ITMI20120664A1 - GELLANE BASED BIOMATERIALS FOR USE AS FILLER IN SURGERY - Google Patents

Description

â € œGELLAN-BASED BIOMATERIALS FOR USE AS A FILLER IN SURGERYâ €

Field of invention

The present invention relates to biomaterials, in gel or fiber form, comprising gellan or its derivatives, alone or in association with hyaluronic acid or its derivatives, for use in surgery as acellular fillers.

State of the art

A wide range of materials, such as membranes, sponges, gauze (or nets), gels, are used in surgery.

The material to be used is chosen according to the type of surgery to be performed.

Therefore, different materials are required with variable characteristics, for example of adhesiveness, elasticity, biocompatibility and biodegradability.

In some cases, the material must be biocompatible but not biodegradable and, therefore, a second surgical intervention is necessary for the removal of the material itself (for example in urogynecological surgery and in ENT surgery). In other cases, the material must be both biocompatible and biodegradable, particularly in dermoaesthetic surgery.

The first filler to be used, in the 1970s, was silicone oil, which is now banned due to its serious side effects.

At the end of the 1970s, the use of bovine collagen was established, which gave very positive results but also caused some allergic reactions.

The materials currently on the market, in the form of membranes (GORE® Medical Membranes); sponges (Valentine R. et al., Otolaryngol Clin North Am; 2009 Oct; 42 (5): 813-28); gauze or nets (Markar Mrcs S.R. et al., Surg Laparosc Endosc Percutan Tech; 2010 Aug; 20 (4): 213-9); gel (Radiesse®; Jacovella P.F., Clin Interv Aging; 2008; 3 (1): 161-74), to be used specifically in dermoaesthetic, urogynecological and ENT surgery, are many and have variable characteristics based on the type of compound they are constituted.

In fact, there are networks of non-absorbable derivatives based on polyesters (MERSILENE), polyamides, polypropylene (Dolphin mesh), used in gynecological surgery and, in particular, as materials for the prevention of urinary incontinence (AMS SPARCâ „¢, AMS Monarcâ „¢, AMS BioArcâ„ ¢ SP and AMS BioArcâ „¢ TO); partially absorbable derivative sponges used in ENT surgery (Meropack, Nasopore); modified / crosslinked hyaluronic acid-based gel or membranes, alone or in association with other polymers, mainly used in dermo-aesthetic surgery (Hydrelleâ „¢, Juvederm®, Perlane® and Restylene®).

The complications, which arise following surgery due to the use of the different known materials, are varied and often related to the nature of the material used or to the inflammatory reactions caused by a prolonged stay in site of the implanted material (Altman D. et al., Obstet Gynecol Surv. 2005 Nov; 60 (11): 753-60).

In particular, complications can arise with biocompatible but non-biodegradable materials or during the degradation of bioabsorbable materials that release inflammatory substances, the formation of the latter still remains one of the most serious complications of numerous surgical procedures (Tatakis D.N. and Trombelli L ., J. Periodontol .; 1999 May; 70 (5): 542-7).

Despite the clinical investigations, aimed at evaluating the efficacy of these materials, have led to strongly discordant results, it can however be noted that the aforementioned materials are associated with significant contraindications.

For example, the use of membranes (in PTFE or polypropylene), as an alternative to materials in gel form, implies the implantation of a synthetic material foreign to the human body, not biodegradable, and may require a second intervention surgery for the removal of the material itself, as this causes unwanted inflammatory reactions or, as in the case of nasal swabs in ENT surgery, often causes pain and bleeding.

Formulations based on gellan, alone or in association with hyaluronic acid derivatives, in particular with sulphated hyaluronic acid, for use in the prevention of surgical adhesions, in particular in the prevention of spinal adhesions, are described in WO 2006 / 037592.

There is still a need to identify new biomaterials that can be used as fillers in the surgical field.

Summary of the invention

The present invention relates to biomaterials comprising gellan or its derivatives, alone or in association with hyaluronic acid or its derivatives, for use as filler in surgery.

Detailed description of the invention

The present invention relates to the use of biomaterials comprising gellan or its derivatives, alone or in association with hyaluronic acid (HA) or its derivatives, as fillers in the surgical field.

These biomaterials are characterized by high biocompatibility and are completely biodegradable, therefore they are suitable for various uses in surgery and do not require a second surgery for their removal from the application sites.

The biomaterials can preferably be in gel or fiber form. Gellan is a linear anionic heteropolysaccharide composed of the repetition of a unit consisting of glucose-glucuronic acid-glucosioramnose.

A derivative of gellan which can preferably be used is deacetylated gellan.

It has been found that gellan is an inert material that can be advantageously used as a filler.

The gellan does not have an active biological role and is characterized by a prolonged stay in the area of application and by high viscosity.

The gellan has a biocompatibility, a prolonged stay in the application site, a degree of bio-adhesiveness and a consistency that allow its use as gel or injectable fiber in biomedical applications.

The gellan, or its derivatives, is preferably pyrogen-free, i.e. it is obtained following a particular purification procedure which leads to obtaining a product with endotoxin content limits lower than 24 UE per milliliter of gel.

The gellan is preferably freeze-dried and soluble up to concentrations of 20 - 30 mg / ml in physiological solutions at 85-90 ° C.

The hyaluronic acid used in the present invention can derive from any source, for example, by extraction from cockscombs (EP 0138572 B1), by fermentation (EP 0716688 B1) or by technological means.

Hyaluronic acid can have a molecular weight between 400 and 3x10 <-6> Da, in particular between 10,000 and 1x10 <-6> Da, and more particularly between 100,000 and 250,000 Da.

According to a preferred embodiment, hyaluronic acid is functionalized with sulphate groups, that is, it is sulphated hyaluronic acid (HA-S).

The sulphation process of hyaluronic acid and its derivatives can take place according to what is known to the person skilled in the art, but preferably according to what is described in the patent EP0702699 B1.

The derivatives of HA that can be used to undergo the sulphation process are listed below:

L. HA salified with organic and / or inorganic bases of molecular weight 50-730 KDa (EP0138572 B1) or with high molecular weight 750-1230 KDa (EP 535200 B1); preferably having a molecular weight comprised between 100 and 250 KDa;

2. Hyaff®: esters of HA with alcohols of the aliphatic, araliphatic, cycloaliphatic, aromatic, cyclic and heterocyclic series (EP 216453 B1); the percentage of esterification of the hyaluronic acid which is subsequently subjected to the sulphation process can vary between 5 and 65%, depending on the type and length of the alcohol used since the product obtained must be soluble in water;

3. ACP®: internal esters of HA (EP 0341745 B1); the percentage of esterification in terms of hyaluronic acid which is subsequently subjected to the sulphation process can vary from 1 to 15% since the product obtained must be soluble in water;

4. Hyoxxâ „¢: percarboxylated derivatives of HA obtained from the oxidation of the primary hydroxyl of the N-acetylglucosamine fraction, (EP1339753); the percentage of percarboxylation of the hyaluronic acid which is subsequently subjected to the sulphation process can vary between 1 and 50%.

All free carboxyl groups of HA can be salified with organic and / or inorganic bases.

The degree of sulfation of hyaluronic acid and / or its derivatives listed above, measured as the number of sulphate groups per repetitive unit, can vary from 0.5 to 3.5 and preferably be equal to 3.

The solubility in water or in physiological solutions is directly proportional to the degree of sulphation of the hyaluronic acid.

Hyaluronic acid is normally characterized by very rapid resorption times, while it is not processable when it is incorporated in the biomaterials of the invention. Therefore, the association of hyaluronic acid or its derivatives with gellan or its derivatives allows its administration during a surgical session.

Biomaterials including gellan or its derivatives and hyaluronic acid or its derivatives can be used as fillers also having biological properties conferred by hyaluronic acid or its derivatives. These biomaterials can be used as bio-revitalizing fillers, for example in the dermo-aesthetic field.

According to a preferred embodiment, the biomaterial consists of a mixture comprising deacetylated gellan and sulfated hyaluronic acid (HA-S).

Sulfated hyaluronic acid (HA-S) has anti-inflammatory and / or antimicrobial properties. These properties are advantageous in a filler used in cosmetic, urogynecological or otolaryngological surgery, as it moderates the onset of inflammatory stress due to the conditions of the original tissue and the stress induced by the surgery.

According to a preferred embodiment, the biomaterials comprise gellan, or deacetylated gellan, pyrogen-free lyophilized and grade 3 sulfated hyaluronic acid.

Preferably, the biomaterials consist only of gellan at a maximum concentration of 30 mg / ml (3% solution) or a mixture comprising gellan with a concentration ranging from 18 to 29 mg / ml and sulfated hyaluronic acid with a concentration ranging from 1 at 12 mg / ml, even more preferably the biomaterial comprises gellan with a concentration equal to 20 mg / ml and sulfated hyaluronic acid with a concentration equal to 10 mg / ml.

The weight ratio between gellan or its derivatives and hyaluronic acid or its derivatives, preferably sulphated hyaluronic acid, can vary between 1.5: 1, 2: 1 and 2: 1.5; The weight ratio 2: l is preferable.

The biomaterials have characteristics similar to native hyaluronic acid, but with residence times that are sufficiently suitable to perform the different functions necessary according to the type of surgery in which they are used. The gellan-based biomaterial alone or in combination with sulphated hyaluronic acid combines the long stay in situ with a very high tolerability profile, testified by the outcome of the biocompatibility tests according to ISO 10993 carried out at the level of the central nervous system. During the same tests, it was possible to demonstrate that a biomaterial based on gellan and hyaluronic acid sulfated, according to the present invention, does not induce sensitization reactions after application. The biomaterial also has a period of permanence after application which is more than two years.

Extrusion tests carried out on biomaterials confirm the properties of handling, easy injection and comfortable positioning that meet the needs of the doctor who performs the intervention.

The biomaterials according to the present invention can be used as acellular fillers in surgery, in particular in dermo-aesthetic surgery, urogenicological surgery and ENT surgery, for example to increase physiological tissue for biofunctional or cosmetic purposes.

As fillers in the urogynecological field they can be used to solve problems due to urinary incontinence thanks to their characteristics of residence time and injectability.

In urogynecology the primary indication of fillers is ISD (sphincter insufficiency) but they are also used in cases of urinary incontinence due to hypermobility of the bladder. In this case, the action of the filler is the improvement of the function of the sphincter. The characteristics of the ideal filler include, in addition to the tolerability profile, the ease of injection, the maintenance of the volume over time and the persistence at the injection site, despite the constant stresses due to movement, of at least 2 years.

The materials according to the present invention satisfy these requirements. In the otolaryngological field, the biomaterials of the present invention can be used in phono surgery, in surgical interventions on the vocal cords, for example for the restoration of the vibratory activities of the vocal cords through the medialization of cords affected by paresis, or, in renosurgery, where A barrier between the sinuses is required.

As regards the application in the field of surgery on the vocal cords, the ideal filler must prove to be biocompatible, non-immunogenic, injectable through needles of dimensions compatible with the common surgical practice, have an adequate residence time and boast viscoelastic properties similar to the physiological ones of the vocal cords in order to guarantee biofunctional restoration.

In dermo-aesthetic surgery, for example, biomaterials can be used as fillers, injected into the skin of the face through a very fine needle, in order to fill wrinkles, folds, depressions or to increase the volume of the lips, chin and cheekbones.

The biomaterials according to the present invention comprising gellan and hyaluronic acid and / or their derivatives can be advantageously obtained, for example, by simple dry mechanical mixing, without the need to form new chemical bonds between the components to obtain derivatives of various kinds, such as cross linked, esters, ethers, amides, ionic complexes, etc.

The following examples further illustrate the invention.

Examples

Preparation example 1

Preparation of the biomaterial in the form of a hydrogel consisting of gellan in association with HA sulphated with a weight ratio of 2: 1

HA is sulphated as per patent EP0702699 B1 with a degree of sulfation equal to 3.

A 20 mg / ml solution of deacetylated gellan (Gelrite®) is prepared by dissolving, under heat (75-85 ° C), 1 g of gellan in 50 ml of 0.9% NaCl. At complete solubilization, 500 mg of sulphated HA is added and complete solubilization is awaited, then it is allowed to cool to room temperature until a hydrogel is obtained which can then possibly be steam sterilized.

Preparation example 2

Preparation of the biomaterial in the form of a hydrogel consisting of gellan in association with HA sulphated with a weight ratio of 1.5: 1

One proceeds as Example 1 by dissolving 750 mg of gellan and 500 mg of HA sulphated.

Preparation example 3

Preparation of the biomaterial in the form of a hydrogel consisting of gellan in association with HA sulfated benzyl ester, with an esterification% of 25% with a weight ratio of 2: 1

The gellan solution is prepared as in Example 1. To it are subsequently added 500 mg of HA sulfated benzyl ester and its complete solubilization is awaited. It is then left to cool to room temperature to obtain a hydrogel which can then be eventually steam sterilized.

Preparation example 4

Preparation of a fiber composed of a mixture of gellan (98%) and HYAFF <®> -11 p75 (2%)

9.8 grams of Kelcogel <®> CG-LA gellan are mixed dry with 0.2 grams of HYAFF <®> -11 p75 powder.

The powder mixture is placed in a mixer and slowly added with 125 ml of water. A mixture is obtained at a concentration of 80 mg / ml.

The dough is transferred to a screw extruder connected to a 60 µ die.

The temperature of the extrusion chamber is brought to 54 ° C, and the material is extruded.

A fiber with an average diameter of 25-30 µ is obtained.

Preparation example 5

Preparation of a fiber composed of a mixture of gellan (95%) and HYAFF <®> -11 p50 (5%)

9.5 grams of Kelcogel <®> CG-LA gellan are mixed dry with 0.5 grams of HYAFF <®> -11 p50 powder.

The powder mixture is placed in a mixer and slowly added with 110 ml of water. A mixture is obtained with a final concentration of about 90 mg / ml. The mixture is transferred to a screw extruder connected to a 40 µ die. The temperature of the extrusion chamber is brought to 54 ° C and the material is extruded.

A fiber with an average diameter of 15-25 µ is obtained.

Preparation example 6

Preparation of a fiber composed of a mixture of gellan (90%) and sulphated HA with a degree of sulfation 1 (10%)

9 grams of Kelcogel <®> CG-LA gellan are mixed dry with 1 gram of sulphated HA with sulphation grade 1, lyophilized.

The mixture of the two polymers is placed in a mixer and slowly added with 100 ml of water. A mixture is obtained with a final concentration of 100 mg / ml. The mixture is transferred to a screw extruder connected to a 150 µ die. The temperature of the extrusion chamber is brought to 54 ° C and the material is extruded.

A fiber with an average diameter of 50-70 µ is obtained.

Preparation example 7

Preparation of a fiber composed of a mixture of gellan (95%) and HYADDâ „¢ (5%)

9.5 grams of Kelcogel <®> CG-LA gellan are mixed dry with 0.5 grams of HYADD <TM> -4 (hexadecyl amide with 2% amidation) in powder form.

The mixture of the two polymers is placed in a mixer and slowly added with 125 ml of water. A mixture is obtained with a final concentration of 80 mg / ml. The dough is transferred to a screw extruder connected to a 60 µ die. The temperature of the extrusion chamber is brought to 54 ° C and the material is extruded.

A fiber with an average diameter of 25-30 µ is obtained.

Preparation example 8

Preparation of a fiber composed of a mixture of gellan (95%) and ACP <®> (5%)

9.5 grams of Kelcogel <®> CG-LA gellan are mixed dry with 0.5 grams of ACP <®> (cross-linked hyaluronic acid) powder.

The mixture of the two polymers is placed in a mixer, and slowly added with 110 ml of water. A mixture is obtained with a final concentration of about 90 mg / ml. The dough is transferred to a screw extruder connected to a 100 µ die. The temperature of the extrusion chamber is brought to 50 ° C and the material is extruded.

A fiber with an average diameter of 30-50 µ is obtained.

Preparation example 9

Preparation of a fiber composed of a mixture of gellan (98%) and HYAFF <®> -11 (2%)

9.8 grams of Kelcogel <®> CG-LA gellan are mixed dry with 0.2 grams of HYAFF <®> -11 powder.

The powder mixture is placed in a mixer and slowly added with 125 ml of water. A mixture is obtained at a concentration of 80 mg / ml. The mixture is transferred to a screw extruder connected to a 60 µ die. The temperature of the extrusion chamber is brought to 54 ° C, and the material is extruded.

A fiber with an average diameter of 25-30 µ is obtained.

Preparation example 10

Step 1: Preparation of a solution of Gellan TBA

25 grams of Kelcogel <®> CG-LA gellan powder, sieved and collected between 140 and 38 micron sieves, are added to 300 ml of water and kept under slow stirring in a thermostat-controlled mixer at a temperature of 60 ° C. After about 10 minutes another 100 ml of water are added and stirring is continued for another 30 minutes until a homogeneous mixture is obtained. The stirring is stopped and 150 ml of activated resin TBA suspended in 100 ml of water are added to the hot gellan mixture. The agitation is resumed, always keeping the speed at a minimum. The ion exchange (Naâ † ’TBA) takes place between 4 and 6 hours and allows a complete dissolution of the gellan gum. After 6 hours the TBA gellan solution is separated from the resin by filtration through a steel filter with a porosity of 45 microns. The gellan solution obtained must have a pH between 7 and 8 and the gellan content must be between 45 and 60 mg / ml.

Preparation example 11

Step 2: Preparation of the gellan fiber

The gellan solution prepared according to example 10 is filtered using a filter cloth with 20 micron pores and transferred to an extrusion reactor thermostated at 55 ° C connected to a multi-wire wet extrusion die consisting of 3000 holes of 80 micron each. The material is extruded through a first coagulum bath, in continuous recirculation, with 3 liters of a solution of sodium chloride in ethanol / water. The threads are introduced by means of transport rollers into a second coagulation tank filled with 0.5 liters of a solution of calcium chloride in ethanol and in subsequent 3 washing tanks filled with 0.5 liters each of absolute ethanol and finally in a ... ™ last wash tank filled with 0.5 liters of acetone. Once the extrusion process has been completed, the fiber is continuously dried by means of hot air ejectors and collected in a reel. A gellan fiber with a diameter of 10-30 microns is obtained.

Example 12

Study of biodegradation, local tolerance and neurotoxicity of the filler (gel) based on gellan gum and sulfated hyaluronic acid towards a dermal filler (gel) based on carboxymethylcellulose and polyethylene oxide (PEO) (commercial name Laresseâ „¢ commercially available as dermatological filler)

The study evaluated the effects of the gel based on gellan gum and sulfated hyaluronic acid and the gel based on carboxymethylcellulose and polyethylene oxide after subdural application in rabbits.

The application of the gellan filler and the commercially available filler (control) was carried out bilaterally in the subdural space of 21 rabbits.

Each group was observed for 3, 6, 9, 15 or 24 months.

Clinical and neurobehavioral observations were performed, food consumption and body weight were also monitored.

At the sacrifice, cerebrospinal fluid and blood values were analyzed, as well as a histological analysis of target organs. Finally, a macroscopic and histological analysis of the implantation sites was performed.

The results indicated a comparable safety profile between the gellan gel and sulfated hyaluronic acid in the study and the control, with no macroscopic and microscopic signs of intolerance or toxicity. No deleterious effects are shown on the cerebrospinal fluid, nor signs of local intolerance or systemic toxicity.

While the control material is no longer highlighted at the first follow-up (3 months), the gellan and sulfated hyaluronic acid gel in the study shows a

very slow and incomplete degradation process after 24 months.

It is noted that, in the field of application as a dermo-aesthetic filler,

this aspect of prolonged residence at the injection site represents a

desirable feature for a successful product. The results of the study

show that the gel based on gellan gum and sulfated hyaluronic acid,

for equal safety, it represents a device with a multiple residence in situ

lasting compared to the commercial comparison product.

Example 13

Measurement of extrusion force as a function of processes

aging

For the purpose of measuring the force of extrusion of the gel, the syringe was

applied a cannula of 10 cm in length, subsequently they were

test four syringes for each sample with an instrument

INSTRON 4520.

The material was tested as soon as it was prepared (Time 0) and after processes

aging both at room temperature and at 40 ° C. It was a test

performed even after freezing (-20 ° C) of the material.

Time Temperature Average force on Semidispersion Deviation ° C 4 measurements (N) (∠') standard (σmax) 0 environment 6.9 0.6 <0.6>

17 h -20 3.6 0.4 <0.4>

3 months environment 8.1 0.8 <0.8>

6 months environment 6.7 0.3 0.4

9 months environment 6.6 0.3 0.4

12 months environment 6.9 0.3 0.5

2 months 40 7.9 0.6 0.6

3 months 40 6.8 0.7 0.5

6 months 40 4.6 0.5 0.3 The study testifies to the fact that during the aging of the product at room temperature no phenomena such as to influence its extrusion characteristics (i.e. degradation) occur.

The extrusion force as a function of the treatment at 40 ° C undergoes a progressive decrease with aging up to 6 months.

Example 14

Evaluation in a canine biofunctional model of the injection of the gel-based filler consisting of gellan gum and sulfated hyaluronic acid in laryngoplasty procedures

A study was performed to test the efficacy, longevity and safety of injections of a gel-based filler consisting of gellan gum and sulfated hyaluronic acid used in canine model laryngoplasty procedures. During the trial, a commercially available control material called Radiesse® Voice (based on calcium hydroxyapatite, CaHA) was used.

The study involved 30 beagle dogs (male, mean weight of 13.6 kg). After inducing complete unilateral paralysis of the vocal cord following resection of the larynx nerve, injections of Radiesse® Voice and gel based on gellan gum and sulfated hyaluronic acid were performed.

Videostroboscopic and clinical analyzes were performed 1, 3, 6, and 9 months after injection by evaluators who were blinded to the treatment group. Histological analyzes were also performed.

At the videostroboscopic analysis at 1 and 9 months after the injection of the CaHA-based material, normal values of mucosal oscillation were found in one vocal cord, while in the other the value had decreased. At 6 months after the injection, the mucosal fluctuations were well detected; but at 3 months there were some decreases in amplitude and periodicity compared to the vocal cord which had not received the injection due to insufficient filling and mass effect of CaHA. Histologically, the stains with hematoxylin, eosin and Masson's trichrome dye obtained at 1, 3, 6 and 9 months after the injection showed a reaction from giant cells which indicates the phagocytic action of macrophages in some areas and reveals that the foreign body reaction is predominant in the tissues that have received the injections with CaHA.

Larynx specimens injected with gellan gum-based filler and sulfated hyaluronic acid show foamy cell formation indicating resorption. Inflammation was found in 4 samples. In 2 cases, signs of fibrosis were found.

Stroboscopically, the mucosal oscillations of the vocal folds treated with the gellan gum and sulfated hyaluronic acid gel are all excellent except one and the like between paralyzed and normal vocal folds.

No protrusions of the material were noted during the study and no systemic or local complications were observed in any group.

The mucosal oscillations of the vocal cords preserved their amplitude and periodicity and were well detectable throughout the follow-up.

In conclusion, the gel based on gellan gum and sulfated hyaluronic acid is a safe and long-lasting filler in the vocal cords and can be considered an adequate material for laryngoplastic injections, like the products currently available on the market. Compared to the control material, there is also the added value of a better effect on the restoration of the natural characteristics and mucosal oscillations of the paralyzed vocal cords thanks to the superior stroboscopic results and the fewer inflammatory reactions associated with the administration of the gel based on gellan gum. and sulfated hyaluronic acid. The type of material injected during the laryngoplasty procedure influences the result in terms of quality.

Claims (14)

CLAIMS 1. Biomaterials including gellan or its derivatives, alone or in association with hyaluronic acid or its derivatives, for use as filler in surgery. 2. Biomaterials according to claim 1, in gel or fiber form. 3. Biomaterials according to claim 1 or 2, wherein the gellan or its derivatives are pyrogen-free. 4. Biomaterials according to claims 1-3, wherein the gellan derivative is deacetylated gellan. 5. Biomaterials according to claims 1-4, wherein the hyaluronic acid derivative is sulfated hyaluronic acid (HA-S). 6. Biomaterials according to claim 5, wherein the degree of sulphation of the hyaluronic acid varies from 0.5 to 3.5. 7. Biomaterials according to claim 6, in the degree of sulphation of hyaluronic acid is equal to 3. 8. Biomaterials according to claims 1-4, wherein the maximum concentration of gellan is equal to 30 mg / ml. 9. Biomaterials according to claims 1-7, wherein the gellan concentration varies from 18 to 29 mg / ml and the sulfated hyaluronic acid concentration varies from 1 to 12 mg / ml. 10. Biomaterials according to claim 9, wherein the concentration of the gellan is equal to 20 mg / ml and the concentration of the sulphated hyaluronic acid is equal to 10 mg / ml. 11. Biomaterials according to claims 1-7, wherein the weight ratio between gellan or its derivatives and hyaluronic acid or its derivatives varies between 1.5: 1, 2: 1 and 2: 1.5. 12. Biomaterials according to claim 11, wherein the weight ratio is 2: 1. 13. Biomaterials according to claims 1-12, for use by injection. 14. Biomaterials according to claims 1-13, for use in dermo-aesthetic surgery, urogynecological surgery and ENT surgery. Milan, April 20, 2012