influence on its rheology before sterilization, but a significant difference becomes observable after sterilization of the hydrogel with heat. On the other hand, contrary to what would be expected by those skilled in the art on the basis of what is described in the prior art with lidocaine and more generally with local anesthetics of the amino-amide class. articaine does not make it possible to obtain a heat-sterilized hydrogel which has a higher elasticity (compared to a reference gel containing no anesthetic), as is the case with lidocaine, but on the contrary, a more low elasticity. This specific property obtained with a gel according to the invention containing articaine provides the following important advantages: - the duration of heat sterilization to obtain the desired rheological properties is shorter, which is a very positive point in the context industrial production of this type of composition (shorter sterilization cycle = better productivity and lower manufacturing cost)

the duration of heat sterilization is shorter, which makes it possible to generate fewer small molecular masses of hyaluronic acid (the hyaluronic acid being sensitive to heat, the latter involving cuts in chains proportional to the duration exposure to temperature) known to be pro-inflammatory and therefore likely to cause adverse effects in the treated patient

- The duration of heat sterilization is shorter which allows to lessen the hyaluronic acid uncrosslinked (more fragile than the crosslinked hyaluronic acid) contained in the composition and acting as a lubricant vis-à-vis the cross-linked hyaluronic acid, which then makes it possible to obtain products that are easier to extrude through a fine needle and therefore easier for the practitioner to use

this difference in behavior of the composition according to the invention during sterilization with heat (= shorter sterilization time) nevertheless makes it possible to obtain rheological / mechanical properties (in the case of viscoelastic modules G 'and G ") and cohesivity quite similar to that of a crosslinked hyaluronic acid composition containing lidocaine since the sterilization time is suitably adapted (= shorter sterilization time than with a product based on cross-linked hyaluronic acid containing lidocaine with an exact sterilization time depending on the specific biophysical properties targeted.) These properties are described as being key in the literature for the safety and clinical performance of an injectable product based on hyaluronic acid. cross-linked (eg, Sundaram et al., Plast Reconst Surg, 2013, 132: 5S-21S). because it offers the possibility of providing practitioners with injectable products with articaine possessing properties similar to those already known today with products containing lidocaine, and therefore with the aim of treating the same indications, while aiming for better safety and performance. clinical.

the sterile injectable composition according to the invention is stable (process and storage) and is perfectly compatible with an expiry period of 18 to 36 months at room temperature and this, in the absence of a stabilizer such as a polyol in the formulation (solution described in the prior art for improving the stability of a composition based on hyaluronic acid)

the kinetics of release of articaine for the composition according to the invention is equivalent (as fast) to that of a product based on hyaluronic acid crosslinked with lidocaine, and this despite the higher liposolubility of articaine compared with On the other hand, it is interesting to demonstrate the following synergy relating to the sterile injectable composition according to the invention: under the conditions of the invention, the crosslinked hyaluronic acid stabilizes the articaine during the process. preparation of the comp but also during storage (as described above). The crosslinked hyaluronic acid, because of its high viscosity, also makes it possible to maintain the articaine at the injection site so that the anesthetic effect is focused / localized at this site (this in order to have anesthesia the more targeted and most effective). The articaine molecule, by virtue of its antioxidant capacity, is thus able to "protect" the cross-linked hyaluronic acid at the level of the treated zone in the first hours following the injection (that is to say during the period for which the emission of free radicals by the body is the strongest), by capturing free radicals (which are therefore no longer able to degrade hyaluronic acid by cutting its chains) and limiting inflammation surrounding tissues (inflammation that generates in particular free radicals), in order to allow the hyaluronic acid to be less altered from the beginning of the implantation and thus to have a longer persistence in the tissues.

The present invention relates, according to a second of its aspects, to a process for preparing the new sterile injectable composition described above.

The process for preparing the composition according to the invention is characterized by the following successive stages: a) preparation of a hydrogel based on crosslinked hyaluronic acid, or one of its salts; b) addition of articaine in the hydrogel with mixing operation

c) sterilization

Step (a) generally begins with the dissolution of the hyaluronic acid and then with its crosslinking, using a crosslinking agent, and it generally ends with the purification of the hydrogel obtained.

By step of crosslinking of hyaluronic acid is meant the step of bridging the hyaluronic acid chains to each other by covalent bonds. Generally, the step of crosslinking hyaluronic acid begins when the crosslinking agent is brought into contact with hyaluronic acid and terminates when the person skilled in the art considers that the reaction kinetics of bridging the chains of hyaluronic acid by the crosslinking agent has reached a negligible level.

The purification of the hydrogel, it allows to remove the undesirable molecules of the prepared gel and in particular the crosslinking residues, following the crosslinking. This purification is carried out according to the techniques well known to those skilled in the art, for example by dialysis baths, by washing by continuous water flow or by precipitation. The preparation of a hydrogel based on crosslinked hyaluronic acid is advantageously carried out according to the methods described in the prior art. For example, applications WO 97/04012, WO 2004/092222, WO 2005/085329 and WO 2009/071697 may be mentioned for the manufacture of a hydrogel based on crosslinked hyaluronic acid. Step (b) consists in adding articaine (or one of its salts, and in particular articaine hydrochloride) in the previously prepared crosslinked hyaluronic acid hydrogel.

This addition may be carried out according to, for example, one of the following 2 solutions: the articaine is added in powder form in the gel and then a mixture is made (during and / or after the addition) so that the molecule is homogeneous in the freeze

articaine is added to the gel in the form of an aqueous solution containing the active principle and then a mixture is made (during and / or after the addition) so that the molecule is homogeneous in the gel

It is important to note that, as part of this addition of articaine, a base (NaOH, KOH, ...) can be added to the gel in order to obtain the desired pH, knowing that the pH of the composition sterile injectable according to the invention must not exceed 7.9. This addition of a base is advantageously in the form of an aqueous solution and it is preferably done at the same time as the addition of articaine and / or after the addition of articaine in the hydrogel.

This addition of articaine is accompanied by a mixing operation intended to homogenize the active ingredient (and the base) within the hydrogel. The mixing can be done during the addition and / or after the addition.

The mixing operation is carried out by techniques well known to those skilled in the art, for example by mechanical mixing within a mixing tank.

The mixing can be carried out at a temperature above ambient temperature and / or under pressure and / or under ultrasound in order to optimize the homogenization of the composition. Step (c) is to sterilize the composition by techniques well known to those skilled in the art; the sterilization being advantageously carried out with moist heat by autoclaving.

An advantageous method according to the invention for the manufacture of a sterile injectable aqueous composition according to the invention comprises at least the following steps: preparation of an aqueous solution of hyaluronic acid cross-linking of hyaluronic acid

purification of the hydrogel, for example by dialysis in a physiological solution addition of articaine in the hydrogel with mixing operation

packaging in syringes

- sterilization

The present invention relates, according to a third of its aspects, the use in humans or animals of the new sterile aqueous injectable composition described above, for aesthetic or therapeutic applications.

The sterile injectable aqueous composition according to the invention is especially used to: fill volumes

generate spaces within certain tissues, thus favoring their optimal functioning to replace physiological fluids or deficient tissues

stimulate or promote tissue regeneration

moisturize and protect tissues

- to deliver substances likely to bring a benefit to the organism and in particular of active substances and / or biological

By way of example, mention may be made of the uses of the hydrogel in the following cases: the formulation of an injectable composition intradermally, in the mucous membranes or subcutaneously for the improvement of the quality of the skin or the filling wrinkles or restoring the volumes of the face (cheekbones, chin, lips, nose, ...) or body formulation of an injectable composition for dental use for example to fill periodontal pockets and / or to stimulate regeneration tissues around the tooth the formulation of an intraocular injectable composition, in particular for applications during surgery for cataract, glaucoma, presbyopia or vitreous - the formulation of an injectable composition in intra-ocular -articular for applications in orthopedics or rheumatology, particularly in the context of viscosupplementation of synovial fluid deficient for the treatment of osteoarthritis but also bone reconstruction or of cartilage regeneration

the formulation of an injectable composition in urology for applications in the treatment of urinary or faecal incontinence

the formulation of an injectable composition used in medicine or general surgery as part of the treatment of fibrosis or to improve the healing of wounds the formulation of an injectable pharmaceutical composition allowing the controlled release of active substances and / or biologicals for different medical applications

The present invention relates, according to a fourth aspect, a method of treatment in humans or animals, by injection- the sterile injectable composition described above for: treating the surface appearance of the skin, especially if it is altered

treat cutaneous signs of chronological aging and / or induced by external factors such as stress, air pollution, tobacco or prolonged exposure to ultraviolet (UV)

to treat the viscoelastic and biomechanical properties of the skin, especially if these properties are impaired

fill the long-term volume defects of the skin, and in particular fill wrinkles or restore volumes in the face and body

regenerate cartilage

- treat osteoarthritis

be used in intraocular ophthalmic surgery, including cataract extraction, intraocular lens insertion and removal, corneal surgery, glaucoma surgery, ocular plastic surgery and muscle surgery

fill volumes

- generate spaces within certain tissues, thus favoring their optimal functioning to replace physiological fluids or deficient tissues

stimulate or promote tissue regeneration

moisturize and protect tissues

to deliver substances likely to bring a benefit to the organism and in particular active substances and / or biological

For example, we can consider the method of treatment consisting in improving the quality of the skin and / or filling wrinkles or hollows and / or restore volumes (cheekbones, chin, lips, nose, ... ) at the level of the face and / or at the level of the body (scars, breasts, buttocks, genitals, ...) in the human by injection (advantageously with a needle and / or a cannula) in intradermal and / or in the mucous membranes and / or in the subcutaneous tissues, of the sterile injectable composition described above. EXAMPLES

The invention will now be illustrated, without limitation, by the following examples.

Sodium hyaluronate, lidocaine hydrochloride, articaine hydrochloride and all the other compounds used in the following examples have a high level of purity. The phosphate buffer solution used has the following composition: 8.5 g of NaCl, 0.041 g of NaH ₂ PO ₄ dihydrate, 0.292 g of Na ₂ HPO ₄ dihydrate in 1 liter of water for injection.

The concentration of articaine in the gels is measured by HPLC-UV and the residual BDDE concentration in the gels is measured by HPLC-MS. The rheological properties (measurement of the elastic modulus G ') of the gels are measured at 25 ° C using an imposed stress rheometer (TA AR2000) and a 4 cm-2 ° cone / plane geometry with a gap 1000 micrometers.

EXAMPLE 1 Preparation of GEL1A and GEL1B Gels According to the Invention and GEL1C Gel (Comparative) 1.27 g of a sodium hyaluronate (NaHA) powder, with a molecular mass of approximately 1.5 MDa, are weighed at a rate of humidity of 8.2%, to which is added 12.9 g of an aqueous solution of NaOH at 0.25 N. The hydration of the powder lasts 30 minutes, with a regular manual homogenization with a spatula. 0.39 g of a solution of 1,4-butanediol diglycidyl ether (BDDE) diluted i / 5 ^th in 0.25 N sodium hydroxide are added to the reaction mixture, followed by mechanical homogenization for 15 minutes before immersion in a bath thermostated at 50 ° C for 2h30. A solution of phosphate buffer containing HCl in the resulting reticulate is added to obtain a pH = 7.3 and a hyaluronic acid concentration equal to 25 mg / ml. The gel is allowed to swell for 24 hours at room temperature in this solution and, at the end of this time, it is homogenized manually with a spatula for 10 minutes before being purified by dialysis for 24 hours using a cellulose-based membrane ( retention level = 10,000 Da) in a phosphate buffer solution. The gel is manually mixed with a spatula for 10 minutes. Let REF1 be the gel thus obtained. The hyaluronic acid concentration of REF1 is 16.8 mg / ml. In 60.0 g of REF1 gel is added 2.5 g of an articaine hydrochloride powder and the gel is manually mixed with the spatula for 10 minutes. Let REF1A be the gel with articaine thus obtained.

In a fraction of the REF1A gel, a 0.2 N NaOH solution is added until a pH of 7.4 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL1AA be the gel thus obtained.

In a fraction of the gel GEL1AA, a solution of 0.2 N NaOH is added again until a pH of 7.9 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL1BB be the gel thus obtained. In a fraction of the GEL1BB gel, a solution of 0.2 N NaOH is again added until a pH of 8.2 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL1CC be the gel thus obtained.

The GEL1AA, GEL1BB and GEL1CC gels are packaged in 1 ml plastic syringes and then autoclaved at 121 ° C for 20 minutes. Let GEL1A and GEL1B (= gels according to the invention) and GELIC, the sterilized gels respectively from GEL1AA, GEL1BB and GEL1CC.

The pHs of the gels GEL1A, GEL1B and GELIC after sterilization are respectively equal to 7.3, 7.9 and 8.1.

EXAMPLE 2 Microscopic Observation of GEL1A and GEL1B Gels According to the Invention and GELIC Gel (Comparative)

An optical microscope observation (X35 magnification) of GEL1A, GEL1B and GELIC (prepared in Example 1) shows that the two sterile injectable compositions GEL1A and GEL1B according to the invention do not have white particles in the d-based hydrogel. cross-linked hyaluronic acid (which is transparent) whereas the GELIC composition, which is outside the scope of the invention because having a pH greater than or equal to 7.9, has white particles identified as articaine particles.

Example 3; Stability of articaine in GEL1A and GEL1D gels according to the invention, in a GEL1E gel (comparative) and in a physiological solution without hyaluronic acid (comparative In a fraction of the REF1A gel prepared in Example 1, a solution of HCl at 0.2 N is added until a pH of 6.2 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GELIDD be the gel thus obtained.

In a fraction of the GELIDD gel, a 0.2 N solution of HCl is again added until a pH of 5.3 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL1EE be the gel thus obtained.

A phosphate buffer solution is also prepared with 40 mg / ml articaine hydrochloride with a pH of 6.2 before sterilization (ie TP-AA the prepared solution) and a pH of 5.3 (ie TP-BB the prepared solution). GELIDD, GEL1EE and TP-AA, TP-BB are packaged in 1 ml plastic syringes and then autoclaved at 121 ° C for 20 minutes. Let GEL1D (= gel according to the invention) and GEL1E, the sterilized gels from GELIDD and GEL1EE, and TP-A and TP-B, the sterilized solutions from TP-AA and TP-BB.

The pH of the gel GEL1D and GEL1E after sterilization are respectively equal to 6.0 and 4.9. The pH values of TP-A and TP-B solutions after sterilization are respectively equal to 6.1 and 4.9.

The concentrations of articaine before or after sterilization of the following products (prepared in Example 1 and in this example) are measured by HPLC-UV:

The above assays demonstrate that articaine is stable in the injectable composition according to the invention during the sterilization process. These assays also show that: pH plays an important role in the stability of articaine during sterilization. A pH below 6.0 (outside the scope of the present invention) implies a deterioration of articaine as evidenced by the lower concentration of articaine (after sterilization compared to the value before sterilization) but also the increase in relative areas. at the peaks of the breakdown products of articaine.

crosslinked hyaluronic acid, under the conditions of the invention, plays a protective role vis-à-vis the thermal degradation of articaine compared to a phosphate buffer solution containing no hyaluronic acid

It is also important to note that gel GEL1E, at pH 4.9, has an extremely fluid consistency with respect to all other sterile or non-sterile compositions tested. In addition to catalyzing a degradation of the articaine active ingredient, a pH below 6.0 of a crosslinked hyaluronic acid and articaine-based formulation appears to catalyze degradation of the cross-linked hyaluronic acid network, which results in a loss of viscoelastic properties. of the composition.

EXAMPLE 4 Preparation of GEL2A, GEL2C and GEL2D Gels According to the Invention and GEL2B and REF2B1 Gels (Comparative)

9.97 g of a sodium hyaluronate (NaHA) powder, with a molecular mass of approximately 1.7 MDa, are weighed at a moisture content of 4.9%, to which 89.0 g of a 0.25 N aqueous solution of NaOH are added. Hydration of the powder lasts 30 minutes, with regular manual homogenization with a spatula. 4.12 g of a solution of 1,4-butanediol diglycidyl ether (BDDE) diluted l / 5 ^th in 0.25 N sodium hydroxide are added to the reaction mixture, followed by mechanical homogenization for 15 minutes before immersion in a bath thermostated at 50 ° C for 2h30. A solution of phosphate buffer containing HCl in the resulting reticulum is added to obtain a pH = 7.3 and a concentration of hyaluronic acid equal to 30 mg / ml. The gel is allowed to swell for 24 hours at room temperature in this solution and, at the end of this time, it is homogenized manually with a spatula for 10 minutes before purifying it by dialysis under conditions A (for a fraction of the gel to be purified) or under conditions B (for the other fraction of the gel to be purified): - conditions A: for 24 hours using a cellulose-based membrane (retention threshold = 10,000 Da) in a buffer solution phosphate - conditions B: either for 48 hours using a cellulose-based membrane (retention threshold = 10,000 Da) in a phosphate buffer solution

Either REF2A and REF2B, gels purified by dialysis for 24h and 48h respectively, both brought to a concentration of hyaluronic acid of 24.5 mg / ml, then mixed with the spatula for 10 minutes each.

In a fraction of the REF2A gel, a solution of articaine hydrochloride in phosphate buffer is added to obtain an articaine concentration of 3 mg / ml in the gel and the gel is manually mixed with the spatula for 10 minutes. 0.2 N sodium NaOH solution is then added until a pH of 7.4 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL2AA be the gel thus obtained.

In a fraction of gel GEL2AA, a BDDE doping is carried out in the gel: 50 ppm of BDDE are added to the gel and a manual mixing with a spatula of 10 minutes is carried out. Let GEL2AA-DOP be the gel thus obtained.

In a fraction of the REF2B gel, a solution of lidocaine hydrochloride in phosphate buffer is added to obtain a lidocaine concentration of 3 mg / ml in the gel and the gel is manually mixed with the spatula for 10 minutes. 0.2 N sodium NaOH solution is then added until a pH of 7.4 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL2BB be the gel thus obtained.

In a fraction of the REF2B gel, a solution of articaine hydrochloride in phosphate buffer is added to obtain an articaine concentration of 3 mg / ml in the gel and the gel is manually mixed with the spatula for 10 minutes. 0.2 N sodium NaOH solution is then added until a pH of 7.4 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL2CC be the gel thus obtained.

In a fraction of the REF2B gel, a solution containing articaine hydrochloride and Γα-tocopherol in phosphate buffer is added to obtain an articaine concentration of 3 mg / ml and a concentration of α-tocopherol of 0.3 mg / ml in the gel and manually mixed the gel with the spatula for 10 minutes. 0.2 N sodium NaOH solution is then added until a pH of 7.4 is obtained. The gel is manually mixed with a spatula for 10 minutes. Let GEL2DD be the gel thus obtained. The volumes of sodium hydroxide solution introduced being equivalent for the 3 formulations, it is deduced that GEL2AA, GEL2BB, GEL2CC and GEL2DD have identical concentrations of hyaluronic acid.

In a fraction of the REF2B gel, a volume (equivalent to that of soda for the GEL2AA, GEL2BB, GEL2CC and GEL2DD gels) of a phosphate buffer solution is added and the gel is manually mixed with the spatula for 10 minutes. Let REF2B1B be the gel thus obtained.

GEL2AA, GEL2AA-DOP, GEL2BB, GEL2CC, GEL2DD and REF2B1B gels are packaged in 1 ml plastic syringes and sterilized by autoclaving at 125 ° C for 9 minutes. Let GEL2A, GEL2C and GEL2D (= gels according to the invention) and GEL2A-DOP, GEL2B, REF2B1 sterilized gels respectively from GEL2AA, GEL2CC, GEL2DD, GEL2AA-DOP, GEL2BB and REF2B1B.

The pH of the GEL2A, GEL2B, GEL2C and GEL2D gels after sterilization are respectively equal to 7.3, 7.3, 7.4 and 7.3.

EXAMPLE 5 Influence of the Residual BDDE Concentration on the Stability of Articaine in the Sterile Injectable Composition According to the Invention

The residual concentration of BDDE is measured by HPLG-MS for GEL2A, GEL2C and GEL2A-DOP gels. It is 9.4 ppm for gel GEL2A, 1.2 ppm for gel GEL2C, 1.4 ppm for GEL2D and 56.7 ppm for gel GEL2A-DOP.

The concentrations of articaine after sterilization of the following products (prepared in Example 4) are measured by HPLC-UV:

The above assays demonstrate that articaine is stable in the injectable composition according to the invention during the sterilization process. These assays also show that the residual BDDE concentration in the sterile injectable composition plays an important role in the stability of articaine during sterilization (but also during storage, even though this fact is not illustrated in FIG. present example). A residual concentration of BDDE greater than 10 ppm catalyzes a breakdown of articaine as evidenced by the lower concentration of articaine (after sterilization compared to the value before sterilization for BDDE-doped gel) but also the increase in relative areas. at the peaks of the breakdown products of articaine.

Example 6 Influence of Articaine versus Lidocaine on the Rheological Properties in the Sterile Injectable Composition According to the Invention

The elastic modules G 'at 0.7 Hz before and after sterilization of the following products (prepared in Example 4) are measured by rheology:

The elasticity measures G 'above show that:

- The 3 products tested have an equivalent rheology before sterilization - on the other hand, after sterilization, unlike a product with lidocaine, the composition according to the invention with articaine has a lower elasticity than the corresponding composition without anesthetic

Heat sterilization therefore plays a major role in the structure of the product obtained with the sterile injectable composition according to the invention. As described above, this lower elasticity obtained in the case of the composition according to the invention is surprising because it goes against the behavior (described in the prior art and confirmed in the present example) of products based on Hyaluronic acid crosslinked with lidocaine. This specific behavior makes it possible to aim for shorter sterilization times with the sterile injectable composition according to the invention, which presents multiple interests such as:

- better productivity and lower manufacturing cost, interesting in the case of industrial production - a heat input required to obtain the desired rheological properties lower, which is greatly beneficial to the stability of articaine, to the appearance of small molecular weights of hyaluronic acid considered proinflammatory, or the ease of extrusion of the composition through a needle or cannula. It is interesting to note that a further test was carried out by sterilizing the GEL2CC composition at 125 ° C for 7 minutes instead of 9 minutes (as in Example 4). With this additional test, it is found that a sterile injectable composition according to the invention is obtained having an elasticity G 'at 0.7 Hz equal to 181 Pa, that is to say equivalent to that of the composition GEL2B based on crosslinked hyaluronic acid and lidocaine of the prior art. This test shows that despite the difference in behavior (= degradation of the different gel during heat sterilization) of the injectable composition according to the invention, it is possible to find rheological properties equivalent to that of a reference composition of the prior art, that is to say a composition based on crosslinked hyaluronic acid and lidocaine.

Example 7 Evaluation of the Stability during Storage at Room Temperature of the Sterile Injectable Composition According to the Invention

The stability during storage at ambient temperature of the GEL2C gel with articaine according to the invention (prepared in Example 4) is compared with that of the gel GEL2B with lidocaine.

It is found that after 9 months at room temperature, GEL2B gels with lidocaine and GEL2C with articaine according to the invention have an equivalent loss of elasticity. This low loss of elasticity highlights the stability of the injectable composition according to the invention and the possibility of aiming for expiry periods of between 18 months and 36 months (as is currently the case with crosslinked hyaluronic acid products containing lidocaine present on the market).

EXAMPLE 8 Influence of the Elasticity G 'on the Product Properties of the Injectable Composition According to the Invention

1.35 g of a sodium hyaluronate (NaHA) powder, with a molecular mass of approximately 1.5 MDa, are weighed at a moisture content of 8.2%, to which 5.4 g of a 0.25 N aqueous solution of NaOH are added. Hydration of the powder lasts 30 minutes, with regular manual homogenization with a spatula. 0.39 g of a solution of 1,4-butanediol diglycidyl ether (BDDE) diluted l / 5 ^th in 0.25 N sodium hydroxide are added to the reaction mixture, followed by mechanical homogenization for 15 minutes before immersion in a bath thermostated at 50 ° C for 2h30. A solution of phosphate buffer containing HCl in the resulting reticulate is added to obtain a pH = 7.3 and a hyaluronic acid concentration equal to 25 mg / ml. The gel is allowed to swell for 24 hours at room temperature in this solution and, at the end of this time, it is homogenized manually with a spatula for 10 minutes before being purified by dialysis for 24 hours using a cellulose-based membrane ( retention level = 10,000 Da) in a phosphate buffer solution. The gel thus obtained is manually mixed with the spatula for 10 minutes in order to obtain the gel G0.

In 30 g of gel G0, 100 mg of a powder of articaine hydrochloride is added and the mixture is homogenized manually with a spatula for 10 minutes. The fraction F1 is obtained.

In 30 g of gel G0, 8.0 g of a phosphate buffer solution and 100 mg of an articaine hydrochloride powder are added and the mixture is homogenized manually with a spatula for 10 minutes. Fraction F2 is obtained. Fractions F1 and F2 are packaged in 1 ml plastic syringes and then autoclaved at 121 ° C. for 20 minutes, ie GEL-F1A and GEL-F2A, the sterile compositions from fractions F1 and F2.

The elasticities G 'at 0.7 Hz are measured: 880 Pa for the injectable composition GEL-F2A according to the invention, and 970 Pa for the GEL-F1A composition (outside the scope of the invention). Five manual extrusion tests are performed by the same operator, mounting a 27G ½ needle for each GEL-F1A and GEL-F2A composition. The results obtained are described in the table below:

The above results show that for an elasticity G 'at 0.7 Hz greater than 880 Pa, the sterile composition with hyaluronic acid and articaine becomes difficult to extrude and heterogeneous. Such a composition therefore no longer meets the goal of having a sterile injectable composition with a high level of safety and performance and is therefore excluded from the scope of the invention.

Example 9 Free State of Articaine in the Injectable Composition According to the Invention

A release study of the active ingredient articaine was performed with the injectable composition GEL2C according to the invention.

The methodology followed to carry out this study of in vitro release kinetics is that of the publication of Mondon et al. Influence of the Macro- and / or Microstructure of Cross-Linked Hyaluronic Acid Hydrogels on the Release of Two Mode! Drugs. J Glycobiol 5: 119., 2016.

The dosages of articaine were made by HPLC-UV. The results obtained in this study show that the release profile of articaine is quite comparable to that obtained and published for lidocaine (in a crosslinked HA gel) in the article by Mondon et al. There is indeed a strong release of articaine in the first minutes after the start of the release study and the entirety of the articaine is released from the gel according to the invention after a few hours, just as it is the case. with lidocaine in a gel of the prior art.

Thus, despite the higher liposolubility of articaine compared to lidocaine, articaine in the injectable composition according to the invention is released very rapidly (as quickly as lidocaine), and this characteristic is entirely compatible with ability to rapidly anesthetize the patient at the treated area during injection and immediate post injection.

Claims

1 - A sterile injectable aqueous composition in the form of a hydrogel comprising at least crosslinked hyaluronic acid, or one of its salts, and articaine, or one of its salts, characterized in that: o mass proportion of water is greater than 51% of the total mass o the concentration of cross-linked hyaluronic acid, or one of its salts, is less than 70 mg / ml

o the concentration of articaine, or one of its salts, is less than 50 mg / ml where the pH is greater than or equal to 6.0 and less than or equal to 7.9

o the residual concentration of 1,4-butanedioldiglycidyl ether (BDDE) is less than or equal to 10 ppm

the elasticity G 'at 0.7 Hz of the composition is between 10 Pa and 880 Pa where the articaine is stable in the composition and it resists degradation

2 - Composition according to claim 1, characterized in that the hyaluronic acid, or one of its salts, is sodium hyaluronate

3 - Composition according to one of claims 1 to 2, characterized in that the articaine, or one of its salts, is articaine hydrochloride

4 - Composition according to one of claims 1 to 3, characterized in that the composition is sterilized with moist heat

5 - Composition according to one of claims 1 to 4, characterized in that the pH is greater than or equal to 6.2 and less than or equal to 7.8

6 - Composition according to one of claims 1 to 5, characterized in that the hyaluronic acid, or one of its salts, is crosslinked using a crosslinking bi- or polyfunctional

7 - Composition according to one of claims 1 to 6, characterized in that the hyaluronic acid, or one of its salts, is crosslinked using 1,4-butanedioldiglycidylether (BDDE)

8 - Composition according to one of claims 1 to 7, characterized in that the residual concentration of 1,4-butanedioldiglycidylether (BDDE) is less than or equal to 2 ppm 9 - Composition according to claim 1 to 8, characterized in that it contains no water-soluble organic product other than hyaluronic acid, or one of its salts, and articaine, or one of its salts

10 - Composition according to one of claims 1 to 9, characterized in that the concentration of hyaluronic acid, or a salt thereof, is between 9 and 30 mg / ml

11 - Composition according to one of claims 1 to 10, characterized in that the concentration of articaine, or one of its salts, is equal to 3 mg / ml

12 - Composition according to one of claims 1 to 11, characterized in that the composition is stable when stored at room temperature over a period of between 18 to 36 months

13 - Process for preparing a sterile aqueous injectable composition having a pH of between 6.0 and 7.9, comprising at least crosslinked hyaluronic acid, or one of its salts, and articaine, or one of its salts, characterized in that it comprises at least the following successive stages: - preparation of an aqueous solution of hyaluronic acid

cross-linking of hyaluronic acid

Hydrogel purification

addition of articaine in the hydrogel with mixing operation

packaging in syringes

- autoclave sterilization

14 - Preparation process according to claim 13, characterized in that the addition of articaine in the composition is carried out in powder form

15 - Preparation process according to one of claims 13 to 14, characterized in that the addition of articaine in the composition is performed in the form of an aqueous solution 16 - Use of the composition according to one of claims 1 at 12 for aesthetic applications

17 - Composition according to one of claims 1 to 12, for use in the context of a therapeutic treatment 18 - sterile injectable aqueous composition which can be administered by injection into humans or animals in the form of a hydrogel comprising at least crosslinked hyaluronic acid, or one of its salts, and articaine, or one of its salts, characterized in that: o the mass proportion of water is greater than 51% of the total mass o the concentration of crosslinked hyaluronic acid, or one of its salts, is less than 70 mg / ml

19 - A sterile injectable aqueous composition according to claim 18 used to treat (a) the surface appearance of the skin, (b) the cutaneous signs of chronological aging and / or induced by external factors such as stress, pollution of the skin, and air, tobacco or prolonged exposure to ultraviolet, (c) viscoelastic and biomechanical properties of the skin, (d) skin volume defects.