Ocular device for the controlled release of an ophthalmic active ingredient, methods for the production of said ocular device and its use for the treatment or prevention of ocular diseases and disorders

Abstract

A device in the form of an ocular insert comprising at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) and at least one ophthalmic active ingredient which is releasable in a controlled manner from said insert is described. Methods of production of said ocular device and its use for the treatment or prevention of ocular diseases and disorders are also described.

Description

[0001] Title: Ocular device for the controlled release of an ophthalmic active ingredient, methods for the production of said ocular device and its use for the treatment or prevention of ocular diseases and disorders

[0002] DESCRIPTION

[0003] Field of application

[0004] In its most general aspect, the present invention relates to an ocular device for targeted and / or controlled release of active pharmaceutical ingredients and / or active molecules to a desired intraocular target tissue by placement of said device in the conjunctival fornix of the eye.

[0005] The invention further relates to methods for the production of such an ocular device and its uses for the treatment or prevention of ocular diseases and disorders.

[0006] Prior art

[0007] It is known that polymers have been extensively studied for their potential use in medical diagnosis and therapy. In ophthalmology, modern polymeric materials provide various alternatives, such as vision enhancement, corneal implants and intraocular lenses, to replace damaged parts of the eye. Advances in methods of synthesis and in molecular structures have led to the widespread use of synthetic polyesters for specific biomedical applications that require biomaterials with customised mechanical, thermal, optical and electrical properties.

[0008] Patients with eye diseases now represent a large category with different needs depending on the severity of their symptoms. Many eye diseases progress due to the difficulty of administering therapeutic agents to the eye in sufficient amount and / or for the duration required to improve the symptoms of the disease. Drug absorption and processing often occur before the drug reaches the ocular target site. Due to metabolism, systemic administration may require unwanted concentrations of drug to reach therapeutic levels at the ocular target site. This can be an impractical and expensive method, as well as lead to a higher incidence of side effects. Topical administration is potentially limited by diffusion through the cornea or dilution of the drug by the action of tear flow. Drugs that pass through the cornea may also be inappropriately excreted from the eye due to ocular-fluid flow and transfer into the general circulation. Therefore, a means of ocular administration of a therapeutic agent in a controlled and targeted manner would solve the limitations of other routes of administration.

[0009] It is known that most ocular devices for pharmaceutical delivery are in the form of contact lenses, implants or invasive inserts with unwieldy diameters and lengths. Furthermore, most devices can only be handled by medical and healthcare professionals.

[0010] Examples of such ocular devices are the products LACRISERT from Bausch and Lomb and MYDRIASERT from TheaFarmaS.p.A.. In particular, Lacrisert consists of hydroxypropyl methylcellulose that is dissolved in the eye, providing a lubricating action to the eye, and it is therefore indicated in patients suffering from moderate to severe dry-eye syndrome. Instead, Mydriasert is an ocular insert consisting of 0.28 mg tropicamide and 5.4 mg phenylephrine hydrochloride and is used to achieve perioperative mydriasis and for diagnostic purposes when monotherapy is inefficient. The insertion of such a device is at the discretion of the physician or healthcare professional.

[0011] The main object of the present invention is thus to provide an ocular device that allows the targeted and / or controlled release of at least one ophthalmic active ingredient in a manner appropriate to therapeutic needs and that can fit in the conjunctival fornix of the eye without creating discomfort to the individual using said device.

[0012] A further object of the present invention to is provide a device as above which can be easily used by individuals / patients in need thereof.

[0013] Summary of the invention These and other objects are solved, according to the present invention, by an ocular device in the form of an insert comprising at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) and at least one ophthalmic active ingredient which is releasable in a controlled manner from said insert.

[0014] Such a copolymer can be obtained by polymerization of a diacid or its ester of succinic acid, for example of methyl succinate, a diacid ether such as diglycolic acid or an ester thereof and butanediol, as will be further discussed below.

[0015] According to the present invention, the expression "ophthalmic active ingredient" means any active ingredient or active molecule that can be used for the treatment or prevention of diseases or disorders affecting the eye.

[0016] According to the present invention, the expression "ocular device" means a medical device in the form of an insert to be placed in an intraocular area and containing at least one ophthalmic active ingredient to be released in a targeted and / or controlled manner in said intraocular area.

[0017] Non-limiting examples of ophthalmic active ingredients that can be introduced into the ocular device according to the invention include lactoferrin, lysozyme, surfactant proteins B and C, mucins, albumins, glycoproteins, hypotonizing active ingredients for the treatment of glaucoma, such as prostaglandins, active ingredients for the treatment of allergies such as cyclosporine, tacrolimus and cortisone, antibiotics for the treatment of infections, nerve growth factors etc. and mixtures thereof.

[0018] Preferably, the at least one ophthalmic ingredient released from the ocular device according to the invention consists of specific tear-film proteins to restore protein levels that are deficient in patients.

[0019] Preferably, the ocular device is in the form of a film, a disc or a cylinder. Preferably, said at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) has a molar ratio of the diacid subunits, succinate and diglycolate, between 50:50 and 20:80.

[0020] In an embodiment of the invention, said insert comprises an inner layer made of at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate), and a coating outer layer for coating said inner layer comprising a biomaterial and said at least one ophthalmic active ingredient.

[0021] The term "biomaterial" means any different polymeric material of natural or synthetic origin which is biodegradable under the conditions of use of the ocular device according to the invention and which is a material different from said copolymer of poly(butylene succinate) and poly (butylene diglycolate) constituting the inner layer of said device.

[0022] Preferably, said biomaterial is selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), agar, and mixtures thereof.

[0023] In particular, the coating outer layer of the ocular device according to the present invention may comprise biomaterials that are biodegradable and soluble in aqueous solutions in which ophthalmic active ingredients that require a longer-lasting release over time or that have special chemicalphysical properties are dissolved.

[0024] Preferably, the at least one copolymer of the ocular device has an elastic modulus between 40- 160 Mpa measured with an Instron 5966 type dynamometer.

[0025] Preferably, the at least one copolymer of the ocular device has a contact angle between 60° and 100° measured with the device KRUSS DSA30.

[0026] Preferably, the at least one copolymer of the ocular device has a melting point at a temperature between 30°C and 60°C, measured with a calorimeter Perkin Elmer DSC6. Advantageously, the ocular device according to the invention is suitable for fitting in the eye area without causing discomfort to the patient and, consequently, leading to reflex tearing which could dilute the released substance. Furthermore, the ocular device is inert and does not interact with the patient's ocular environment and alter its characteristics.

[0027] Furthermore, the ocular device according to the present invention is advantageously inert with respect to the active ingredient inserted therein; in fact, any type of active ingredient can be loaded, modulating the composition of the ocular device so as to obtain the insert with the most optimal release.

[0028] Advantageously, the ocular device according to the invention can be applied by the patient autonomously by gently inserting the ocular device into the lower or upper conjunctiva of the eye. In fact, the ocular device has a shape that easily adapts to the contact surface of the eye. The ocular device allows the gradual release of therapeutic molecules throughout the day, providing a prolonged and continuous treatment and reducing the need for frequent application of drops or medication. Moreover, since the ocular device acts locally on the surface of the eye, none of the side effects of systemic drugs occur.

[0029] The above technical problem is further solved by methods for producing the ocular device according to the present invention.

[0030] In an embodiment, the method for producing the ocular device according to the present invention comprises the steps of:

[0031] - preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),

[0032] - melting said at least one copolymer with at least one ophthalmic active ingredient and extruding the resulting melt blend, thereby obtaining an extrudate made of said at least one copolymer in which said at least one ophthalmic active ingredient is incorporated, - molding said extrudate so as to obtain an insert having a predetermined shape and made of said at least one copolymer in which said at least one ophthalmic active ingredient is incorporated, thereby obtaining said ocular device.

[0033] Preferably, the melting of the at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate), and of the at least one ophthalmic active ingredient is carried out in an extruder at a temperature between 30°C and 70°C and the resulting melt blend is extruded by an extruder head using per se conventional procedures, obtaining the above-mentioned extrudate.

[0034] Preferably, the molding of the extrudate is carried out by die-casting at a temperature higher than 30°C and a pressure between 3- 10 tons / m2, thereby obtaining an insert in the form of a film containing the at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate), in which the at least one ophthalmic active ingredient is incorporated.

[0035] In another embodiment, the method for producing the ocular device according to the present invention comprises the steps of:

[0036] - preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),

[0037] - molding said at least one copolymer so as to obtain an insert having a predetermined shape,

[0038] - adsorbing at least one ophthalmic active ingredient on the surface of said insert of said at least one copolymer, thereby obtaining said ocular device.

[0039] Preferably, the molding of the at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) is carried out by die-casting at a temperature higher than 30°C and a pressure between 3- 10 ton / m2, thereby obtaining an insert in the form of a film. Preferably, adsorption of the at least one ophthalmic active ingredient is carried out by dipping the insert made of the at least one copolymer into a solution containing at least one ophthalmic active ingredient for a time sufficient to allow the adsorption of said at least one active ingredient on the insert surface, followed by drying of the insert extracted from said solution.

[0040] In a further embodiment, the method for producing the ocular device according to the present invention comprises the steps of:

[0041] - preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),

[0042] - molding said at least one copolymer so as to obtain a layer having a predetermined shape,

[0043] - coating said layer with a coating outer layer comprising at least one biodegradable material (biomaterial) and at least one ophthalmic active ingredient dispersed in said biodegradable material, thereby obtaining said ocular device.

[0044] Preferably, the coating of the layer made of the at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) is carried out by dipping said layer into a solution containing at least one ophthalmic active ingredient and at least one biodegradable material for a predetermined time followed by drying after extraction from said solution, thereby obtaining an insert comprising an inner layer made of said at least one copolymer and a coating outer layer comprising at least one biodegradable material and at least one ophthalmic active ingredient dispersed in said biodegradable material.

[0045] In the methods according to the invention, the preparation of the at least one copolymer can be carried out in a per se conventional manner.

[0046] For example, the preparation of the at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) can be carried out by polymerization with esterification and / or transesterification from the monomers of the diacid component, such as dimethylsuccinate and diglycolic acid, and from butanediol as a glycolic monomeric component.

[0047] Polymerisation can be carried out in the presence of a catalyst such as titanium tetrabutoxide at a temperature preferably between 175°C and 200°C in a first step and then raising the temperature in a range preferably between 210°C and 250°C and applying a vacuum so as to obtain a copolymer of poly(butylene succinate) and poly(butylene diglycolate) .

[0048] At the end of the polymerization, the copolymer obtained may be subjected to a purification step using per se conventional procedures, for example by precipitating the copolymer from the reaction mixture in suitable non-solvents and separating the precipitate thus obtained, for example by filtration.

[0049] Preferably, in the preparation of the copolymer of poly(butylene succinate) and poly(butylene diglycolate), the molar ratio between the monomers of the diacid component, such as dimethyl succinate (DMS) and diglycolic acid (DGA), is between 50:50 and 20:80, whereas butanediol is used in a molar excess compared to the sum of the moles of the diacid monomers, preferably an excess between 20% and 100%, preferably an excess of 20%.

[0050] The aforementioned technical problem is further solved by the use of a copolymer of poly(butylene succinate) and poly(butylene diglycolate) in the production of the ocular device according to the present invention.

[0051] Preferably, the copolymer of the ocular device according to the invention has a melting point at a temperature between 30°C and 60°C.

[0052] Advantageously, the copolymer makes the ocular device soft and flexible.

[0053] Advantageously, the copolymer has high biocompatibility and is biodegradable. It has surprisingly been found that copolymers of poly(butylene succinate) and poly(butylene diglycolate) can be used effectively for the producing ocular devices in the form of inserts that have desired properties, in particular good wettability and flexibility, a relatively low melting point, i.e., in particular, that allows one or more ophthalmic active ingredients to be incorporated into the copolymer without compromising the activity of such active ingredients, and high biocompatibility and biodegradability. In particular, the diacid comonomer or its ester, such as dimethylsuccinate, contributes to determining the crystallinity and melting-point characteristics of the copolymer obtained, whereas the ether co-monomer, such as diglycolic acid, contributes to determining its hydrophilicity (wettability) and flexibility characteristics. Thus, by appropriately choosing the type and amount of the aforementioned co-monomers in the polymerisation process, it is possible to obtain a copolymer with an appropriate balance of desired characteristics of the aforementioned type.

[0054] It is believed that similar results can also be achieved by polyester copolymers similar to copolymers of poly(butylene succinate) and poly(butylene diglycolate) obtained by polymerization of respective dicarboxylic monomers or their esters and dicarboxylic ether monomers or diol ethers for the diacid component and diol monomers for the glycol component.

[0055] Further characteristics and advantages of the present invention will result from the description below of preferred embodiments thereof, given by way of non-limiting example.

[0056] Description of the figures

[0057] Figure 1 represents the 'H-NMR spectrum of the copolymer P(BS50BDG50) obtained through the device Varian Inova 400MHz and the relative peak assignment.

[0058] Figure 2 shows the wettability tests, in particular the water-droplet absorption behaviour at different times on the copolymers used according to the invention.

[0059] Figure 3 shows the thermogravimetric curves of the copolymers P(BS50BDG50) and P(BS20BDG80) obtained through the device TGA4000, Perkin Elmer.

[0060] Figure 4 shows the I and II scan DSC curves of the copolymers P(BS50BDG50) and P(BS20BDG80).

[0061] Figure 5 shows the stress-strain curve plot of the copolymers P(BS50BDG50) and P(BS20BDG80).

[0062] Figure 6 shows the cytotoxicity assay, wherein copolymers A (P(BS50BDG50)) and copolymers B (P(BS20BDG80)) are in direct contact with the human conjunctival fibroblast cell line (HconF).

[0063] Figure 7 shows the cytotoxicity assay, wherein copolymers A (P(BS50BDG50)) and B (P(BS20BDG80)) are in indirect contact with the HConF cell line.

[0064] Figure 8 shows the cytotoxicity assay by means of 100%, 50% and 25% extracts of copolymers A and B. In particular, the HConF cell line in contact with the extracts of copolymers A and B at 100% (Figure 8a), 50% (Figure 8b) and 25% (Figure 8c).

[0065] Figure 9 shows the cytotoxicity assay, wherein copolymers A P(BS50BDG50) and B P(BS20BDG80) are in direct contact with the conjunctival epithelial cell line (HCE).

[0066] Figure 10 shows the cytotoxicity assay using 100%, 50% and 25% extracts of copolymers A and B. In particular, the HCE cell line in contact with the extracts of copolymers A and B at 100% (Figure 10a), 50% (Figure 10b) and 25% (Figure 10c).

[0067] Figure 11 represents the release kinetics assay of lactoferrin release from the ophthalmic inserts according to the invention, wherein loading of the ophthalmic active ingredient was carried out by extrusion.

[0068] Figure 12 represents the release kinetics assay of lysozyme release from the ophthalmic inserts according to the invention, wherein loading of the ophthalmic active ingredient was carried out by extrusion.

[0069] Figure 13 depicts the release kinetics assay of lysozyme release from the ocular device formed from copolymer A according to the invention, wherein loading of the ophthalmic active ingredient was carried out by dipping the active-ingredient-free ocular device into an active-ingredient mixture.

[0070] Figure 14 depicts the release kinetics assay of lysozyme release of the ocular device formed by copolymer B from the ophthalmic inserts according to the invention, wherein loading of the ophthalmic active ingredient was carried out by dipping the active-ingredient-free ocular device into an active-ingredient mixture.

[0071] Figure 15 represents a comparison of the release kinetics curves of lactoferrin release from the inserts comprising copolymer A and B, respectively, according to the invention, wherein loading of the ophthalmic active ingredient was carried out by dipping the active- ingredient-free ocular device into an active-ingredient mixture.

[0072] Figure 16 depicts the kinetics of lysozyme release from the ocular device in the form of an insert comprising an inner layer of copolymer of poly(butylene succinate) and poly(butylene diglycolate) and a coating outer layer comprising the ophthalmic active ingredient and biodegradable biomaterials.

[0073] Figure 17 represents the kinetics of lactoferrin release from the ocular device comprising an inner layer of copolymer of poly(butylene succinate) and poly(butylene diglycolate) and a coating outer layer comprising the ophthalmic active ingredient and biodegradable biomaterials. In Figure 17, Lf indicates the lactoferrin standard used as a reference. Detailed description

[0074] The following are non-limiting examples relating to the synthesis of copolymers used for making the ocular device according to the invention and their characterisations, non-limiting embodiments of preferred shapes of the ocular device according to the invention, and examples relating to release kinetics and cytotoxicity of the ocular device.

[0075] 1. SYNTHESIS AND CHARACTERISATION OF MATERIALS

[0076] 1. 1 Synthesis of statistical copolymers with different compositions

[0077] The copolymer syntheses were carried out by two-stage copolymerisation in the molten state or polycondensation, by putting an amount of monomers consisting of dimethyl succinate (DMS) and diglycolic acid (DGA) for the acid counterpart into a glass reactor in a molar ratio of 50:50 or 20:80, butanediol (BD) as glycol, the latter in a molar excess of 20% with respect to the combination of the acid counterpart to promote the dissolution of the monomers of the acid counterpart and to facilitate the esterification / transesterification reactions in the first step of the synthesis. Titanium tetrabutoxide, a biocompatible catalyst, was also added to the reaction environment.

[0078] The reactor was brought to a temperature of 180 °C, under nitrogen flow and continuous stirring (100 rpm) for about 2 hours, so that the esterification and transesterification reactions could take place, thereby forming oligomers (as well as the formation of low-molecular-weight products such as water and methanol) .

[0079] Subsequently, the temperature was progressively increased up to 220 °C and a progressive vacuum was applied (up to 0.06 mbar), to promote the increase of molecular weight and the removal of excess glycol; in parallel, the torque value was constantly monitored, which is an index of the viscosity of the polymeric fluid and is directly proportional to the molecular weight. The synthesis ends when the torque value becomes constant and no further distillation occurs. In this way, two statistical copolymers with different compositions of poly(butylene succinate / diglycolate) were obtained, P(BSxBDGy), where x and y represent the relative molar ratios between the two diacid subunits, i.e. dimethyl succinate (DMS) and diglycolic acid (DGA), in this case having a molar ratio of 50:50 (P(BS50BDG50)) and 20:80 (P(BS20BDG80)).

[0080] 1.2 Purification

[0081] Next, a purification was carried out to separate the catalyst, oligomers, low-molecular-weight residues, unreacted monomers and reaction byproducts from the copolymer. The blend of copolymer, P(BS50BDG50) and P(BS20BDG80), respectively, was thoroughly purified by dissolution in chloroform, precipitated in methanol and finally both copolymers were recovered by filtration. The copolymers P(BS50BDG50) and P(BS20BDG80) thus obtained were kept under vacuum at room temperature for several days in order to remove the residual solvent.

[0082] 1.3 Characterisation of the copolymers

[0083] 1.3.1 Molecular characterisation:

[0084] NMR

[0085] The copolymers were characterised by proton nuclear magnetic resonance spectroscopy (XH-NMR), with which it was possible to confirm both the chemical structure of the copolymers obtained (no other peaks were detected other than those related to the protons present in the chain) and their composition, since the relative intensities of the peaks related to the two co-units BS and BDG are compatible with the copolymer blend (Figure 1).

[0086] Gel permeation chromatography (GPC)

[0087] The molecular weights of the copolymers were determined by a process of physical separation of the chains of different molecular weights by gel permeation chromatography (GPC) with an HPLC 1100 device from Agilent Technologies, equipped with a 5-mm MiniMIX- C) Plgel column, and using chloroform as eluent.

[0088] The molecular weights (Mn) determined by GPC analysis, are high (higher than 46000 g / mol) and comparable, with a polydispersity index D slightly higher than 2 (Table 1), a value in line with copolymers traditionally obtained by polycondensation, which confirms the good control over the synthesis process.

[0089] Table 1

[0090] From the results obtained, it can be seen that the syntheses were successful, as the copolymers obtained have a high and comparable molecular weight, polydispersity indices in line with those typical of polycondensate materials.

[0091] 1.3.2 Contact-angle measurements (WCA)

[0092] In order to determine the hydrophilic nature of the copolymers obtained, contact-angle measurements were carried out immediately after the deposition of a drop of water of known volume and 120 seconds after deposition, evaluating any evolution in the drop profile. As can be seen in Figure 2, immediately after deposition, the copolymer P(BS20BDG80) is hydrophobic (WCA > 90°), whereas P(BS50BDG50) immediately shows greater hydrophilicity, with WCA = 80°. After 120 seconds, a considerable decrease in contact-angle values can be seen in both cases, indicating that the polymer surfaces become increasingly hydrophilic over time.

[0093] Table 2

[0094] Contact angle (WCA) measurements showed that copolymerisation is also responsible for a higher surface wettability than poly(butylene succinate) alone, whose WCA, according to the literature, is 91 ± 2 and does not evolve over time. This property is important since the insert has to be applied in the ocular environment.

[0095] 1.3.3 Thermal characterisation

[0096] The copolymers obtained were characterised by thermogravimetry, in order to identify the temperature of onset of degradation (Tid), which must never be exceeded during the process of producing the ocular device according to the invention to avoid its degradation, and the temperature of maximum degradation rate (T max) .

[0097] Furthermore, the said copolymers were subjected to differential scanning calorimetry (DSC) in order to identify the glass-transition temperature, the melting temperature and the relative associated heats.

[0098] Thermogravimetric curves (Figure 3) show comparable high thermal stability for both materials, regardless of their composition, with Tid around 350 °C and Tmax around 380 °C (Table 3). As a result, these materials are suitable for in-body applications and can be processed in the molten state without being degraded.

[0099] From the DSC analyses (Table 3 and Figure 4), it can be observed that on first scan, both materials are semi-crystalline, with the baseline endothermic jump related to the glass transition below room temperature (indicating a mobile amorphous phase) and a melting peak at a higher temperature, around 40 °C for P(BS50BDG50), around 50 °C for P(BS20BDG80). Such melting temperatures are suitable for the use of such materials in the production of an ocular device according to the invention. Indeed, on the one hand, such materials must not be melted inside the human body. On the other hand, since in an embodiment of the ocular device according to the present invention the at least one ophthalmic active ingredient (e.g. a growth factor) may be mixed with such materials in a molten state and said at least one ophthalmic active ingredient might be inactivated at temperatures higher than 60°C, it is desirable that the polymers melt within a limited temperature range compatible with maintaining the activity of the at least one ophthalmic active ingredient. In this sense, by conveniently adjusting the amount of co-monomers in the polymerisation process, this goal can be achieved. As for the values of the enthalpy of melting, AHm, one is double the other (Table 3, below), indicating a different amount of crystalline portion within the two materials.

[0100] The samples, once melted, were cooled quickly in order to limit the crystallisation phenomenon as much as possible and to better observe the glass transition. In both cases, it can be observed that in the second scan (II scan) the materials are completely amorphous and only the endothermic jump related to the glass transition (Tg) can be observed.

[0101] By means of TGA, it was possible to confirm the good thermal stability of the materials in question, while by means of DSC, the decrease in crystallinity and melting temperature in comparison with the homopolymer poly(butylene succinate) was highlighted. See Table 3 below

[0102] Table 3

[0103] 1.3.4 Mechanical tests

[0104] The above-mentioned copolymers were subjected to tensile mechanical tests to determine mechanical data such as elastic modulus, deformation and stress at break by applying a constant force to a sample and 5 measuring the corresponding deformation.

[0105] P(BS20BDG80) is more rigid, with a value of elastic modulus E of about 140 MPa, whereas in the case of P(BS50BDG50) this value is reduced by about 70% (E = 53 MPa) (Table 4). The reason for this behaviour can be explained on the basis of the higher crystallinity of the former copolymer0 compared to the latter. It should be noted, however, that these values are much lower than those of other aliphatic copolymers commonly used in the biomedical field, such as polylactic acid. Thus, even the copolymer with the highest elastic modulus can be considered flexible, and therefore suitable for the required application. In any case, the values of tensile5 strength at break (OB) are high, between 15 and 21 MPa; the values of elongation at break (EBJ are also particularly high and comparable in both cases (Table 4 and Figure 5), confirming the high toughness and flexibility of these materials. Thanks to this characteristic the polymers in question are easy to handle and do not break even when subjected to rather high0 mechanical stresses. This flexibility of the copolymers makes the insert suitable for being put in contact with a soft, delicate tissue such as the ocular tissue.

[0106] Table 4

[0107] 2. MATERIAL-COMPATIBILITY TESTS

[0108] The biocompatibility tests of the copolymers P(BS50BDG50), referred to as Copolymer A, and P(BS20BDG80), referred to as Copolymer B, were performed as cell-cytotoxicity analyses according to directive ISO 10993_5, carried out on two human cell lines:

[0109] -conjunctival fibroblasts (HConF), (Wong- Kilbourne derived (WKD) from Chang human)

[0110] - conjunctival epithelial cells (HCE) obtained from ATCC®, CCL 20.2; clone l-5c-4).

[0111] Each copolymer was transformed into a film which was then processed referring to the instructions in ISO 10993-5. The films of the above- mentioned copolymers were then sterilised in 90% ethanol for 30 minutes, followed by 70% ethanol for 30 minutes and washed in IX PBS (phosphate buffered saline) pH 7.4 and equilibrated in medium for 15 minutes.

[0112] Cell-cytotoxicity assays were carried out by the following methods:

[0113] Direct contact: the cells are seeded (cell density 2xl04) on top of the films of the above-mentioned copolymers, positioned in the centre of each well of a multiwelL The cells were incubated at 37°C in direct contact with each film for 24 h and 48 h (Fig.6 for HConF and Fig.9 for HCE).

[0114] Indirect contact: films of the aforementioned copolymers are placed inside wells of a multiwell in which the seeded cells (cell density 2xl04) have reached confluence. The cells were incubated at 37°C in contact with each film for 24h and 48h (Fig.7 for HConF and Fig. 9 for HCE).

[0115] Test on extracts: the films of each polymer are cut referring to the instructions in ISO 10993-5 and incubated at 37°C for 24h in Dulbecco’s modified Eagle medium co-supplemented with fetal bovine serum (DMEM + 5% FBS). 24 h after seeding, the culture medium in each well of a 96-well was replaced with the medium in which the films were incubated for 24 h (100% extract). The 100% extract was then diluted 50% and 25% with fresh complete medium. The cells were incubated at 37°C with the extracts from each film for 24h, 48h and 72h (Fig.8a-c for HConF and Fig. lOa-c for HCE).

[0116] Cell viability was assessed by MTT assay (i.e. by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide compound).

[0117] Cytotoxicity analyses of copolymers A and B with HConF show that both copolymers support cell growth for more than 24 h, showing cell-viability values higher than 70%, as indicated in the ISO (Fig. 6, Fig. 7 and Fig. 8a-c).

[0118] Cytotoxicity analyses of copolymers A and B with HCE show that both copolymers support cell growth for more than 24 h, showing cell-viability values higher than 70%, as indicated in the ISO (Fig. 9 and Fig. lOa-c).

[0119] 3. TESTS OF LOADING AND RELEASE KINETICS OF PILOT PROTEINS (LYSOZYME AND LACTOFERRIN)

[0120] In order to confirm the ability of the copolymers to release molecules, tests of loading of the ophthalmic active ingredient to obtain the ocular device according to the invention and tests of release of the ophthalmic active ingredient were carried out. Two model proteins that are physiologically present in tears, such as lysozyme and lactoferrin, having different molecular weights of 14,600 and 75,000 Dalton respectively, were chosen as active ingredients. 3. 1 Loading of the ophthalmic active ingredient by melting

[0121] Copolymers P(BS50BDG50) and P(BS20BDG80) were respectively loaded with both proteins in an amount of 10 mg of each protein per gram of copolymer.

[0122] The proteins and copolymers were weighed respectively. Each copolymer was melted with one of the proteins using a Minimixer, reaching a melting temperature of 65°C for 5 minutes. The resulting blend containing the copolymer with the active ingredient was then extruded and a film was obtained from the extrudate by die-casting with a laboratory press (Device: CarverC12).

[0123] To obtain films by die-casting, 2 grams of each copolymer were placed between two Teflon plates and placed inside a press heated at a temperature higher than 30°C. Once the polymer was melted, a pressure of approximately 0.5 bar was applied for approximately two minutes. Subsequently, the ocular devices (inserts) in the form of films thus obtained were cooled down, holding them under pressure, to room temperature.

[0124] As a result, the following were obtained:

[0125] - an ocular device made of P(BS50BDG50) with lysozyme

[0126] - an ocular device made of P(BS50BDG50) with lactoferrin

[0127] - an ocular device made of P(BS20BDG80) with lysozyme

[0128] - an ocular device made of P(BS20BDG80) with lactoferrin

[0129] 3.1.1 Lysozyme and lactoferrin release tests

[0130] Smaller discs with a diameter of approximately 1 cm2were subsequently obtained from the above-mentioned films. Each disc was dipped in lx phosphate buffered saline (PBS), pH 7.4 and aliquots were taken at predetermined times until complete release of the active ingredient from the disc, i.e. 120 min for lysozyme (Figure 11) and up to 320 min for lactoferrin (Figure 12).

[0131] Quantification of protein concentrations was assessed by automatic electrophoresis with the Bioanalyzer 2100 device (Agilent).

[0132] The loading of the ophthalmic active ingredients by melting with the copolymer makes it possible to obtain an ocular device (insert) with constant release over time for both copolymers. In particular, the B copolymer insert releases less drug than the A copolymer insert due to its lower hydrophilicity. Clearly, the molecular weight and the steric hindrance of the molecule affect the release, since, as can be seen, lactoferrin that has a higher weight is released over a longer period of time, because probably either the steric hindrance or the bonds formed between the copolymers allow for a longer release.

[0133] 3.2 Loading of the ophthalmic active ingredient by dipping

[0134] Small discs of copolymers A and B, obtained from their respective films after die-casting, were loaded with 3 mg / mL lysozyme and lactoferrin by dipping, respectively. In particular, each protein was individually suspended in PBS and then the small discs were dipped in the solution containing the diluted protein for 3h.

[0135] As a result, the following were obtained:

[0136] - an ocular device made of P(BS50BDG50) with lysozyme

[0137] - an ocular device made of P(BS50BDG50) with lactoferrin

[0138] - an ocular device made of P(BS20BDG80) with lysozyme

[0139] - an ocular device made of P(BS20BDG80) with lactoferrin.

[0140] 3.2.1 Lysozyme and lactoferrin release tests

[0141] Each disc was dipped in lx phosphate buffered saline (PBS), pH 7.4 and aliquots were taken at predetermined times, up to 90 minutes (Figure 13 and Figure 14 for the lysozyme release graphs and Figure 15 for the lactoferrin release graph), in order to assess the cumulative protein concentration over time.

[0142] As can be seen from the graphs, release occurs in about 100 minutes and the copolymer B insert, for both lysozyme and lactoferrin, shows the slowest release due to its lower hydrophilicity.

[0143] 3.3 Loading of the ophthalmic active ingredient into the coating outer layer

[0144] The extruded copolymer A (wire with 0.25 mm diameter) was split to form small cylinders, which were coated with a coating layer. The coating outer layer was prepared using different polymers, each suspended in water and prepared according to the instructions for reagent preparation. The polymers used for each outer layer were polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) (Mw: 85000 and 130000) and Agar. The proteins (10 mg / mL) were respectively added to each suspension of polymer and water, so as to form a homogeneous mixture. Subsequently, each cylinder was put into each mixture for 3 h and after extraction it was dried at room temperature so as to obtain a cylinder coated with a coating outer layer.

[0145] As a result, the following were obtained:

[0146] - an ocular device made of P(BS50BDG50) and coating made of PVA 85Mw with lysozyme

[0147] - an ocular device made of P(BS50BDG50) and PVA coating with lactoferrin

[0148] - an ocular device made of P(BS50BDG50) and PVP coating with lysozyme

[0149] - an ocular device made of P(BS50BDG50) and PVP coating with lactoferrin - an ocular device made of P(BS50BDG50) and coating made of PVA 130 Mw with lysozyme

[0150] - an ocular device made of P(BS50BDG50) and agar coating with lactoferrin - an ocular device made of P(BS50BDG50) and agar coating with lysozyme

[0151] 3.3.1 Lysozyme and lactoferrin release tests

[0152] The above-mentioned ophthalmic inserts were then dipped in PBS respectively.

[0153] The concentration of released protein was assessed by taking volumes at different time-points, up to 24h. The release curves are shown in Figure 16 and Figure 17 for the inserts with the coating outer layer comprising lysozyme and the inserts with the coating outer layer comprising lactoferrin, respectively.

[0154] Release analyses show that both copolymers support a gradual release of the pilot proteins over time within 24h. Furthermore, based on the biomaterial of the outer layer, the release changes and, therefore, can be modulated according to the patient's needs. In particular, PVA is the biomaterial that retains the most active ingredient over time.

Claims

CLAIMS1. An ocular device in the form of an insert comprising at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) and at least one ophthalmic active ingredient which is releasable in a controlled manner from said insert.

2. The ocular device according to claim 1, wherein said at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) has a molar ratio of the diacid subunits, succinate and diglycolate, between 50:50 and 20:80.

3. The ocular device according to any one of the preceding claims, wherein said at least one ophthalmic active ingredient is selected from lactoferrin, lysozyme, surfactant proteins B and C, mucins, albumins, glycoproteins, hypotonizing active ingredients for the treatment of glaucoma such as prostaglandins, active ingredients for the treatment of allergies such as ciclosporin, tacrolimus and cortisone, antibiotics for the treatment of infections, nerve growth factors and mixtures thereof.

4. The ocular device according to any one of the preceding claims, wherein said ocular device is in the form of a film, a disc or a cylinder.

5. The ocular device according to any one of the preceding claims, wherein said at least one copolymer has an elastic modulus between 40- 160 MPa measured with a dynamometer Instron 5966, a contact angle between 60° and 100° measured with the device KRUSS DSA30 and / or a melting point at a temperature between 30°C and 60°C, measured with the calorimeter DSC6 Perkin Elmer.

6. The ocular device according to any one of the preceding claims, wherein said insert comprises an inner layer made of said at least one copolymer, and a coating outer layer for coating said inner layer, said coating outer layer comprising a biomaterial and at least one ophthalmic active ingredient dispersed in said biomaterial, said biomaterial being preferably selected from the group consisting of polyvinylpyrrolidone(PVP), polyvinyl alcohol (PVA), agar, and mixtures thereof.

7. A method for the production of the ocular device according to any one of the preceding claims 1-5, comprising the steps of:- preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),- melting said at least one copolymer with at least one ophthalmic active ingredient, and extruding the resulting melt blend, thereby obtaining an extrudate made of said at least one copolymer in which said at least one ophthalmic active ingredient is incorporated,- molding said extrudate so as to obtain an insert having a predetermined shape and made of said at least one copolymer in which said at least one ophthalmic active ingredient is incorporated, thereby obtaining said ocular device.

8. The method according to claim 7, wherein the melting of the at least one copolymer and the at least one ophthalmic active ingredient is carried out in an extruder at a temperature between 30°C and 70°C, and the resulting melt blend is extruded by a head of said extruder, thereby obtaining said extrudate.

9. The method according to claim 7 or 8, wherein the molding of the extrudate is carried out by die-casting at a temperature higher than 30°C and a pressure between 3- 10 ton / m2, thereby obtaining an insert in the form of a film containing said at least one copolymer in which said at least one ophthalmic active ingredient is incorporated.

10. A method for the production of the ocular device according to any one of the preceding claims 1-5, comprising the steps of:- preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),- molding said at least one copolymer so as to obtain an insert having apredetermined shape,- adsorbing at least one ophthalmic active ingredient on the surface of said insert made of said at least one copolymer, thereby obtaining said ocular device.

11. The method according to claim 10, wherein the molding of said at least one copolymer is carried out by die-casting at a temperature higher than 30°C and a pressure between 3- 10 ton / m2, thereby obtaining an insert in the form of a film.

12. The method according to claim 10 or 11, wherein the adsorption of said at least one ophthalmic active ingredient is carried out by dipping the insert made of the at least one copolymer into a solution containing at least one ophthalmic active ingredient for a time sufficient to allow the adsorption of said at least one active ingredient on the insert surface, followed by drying of the insert extracted from said solution.

13. A method for the production of the ocular device according to claim 6, comprising the steps of:- preparing at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate),- molding said at least one copolymer so as to obtain a layer having a predetermined shape,- coating said layer with a coating outer layer comprising at least one biomaterial and at least one ophthalmic active ingredient dispersed in said biomaterial, thereby obtaining said ocular device.

14. The method according to claim 13, wherein the coating of the layer made of said at least one copolymer is carried out by dipping said layer into a solution containing at least one ophthalmic active ingredient and at least one biomaterial for a predetermined time, followed by drying after extraction from said solution, thereby obtaining an insert comprising aninner layer made of said at least one copolymer and a coating outer layer comprising at least one biomaterial and at least one ophthalmic active ingredient dispersed in said biomaterial.

15. The method according to any one of claims 7- 14, wherein said at least one copolymer is obtained by polymerization from dimethyl succinate(DMS), diglycolic acid (DGA), and butanediol, wherein the molar ratio between dimethyl succinate (DMS) and diglycolic acid (DGA) is preferably between 50:50 and 20:80, whereas butanediol is used in a molar excess compared to the sum of DMS and DGA moles, preferably an excess between 20% and 100%, in particular an excess of 20%.

16. Use of at least one copolymer of poly(butylene succinate) and poly(butylene diglycolate) in the production of an ocular device according to any one of the preceding claims 1 to 6.

17. The ocular device according to any one of claims 1 to 6, for use in the treatment or prevention of ocular diseases and disorders.

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