EP2170961A1

EP2170961A1 - Hyaluronic acid dispersion, production and use

Info

Publication number: EP2170961A1
Application number: EP07786333A
Authority: EP
Inventors: Christine Kreiner; Lidia Nachbaur
Original assignee: S & V Technologies AG
Current assignee: S & V Technologies AG
Priority date: 2007-07-25
Filing date: 2007-07-25
Publication date: 2010-04-07
Also published as: WO2009021526A1; CA2658681A1; US20110166530A1

Abstract

The invention relates to a hyaluronic acid dispersion for use in aesthetics medicine and orthopedics, wherein the dispersed phase comprises particles made of cross-linked hyaluronic acid, and the continuous phase substantially comprises linear hyaluronic acid.

Description

Hyaluronic acid dispersion, preparation and application

Background of the invention

Hyaluronic acid and preparations thereof have long been known. Hyaluronic acid is an important component of human tissue and occurs in the human body in the eye (vitreous), in the joints of the bones and in the epidermis. In the body of a 70 kg person approx. 15 g of hyaluronic acid are present.

Hyaluronic acid is a macromolecular chain of disaccharides that consists of two glucose derivatives: D-glucuronic acid and N-acetyl-D-gucosamine. In the disaccharide, the glucuronic acid is linked to the N-acetylglucosamine, which in turn is linked to the next glucuronic acid in the polymeric chain / (1 → 4). A chain typically consists of 250-50,000 disaccharides.

Hyaluronic acid and its preparations are used in the cosmetic, pharmaceutical and medical sectors. In medicine hyaluronic acid preparations are used for the treatment of joint complaints, in particular arthritic complaints. Here, the Hyalu serves Medicine hyaluronic acid preparations are used for the treatment of joint complaints, in particular arthritic complaints. Here, hyaluronic acid, injected directly into the joint, serves as synovial fluid to improve the mobility of the joint apparatus. Another application of hyaluronic acid preparations in medicine is the field of ophthalmology, in particular cataract surgery.

In pharmacy, hayluronic acid preparations serve as a medicament carrier system, because hyaluronic acid, due to its high molecular weight and its special chemical structure, is able to stabilize and quasi encapsulate chemical substances in order to transport them into the cell interior with the aid of a suitable, acceptable carrier material where the chemical substances unfold their effect.

In the large field of aesthetics and cosmetics, hyaluronic acid is used in particular as a water reservoir. Here both in topical preparations, as well as in the injection. By injecting Hyaluronic Acid directly under the skin, water deposits are formed that swell up like a sponge, visibly "wrinkling" wrinkles outward, and when injected into the lips, make them appear plump and well-formed.Topically applied, hyaluronic acid increases water retention the skin retains a fresh, youthful and toned appearance while remaining elastic and supple, and with repeated use, it also reduces the appearance of minor wrinkles on topically applied hyaluronic acid preparations.

In aesthetics and cosmetics, hyaluronic acid, when used topically, is usually used in solution or emulsified. To achieve a sufficient cosmetic effect, preparations based on yellow or emulsion are often not suitable because the other ingredients, such as preservatives, emulsifiers, solubilizers and surfactants, but also pigments and dyes, the degradation reactions of hyaluronic acid, so the cleavage of the molecular chains strongly catalyze. Hyaluronic acid preparations are therefore often only of insufficient durability, usually with little effect. An improvement in terms of reduced chemical degradation of the molecules is provided by hyaluronic acid preparations having hyaluronic acid chains with cross-linked structures. For this purpose, the reactive side groups are reacted with suitable reactants, ie bridge molecules, whereby a three-dimensional network structure is formed. This, in turn, results in a large-scale network structure with excellent water storage capacity.

For the injection of hyaluronic acid, an aqueous hyaluronic acid solution is usually used. Hyaluronic acid is, as already stated, a macromolecule, which has a high space requirement due to its high molecular weight and its three-dimensional, coiled structure. The use concentrations are therefore rather low. The creased, band-like entangled structure is due to the fact that the individual molecule sections enter into constructive interactions with each other, and thereby also solvent molecules, usually water, attach. Due to its chemical and physical structure, hyaluronic acid is a viscoelastic gel solution in water. The viscosity is still significantly increased by cross-linking. In order to counteract premature degradation of the hyaluronic acid chains and thereby prolong the efficacy of the hyaluronic acid, a sufficiently high degree of cross-linking is necessary. Crosslinked hyaluronic acid molecules are substantially more stable to hydroxylation and / or chemical and enzymatic degradation by reactive molecules than non-crosslinked hyaluronic acid chains. Therefore, especially in medicine, aesthetics and cosmetics, where a lasting effect is crucial to the success of the treatment, exclusively stabilized cross-linked hyaluronic acid is used.

Due to the high viscosity of cross-linked hyaluronic acid, the applicability by injection to wrinkle injection is limited, but limited. For injection, the crosslinked hyaluronic acid is diluted in the dispersion to be applied, in order to be able to use relatively thin needles of inner diameter.

The object of the present invention is to provide a hyaluronic acid preparation which is easy to inject and disperse and which is resistant to hydroxylation. - A -

tion and chemical and enzymatic degradation is resistant and beyond with respect to the commercial Hyaluronsäurepräparate a comparably good, if not improved mode of action, in particular with respect to Viskoaugmentation has.

Detailed description of the invention

The object is achieved by a composition as disclosed in claim 1. Surprisingly, it has been found that a hyaluronic acid dispersion with a dispersed phase consisting of particles of crosslinked hyaluronic acid in a continuous phase of non-crosslinked hyaluronic acid achieves the stated object.

As already stated, hyaluronic acid is a macromolecule. In particular, cross-linked hyaluronic acid is no longer able to dissolve in a surrounding solvent because of its high molecular weight and its coiled structure. Therefore, one speaks of a Hyaluronsäuredispersion, so a distribution of hyaluronic acid in the surrounding solvent. The predominant proportion of "solvent" or rather dispersant, the continuous phase, consists of uncrosslinked hyaluronic acid., Unlike in the solvent water, in such a dispersion as defined in claim 1 and the further embodiments, the behavior of the Hyaluronic acid dispersion is viscoelastic, in particular thixotropic, which means that the dispersion liquefies upon application of shear force and re-solidifies immediately upon completion of the shear force and returns substantially to its original viscous structure.

Without being bound by theory, it is believed that the cause of this behavior is due to: The solvent water is a highly polar molecule of oxygen and hydrogen atoms. The hyaluronic acid also has polar groups in its chemical structure. In cross-linked structure, however, the polar anchor groups are reacted with another molecule, so that the polar character is reduced. This results in a significantly reduced solubility of the crosslinked in aqueous solution Hyaluronic acid. Like a drop of oil in an aqueous environment, the cross-linked hyaluronic acid in water therefore increasingly coalesces to form insoluble subregions in which the viscosity is extremely high. Due to the low solubility and therefore the pronounced formation of balls, such a preparation has a high viscosity and thus a lower dispersibility and injectability.

In contrast, in the invention, the effect of shearing force causes the viscosity of the dispersion according to the invention to decrease markedly at the moment of the force effect, and to build up again when the shear force is reduced. This thixotropy of the hyaluronic acid dispersion according to the invention is decisive for the ease of injectability, which makes it possible to use smaller needle diameters when injected. Furthermore, the hyaluronic acid dispersion according to the invention is optimally suitable for gentle tissue augmentation Once injected under the skin, the viscosity builds up again, so that in particular the wrinkle filling effect occurs immediately after injection and thus the hyaluronic acid dispersion according to the invention for viscoaugmentation long-term effectiveness and at the same time excellent biocompatibility is suitable.

The proportion of cross-linked hyaluronic acid is approximately between 0.1 and 99.0 wt .-%, based on the total weight of Hyaluronsäuredispersion. Preferably, 50 to 95 wt .-% are used. Higher concentrations than 99% by weight lead to an increase in viscosity, ie to a viscosity that does not differ significantly from pure cross-linked hyaluronic acid. Such a dispersion can likewise be injected if the particle size is selected accordingly. In order to bring sufficiently cross-linked hyaluronic acid to the site of action, about 50 to 95% by weight of cross-linked hyaluronic acid are optimally suited to achieving a long-term effect. At lower levels, the duration of effectiveness may be shortened.

The hyaluronic acid particles or dispersion droplets of the crosslinked hyaluronic acid preferably have a diameter of about 80 to 300 μm. In particular, transparent, gelatinous dispersions for injection purposes are used, the particle diameter is preferably 80 to 300 microns. The lower limit of the particle diameter is to be selected in view of the desired high efficiency and the desired thixotropic properties.

Preferably, a crosslinked hyaluronic acid having a molecular weight of about 0.8 to 3 million daltons is used. Low molecular weight hyaluronic acid molecules and therefore less cross-linked hyaluronic acid molecules are therefore subject to accelerated degradation and thus can not develop a long-term effect.

In the attached figure, the structure of the Hyaluronsäuredispersion according to the invention is shown schematically. Cross-linked hyaluronic acid particles 1 are distributed in entangled linear hyaluronic acid 2. The entangled linear hyaluronic acid 2 also provides shell-in-shell protection against degradation, thereby providing the desired sustained efficacy after injection.

Rheoloqische measurements on Ausführunqsbeispielen

The rheological measurements were carried out on the shear stress controlled rheometer AR-G2 (Ta Instruments) at 25 ° C. The material functions were performed with a cone plate geometry 0:40 mm, cone angle: 1 °, gap: 28 μm) in a frequency range of ω = 100 to 0.01 rad.s ^"1 at deformations of Y = 0.08% ( Example 1) or 0.1% (Examples 2 and 3).

The oscillation experiment was started only after normal force constancy of the filling, ie after relaxation of the sample in the measuring gap. Table 1 shows an overview of the measurement conditions: Table 1: Overview of the measurement conditions

Device TA AR-Ü2

Cone-plate geometry 40 mm diameter, gap spacing 28 μm

Kcgehvinkel 1 °

Frequency range 10 ^" '- 10O nKI s ^'

Deformation 0.08% (NaturalFacc strueture). 0.1% (Naturall ^; ace contour)

Temperature 25 ⁰ C j

Data points 10 per decade

Results:

All three experiments were oscillator rad in a frequency range from 100 to 0.01 ^{^»s' 1} is performed. To determine the viscoelastic region of the respective sample, a so-called amplitude sweep was carried out prior to each measurement. All samples show a plateau behavior over the entire measuring range with little decrease of the modules towards smaller frequencies (halving of the memory module over a measuring range of four decades) for the storage or loss module (Fig. 1 to 3). By definition, this behavior is a feature of cross-linked samples. The complex viscosity \ η * \ has a uniform slope over the entire measurement range towards high frequencies, which also indicates cross-linked samples. For this reason, zero shear viscosity can not be determined for any of the three samples. By definition, it is never attainable for cross-linked samples even at even lower frequencies.

Figure 1: Dependence of the complex oscillation viscosity η ^* , the storage modulus G 'and the loss modulus G "on the applied angular frequency ω for Example 1 (8 mg / ml cross-linked and 0.4 mg / ml non-crosslinked sodium hyaluronate solution).

-1 - ω / [rad-s ^" ]

Figure 2: Dependence of the complex vibration viscosity η *, the storage modulus G 'and the loss modulus G "on the applied angular frequency ω for Example 2 (22 mg / ml cross-linked and 2 mg / ml uncrosslinked sodium hyaluronate solution).

Figure 3: Dependence of the complex oscillation viscosity η *, the storage modulus G 'and the loss modulus G "on the applied angular frequency ω for example 3 (22 mg / ml crosslinked and 2 mg / ml uncrosslinked sodium hyaluronate solution).

The oscillator experiments of the samples of the three exemplary embodiments each have a plateau behavior of the modules over the entire measuring range. In this area, the behavior of the examples is viscoelastic due to a quasipermanent network. Storage and loss module of Example 1 are about a decade below the two examples 2 and 3. The storage modulus G 'decreases in Example 1 of 276 Pa at 100 rad ^« s ^{' 1} to a value of 111 Pa at 0.01 rad ^« s ^'1 . The development of the complex viscosity \ η ^* \ in Example 1 has a similar course to both Examples 2 and 3. The values of the In this case, game 1 is about a decade lower than the other two examples. The reason for this is the low concentration of hyaluronic acid particles, the height of the plateau value being determined mainly by the proportion of crosslinked hyaluronic acid.

Examples 2 and 3 show an identical course within the scope of measurement accuracy both for the course of the two modules G 'and G "and for the complex viscosity \ η ^* \ In example 2, the memory modulus of 2439 Pa decreases at one frequency from 100 rads ^"1 to a value of 1327 Pa at 0.01 rads ^""1 and in example 3 from 2800 Pa at 100 rads ^" ¹ to 1382 Pa at 0.01 rads ^" the different particle sizes of the two examples ( 150 μm in the example and 350 μm in Example 3) have only a very small influence on the position of the two modules.

The rheological measurement results show that the viscosity of the dispersion decreases rapidly even at the lowest shear stress. Such a hyaluronic acid dispersion is therefore particularly suitable for injection, in particular for aesthetic medicine. Due to its low viscosity when subjected to shear, the dispersion liquefies so that cannulae of less than 0.2 mm in diameter (eg 0.133 mm or 0.184 mm) in diameter are sufficient to deliver an effective amount of hyaluronic acid to the site of action to inject.

Further, a hyaluronic acid dispersion as described above may be injected as an arthritis drug into an arthritic joint. The proportion of cross-linked hyaluronic acid from the dispersion is able to store large amounts of water. This function allows hyaluronic acid dispersion to function as a synovial fluid replacement, preventing or reducing further abrasion of cartilage, and reducing the pain caused by lining up on insufficiently lubricated cartilage.

For such applications, a kit is provided which contains both a hyaluronic acid dispersion according to claim 1 and a suitable application advises. This may be, for example, a syringe whose diameter is optimized for the viscosity of the hyaluronic acid dispersion. It can needle inside diameter of less than 0.2 mm, in particular 18 to 22 gears are used.

Furthermore, a hyaluronic acid dispersion as described above can also be used for aesthetic and cosmetic purposes. It is ideal for injecting wrinkles, especially the sensitive lips. Due to the reduced needle cross-section of the injection needle, the puncture in the skin surface leaves almost no noticeable traces.

In addition, hyaluronic acid dispersions as disclosed in claim 1 of the present invention may also be used for topical application. For this purpose, the hyaluronic acid dispersion is combined with common cosmetic raw materials. In the following, two examples of cosmetic preparations are described which contain such a hyaluronic acid dispersion. The examples are not intended to be limiting, but merely exemplary understood.

example 1

hyaluronic acid cream

production:

Water, PEG-16 Macadamia Glycerides and ethanol are placed in a suitable container. While stirring at room temperature with a paddle stirrer, the preservatives (phenoxyethanol, sodium methylparaben and sodium propylparaben) are added. With vigorous stirring, the hyaluronic acid dispersion is added and stirring is continued until a homogeneous mixture is obtained. Finally, the thickener (sodium polyacrylate) is added, whereby the mixture thickens and forms a gel. The finished gel can be transferred to a suitable container, such as a dispenser or can.

The resulting hyaluronic acid gel can be used as a moisturizing gel for the treatment of dry skin or as a wrinkle-smoothing gel. In particular, it exerts its effect when applied to the cleansing of the face under the lip balm. Example 2

Hvaluronsäurecreme

production:

The water is placed in a suitable container and stirred with a paddle stirrer at room temperature. Subsequently, the imidazolidinyl urea and the inulin are added. Once the solution is clear, the hyaluronic acid dispersion is added and stirred vigorously until the mixture is homogeneous. Ssend subse- the mixture at 45 ⁰ C is heated. In a separate container, the beeswax is weighed with the polyglyceryl-3 methylglucose distearate and the Buxus Chinensis OiI and heated to 70 ⁰ C with stirring with a paddle stirrer. Once the waxes have melted and a homogeneous mixture is formed, the parabens are added. When both phases have reached their setpoint temperature, the wax phase is slowly added to the water phase with vigorous stirring. Subsequently, the mixture is cooled to 40 ° C. With further stirring, the silica is finally added and the cream is stirred until it reaches room temperature.

It is a cream of light consistency, which is very well suited as a topical cream and thereby reduces facial wrinkles.

Claims

claims

1. hyaluronic acid dispersion, characterized in that the dispersed phase consists of particles of cross-linked hyaluronic acid and the continuous phase consists essentially of linear hyaluronic acid.

2. hyaluronic acid dispersion according to claim 1, characterized in that the proportion of dispersed phase is about 0.1 to 90 wt .-% based on the total hyaluronic acid dispersion.

3. hyaluronic acid dispersion according to claim 2, characterized in that the proportion of dispersed phase is about 50 to 75 wt .-% based on the total hyaluronic acid dispersion.

4. hyaluronic acid dispersion according to claims 1 to 3, characterized in that the particle size of the crosslinked hyaluronic acid is about 80 to 300 microns.

5. hyaluronic acid dispersion according to any one of the preceding claims, characterized in that the molecular weight of the crosslinked hyaluronic acid is about 0.8 x 10 ⁶ to 3.0 x 10 ⁶ daltons.

6. hyaluronic acid dispersion according to any one of the preceding claims, characterized in that it is a clear gel.

7. hyaluronic acid dispersion according to any one of the preceding claims, characterized in that it shows pseudoplastic behavior.

8. hyaluronic acid dispersion according to claim 7, characterized in that it exhibits a thixotropic behavior.

9. Use of a hyaluronic acid dispersion according to claim 1 for the preparation of a preparation in cosmetics or aesthetics, in particular aesthetic medicine or in orthopedics, in particular as an arthritis drug.

10. Use of a hyaluronic acid dispersion according to claim 1 and 8, characterized in that it is applied topically or is injected.

11. Cosmetic composition containing a Hyaluronsäuredispersion, characterized in that the dispersed phase of particles of cross-linked hyaluronic acid and the continuous phase of linear

Hyaluronic acid exists.

12. Preparation of a cosmetic composition according to claim 11, wherein the particles of cross-linked hyaluronic acid are dispersed in linear hyaluronic acid.

13. Use of a hyaluronic acid dispersion according to claim 1 for the manufacture of a medicament.

A kit comprising a hyaluronic acid dispersion according to claim 1 and an applicator.

15. Kit according to claim 12, characterized in that the applicator is a syringe.

16. Kit according to claim 12 and 13, characterized in that the syringe has an inner diameter of at least 0.2 mm and in particular from 0.133 mm to 0.184 mm.