A method for inducing an improvement in the mechanical strength of an implantable device comprising one or more PLA filaments after a specified hydrolysis, and an implantable device obtainable by said method.

Abstract

The present invention relates to a method for inducing an improvement in the mechanical strength (N / cm) of an implantable device after a specified period of hydrolysis, said method comprising: i) a step of supplying an implantable device comprising one or more wires comprising at least one (co)polymer of lactic acid; ii) a step of treating said implantable device with supercritical carbon dioxide (CO2); iii) a step of obtaining an implantable device having a mechanical strength greater than or equal to 10 N / cm, preferably greater than or equal to 25 N / cm, after 20 weeks of hydrolysis, particularly in an aqueous medium. The present invention also relates to an implantable device obtainable by said method, and to the use of supercritical (CO2) to induce an improvement in the mechanical strength of an implantable device comprising one or more wires comprising one or more (co)polymers of lactic acid.Figure for the abridged version: Fig.5.

Description

Title of the invention: A method for inducing an improvement in the mechanical resistance of an implantable device comprising one or more PLA filaments after a specified hydrolysis, and an implantable device obtainable by said method. Technical field

[0001] The present invention relates to the technical field of implantable devices at least partly resorbable and at least partly textile, in particular for the treatment of hernias, having improved mechanical resistance at the end of a determined prolonged hydrolysis period.

[0002] The present invention also relates to the technical field of methods for improving the mechanical resistance at the end of a prolonged hydrolysis period of implantable devices that are at least partly textile and at least partly resorbable, in particular for the treatment of abdominal hernias. Previous technique

[0003] It is known to use implantable devices at least partly made of textiles and at least partly resorbable or non-resorbable for the treatment of abdominal hernias.

[0004] These implantable devices generally comprise an implantable textile panel, at least partially resorbable or non-resorbable, substantially flat and / or having a three-dimensional anatomical shape to fill a parietal defect. The textile panel is generally a knit or fabric, for example, a knit of monofilament yarns providing sufficient mechanical resistance, made of polypropylene or polyethylene, for example, when non-resorbable, or of P4HB when resorbable, for example. When the reinforcing textile panel is non-resorbable, it is intended to remain implanted in the patient during hernia treatment. When the reinforcing textile panel is resorbable, it is intended to be hydrolyzed by the patient's natural implantation environment, which is an aqueous environment, and thus disappear after a predetermined period.

[0005] The choice of a resorbable or non-resorbable implantable device depends in particular on the type of patient, especially if the latter presents risks such as obesity, diabetes, smoking, or a combination of these different risks.

[0006] It has been observed that patients with one or more of the risk factors listed above are more susceptible to recurrent abdominal hernias, and especially to infections at the site of the implanted device. These infections When infections cannot be treated with medication, surgical intervention is required to remove the implanted device. These infections generally occur after a period of several months. Surgical practice in the treatment of ventral hernias is therefore moving away from using polypropylene or polyester implantable devices, i.e., non-absorbable ones, to treat patients with risk factors for infection, as these patients will require corrective surgery to remove the implanted device. To overcome this drawback, patients with risk factors for infection are treated with absorbable implantable devices.For the treatment of abdominal hernias in patients at risk of infection, the implantable device marketed under the brand name PHASIX® is known, using absorbable P4HB sutures with complete resorption after 18 months. Thus, in the event of infection several months after implantation, it is not necessary to remove the implanted device.

[0007] Resorbable implantable devices available on the market allow for relatively proper treatment of the infection without having to explant the implanted device (since it disappears completely in the long term) but the probability of recurrence of the hernia is greater.

[0008] For patients at risk of infection, the majority of recurrences occur before the end of the first year after implantation, i.e., around 12 months. These recurrences occurring during the first year appear at the periphery of the implanted device, i.e., in anatomical areas not covered by the implanted device. After the first year, recurrences appear in anatomical areas covered by the implanted resorbable device, which ruptures due to a loss of resistance caused by degradation through hydrolysis.

[0009] It is thus sought to improve the mechanical resistance of implanted resorbable devices during hydrolysis, and this several months after the start of hydrolysis, in order to avoid a recurrence of the hernia.

[0010] The publication entitled “In Vitro Degradation of Poly(L-lactic acid) fibers produced by melt spinning”; A. Pegoretti, L. Fambri, C. Migliaresi, Department of Materials Engineering, University of Trento, via Mesiano 77, 38050 Trento, Italy, highlights that the mechanical properties of smaller diameter fibers (approximately 72 pm) degrade more rapidly than those of larger diameter fibers (approximately 120 pm) under the effect of PLLA hydrolysis. This study demonstrates that the degradation rate depends on numerous factors, including the type of polymer, the PLLA manufacturing conditions (melt or solvent-based), and the degradation medium. In particular, the lower the surface area to volume ratio and the higher the initial molar mass, the greater the degradation rates of both the molar mass and the mechanical properties. Mechanical processes are slowed. It is observed that after 16 weeks (4 months), the tensile strength (MPa), recorded in [Fig. 6], drops from 900 MPa to approximately 225 MPa for a monofilament with a diameter of 120 microns, representing a loss of mechanical strength of around 75% over a 4-month hydrolysis period. For fibers with a diameter of 72 microns, the tensile strength drops from 975 MPa to 110 MPa after 4 months of hydrolysis (representing a loss of mechanical strength of 89%, see Figure 7b). The 120 µm fibers retain a higher tensile strength than the 72 µm fibers, but the degradation of tensile strength is greater than or equal to 75% in both cases after a 4-month hydrolysis period in a buffered solution at pH 7.4 and a temperature of 37°C.

[0011] A person skilled in the art is thus encouraged to increase the diameter of the filaments of implantable devices in order to delay the loss of mechanical strength; however, an excessive loss of mechanical strength (70%) is observed after 4 months. The desired result is a mechanical strength that is not too significantly reduced after 4 months, and ideally still significant after 5 months, and again after 8 months, since the risks of infection and recurrence are higher around 12 months.

[0012] Furthermore, it is not possible to implement filaments with too large a diameter because the implantable device must remain flexible, in particular enough to be able to be wound on itself and placed in an insertion trocar of a few mm in diameter and then unwound at the implantation site.

[0013] It has therefore been proposed to add a resorbable coating to the resorbable filaments themselves in order to delay the hydrolysis of said filaments and postpone the loss of mechanical strength. However, this arrangement requires a coating step for the filaments and tends to stiffen them, which is detrimental to patient comfort and reduces the flexibility of the implantable device.

[0014] The present invention thus relates to a method for inducing an improvement in the mechanical resistance to hydrolysis, in particular in aqueous media, of an implantable device comprising one or more monofilamentary wire(s) in (co)polymer(s) of lactic acid, and this without loss of the flexibility of said implantable device so that it can be inserted into a trocar.

[0015] The present invention also relates to an implantable device that is wholly or partly resorbable, comprising one or more wires made of (co)polymer lactic acid, and having improved mechanical resistance to hydrolysis, particularly in aqueous media, particularly at 5 months and / or 8 months. Description of the invention

[0016] The present invention addresses the aforementioned problems in that, according to a first aspect, it relates to a method for inducing an improvement in resistance mechanical strength (N / cm) of an implantable device after a specified period of hydrolysis of said implantable device, in particular measured in weeks or months, said implantable device comprising one or more wires comprising at least one (co)polymer of lactic acid, said process further comprising, said steps advantageously taking place in this order: (i) - a step of supplying an implantable device comprising one or more wires comprising at least one (co)polymer of lactic acid; ii)- a step of treating said implantable device with supercritical carbon dioxide (CO2); iii)- a step of obtaining an implantable device having a mechanical resistance greater than or equal to 10 N / cm, or 15 N / cm, or 20 N / cm, or 22 N / cm, preferably greater than or equal to 25 N / cm or 27 N / cm or 29 N / cm, after 20 weeks of hydrolysis, in particular in an aqueous medium.

[0017] It has been surprisingly discovered that the treatment with CO2sc of an implantable device at least partly textile and at least partly resorbable, with lactic acid (co)polymer threads makes it possible to improve the mechanical resistance of this implantable device during its hydrolysis.

[0018] Thus, it has been observed that an implantable device at least partly textile comprising monofilament yarns in (co)polymer of lactic acid treated with sc CO2 has a mechanical resistance (N / cm) multiplied by at least three at 5 months of hydrolysis compared to an identical implantable device not treated with sc CO2. Implantable device

[0019] Preferably, the implantable device includes, in particular, a flat or three-dimensional textile plate or comprising a flat part and a three-dimensional part.

[0020] In the present text, a flat textile plate or flat part is understood to mean that this part or plate extends in a two-dimensional plane along x and y axes, the thickness of the plate or part being insignificant and / or not considered.

[0021] In the present text, a three-dimensional textile plate or three-dimensional part is understood to mean that this part or plate extends in three dimensions, along x, y and z axes, the thickness of the plate or part being measured along the z axis.

[0022] Preferably, the implantable device comprises one or more textiles, in particular one or more textile panels, knitted and / or woven and / or braided, preferably knitted.

[0023] Preferably, the implantable device, in particular the textile or textile panel, has a surface mass greater than or equal to 10 g / m2, or 20 g / m2, or 30 g / m2, or 40 g / m2.

[0024] Preferably, the implantable device, in particular the textile or textile panel, has a surface mass greater than or equal to 50 g / m2, or 60 g / m2 or 70 g / m2 or 80 g / m2 or 90 g / m2 or 100 g / m2, preferably greater than or equal to 110 g / m2.

[0025] Preferably, the implantable device, in particular the textile or textile panel, has a surface mass less than or equal to 300 g / m2, or 250 g / m2 or 230 g / m2, or 220 g / m2 or 200 g / m2, more preferably less than or equal to 190 g / m2 or 180 g / m2.

[0026] Advantageously, the flat or three-dimensional textile plate comprises, or is essentially made up of, one or more textile(s).

[0027] In one embodiment, the knitting is a knitting with picked stitches or chain stitches (i.e. with dropped stitches).

[0028] Preferably, the implantable device comprises, or the textile or textile plate is, a knitted fabric with dropped stitches, even more preferably said knitted fabric with dropped stitches comprises one or more monofilamentary yarn(s).

[0029] Preferably, the implantable device is arranged for the treatment of an abdominal hernia, for example ventral or inguinal.

[0030] Advantageously, the implantable device is at least partly textile.

[0031] Advantageously, the implantable device and / or the textile and / or the textile plate is / are at least partly resorbable, preferably at least 50% or 60% or 70% or 80% or 90% or 95% or 99% or 100% approximately by mass of the implantable device or the textile or the plate is resorbable.

[0032] In the present text, "resorbable" means that part or all of the implantable device and / or textile and / or textile plate is resorbable by hydrolysis, that is to say, it is chemically and / or mechanically degraded progressively by hydrolysis in an aqueous medium at room temperature (for example at a temperature greater than or equal to 20°C, or at 37°C) after a determined period and / or once implanted in a living organism (bioresorbable), in particular a mammal, more particularly the human body, after a determined period by hydrolysis, for example of 4 months or 5 months or 8 months or 10 months or 12 months or more.

[0033] A textile may comprise one or more monofilamentary yarn(s) and / or one or more multifilamentary yarn(s).

[0034] Preferably, the aqueous medium comprises at least 50% or 60% or 70% or 80% or 90% by mass or by volume of water, in particular distilled and / or reverse osmosis water.

[0035] Preferably, the aqueous medium has a pH greater than or equal to 6 and less than or equal to 8, more preferably greater than or equal to 6.5 or 6.7 or 6.8 or 7.0 or 7.2, preferably less than or equal to 7.8 or 7.6.

[0036] For example, the aqueous medium has a pH of the order of 7.4 at + / - 0.1.

[0037] Preferably, the aqueous medium is buffered with a phosphate-buffered saline solution (PBS).

[0038] Preferably, a monofilamentary wire has a diameter greater than or equal to 0.01 mm, more preferably greater than or equal to 0.05 mm, preferably greater than or equal to 0.10 mm.

[0039] Preferably, a monofilamentary wire has a diameter less than or equal to 3 mm, more preferably less than or equal to 2 mm or 1 mm or 0.80 mm, preferably less than or equal to 0.70 mm or 0.60 mm or 0.50 mm or 0.40 mm or 0.30 mm or 0.20 mm.

[0040] Preferably, the monofilamentary filament(s) and / or multifilamentary filament(s) comprise (each), or are made up of, one or more (bio)resorbable materials selected from: a lactic acid polymer of L or D form or of L and D forms, a glycolic acid polymer, a copolymer of lactic acid (L and / or D) and glycolic acid, polycaprolactone, poly-4-hydroxybutyrate (P4HB), or a mixture of the latter.

[0041] The L (Levogyre) form and the D (Dextrogyre) form are two isomers of lactic acid.

[0042] The lactic acid polymer can be a homopolymer or a copolymer.

[0043] In the present text, the term copolymer means any polymer comprising at least two different repeating units, and possibly at least three different repeating units (for example, a terpolymer).

[0044] Lactic acid (co)polymer is understood to mean a lactic acid homopolymer (comprising L-shaped and / or D-shaped repeat units), and any copolymer comprising at least lactic acid repeat units (comprising L-shaped and / or D-shaped repeat units) and repeat units other than lactic acid, for example glycolic acid.

[0045] In one embodiment, the monofilamentary yarn(s) has (each) an elongation at break less than or equal to 100%, in particular less than or equal to 70%, more particularly less than or equal to 60% or 50% or 45%.

[0046] Advantageously, the monofilamentary wire(s) has (each) an elongation at break greater than or equal to 10%, in particular greater than or equal to 15% or 20%.

[0047] In one embodiment, the monofilamentary yarn(s) has (each) a tenacity (cN / dtex) greater than or equal to 1 cN / dtex, preferably greater than or equal to 2 or 3 cN / dtex.

[0048] Advantageously, the monofilament yarn(s) has / have (each) a tenacity (cN / dtex) less than or equal to 30 cN / dtex, preferably less than or equal to 20 cN / dtex, more preferably less than or equal to 15 cN / dtex, in particular less than or equal to 10 cN / dtex.

[0049] In one embodiment, the monofilamentary wire(s) has (each) a breaking load greater than or equal to 300 cN, preferably greater than or equal to 400 cN or 500 cN or 600 cN or 700 cN or 800 cN.

[0050] Advantageously, the monofilamentary wire(s) has (each) a breaking load less than or equal to 3000 cN, preferably less than or equal to 2000 cN or 1500 cN.

[0051] The breaking load, toughness, and elongation at break of the monofilament yarn were measured according to standard EN 13895 dated June 2003, entitled "Textiles - Monofilaments - Determination of tensile properties".

[0052] In one embodiment, the monofilament yarn(s) has (each) a linear density (dtex) greater than or equal to 50 dtex, preferably greater than or equal to 100 dtex or 150 dtex or 180 dtex or 200 dtex.

[0053] Advantageously, the monofilamentary yarn(s) has (each) a linear mass (dtex) less than or equal to 800 dtex, preferably less than or equal to 700 dtex or 600 dtex or 500 dtex or 400 dtex or 300 dtex, for example in the order of 220 dtex at + / - 50 dtex.

[0054] The linear mass is measured using the standard NF EN 13392 dated September 2001, entitled "Textiles - Monofilaments - Determination of linear mass".

[0055] A monofilamentary yarn is understood to mean any yarn comprising a single filament, and capable of being used on a textile machine, in particular a knitting machine, a weaving machine, a braiding machine.

[0056] In one embodiment, the implantable device comprises a knitted fabric with single-stitched loops comprising monofilament yarns, in particular: - a first monofilament yarn forms open and / or closed knitted stitches, in particular atlas stitches, more particularly extending over at least three columns of stitches (or at least three needles), in particular over at most 20, 15, or 10 columns of stitches (or needles); and - a second monofilament yarn forms open and / or closed knitted stitches, in particular atlas stitches, more particularly extending over at least three columns of stitches (or at least three needles), in particular over at most 20, 15, or 10 columns of stitches (or needles), the second yarn being supported by a guide bar working in a direction opposite to the guide bar supporting the first monofilament yarn; and

[0057] - possibly a third monofilament yarn forms open knitted stitches and / or closed, in particular atlas stitches, more particularly extending over at least three columns of stitches (or over at least three needles), in particular over at most 20 or 15 or 10 columns of stitches (or needles), in particular according to the same mesh pattern than that of the first monofilamentary wire; and

[0058] - possibly a fourth monofilamentary yarn forms knitted stitches open and / or closed, in particular atlas stitches, more particularly extending over at least three columns of stitches (or over at least three needles), in particular over at most 20 or 15 or 10 columns of stitches (or needles), the fourth yarn is supported by a guide bar working in a direction opposite to the guide bar supporting the third monofilament yarn.

[0059] In one embodiment, the knitting comprises:

[0060] - a first monofilament threaded, in particular fully threaded, onto a first bar with B1 loops according to the following armor described in accordance with ISO 11676, dating from 2014: 2- 3 / 2- 1 / 2- 3 / 2- 1 / 1- 0 / 1- 2 / 1- 0 / 1- 2 / / ;

[0061] - a second monofilament threaded, in particular fully threaded, onto a second bar B2 loops according to the following armor described in accordance with ISO 11676, dating from 2014: 1- 0 / 1- 2 / 1- 0 / 1- 2 / 2- 3 / 2- 1 / 2- 3 / 2- 1 / / ;

[0062] - and possibly:

[0063] - a third monofilament thread threaded, in particular fully, onto a third B3 slotted bar according to the following weave described in accordance with ISO 11676, 2014: 2-3 / 2-1 / 2-3 / 2-1 / 1-0 / 1-2 / 1-0 / 1-2 / / ; and / or

[0064] - a fourth monofilament threaded, in particular fully, onto a fourth B4 slotted bar according to the following armor described in accordance with ISO 11676, dated 2014: 1- 0 / 1- 2 / 1- 0 / 1- 2 / 2- 3 / 2- 1 / 2- 3 / 2- 1 II.

[0065] Preferably, the bar B1 moves / knits in a direction opposite to the direction of movement / knitting of the bar B2.

[0066] Preferably, the bar B3 moves / knits in a direction opposite to the direction of movement / knitting of the bar B4.

[0067] Preferably, the bar Bl, respectively B2, moves / knits in the same direction as the direction of movement / knitting of the bar B3, respectively B4.

[0068] Advantageously, working with loop bars having the same movement allows knitting with a single yarn per bar, and thus better balancing the tensions exerted on a yarn than if a bar supports two yarns, while increasing the surface mass of the knitting.

[0069] For example, a knitted fabric with two bars B1 and B2, each bar supporting a yarn, makes it possible to obtain a surface mass of approximately 120 g / m2 at + / - 20 g / m2.

[0070] For example, a knitted fabric with four bars Bl, B2, B3 and B4, each bar supporting a yarn, makes it possible to obtain a surface mass of approximately 170 g / m2 at + / - 20 g / m2.

[0071] The implantable device may comprise a textile, for example a knit, comprising one or more absorbable polymer coating(s), for example with Based on polyvinylpyrrolidone, a cellulosic polymer, a cyclodextrin polymer, a k-carrageenan polymer, or a combination thereof. Improved mechanical strength (N / cm)

[0072] The mechanical resistance (Newtons / cm), or bursting value (Newtons / cm), is measured according to the test method described in ASTM D3787-7 (2011), entitled "Bursting Strength of Textiles - Constant-Rate of Traverse (CRT) Bail Burst Test" or "Bursting Strength of Textiles - Constant-Rate of Traverse (CRT) Bail Burst Test".

[0073] In particular, this standard allows for the determination of a total tensile strength F expressed in newtons. The tensile strength expressed in N / cm is calculated by dividing the total tensile strength expressed in Newtons by the perimeter of the ball expressed in cm.

[0074] In particular, the diameter of the ball, conforming to ASTM D3787-7 (2011), is 2.54 cm (i.e., "one English inch" or "international technical inch") and therefore has a perimeter of 2.54 x Pi in cm. The breaking strength expressed in N / cm is therefore calculated according to the formula: F / (2.54 x Pi).

[0075] In particular, the tests are carried out on an average of three to six textile samples, specifically six, of approximately 10 cm x 10 cm. More specifically, the sample (10 cm x 10 cm) is securely fixed without tension between two grooved circular plates. Then, the movable accessory, comprising a rod with a ball at one end, is fixed to the traction jaw, and the accessory moves toward the surface of the textile sample so that the ball pierces said textile sample at a constant travel speed of 305 mm / min. A force is exerted against the surface of the textile sample by the steel ball (the diameter of the ball is, in particular, one inch, or 2.54 cm). The burst value of the ball corresponds to the force required to pierce the sample.This value in newtons is divided by the circumference of the ball with a diameter of one English inch (2.54 x Pi = approximately 7.98 cm) to obtain the resistance value in newtons per centimeter (N / cm).

[0076] This test advantageously allows the entire textile surface of the sample tested to be involved.

[0077] Advantageously, the implantable device, in particular the textile plate (flat or three-dimensional) or the knit, has a mechanical resistance or burst value before implantation or at 0 days of hydrolysis, greater than or equal to 16 N / cm for the treatment of an inguinal hernia.

[0078] Advantageously, the implantable device, in particular the textile plate (i.e., flat or three-dimensional) or the knit, has a mechanical resistance or burst value before implantation or at 0 days of hydrolysis, greater than or equal to 32 N / cm for the treatment of a ventral hernia.

[0079] Preferably, the implantable device, in particular the textile plate (i.e., flat or three-dimensional) or the knit, has a mechanical resistance (N / cm) of RO (N / cm) before implantation or at 0 days of hydrolysis, and a mechanical resistance (N / cm) RI at the end of 3 months of hydrolysis, with RI less than or equal to 0.98 x RO or 0.93 x R0 and greater than or equal to 0.60 x R0 or 0.70 or 0.80 x R0.

[0080] Preferably, the implantable device has a mechanical resistance (N / cm) of R0 (N / cm) before implantation or at 0 days of hydrolysis, and a mechanical resistance (N / cm) R2 after 5 months of hydrolysis, with R2 less than or equal to 0.94 x R0 or 0.89 x R0 and greater than or equal to 0.50 x R0 or 0.60 x R0. Preferably, the implantable device has a mechanical resistance (N / cm) of R0 (N / cm) before implantation or at 0 days of hydrolysis, and a mechanical resistance (N / cm) R3 at 8 months of hydrolysis, with R3 less than or equal to 0.60 or 0.50 x R0 and greater than or equal to 0.20 or 0.30 or 0.35 x R0.

[0081] Preferably, the decrease in mechanical resistance observed for the implantable device treated according to the invention is between a minimum of 10% and a maximum of 27% after 3 months of hydrolysis against more than 30% for an implantable device of identical structure but not treated according to the invention with CO2sc.

[0082] Advantageously, the decrease in mechanical resistance (N / cm) observed for the implantable device treated according to the invention with CO2sc, in particular deduced from the EX1 curve shown on the attached [Fig.4], is about 12% after 5 months of hydrolysis and 61% after 8 months of hydrolysis compared to 95% after 5 months of hydrolysis and 100% after 8 months of hydrolysis, in particular deduced from the EXC2 curve shown on the attached [Fig.4], for an implantable device of identical structure not treated according to the invention with CO2sc.

[0083] CO2sc, or supercritical carbon dioxide or carbon dioxide in a supercritical state

[0084] Pure carbon dioxide passes into a supercritical state when subjected to a pressure greater than a critical pressure and heated above a critical temperature, in particular according to the pressure (bars) and temperature (°C) diagram shown in the attached [Fig.1].

[0085] Advantageously, the critical pressure is greater than or equal to 73 bars, and the critical temperature is greater than or equal to 31°C.

[0086] Advantageously, carbon dioxide in a supercritical state has particular properties: comparable to those of a liquid with a density greater than or equal to 0.2 g / cm3 and less than or equal to 1 g / cm3 with a solvent power, and comparable to those of a gas with a high diffusivity greater than or equal to 10 4 cm2 / second, and less than or equal to 103 cm2 / second, in particular is miscible with other gases, and / or has a low surface tension.

[0087] Advantageously, carbon dioxide in a supercritical state (referred to above and below as CO2sc) has a viscosity greater than or equal to 10 pPa.s and less than or equal to 100 pPa.s.

[0088] In one embodiment, the processing step (ii) comprises the following steps, in particular taking place in the following order:

[0089] - iia) the supply of liquid carbon dioxide;

[0090] - iib) the application to carbon dioxide of temperature and pressure conditions allowing carbon dioxide to transition from a liquid state to a supercritical state;

[0091] - iic) supplying carbon dioxide in a supercritical state to an enclosure, in in particular an autoclave, including the implantable device, in particular said enclosure includes a hermetically sealed treatment volume in which the temperature and pressure conditions are determined so as to maintain the carbon dioxide in a supercritical state.

[0092] Advantageously, carbon dioxide is stored in a container in liquid form during step iia).

[0093] Advantageously, step iib) first includes pumping carbon dioxide in the liquid state and applying a determined pressure for the transformation of the carbon dioxide in the liquid state into a gaseous state, then the carbon dioxide in the gaseous state is heated to a determined temperature for the transformation of the carbon dioxide in the gaseous state into carbon dioxide in a supercritical state.

[0094] Advantageously, step iic) includes pumping and supplying the treatment volume of the enclosure with CO2sc.

[0095] Advantageously, after step iic), the pressure of the CO2sc is lowered, for example according to a pressure determined on the diagram of [Fig.1], to reach a gaseous state, then the gaseous CO2 obtained undergoes a separation step allowing the CO2 to be separated from any contaminant(s), the resulting gaseous CO2 is condensed to reach a liquid state, and possibly be fed into the storage container (for example to undergo a new treatment cycle according to step ii)).

[0096] Preferably, in step ii), in particular in step iib) and / or iic), the carbon dioxide is heated, in particular maintained in step iic), at a temperature greater than or equal to 10°C, more preferably greater than or equal to 20°C, preferably greater than or equal to 25°C or 30°C or 33°C or 35°C.

[0097] Preferably, in step ii), in particular in step iib) and / or iic), the carbon dioxide is heated, in particular maintained in step iic), at a temperature less than or equal to 100°C, more preferably less than or equal to 80°C, preferably less than or equal to 70°C or 60°C or 55°C or 50°C.

[0098] Preferably, in step ii), in particular in step iib) and / or iic), the carbon dioxide is pressurized, in particular maintained in step iic), at a pressure greater than or equal to 50 bar, more preferably greater than or equal to 60 bar, more preferably greater than or equal to 70 bar or 80 bar or 90 bar, more preferably greater than or equal to 100 bar or 110 bar or 120 bar or 130 bar or 140 bar or 150 bar.

[0099] Preferably, in step ii), in particular in step iib) and / or iic), the carbon dioxide is pressurized, in particular maintained in step iic), at a pressure less than or equal to 600 bars, more preferably less than or equal to 500 bars, more preferably less than or equal to 480 bars or 460 bars or 440 bars, more preferably less than or equal to 420 bars or 380 bars or 360 bars or 340 bars or 320 bars or 300 bars or 250 bars or 200 bars.

[0100] In one embodiment, in step ii), in particular in step iib) and / or iic), carbon dioxide is pressurized to a pressure between 100 bar and 300 bar and heated to a temperature between 35°C and 50°C.

[0101] In a preferred embodiment, in step ii), in particular in step iib) and / or iic), carbon dioxide is pressurized to a pressure of 150 bar to within + / - 20 bar, and heated to a temperature of 38°C to within + / - 5°C.

[0102] Preferably, the treatment time of the implantable device in step ii), in particular in step iic) is greater than or equal to 5 minutes, more preferably greater than or equal to 10 minutes or 15 minutes or 20 minutes, preferably greater than or equal to 25 minutes or 30 minutes.

[0103] Preferably, the treatment time of the implantable device in step ii), in particular in step iic), is less than or equal to 60 minutes, more preferably less than or equal to 50 minutes or 40 minutes or 35 minutes.

[0104] In a preferred embodiment, the processing time of the implantable device in step ii), in particular in step iic), is approximately 30 minutes at + / - 5 minutes.

[0105] In a preferred embodiment, the quantity of carbon dioxide in the supercritical state fed to the enclosure in step iic) is between 500 Kg / m3 and 1200 Kg / m3, preferably between 600 Kg / m3 and 1100 Kg / m3, even more preferably between 700 Kg / m3 and 900 Kg / m3, preferably from 800 Kg / m3 to within + / - 50 Kg / m3.

[0106] In one embodiment, the volume of CO2sc supplied into the treatment chamber corresponds to at least 20%, or at least 30% or at least 40%, preferably at least 50%, of the total treatment volume of the treatment chamber, even more preferably about 66% at + / - 10% of the total treatment volume of the treatment chamber. Hydrolysis protocol

[0107] The hydrolysis of a textile, and in particular of the inventive implantable device or The comparative section includes the following steps: One or more samples of the implantable device, including one or more textile samples, each measuring 10 cm x 10 cm, are placed in a glass container containing 10 liters of purified water buffered with phosphate-buffered saline (PBS) to achieve a pH of 7.4. The container is made of an inert material, such as glass, and hermetically sealed with a lid to prevent water loss through evaporation (thus maintaining a constant volume of 10 liters). This container is then placed in an oven at a temperature of 37°C. Manual stirring is performed daily for approximately 15 seconds to ensure uniformity of the hydrolysis medium. Specifically, no additional mechanical stirring is performed between manual stirrings.

[0108] The sample whose mechanical resistance is to be analyzed after a period of n months, or n*4 weeks, of hydrolysis is extracted from the container and then dried, in particular in an oven at 37°C for 60 minutes. The hydrolysis time thus corresponds to the time during which the sample remained in the volume of PBS and placed in the oven at 37°C.

[0109] In this text, n months is understood to mean a duration equivalent in weeks to n * 4, where n is an integer.

[0110] In one embodiment, at least 80% by mass, preferably at least 85% or at least 87% or at least 89% or at least 91% or at least 93% or at least 95% or at least 97% or at least 99% or about 100% by mass, of the total mass of the implantable device supplied in step i) is resorbable, in particular bioresorbable.

[0111] Preferably, at least 85% or at least 87% or at least 89% or at least 91% or at least 93% or at least 95% or at least 97% or at least 99% or approximately 100% by mass, of the total mass of the implantable device and / or of a textile (comprising the implantable device) supplied in step i) is formed of one or more (co)polymer(s) selected from: - a lactic acid polymer of L or D form or of L and D forms, of one or more glycolic acid polymers, of one or more copolymers of lactic acid (L and / or D) and glycolic acid, or a mixture thereof, preferably of one or more lactic acid polymers of L or D form or of L and D forms (List I); and / or - is formed of one or more monofilament(s) each comprising one or more (co)polymer(s) chosen from list I above.

[0112] In one embodiment, said method includes a step iv) of sterilizing the implantable device carried out after step iii), in particular including the application of ethylene oxide to said implantable device.

[0113] Advantageously, any sterilization method known to a person skilled in the art may be used.

[0114] In one embodiment, the implantable device of step iii) has a mechanical resistance, or burst value (Newtons / cm), greater than or equal to 10 N / cm after 32 weeks or 8 months of hydrolysis, in particular in an aqueous medium buffered with a phosphate saline solution at a pH of 7.4 and maintained at a temperature of 37 °C in a hermetically sealed medium.

[0115] In one embodiment, the temperature of the supercritical CO2 during step ii), in particular during step iib) and / or iic), is less than or equal to 70°C, in particular greater than or equal to 10°C.

[0116] In one embodiment, the treatment step ii), in particular during step iib) and / or iic), comprises the application of supercritical CO2 at a pressure greater than or equal to 50 bars, in particular less than or equal to 400 bars.

[0117] Advantageously, the applied temperature and pressure do not alter the mechanical properties of the implantable device.

[0118] In one embodiment, treatment step ii), in particular during step iib) and / or step iic), includes the application of supercritical CO2 at a pressure greater than or equal to 100 bars.

[0119] In one embodiment, the implantable device provided in step i) comprises one or more monofilamentary wire(s) each comprising at least one (co)polymer of lactic acid, in particular a lactic acid polymer of L-form or D-form, or a combination thereof.

[0120] In one embodiment, the monofilamentary wire(s) each comprising at least one (co)polymer of lactic acid has, or have, each a diameter greater than or equal to 50 pm (i.e. 0.050 mm) and less than or equal to 500 pm (i.e. 0.50 mm), in particular less than or equal to 300 pm (i.e. 0.30 mm).

[0121] In one embodiment, said at least one (co)polymer of lactic acid has a glass transition temperature (Tg) greater than or equal to 40°C and less than or equal to 150°C.

[0122] Preferably, said at least one (co)polymer of lactic acid has a glass transition temperature (Tg) greater than or equal to 50°C, more preferably greater than or equal to 60°C, more preferably greater than or equal to 70°C, more preferably greater than or equal to 80°C.

[0123] Preferably, said at least one (co)polymer of lactic acid has a glass transition temperature (Tg) less than or equal to 120°C, more preferably less than or equal to 110°C, preferably less than or equal to 100°C, more preferably less than or equal to 95°C.

[0124] In one embodiment, said at least one (co)polymer of lactic acid has a melting temperature (Tf) greater than or equal to 130°C and less than or equal to 210°C.

[0125] Preferably, said at least one (co)polymer of lactic acid has a melting temperature (Tf) greater than or equal to 140°C, more preferably greater than or equal to 150°C, more preferably greater than or equal to 160°C, more preferably greater than or equal to 165°C.

[0126] Preferably, said at least one (co)polymer of lactic acid has a melting temperature (Tf) less than or equal to 200°C, more preferably less than or equal to 190°C, preferably less than or equal to 180°C.

[0127] Preferably, said at least one (co)polymer of lactic acid has a degree of crystallinity greater than or equal to 30%, or 40% or 45%, more preferably greater than or equal to 50% or 53%.

[0128] Preferably, said at least one (co)polymer of lactic acid has a degree of crystallinity less than or equal to 80%, or 70% or 65%, again preferably less than or equal to 60%.

[0129] Advantageously, the degree of crystallinity is understood to be the ratio of the total sum by volume or mass of the crystalline fractions of a given sample to the total mass or volume of said sample.

[0130] Advantageously, the glass transition temperature, the melting temperature, and the degree of crystallinity are determined on the monofilamentary wire comprising said (co)polymer of lactic acid.

[0131] Preferably, the melting and glass transition temperatures, and the degree of crystallinity, are measured using the following standards: ISO 11357-2 (2013) entitled "Determination of glass transition temperature and glass transition plateau height", ISO 11357-3 (2018) entitled "Determination of melting and crystallization temperature and enthalpy.

[0132] The apparatus is a power-compensated DSC, DSC Q2000 (TA Instruments). The operating conditions are as follows: the apparatus is in standard mode, the sample crucibles are airtight aluminum, the purge gas is U-grade nitrogen (50 ml / min), the temperature ramp is isothermal at 25°C for 5 minutes, then increases from 25°C to 250°C with a gradient of 10°C per minute. The test specimens are kept for two hours at room temperature (23°C) and 50% relative humidity ±10%.

[0133] In one embodiment, said at least one (co)polymer of lactic acid has a weight average molar mass Mw greater than or equal to 70,000 g / mol and less than or equal to 300,000 g / mol.

[0134] Preferably, said at least one (co)polymer of lactic acid has a weight-average molar mass Mw greater than or equal to 80,000 g / mol, or 90,000 g / mol, or 100,000 g / mol, or preferably greater than or equal to 110,000 g / mol, or 120,000 g / mol, or 130,000 g / mol, or 140,000 g / mol, or 145,000 g / mol.

[0135] Preferably, said at least one (co)polymer of lactic acid has a weight-average molar mass Mw less than or equal to 250,000 g / mol, or 230,000 g / mol, or 210,000 g / mol, or more preferably less than or equal to 200,000 g / mol, or 190,000 g / mol, or 180,000 g / mol, or 170,000 g / mol, or 160,000 g / mol.

[0136] In an alternative embodiment, said at least one (co)polymer of lactic acid has an average number molar mass Mn greater than or equal to 10,000 g / mol and less than or equal to 120,000 g / mol or 110,000 g / mol.

[0137] Preferably, said at least one (co)polymer of lactic acid has a number-average molar mass Mn greater than or equal to 20,000 g / mol, or 30,000 g / mol, more preferably greater than or equal to 40,000 g / mol, or 45,000 g / mol.

[0138] Preferably, said at least one (co)polymer of lactic acid has an average molar mass number Mn less than or equal to 90,000 g / mol, or 80,000 g / mol, more preferably less than or equal to 70,000 g / mol, or 60,000 g / mol.

[0139] In one embodiment, said at least one (co)polymer of lactic acid has a polydispersity Ip (Mw / Mn) greater than or equal to 1.5 or 2 and less than or equal to 5, preferably less than or equal to 4, more preferably less than or equal to 3.5 or 3.

[0140] Advantageously, the average molar masses by weight and by number (g / mole) are determined on the monofilamentary wire comprising said (co)polymer of lactic acid.

[0141] Preferably, the number-average and weight-average molar masses are measured using ASTM D3536-91, "Standard Test Method for Weight-Average Molecular Masses and Their Distribution by Size Exclusion Chromatography (Gel Permeation Chromatography - GPC)." This technique is also known as size-exclusion chromatography.

[0142] Preferably, the operating conditions are as follows: Agilent 1260 Infinity GPC systems, Waters Styragel 4-column system, 300*4.6 mm, 5 pm particles, porosity of 50 to 104 A, assembly thermostated at 40°C, a filtered analytical grade THF eluent with a flow rate of 0.5 ml / min, pre-filtration of samples on 0.2 pm PTFE filter, dual detection RI and UV (254 nm), polystyrene calibration, sample preparation by dissolution in a tetrahydrofuran (THF) / Toluene mixture (used as a marker).

[0143] In one embodiment, said at least one (co)polymer of lactic acid comprises L-form lactic acid units and D-form lactic acid units.

[0144] Advantageously, the shapes L and D and their proportions are determined on the monofilamentary yarn comprising said (co)polymer of lactic acid.

[0145] Preferably, to determine the optical rotation, the samples to be tested are put into solution in chloroform at a concentration of Ig / dl.

[0146] Preferably, the D or L form monomer is quantified by gas chromatography coupled with mass spectrometry.

[0147] Preferably, the operating conditions are as follows: each sample is extracted in dichloromethane, the polymer is precipitated in hexane, and the mixture is filtered through a 0.2pm PTFE syringe filter, the assay is carried out by external calibration (lactide monomer form D or L) using four standards prepared at different concentrations; The chromatographic conditions are preferably as follows: Agilent HP5975C spectrometer, Agilent GC 7890, HP-5MS column (5% polyphenyl-silowane) 30m, thickness 0.25 pm, diameter 0.25 mm, isotherm of 1 min at 50°C then heating at 25°C / min from 50°C to 320°C, isotherm of 5 min at 320°C, the injector is heated to 200°C, the injection of 2pl in splitless mode, detection in SCAN mode.

[0148] In one embodiment, said at least one (co)polymer of lactic acid comprises at least 80% by mass of L-form lactic acid units and less than 20% by mass of D-form lactic acid units.

[0149] Preferably, said at least one (co)polymer of lactic acid comprises at least 85% or 88% or 90% or 92% or 94% or 96% or 98% by mass of L-form lactic acid units.

[0150] Preferably, said at least one (co)polymer of lactic acid comprises at most 15% or at most 10% or at most 8% or at most 6% by mass of D-form lactic acid units, more preferably at most 5% or 4% by mass of D-form lactic acid units.

[0151] Preferably, said at least one (co)polymer of lactic acid comprises at least 0.5% or 1% or 1.5% by mass of D-form lactic acid units.

[0152] In one embodiment, at least 80%, preferably at least 85% or 90% or 95%, by mass of the implantable device comprises one or more monofilamentary wire(s) in one or more (co)polymer(s) of lactic acid.

[0153] The improvement in mechanical resistance, or burst value, to hydrolysis is significant from 3 months of hydrolysis for an implantable device comprising monofilamentary wires in (co)polymer of lactic acid, knitted with discarded stitches, and in particular with a lactic acid polymer as described above.

[0154] In one embodiment, said method includes a heat-fixing step of the textile(s) (which comprise the implantable device) or of the implantable device, preferably taking place before step ii) or after step ii).

[0155] Preferably, said heat-setting step comprises the application of a temperature greater than or equal to 80°C and less than or equal to 130°C, furthermore preferably greater than or equal to 90°C and less than or equal to 120°C, preferably from 110°C to + / - 5°C.

[0156] Preferably, the duration of said heat-fixing step is greater than or equal to 30 seconds, more preferably greater than or equal to 60 seconds, preferably about 120 seconds at + / - 30 seconds.

[0157] Preferably, the duration of said heat-fixing step is less than or equal to 2 hours, more preferably less than or equal to 1 hour, preferably less than or equal to 30 min or 20 min or 10 min or 5 min.

[0158] Preferably, no tensile force is exerted on the knit or the implantable device during the heat-fixation step, in particular the knit or the device is / are tension-free.

[0159] The present invention relates, according to the second aspect, to an implantable device for the treatment of an abdominal hernia, in particular ventral or inguinal, which can be obtained by the method according to any of the embodiment variants with reference to the first aspect of the invention and / or as described in this text.

[0160] Advantageously, the implantable device obtained has improved mechanical resistance or burst value after three to eight months of hydrolysis compared to a similar device not treated with sc CO2.

[0161] In one embodiment, at least 80% by mass, preferably at least 85% or 90% or 95% or 98% by mass, of the implantable device is formed of one or more monofilamentary wire(s) in one or more (co)polymer(s) of lactic acid, and the implantable device has a mechanical resistance greater than or equal to 1N / cm, preferably greater than or equal to 15N / cm or 20N / cm, more preferably 25N / cm, at the end of 20 weeks of hydrolysis.

[0162] The variants and definitions according to the first aspect of the invention apply independently of each other to the implantable device according to a second aspect of the invention.

[0163] The present invention relates, according to a third aspect, to the use of supercritical CO2 to improve the mechanical resistance (N / cm), or burst value (N / cm), of an implantable device comprising one or more wires comprising at least one (co)polymer of lactic acid at the end of a determined hydrolysis period, in particular in a determined aqueous medium, in particular at the end of a period of at least 20 weeks to obtain a mechanical resistance greater than or equal to 10 N / cm, preferably greater than or equal to 15 N / cm or 20 N / cm, even more preferably greater than or equal to 25 N / cm.

[0164] In particular, said use includes the application of supercritical CO2 to said implantable device and / or to said monofilamentary wire(s).

[0165] The variants and definitions according to the first aspect of the invention and / or the second aspect of the invention apply independently of each other to the third aspect of the invention.

[0166] The present text also includes, according to a fourth aspect, a method of using an implantable device comprising:

[0167] - the implementation of the process to induce an improvement in resistance mechanics of an implantable device comprising one or more wire(s) each comprising one or more lactic acid (co)polymer(s) according to any one of the embodiments referred to in the first aspect of the invention, or the provision of an implantable device according to a second aspect of the invention or capable of being obtained by said process to induce an improvement in mechanical resistance according to any one of the embodiments referred to in the first aspect of the invention, and

[0168] - the selection of a group of patients chosen from the following groups: the patients patients with a BMI greater than or equal to 30, patients with type I and / or II diabetes, patients who smoke (or suffer from smoking), and patients chosen from a combination of said patient groups;

[0169] - the treatment of the patient group selected for the treatment of an ab hernia dominal, in particular ventral or inguinal, with said implantable device.

[0170] BMI is the acronym for "Body Mass Index" calculated by dividing weight (Kg) by height (cm) squared. Description of the drawings

[0171] The present invention will be better understood upon reading the following embodiments, cited by way of non-limiting example, and illustrated by the figures in which:

[0172] [Fig-1] [Fig.1] schematically represents the different states (solid, liquid, gaseous, supercritical) of carbon dioxide as a function of pressure (bars) on the ordinate and temperature (°C) on the abscissa;

[0173] [Fig.2] [Fig.2] is a table showing the mechanical resistance values ​​(value bursting at the ball) for an example according to the invention (EX1) and two comparative examples (EXC1, EXC2) without hydrolysis and for different periods of hydrolysis: 1 month, 2 months, 3 months, 5 months, and 8 months;

[0174] [Fig.3] [Fig.3] is a table showing the mechanical resistances (values residual burst strengths measured by relating the mechanical resistance at T 1,2,3,5, or 8 months to the initial mechanical resistance T0 multiplied by 100, said mechanical resistances being indicated in [Fig.2];

[0175] [Fig.4] [Fig.4] is a graph representing the burst values ​​on the y-axis residual bead (%) on the y-axis as a function of hydrolysis time on the x-axis of several examples of implantable devices according to the invention and comparative examples of implantable devices;

[0176] [Fig.5] [Fig.5] is a graph representing on the ordinate the ball burst values ​​(N / cm) on the ordinate as a function of the hydrolysis time on the abscissa of several examples of implantable device according to the invention and comparative examples of implantable devices;

[0177] [Fig. 6] [Fig. 6] shows the mesh diagram of the first example of an implantable device according to the invention and comparative examples of implantable devices. Description of embodiments

[0178] The diagram in [Fig.1] represents the different states: solid, liquid, gaseous and supercritical of carbon dioxide according to the pressure (bars) and temperature conditions applied to it.

[0179] Thus, we observe a so-called triple point at -56°C and 5.18 bars at the intersection of which we observe the boundaries between the solid, liquid and gaseous states.

[0180] The critical point at which carbon dioxide is in a supercritical state includes a temperature greater than or equal to 31°C combined with a pressure greater than or equal to 73.85 bar. It is observed that in this supercritical state, carbon dioxide is simultaneously in conditions close to a liquid state, allowing it to behave as a solvent; in conditions between a gas and a liquid, allowing it to impregnate the implantable device; and in conditions close to a gaseous state, allowing it to diffuse into the structure of the lactic acid-based monofilament fibers. The Applicant has surprisingly observed that treatment with CO2sc, particularly of the textile structure of the implantable device, significantly improves the mechanical resistance of the implantable device during its hydrolysis.

[0181] Advantageously, the CO2sc treatment according to the invention improves the mechanical behavior of the implantable device during hydrolysis, in particular by reducing the hydrolysis rate, but is not a sterilization treatment. In one embodiment, a sterilization step, separate from the CO2sc treatment step for inducing improved mechanical resistance, is required. This sterilization step can be performed by any sterilization method known in the technical field for sterilizing an implantable device, particularly one already placed in a double pouch.

[0182] Figures 2 to 5 represent the results of the hydrolysis tests obtained for an EX1 example of an embodiment according to the invention, and two comparative examples EXC1 and EXC2.

[0183] Example EX1 is a 10-stitch knit with yarn overs worked according to the stitch pattern re presented in [Fig. 6]. This knit comprises a first monofilament yarn 20 in a lactic acid polymer having a diameter of 0.15 mm and a linear density of 220 dtex, and a second monofilament yarn 30 similar to the first monofilament yarn (in a lactic acid polymer having a diameter of 0.15 mm and a linear density of 220 dtex). The first yarn 20 is supported by a first guide bar B1 on the knitting machine whose movement is as follows: 2-3 / 2-1 / 2-3 / 2-1 / 1-0 / 1-2 / 1-0 / 1-2 / / .

[0184] The second yarn 30 is supported by a second guide bar B2 on the knitting machine whose movement is as follows: 1-0 / 1-2 / 1-0 / 1-2 / 2-3 / 2- 1 / 2- 3 / 2- 1 / / .

[0185] Knit 10 has a surface mass of approximately 120 g / m2, and is totally absorbable.

[0186] The first and second guide bars, or so-called slotted bars, Bl, B2 work / knit across the entire width of the knitting 10 and across its entire height.

[0187] Advantageously, the first and second guide bars B1, B2 work in opposition: the first guide bar supporting the wire 20 works in the direction F2 when the second guide bar supporting the wire 30 works in the direction Fl, the directions Fl and F2 being opposite as shown in [Fig.6]. In this specific example, knit fabric 10 undergoes a heat-setting step at 110°C for 2 minutes, followed by a supercritical CO2 treatment consisting of placing it in an autoclave at 38°C under a pressure of 150 bar for 30 minutes to maintain the CO2 in its supercritical state. The volume of supercritical CO2 supplied to the treatment chamber represents approximately 66% of the chamber's total treatment volume.

[0188] Comparative examples EXC1 and EXC2 are each in the same knit as knit 10 but do not undergo any CO2sc treatment. EXC2 undergoes a heat-setting step at 110°C for 2 minutes similar to the heat-setting step of EX1, while EX1 does not undergo a heat-setting step.

[0189] For the hydrolysis tests: 30 10cm x 10cm knitted fabric samples are placed in a stainless steel container containing PBS-buffered water of each example (EX1, EXC1, EXC2) according to the hydrolysis protocol described above. At the end of each targeted hydrolysis period (1 month, 2 months, 3 months, 5 months, 8 months), 18 samples (6 samples of each example) are removed from the stainless steel container and then oven-dried at 37°C for one hour. These 18 samples are all evaluated using the burst strength test described above (ASTM D3787-7 (2011)) immediately after drying.

[0190] The mechanical resistance evaluated here is advantageously a ball burst strength value. It could be another mechanical resistance value, such as the breaking load in the warp or weft direction of the knit, i.e., any measure allowing evaluation of the improvement in the mechanical resistance of the knit.

[0191] The melting temperature and degree of crystallinity measured for EXl at T0 are res- respectively of 169.53°C and 59%, and are at Tl (month) of 167.88°C and 46%.

[0192] The melting temperature and the degree of crystallinity measured for EXCl at T0 are respectively 166.76°C and 56%, and are at Tl (months) 166.83°C and 56%.

[0193] Surprisingly, Figures 4 and 5 show that after just two months of hydrolysis, the mechanical strength of EX1 according to the invention is degraded but remains at over 80% of its initial mechanical strength, whereas the strengths of examples EXC1 and EXC2 begin to decline significantly. After three months and up to approximately five months, the mechanical strength of EX1 is still at least 80% of its initial mechanical strength, while it drops by more than 40% at three months and by more than 75% at five months of its initial strength for examples EXC1 and EXC2. Finally, after eight months of hydrolysis, the knit fabric according to EX1 still exhibits a mechanical strength corresponding to approximately 40% of its initial strength, while the knit fabrics of examples EXC1 and EXC2 are completely hydrolyzed or too hydrolyzed for a strength value to be measured.

[0194] The use of CO2sc to improve the mechanical resistance of a textile comprising monofilaments in a lactic acid (co)polymer makes it possible to improve the hydrolysis behavior of the latter, in particular to reduce its hydrolysis rate, in a simple and reliable manner, starting from a resorbable textile structure, for example in the treatment of a hernia. This arrangement will thus make it possible to prolong the mechanical reinforcement provided by the implantable device, while limiting the risks of infection, and will avoid the need for surgical removal of the implantable device in the event of infection since the device will eventually be completely resorbed.

Claims

Demands

1. A method for inducing an improvement in the mechanical resistance (N / cm) of an implantable device (10) after a specified period of hydrolysis of said implantable device (10), said implantable device (10) comprising one or more wires (20,30) comprising at least one (co)polymer of lactic acid, said method comprising: i)- a step of supplying an implantable device (10) comprising one or more wires (20,30) comprising at least one (co)polymer of lactic acid; ii)- a step of treating said implantable device with supercritical carbon dioxide (CO2); iii)- a step of obtaining an implantable device (10) having a mechanical resistance greater than or equal to 10 N / cm, preferably greater than or equal to 25 N / cm, after 20 weeks of hydrolysis, in particular in an aqueous medium.

2. A method according to claim 1, characterized in that at least 80% by mass of the total mass of the implantable device (10) supplied in step i) is resorbable.

3. A method according to either of claims 1 and 2, characterized in that it comprises a step iv) of sterilizing the implantable device (10) carried out after step iii), in particular comprising the application of ethylene oxide to said implantable device (10).

4. A method according to any one of claims 1 to 3, characterized in that the implantable device (10) of step iii) has a mechanical resistance greater than or equal to 10 N / cm after 32 weeks of hydrolysis in an aqueous medium.

5. A method according to any one of claims 1 to 4, characterized in that the temperature of supercritical CO2 during step ii) is less than or equal to 70°C, in particular greater than or equal to 10°C.

6. A process according to any one of claims 1 to 5, characterized in that treatment step ii) comprises the application of supercritical CO2 at a pressure greater than or equal to 10 bars, in particular less than or equal to 500 bars.

7. A process according to any one of claims 1 to 6, characterized in that treatment step ii) comprises the application of supercritical CO2 at a pressure greater than or equal to 100 bar.

8. A method according to any one of claims 1 to 7, characterized in that the implantable device (10) supplied in step i) comprises one or more monofilamentary wire(s) (20,30) each comprising at least one (co)polymer of lactic acid.

9. A method according to claim 8, characterized in that said monofilamentary yarn(s) (20,30) each comprising at least one (co)polymer of lactic acid has, or have, each a diameter greater than or equal to 50 pm and less than or equal to 500 pm, in particular less than or equal to 300 pm.

10. A process according to any one of claims 1 to 9, characterized in that said at least one (co)polymer of lactic acid has a glass transition temperature (Tg) greater than or equal to 40°C and less than or equal to 150°C.

11. A process according to any one of claims 1 to 10, characterized in that said at least one (co)polymer of lactic acid has a melting temperature (Tf) greater than or equal to 130°C and less than or equal to 210°C.

12. A process according to any one of claims 1 to 11, characterized in that said at least one (co)polymer of lactic acid has a weight average molar mass Mw greater than or equal to 70,000 g / mol and less than or equal to 300,000 g / mol.

13. A process according to any one of claims 1 to 12, characterized in that said at least one (co)polymer of lactic acid has a polydispersity Ip (Mw / Mn) greater than or equal to 1.5 and less than or equal to 5

14. J. A process according to any one of claims 1 to 13, characterized in that said at least one (co)polymer of lactic acid comprises L-form lactic acid units and D-form lactic acid units.

15. A process according to any one of claims 1 to 14, characterized in that said at least one (co)polymer of lactic acid comprises at least 80% by mass of L-form lactic acid units and less than 20% by mass of D-form lactic acid units.

16. A method according to any one of claims 1 to 15, characterized in that at least 80% by mass of the implantable device (10) comprises one or more monofilamentary wire(s) (20,30) in one or more (co)polymer(s) of lactic acid.

17. Implantable device for the treatment of an abdominal hernia (10) capable of being obtained by the process according to any one of the re- demands 1 to 16.

18. Implantable device (10) according to claim 17, characterized in that it comprises at least 80% by mass of one or more monofilamentary wire(s) (20,30) in one or more (co)polymer(s) of lactic acid, and in that the implantable device (10) has a mechanical resistance greater than or equal to 25 N / cm at the end of 20 weeks of hydrolysis.

19. Use of supercritical CO2 to improve the mechanical strength (N / cm) of an implantable device (10) comprising one or more wires (20,30) comprising at least one (co)polymer of lactic acid after a specified hydrolysis period, in particular after a hydrolysis period of at least 20 weeks to obtain a mechanical strength greater than or equal to 10 N / cm, in particular greater than or equal to 25 N / cm.

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