Soft contact lenses

Abstract

The soft contact lens comprises a polymer-based solid component and a liquid component substantially uniformly distributed within the solid component, the liquid component comprising an effective amount of a compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine, and dopamine, which can prevent or at least limit the progression of myopia in the eye. [Selected Figure] Figure 1

Description

[Technical field]

[0001] The present invention relates to a soft contact lens having the characteristics stated in the preamble of the main claim.

[0002] In particular, the present invention relates to soft contact lenses capable of controlled release of active ingredients beneficial in slowing the progression of myopia.

[0003] Additionally, the present invention relates to packaging for containing soft contact lenses and to processes for making soft contact lenses. [Background technology]

[0004] Myopia is a very common vision disorder caused by parallel light rays arriving from outside the eye not being focused properly on the retina, but instead falling to a focus in front of the retina.

[0005] This visual impairment is often caused by imperfect spherical formation of the eyeball, particularly its elongated shape along the visual axis.

[0006] Myopia generally begins in infancy and increases with age, so the severity of myopia may increase gradually and tends to increase to a maximum value that varies from person to person.

[0007] 2. Description of the Related Art A widely used device for correcting visual impairments, particularly refractive errors such as myopia, is the contact lens, particularly the soft contact lens.

[0008] One of the features that soft contact lenses are particularly valued by users in comparison with other types of contact lenses (hard or semi-rigid) is their high level of comfort when worn.

[0009] This advantageous feature is provided by the high hydrophilic capacity of the lens, which, when containing an appropriate proportion of water, can improve the fit between the lens and the eye, in addition to increasing the deformability of the lens, which allows the lens to better adapt to the surface of the eye.

[0010] Traditionally, soft contact lenses are made by a process which includes a first step of obtaining a dry semi-finished product with lenticular morphology formed from a polymeric material obtained by polymerizing a monomer directly in a mold (injection molding technique) or by turning a disk formed from an already polymerized material (turning technique).

[0011] Apart from the technique used for its preparation, the dried semi-finished product is then hydrated and, if applicable, neutralized by immersion in a saline solution (also known as physiological saline), made from about 1% by weight of sodium chloride in water. The polymeric material used typically has optimal hydrophilic properties, for example polymer mixtures based on HEMA or polymers based on silicone. This ensures that an appropriate amount of saline solution, between 25% and 75%, is absorbed into the dried semi-finished product.

[0012] The absorption of the liquid components gives the lens the above-mentioned properties of conformability and softness, and is accompanied by a physical expansion of the dried semi-finished product in the radial and linear directions, which determines both the final dimensions of the contact lens and its optical properties.

[0013] The contact lens thus obtained comprises a solid component, which defines the structural portion of the lens and is made up of a polymeric material, and a liquid component, which is made up of saline solution substantially uniformly distributed throughout the solid component. Summary of the Invention [Problem to be solved by the invention]

[0014] The problem that the present invention seeks to solve is to provide soft contact lenses which are constructed such that their use will slow the progression of a user's myopia. [Means for solving the problem]

[0015] The above problems are solved according to the present invention by soft contact lenses made according to the appended claims.

[0016] Thus, in a first aspect, the present invention relates to a soft contact lens comprising a solid component based on a polymer and a liquid component distributed in the solid component and comprising an effective amount of a compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine.

[0017] In this way, the contact lenses can slowly release into the eye over an extended period of time an appropriate and predetermined amount of the compound that slows the progression of myopia.

[0018] Furthermore, in a second aspect, the present invention relates to a package containing a soft contact lens made according to the first aspect and immersed in a storage solution, the storage solution comprising at least one compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine, in a concentration at least equal to that present in the liquid component of the soft contact lens.

[0019] This prevents any active compounds present in the liquid component of the soft contact lens from being released into the storage solution during the period between its packaging and its use by the user.

[0020] Furthermore, in a third aspect, the present invention relates to a process for making a soft contact lens according to the first aspect, the process comprising: Providing a dry semi-finished product of a soft contact lens based on a polymer and intended to constitute a solid component of the soft contact lens; hydrating the dried semi-finished product by immersion in an aqueous solution containing an effective amount of a compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine, bringing the liquid component containing said compound closer to the solid component to obtain a soft contact lens according to the first aspect; Includes.

[0021] Furthermore, in a fourth aspect, the present invention relates to an additional process for making a soft contact lens according to the first aspect, the process comprising: Providing a dry semi-finished product of a soft contact lens based on a polymer and intended to constitute a solid component of the soft contact lens; - hydrating the dried semi-finished product by immersion in an aqueous solution to bring the liquid component closer to the solid component and obtain a soft contact lens; packaging the soft contact lens in a container in which the soft contact lens is immersed in a storage solution; subjecting the package containing the soft contact lenses to a sterilization operation in an autoclave; Includes.

[0022] These processes advantageously allow the contact lenses of the present invention to be obtained simply and effectively.

[0023] In the first process, an aqueous solution containing a compound capable of slowing the progression of myopia is homogeneously distributed in the polymer and introduced inside the dried semi-finished product to form the liquid component of the contact lens.

[0024] In the second process, the contact lens is placed in contact with a storage solution containing a compound capable of slowing the progression of myopia when myopia has already occurred.However, in this case, the introduction of the compound into the lens and its homogeneous distribution in the liquid component of the lens can also be observed.This effect is particularly promoted by the effect of the heat to which the contact lens and the storage solution are subjected during the sterilization process, and by the fact that the compound has a relatively low molecular weight so that its size does not substantially hinder its passage through the voids of the polymers that form the soft contact lens.

[0025] In at least one of the above aspects, the invention may have one or more of the following preferred features.

[0026] The solid component of a soft contact lens serves to give the contact lens its shape and structure and is preferably made from a hydrophilic polymer, such as HEMA, or silicone.

[0027] However, the soft contact lenses of the present invention may be made using any other polymer or copolymer suitable for the purpose and commonly used in the art.

[0028] The liquid component of a soft contact lens can promote compatibility between the contact lens and the eye of the lens user.

[0029] Preferably, the liquid component is substantially uniformly distributed throughout the solid component.

[0030] The liquid component is an aqueous solution, preferably a saline solution, containing a suitable concentration of NaCl, for example about 0.9 g / l.

[0031] Preferably, the liquid component has an osmotic pressure of 150 to 350 mOsm, preferably 280 to 310 mOsm.

[0032] In a preferred embodiment, the liquid component also contains a suitable amount of a lubricating compound. Examples of suitable lubricating compounds include polyvinyl alcohol, polysaccharides such as trehalose, cellulose derivatives such as hydroxypropyl cellulose, methyl cellulose and carboxymethyl cellulose, and polyethers such as polyethylene glycol. These compounds may be present in the liquid component at a concentration of about 0.1% to about 5%.

[0033] Furthermore, in one preferred embodiment, the liquid component comprises a tailoring compound for the rheological properties, capable of giving the liquid component viscoelastic properties as similar as possible to those of tear fluid.

[0034] In a preferred embodiment, the adjusting compound for the rheological properties comprises hyaluronic acid or its salts, or a polysaccharide such as galactoxyloglucan extracted from tamarind seed (TSP), which has a suitable molecular weight, for example, between 500 KDalton and 1000 KDalton.

[0035] As noted above, the liquid component comprises an effective amount of a compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine.

[0036] Preferably, the concentration of this compound in the liquid component is substantially constant in different regions of the contact lens, in particular, the concentration varies by no more than 20% between different regions of the contact lens.

[0037] Dopamine is a catecholamine and its molecular structure is shown in the following formula (I):

[0038] [ka]

[0039] Dopamine is a neurotransmitter that is involved in mediating a variety of functions within the eye, including the development of retinal tissue, the transmission of visual signals, and the development of correct refraction.

[0040] Furthermore, dopamine has effects relevant to the control of eye growth: in particular, dopamine action has been observed to slow the axial growth of the eye, slowing the elongation of the eye along the visual axis, which is the main cause of myopia.

[0041] Due to this particular action, it is believed that the presence of adequate concentrations of dopamine in the eye can effectively slow the progression of myopia.

[0042] In fact, it has been shown that high outdoor activity slows the progression of myopia, possibly through the action of the violet component of sunlight (wavelengths: 360-400 nm). Violet light acts by activating the EGR1 gene, an inhibitor of myopia, and by stimulating the production of dopamine in the retina.

[0043] Applicants have demonstrated how effective amounts of dopamine can be released to the eye through soft contact lenses of a liquid composition in which appropriate concentrations of dopamine or its precursors are present.

[0044] The presence of dopamine in the liquid component of the contact lens allows for a gradual and continuous release over time, facilitating the effective action of dopamine within the eye.

[0045] In this way, contact lenses may be advantageously used not only to correct myopia, but also to prevent or at least inhibit the progression of this vision disorder.

[0046] In a first preferred embodiment, the liquid component of the soft contact lens comprises a precursor of dopamine.

[0047] In this way, a compound that is easier to administer and use than dopamine can be used during the preparation of contact lenses.

[0048] In particular, the precursor of dopamine is preferably tyrosine or a derivative or precursor of tyrosine.

[0049] Tyrosine is a polar amino acid and its molecular structure is shown in the following formula (II):

[0050] [ka]

[0051] Tyrosine contains three isomers (para, meta and ortho tyrosine), of which the most common is the para isomer (shown in formula (II) above). Furthermore, tyrosine is an optically active molecule and has two enantiomers, L and D.

[0052] In nature, the enantiomer L (L-tyrosine) is the most common, representing one of the 20 naturally occurring amino acids.

[0053] The term tyrosine is intended to mean all isomers and enantiomers of tyrosine, preferably the enantiomer L of paratyrosine.

[0054] Tyrosine may give rise to a variety of compounds, particularly dopamine, which act to prevent the progression of myopia as mentioned above.

[0055] Examples of derivatives of tyrosine include phosphorylated tyrosine and sulfated tyrosine, where tyrosine is modified by the addition of a phosphate group and a sulfate group, respectively.

[0056] These derivatives of tyrosine are more polar relative to tyrosine and may advantageously result in a slower and more gradual release of the compound in the eye.

[0057] An example of a precursor of tyrosine is phenylalanine, the molecular structure of which is shown in formula (III) below.

[0058] [ka]

[0059] In a preferred embodiment of the invention, the concentration of tyrosine present in the liquid component of the soft contact lens is greater than 1 mg / l.

[0060] The concentration of tyrosine in the liquid component of the soft contact lens is preferably 1 to 500 mg / l, more preferably 1 to 200 mg / l, and even more preferably 10 to 100 mg / l.

[0061] In another preferred embodiment, the liquid component of a soft contact lens according to the present invention comprises an effective amount of an antioxidant compound.

[0062] Preferably, the antioxidant compound comprises vitamin E or vitamin B2 or a mixture thereof.

[0063] Vitamin E is a fat-soluble antioxidant that plays an important role in preventing the oxidation of fatty polyunsaturated acids and inhibiting the action of free radicals.

[0064] There are eight tocotrienols and tocopherols in vitamin E. Of these, the most active and powerful vitamin compound is α-tocopherol.

[0065] Vitamin B2 (riboflavin) also has antioxidant properties.

[0066] The presence of antioxidant compounds such as vitamin E and vitamin B2 can reduce the negative effects of the action of sunlight, which on the one hand is advantageous for promoting the correct production of dopamine, but on the other hand is potentially harmful to the processes of cellular oxidation induced, especially by its ultraviolet component.

[0067] Preferably, α-tocopherol is present in the liquid component of a soft contact lens according to the invention in a concentration of at least 1 mg / l, for example 1-500 mg / l, more preferably 1-100 mg / l, even more preferably 2-20 mg / l.

[0068] Preferably, riboflavin is present in the liquid component of the soft contact lenses according to the invention in a concentration of at least 1 μg / l, for example 1-1000 μg / l, more preferably 1-100 μg / l, even more preferably 2-50 μg / l. [Brief description of the drawings]

[0069] The features of the invention will become more apparent from the following detailed description of preferred embodiments, illustrated by way of non-limiting example with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic perspective view of a contact lens made according to the present invention. [Diagram 2] FIG. 2 is a schematic perspective view of a package for storing and protecting the contact lens of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] In the accompanying drawings, a soft contact lens made in accordance with the present invention is indicated generally by the reference numeral 4.

[0071] The soft contact lenses 4 are preferably corrective lenses, but may generally be of any known type.

[0072] The soft contact lens 4 is made according to the following process.

[0073] In a first step, a dry semi-finished product made of a polymeric material capable of giving the lens its final structure and shape is produced, generally according to conventional techniques (by injection molding or turning). The dry semi-finished product may be obtained from a polymer mixture based on HEMA or any other polymer or copolymer suitable for this purpose or commonly used in the art, such as, for example, a silicone-based polymer.

[0074] In a subsequent processing step, the dried semi-finished product is hydrated by immersion in an aqueous solution, advantageously with stirring, so that the liquid components that facilitate comfortable use of the contact lens are substantially uniformly absorbed into the solid components, resulting in compatibility with the user's eye.

[0075] At the end of the hydration step, the soft contact lens 4 is ready to be packaged and then sterilized by treatment in an autoclave at about 120° C. for about 20 minutes.

[0076] 2 shows a package for storing and protecting a soft contact lens 4, generally designated by the reference numeral 1. The package 1 comprises a support 2, for example made of a plastic material, shaped to define a container 3 in which the soft contact lens 4 is immersed in a storage solution 5.

[0077] Furthermore, the packaging 1 comprises a membrane 6 which is connected to the periphery of the support 2, for example by heat welding, thereby sealing the container 3 and making it possible to prevent the escape of the soft contact lens 4 or the storage solution 5.

[0078] For greater clarity, in FIG. 2 the membrane 6 is shown in a partially lifted state.

[0079] According to a first aspect of the present invention, the aqueous solution in which the dried semi-finished product is immersed for the hydration treatment contains an effective amount of a compound selected from the group consisting of tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine. In a preferred embodiment described herein, the aqueous solution comprises an effective amount of L-tyrosine, for example at a concentration of 10-100 mg / l, sodium chloride in an amount of about 0.9 g / l, vitamin E at a concentration of 1-100 mg / l, and / or vitamin B2 at a concentration of 1-100 μg / l. Optionally, the aqueous solution may contain a lubricating compound, for example polyvinyl alcohol, or a modifying compound for the rheological properties, for example sodium hyaluronate or galactoxyloglucan extracted from tamarind seeds at a concentration of about 0.2%.

[0080] The aqueous solution may also contain a surfactant in the amount of about 0.1%, a disinfectant such as disodium EDTA, and a buffer such as sodium phosphate to maintain the overall pH at about 7.3 to about 7.4.

[0081] The soft contact lens 4 thus obtained comprises, at the level of a conventional lens, a solid component substantially constituted by polymeric material and a liquid component substantially uniformly distributed in the solid component, the liquid component having substantially the same composition as the aqueous solution in which the dried semi-finished product is immersed.

[0082] The liquid content of soft contact lenses is 25% to 75%.

[0083] In an alternative manufacturing process, the contact lens 4 may be hydrated with an aqueous solution that does not contain L-tyrosine and vitamin E and / or vitamin B2, although these compounds may be present in the concentrations mentioned above in the storage solution 5 in which the contact lens 4 is immersed for packaging thereof after it has been formed. In this case, the introduction of L-tyrosine and vitamin E and / or vitamin B2 in the liquid component of the contact lens 4 occurs during the sterilization step of the package 1.

[0084] According to another embodiment of the present invention, the storage solution 5 contains L-tyrosine in a concentration at least equal to that present in the liquid component of the soft contact lens 4.

[0085] Using the second fabrication process, the storage solution 5 will of course contain substantially the same concentrations of L-tyrosine and vitamins E and B2 as the liquid components of the contact lens 4.

[0086] When the soft contact lens 4 is removed from the package 1 and worn by the user, it slowly and gradually releases L-tyrosine into the eye, producing dopamine at the appropriate time, thereby acting to limit or prevent the progression of myopia.

[0087] Additionally, the soft contact lenses 4 slowly and gradually release antioxidant compounds Vitamin E and / or Vitamin B2 into the user's eye to combat the damaging effects of exposure to sunlight, which is advantageous in slowing the progression of myopia.

[0088] Contact lenses according to the present invention may also be made to be replaced monthly or more frequently, for example daily, weekly or biweekly, depending on the preselected polymeric material and its properties for retaining the liquid components.

[0089] Preferably, contact lenses are provided to be replaced weekly or daily.

[0090] Therefore, the present invention solves the above-mentioned problems by providing a soft contact lens that is able to prevent or at least limit the progression of myopia.

[0091] However, the present invention provides many other advantages, including the fact that said soft contact lenses can be made by a simple and inexpensive manufacturing process.

Claims

1. A soft contact lens (4), a polymer-based solid component that serves to give said soft contact lens its shape and structure; A liquid component which is hydrated by immersing the dried semi-finished product of the solid component in an aqueous solution and is distributed in the solid component; Including, The liquid component contains tyrosine at a concentration of 1 to 200 mg / l. Soft contact lenses.

2. The concentration of tyrosine in the liquid component is 10 to 100 mg / l. The soft contact lens according to claim 1.

3. The liquid component is L-tyrosine. The soft contact lens according to claim 1 or 2.

4. The liquid component further comprises an antioxidant compound. The soft contact lens according to any one of claims 1 to 3.

5. The antioxidant compound comprises vitamin E or vitamin B2 or a mixture thereof. The soft contact lens according to claim 4.

6. The concentration of vitamin E is 1 to 500 mg / l. The concentration of vitamin B2 is 1 to 1000 μg / l. The soft contact lens according to claim 5.

7. The concentration of vitamin E is 1 to 100 mg / l; The concentration of vitamin B2 is 1 to 100 μg / l; The soft contact lens according to claim 5.

8. The concentration of vitamin E is 2 to 20 mg / l; The concentration of vitamin B2 is 2 to 50 μg / l. The soft contact lens according to claim 5.

9. A package (1) containing a soft contact lens (4) immersed in a storage solution (5), The soft contact lens is as described in any one of claims 1 to 8, a polymer-based solid component and a liquid component distributed in the solid component, The liquid component contains dissolved tyrosine at a concentration of 1 to 200 mg / l. The storage solution (5) is characterized in that it contains a tyrosine concentration equal to or higher than that present in the liquid component. packaging.

10. A process for making a soft contact lens according to any one of claims 1 to 8, comprising the steps of: providing a dry semi-finished product of said soft contact lens, based on a polymer, intended to constitute the solid component of said soft contact lens; - hydrating said dried semi-finished product by immersion in an aqueous solution to bring the liquid component closer to said solid component and to obtain said soft contact lens; Including, The aqueous solution contains tyrosine at a concentration of 1 to 200 mg / l. process.

11. A process for making a soft contact lens according to any one of claims 1 to 8, comprising the steps of: providing a dry semi-finished product of said soft contact lens, based on a polymer, intended to constitute the solid component of said soft contact lens; - hydrating said dried semi-finished product by immersion in an aqueous solution to bring the liquid component closer to said solid component and to obtain said soft contact lens; packaging the soft contact lens in a container in which the soft contact lens is immersed in a storage solution; - subjecting the packaging containing the soft contact lenses to a sterilization operation in an autoclave; Including, The preservation solution is characterized in that it contains tyrosine at a concentration of 1 to 200 mg / l. process.

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