Contact lens formulation and contact lens

Abstract

Silicone hydrogel contact lens formulations are described herein. The formulation has a silicone component and a silicone-free component. The silicone component comprises two or three compounds represented by a formula 1, a formula 2 or a formula 3. The silicone-free component includes a methacrylate component and an N-vinyl amide component. The methacrylate component is prepared from hydroxybutyl methacrylate (HOB) and isobornyl methacrylate (IBM). And the N-vinyl amide component is prepared from N-vinyl N-methyl acetamide. When compounds of Formula 1 and Formula 2 are present in the formulation in specific ratios to each other, specific amounts of HOB and IBM are provided to achieve specific ratio results in desired silicone hydrogel contact lenses. Silicone hydrogel contact lenses are also described.

Description

Technical Field

[0001] This invention relates to a novel silicone hydrogel contact lens formulation, and ophthalmic lenses, particularly contact lenses, and more particularly silicone hydrogel contact lenses comprising reaction products of polymerizable compositions. Background Technology

[0002] Silicone hydrogel contact lenses have proven to be an acceptable alternative to hydrogel contact lenses. Contact lens manufacturers are frequently asked to introduce novel contact lenses to meet market demands. Therefore, there is a continuous need to develop novel silicone hydrogel contact lenses to address this demand.

[0003] In the development of silicone hydrogel contact lenses, predicting whether a novel silicone hydrogel contact lens formulation will produce a clinically acceptable silicone hydrogel contact lens is difficult. Achieving successful fit, acceptable comfort, acceptable handling experience, and acceptable visual improvement is influenced by various variations in lens chemistry, lens design, and manufacturing processes. For example, changing the formulation of a silicone hydrogel contact lens can alter oxygen permeability, water content, lens surface wettability, and mechanical properties (such as modulus, tensile strength, and elasticity). Therefore, it is unpredictable which combination of chemicals in the formulation will result in the desired lens properties. Summary of the Invention

[0004] This invention addresses this persistent need. The inventors have discovered that when using specific combinations of certain silane compounds in silicone hydrogel contact lens formulations, it is necessary to adjust other monomers in the formulation in previously unknown ways to achieve certain desired contact lens properties. The invention is described in more detail herein.

[0005] The applicant has identified that suitable silicone hydrogel contact lens formulations can be formed using a reaction mixture containing a silicone component and a silicone-free component. The silicone component comprises two compounds, and preferably consists substantially of two compounds, namely Formula 1:

[0006]

[0007] Where R1 is selected from hydrogen or methyl; R2 is selected from hydrogen or C 1-4 Hydrocarbon group; m represents an integer from 0 to 10; n represents an integer from 4 to 100; a and b represent integers of 1 or greater; a+b is from 20 to 500; b / (a+b) is from 0.01 to 0.22, and the configuration of the siloxane unit includes random configuration; and

[0008] Formula 2:

[0009]

[0010] Where n is an integer from 10 to 25.

[0011] The combination of compounds of formula 1 and formula 2 in a ratio of 50:50 to 77:23 and in an amount of 45 to 55% by weight is critical. Preferably, the ratio of compound 1 to compound 2 is from 53:47 to 77:23.

[0012] In some embodiments, in the compound of formula 1, R1 is selected from hydrogen or methyl; R2 is selected from hydrogen or C 1-4 Hydrocarbon group; m is 0; n represents an integer from 4 to 15; a represents an integer from 50 to 250; b represents an integer from 5 to 50; and the configuration of the siloxane unit includes random configuration, wherein the ratio of a:b is from 5:1 to 30:1, preferably from 10:1 to 20:1.

[0013] In another embodiment, the silicone component further comprises an additional 3-silicone compound:

[0014]

[0015] Where m represents an integer from 3 to 12, n represents an integer from 1 to 10, and R 1 Selected from alkyl groups having 1 to 4 carbon atoms, R 2 It is a hydrogen atom or a methyl group, and R 3 It can be a hydrogen atom or a methyl group.

[0016] In some embodiments, in the compound of formula 3, m is 4 and n is 1, R 1 For butyl, R 2 Let H be the number of 'R', and R be the number of 'R'. 3 It is a methyl group.

[0017] In the presence of compound 3, it is used in an amount less than 1% of the total contact lens formulation. In a preferred embodiment of the formulation of the present invention, the silicone component is substantially composed of formulas 1, 2 and 3.

[0018] The combination of compounds of formula 1 and formula 2 advantageously allows for the use of lower amounts of silicone components while still producing contact lenses with good oxygen permeability. This also allows for high water content, which is beneficial for wettability.

[0019] However, when using compounds of Formula 1 and Formula 2 to prepare contact lens formulations, even at these lower amounts, the tensile strength and Young's modulus can be high, as seen in Examples 15 to 17 of US8129442.

[0020] The applicant has identified that lenses with tensile strength substantially lower than that seen in formulations containing compounds of formula 1 and formula 2 can be prepared by selectively choosing the ratios and / or amounts of specific other monomers.

[0021] The silicone-free component comprises an N-vinylamide component and a methacrylate component.

[0022] The methacrylate component comprises hydroxybutyl methacrylate (HOB) and isobornyl methacrylate (IBM), and in some embodiments, is substantially composed of or consists of these components. It is crucial that HOB and IBM are present in amounts from 8.5 to 16% by weight, with the total amount of IBM being less than 5% by weight. Preferably, HOB to IBM is present in the formulation at a weight ratio from 70:30 to 90:10. Preferably, the weight ratio of HOB to IBM is from 85:15 to 90:10, and more preferably, the ratio is about 88:12.

[0023] The N-vinylamide component comprises N-vinyl-N-methylacetamide (VMA). In some embodiments, the N-vinylamide component also comprises N-vinylpyrrolidone (NVP). When the N-vinylamide component comprises both NVP and VMA, the ratio of NVP to VMA is preferably from 70:30 to 30:70. In a preferred embodiment, the N-vinylamide component consists essentially of NVP and VMA, and more preferably of the same. Preferably, the N-vinylamide component is present in an amount from 33 to 37% by weight.

[0024] It has been unexpectedly found that the specific ratio of HOB to IBM, along with the inclusion of VMA and optionally NVP, results in lenses with desirable properties compared to existing lenses formed using combinations of polysiloxane compounds of Formulas 1 and 2, particularly lenses with low tensile strength and low Young's modulus.

[0025] The N-vinylamide component is substantially composed of N-vinylpyrrolidone (NVP) and N-vinyl-N-methylacetamide (VMA), and in some embodiments, is composed of the same.

[0026] In some embodiments, the total amount of the compound of Formula 2, VMA, and HOB is greater than 28 by weight.

[0027] In a first particularly preferred embodiment, the contact lens formulation comprises a silicone component substantially composed of Formula 1 and Formula 2, wherein the ratio of Formula 1 to Formula 2 is from 53:47 to 57:43. The N-vinylamide component substantially consists of NVP and VMA, wherein the NVP:VMA ratio is from 68:32 to 72:28. The methacrylate component substantially consists of HOB and IBM, wherein the HOB:IBM ratio is from 85:15 to 90:10. Preferably, the silicone component comprises 45 to 55% by weight of the formulation. More preferably, the methacrylate component comprises 10 to 20% by weight of the formulation. Still more preferably, the N-vinylamide component comprises 30 to 40% by weight of the formulation.

[0028] In a second particularly preferred embodiment, the contact lens formulation comprises a silicone component substantially composed of Formula 1 and Formula 2, wherein the ratio of Formula 1 to Formula 2 is from 73:27 to 77:23. The N-vinylamide component substantially consists of NVP and VMA, wherein the NVP:VMA ratio is from 32:68 to 28:72. The methacrylate component substantially consists of HOB and IBM, wherein the HOB:IBM ratio is from 85:15 to 90:10. Preferably, the silicone component comprises 45 to 55% by weight of the formulation. More preferably, the methacrylate component comprises 10 to 20% by weight of the formulation. Still more preferably, the N-vinylamide component comprises 30 to 40% by weight of the formulation.

[0029] In a third particularly preferred embodiment, the contact lens formulation comprises a silicone component substantially composed of Formulas 1, 2, and 3, wherein Formula 3 is present in an amount of less than 0.6% by weight of the formulation, and wherein the ratio of Formula 1 to Formula 2 is from 60:40 to 65:35. The N-vinylamide component is substantially composed of VMA. The methacrylate component is substantially composed of HOB and IBM, wherein the ratio of HOB to IBM is from 75:25 to 80:20. Preferably, the silicone component accounts for 45 to 55% by weight of the formulation. More preferably, the methacrylate component accounts for 5 to 15% by weight of the formulation. Still more preferably, the N-vinylamide component accounts for 30 to 40% by weight of the formulation.

[0030] Preferably, the formulation further comprises at least one of the following: a photoinitiator, a thermal initiator, a crosslinking monomer, a UV blocker, and a colorant.

[0031] In another embodiment of the invention, a silicone hydrogel contact lens is disclosed, comprising the polymerization reaction product of any of the formulations of the foregoing embodiments.

[0032] The silicone hydrogel contact lens may have a tensile strength from 0.4 MPa to 1.0 MPa. The silicone hydrogel contact lens typically has a tensile strength of less than or equal to 1.0 MPa, and preferably less than or equal to 0.9 MPa. The silicone hydrogel contact lens typically has a tensile strength of at least 0.4 MPa, and more preferably at least 0.5 MPa. In at least some preferred embodiments, the silicone hydrogel contact lens has a tensile strength from 0.5 MPa to 0.9 MPa.

[0033] The silicone hydrogel contact lens may have a droplet contact angle of less than 30°, more preferably less than 25°.

[0034] The silicone hydrogel contact lenses may have a balanced water content ranging from 45% to 55% by weight.

[0035] The silicone hydrogel contact lens may have an oxygen permeability of greater than 100 barrers, preferably greater than 110 barrers, more preferably greater than 120 barrers, and especially from 110 to 140 barrers.

[0036] The silicone hydrogel contact lens may have a Young's modulus of less than or equal to 1.1 MPa, preferably less than or equal to 1.0 MPa. The Young's modulus is preferably at least 0.3 MPa, more preferably at least 0.5 MPa. A preferred range is from 0.5 MPa to 0.95 MPa.

[0037] The silicone hydrogel contact lenses may have chord diameters ranging from 13.5 to 15.5 mm and base curves ranging from 7.5 to 9.5 mm. Skilled technicians are familiar with other suitable chord diameters and base curves.

[0038] By using the above amounts of these components, lenses with a good balance of properties, especially suitable for low modulus and tensile strength, can be produced.

[0039] When using specific selected silicone components, the applicant has identified that a balance of silicone-free methacrylate components is important for providing good properties of the resulting lenses.

[0040] One method for determining whether a lens possesses good properties is to check whether it satisfies the product of relative methacrylate flexibility. The applicant has identified that a good lens has a value of this product greater than 1.25. Preferably, it has a value greater than 2.5, and more preferably greater than 5. Lenses with a product that satisfies this value exhibit a good balance of physical properties and, in particular, a good degree of flexibility.

[0041] The relative flexibility product of methacrylates is measured as follows:

[0042] (weight% HOB / weight% IBM) * (tensile strength / modulus)

[0043] This unitless parameter allows skilled technicians to quickly assess whether lenses made from the main monomers identified above will have good properties. Detailed Implementation

[0044] This document describes silicone hydrogel contact lenses that exhibit good dimensional stability, are ocularly acceptable, and can be manufactured in formulations without the use of volatile organic solvents or diluents. The silicone hydrogel contact lenses comprise a polymeric lens body, which is a polymerizable composition comprising silicone and silicone-free components, or a reaction product of a silicone hydrogel contact lens formulation. The silicone component comprises two compounds (i.e., Formula 1 and Formula 2), or is substantially composed of them. The ratio of Compound 1 to Compound 2 from 50:50 to 77:23 and in a combined amount from 45 to 55% by weight are critical.

[0045] In this article, "at least one" in the context of a component refers to both a) a single component and b) a combination of two or more components of the same type.

[0046] Throughout this disclosure, the “total amount” of a particular component (i.e., a combination of two or more components of the same type) in a polymerizable composition refers to the sum of the amounts of all components of the same type.

[0047] Unless the context otherwise specifies, the following definitions of the cited terms provided below shall apply in this document:

[0048] "Monomer" means any molecule that can react with the same or different other molecules to form a polymer or copolymer. Therefore, the term includes polymerizable prepolymers and macromonomers, and there is no size limitation on monomers unless otherwise specified.

[0049] "Siloxane monomers" contain at least one Si-O group and are typically "monofunctional" or "polyfunctional," meaning they have one or more polymerizable groups. "Non-siloxane monomers" are monomers that do not contain any Si-O groups.

[0050] "Silicone component" refers to the component or portion of a silicone hydrogel contact lens formulation consisting of all siloxane monomers.

[0051] "Silicone-free components" refers to components or portions of silicone hydrogel contact lens formulations that consist of all non-siloxane monomers.

[0052] "N-Vinylamide component" is a component or portion of the silicone-free component of a silicone hydrogel contact lens formulation, which consists of at least one nonsiloxane monomer having a vinyl group directly bonded to a nitrogen atom.

[0053] "Methacrylate component" is a component or portion of the silicone-free component of a silicone hydrogel contact lens formulation, which consists of at least one nonsiloxane monomer having a single polymerizable methacrylate group.

[0054] "(meth)acrylate-containing monomers" refers to any non-siloxane monomer having a single polymerizable (meth)acrylate group (e.g., methyl methacrylate, etc.). Hereinafter, siloxane monomers having at least one polymerizable (meth)acrylate group are referred to as "(meth)acrylate-containing siloxane monomers". "(meth)acrylate" encompasses both methacrylate and acrylate groups. Where only methacrylate or acrylate is covered, it will be explicitly stated.

[0055] "Composed of" means that the preparation or component contains only the listed components, compounds or monomers.

[0056] "Substantially composed of..." means that the formulation or component contains not only the listed compounds or monomers, but may also contain other monomers or compounds falling within the definition of the formulation or component, such as dimers or polymeric impurities. These additional monomers or compounds may be present in amounts that do not affect the final lens formulation. Additional monomers or reactive entities may be present in amounts less than 5%, 2%, 1%, 0.5%, or 0.1% based on the total amount of a particular formulation or component.

[0057] "Polymerizable composition" is a composition containing polymerizable components, wherein the composition has not been subjected to conditions that would cause the polymerizable components to polymerize. Therefore, the silicone hydrogel contact lens formulation of the present invention is considered a polymerizable composition.

[0058] In the case of polyorganosiloxane prepolymers and other polydisperse monomers, as used herein, the term "molecular weight" refers to the absolute number average molecular weight M of the monomer. n (Units are Daltons (Da / Da) or g / mol). Number average molecular weight is typically determined using GPC with polystyrene standards. Alternatively, number average molecular weight can be determined by identifying the number average molecular weight on the technical data sheet or specification sheet provided by the chemical supplier to the contact lens manufacturer.

[0059] In this disclosure, when values ​​are given for repeating groups in structural formulas (such as Formula 1, Formula 2, or Formula 3), they are average values. Those skilled in the art will understand that this type of complex molecule contains a mixture of components.

[0060] As used herein, the terms “total formulation” or “total contact lens formulation” refer to all formulation components, excluding diluents and / or solvents not incorporated into the final polymeric contact lens material. It should be understood that when provided as a percentage by weight of the components of the total formulation, it refers to the weight of said component based on the total weight of the formulation.

[0061] Throughout this disclosure, references to “example” or “specific example” or similar phrases are intended to introduce one or more features of a contact lens, polymerizable composition, or method of manufacture (depending on the context), unless a particular combination of features is mutually exclusive, or if the context otherwise specifies, it may be combined with any combination (i.e., features) of the examples previously described or subsequently described.

[0062] Throughout this disclosure, when a series of lower bound ranges and a series of upper bound ranges are provided, all combinations of the provided ranges are considered as if each combination were explicitly listed. Similarly, throughout this disclosure, when a series of values ​​is presented with a modifier preceding a first value, the modifier is intended to implicitly precede each value in the series unless the context otherwise specifies. For example, for the values ​​listed above, the modifier "self-limitation" is intended to implicitly precede the ratio 50:50, and the modifier "to approximately" is intended to implicitly precede the ratio 80:20.

[0063] As used herein, unless otherwise specified, ratios refer to weight ratios. As used herein, a weight ratio means the ratio between the weight of the first component and the weight of the second component in a formulation.

[0064] This article discloses silicone hydrogel contact lens formulations containing silicone components; and silicone-free formulations.

[0065] The silicone component comprises, or is substantially composed of, a siloxane monomer containing a difunctional (meth)acrylate and a siloxane monomer containing a monofunctional methacrylate, or in some embodiments, is composed of.

[0066] Siloxane monomers containing bifunctional (meth)acrylates are represented by Formula 1:

[0067]

[0068] Where R1 is selected from hydrogen or methyl; R2 is selected from hydrogen or C 1-4 Hydrocarbon group; m represents an integer from 0 to 10; n represents an integer from 4 to 100; a and b represent integers of 1 or greater; a+b is from 20 to 500; b / (a+b) is from 0.01 to 0.22, and the configuration of the siloxane unit includes random configuration.

[0069] The difunctional (meth)acrylate-containing siloxane monomer of Formula 1 may have an average molecular weight Mw of at least 8,000, 10,000, 12,000, or 15,000 Da. The difunctional (meth)acrylate-containing siloxane monomer of Formula 1 may have an average molecular weight Mw of less than 25,000, 20,000, 12,000, 11,000, 10,000, or 9,000 Da. Preferably, the difunctional (meth)acrylate-containing siloxane monomer has an average molecular weight Mw from 8,000 to 20,000 Da. In a preferred embodiment, the difunctional (meth)acrylate-containing siloxane monomer of Formula 1 has an average molecular weight Mw from 8,000 to 11,000 Da. In another preferred embodiment, the siloxane monomer of Formula 1 containing a difunctional (meth)acrylate has an average molecular weight Mw ranging from 15,000 to 20,000 Da.

[0070] In some embodiments, in the compound of formula 1, R1 is selected from hydrogen or methyl; R2 is selected from hydrogen or C 1-4 The hydrocarbon group; m is 0; n represents an integer from 4 to 15; a represents an integer from 50 to 250; b represents an integer from 5 to 50; and the configuration of the siloxane unit includes random configuration, wherein the ratio of a:b is from 5:1 to 30:1, preferably from 10:1 to 20:1.

[0071] Preferably, R1 is methyl. Preferably, R2 is H or methyl, and more preferably methyl. Further preferably, m is 0. Preferably, n is from 6 to 9.

[0072] In a preferred embodiment, a is from 60 to 100, more preferably from 70 to 80, and b is from 4 to 8, more preferably from 5 to 8. Also preferably, R1 is methyl, R2 is methyl, m is 0, and n is from 7 to 8.

[0073] The preferred siloxane monomers containing bifunctional (meth)acrylates have CAS Registry Number 1216820-69-7.

[0074] In another preferred embodiment, a is from 140 to 220, more preferably from 150 to 200, and b is from 8 to 15, more preferably from 9 to 13. Also preferably, R1 is methyl, R2 is methyl, m is 0, and n is from 7 to 8.

[0075] The method for preparing the compound of Formula 1 is described in U.S. Patent No. 8,129,442 (which is incorporated herein by reference).

[0076] Siloxane monomers containing monofunctional methacrylates are represented by Formula 2:

[0077]

[0078] Where n is an integer from 10 to 25, preferably from 13 to 18.

[0079] The monofunctional methacrylate-containing siloxane monomer of Formula 2 has an average molecular weight of less than 2,000, preferably less than 1,800 Da, and greater than 800, preferably greater than 1,000 Da. In another specific example, the monofunctional methacrylate-containing siloxane monomer may have an average molecular weight from 1,000 to 1,800 Da.

[0080] Preferably, the siloxane monomer containing monofunctional methacrylate has a CAS registry number of 697234-76-7.

[0081] The siloxane monomer of Formula 2 is described in U.S. Patent No. 6,310,169 (which is incorporated herein by reference).

[0082] The compounds of Formula 1 and Formula 2 are in weight ratios ranging from 50:50 to 77:23. In a preferred embodiment, the weight ratio of compound 1 to compound 2 is from 53:47 to 77:23. In some specific embodiments, the weight ratio is from 52:48 to 58:42. In some specific embodiments, the weight ratio is from 60:40 to 65:35. In some specific embodiments, the weight ratio is from 70:30 to 77:23. In some specific embodiments, the weight ratio is about 55:45, about 63:37, or about 75:25.

[0083] The compounds of Formula 1 and Formula 2 are combined in amounts ranging from 45% to 55% by weight.

[0084] In an additional embodiment, the silicone component comprises an additional silicone compound, which is a siloxane monomer of formula 3 containing a monofunctional (meth)acrylate:

[0085]

[0086] In equation 3, m represents an integer from 3 to 12, n represents an integer from 1 to 10, and R... 1 Selected from alkyl groups having 1 to 4 carbon atoms, and R 2 and R 3 Each is independently selected from either a hydrogen atom or a methyl group.

[0087] In some embodiments, in the compound of formula 3, m is 4 and n is 1. More preferably, R 1 For butyl, R 2 Let H be the number of 'R', and R be the number of 'R'. 3 It is a methyl group.

[0088] In the presence of compound 3, it is used in an amount of less than 1% by weight, preferably less than 0.8% by weight, more preferably less than 0.6% by weight of the total contact lens formulation. In a preferred embodiment of the formulation of the present invention, the silicone component is substantially composed of, and preferably composed of, formulas 1, 2 and 3.

[0089] In some embodiments, the silicone component is present in a weight percentage greater than 48%, 48.5%, or 49%. In some embodiments, the silicone component is present in a weight percentage less than 53%, 52.5%, 52%, 51.5%, 51%, or 50.5%. In some embodiments, any of the lower limits of the weight percentage of the silicone component is combined with any of the upper limits of the weight percentage of the silicone component. For example, the silicone component may be present in the formulation from 48% (wt / wt) to 53% (wt / wt), preferably from 48% to 51%.

[0090] In another preferred embodiment, preferably, the amount of compound 2 is greater than 12% by weight of the total composition. More preferably, the amount of compound 2 is less than 25% by weight. For example, compound 2 may be present in the formulation at 12 to 25% (wt / wt).

[0091] In another preferred embodiment, preferably, the amount of the compound of Formula 1 is less than 38% by weight. More preferably, the amount of the compound of Formula 1 is greater than 26% by weight. For example, the compound of Formula 1 may be present in the formulation at 26% to 38% (wt / wt).

[0092] Particularly preferred is that the amount of compound 2 is greater than 12% by weight and the amount of compound 1 is less than 38% by weight.

[0093] Furthermore, it should be understood that the silicone component of the formulations of the present invention does not contain hydroxyl-functionalized siloxane compounds, does not contain TRIS, or does not contain both.

[0094] The silicone-free component comprises an N-vinylamide component (c) and a methacrylate component (d).

[0095] The N-vinylamide component comprises N-vinyl-N-methylacetamide (VMA). Optionally, the N-vinylamide component also comprises N-vinylpyrrolidone (NVP). More preferably, the N-vinylamide component consists essentially of NVP and VMA, and most preferably of both.

[0096] In a preferred embodiment, when the N-vinylamide component comprises both NVP and VMA, the NVP to VMA ratio is from 70:30 to 30:70. In some embodiments, the ratio is about 70:30. In some embodiments, the ratio is about 30:70. In another specific example, the polymerizable composition has a weight ratio of the total amount of the N-vinylamide component to the total amount of the (meth)acrylate-containing siloxane monomer (i.e., siloxane monomers containing monofunctional and difunctional (meth)acrylates) from about 40:60 to 45:55. More preferably, the ratio is from 41:59 to 42:58.

[0097] In some embodiments, the N-vinylamide component is greater than 34% or 34.5% by weight. In some embodiments, the N-vinylamide component is less than 40%, 39%, 37%, or 36.5% by weight. In some embodiments, any of the lower limits of the N-vinylamide component by weight is combined with any of the upper limits of the N-vinylamide component by weight. In some embodiments, the N-vinylamide component by weight is between 34.5% and 35.5%.

[0098] In a preferred embodiment, the N-vinylamide component is substantially composed of VMA, and preferably composed of VMA. In another specific example, the polymerizable composition has a weight ratio of the total amount of the N-vinylamide component to the total amount of the (meth)acrylate-containing siloxane monomer (i.e., siloxane monomers containing monofunctional and difunctional (meth)acrylates) from about 40:60 to 45:55. More preferably, the ratio is from 44:56 to 45:55.

[0099] When the N-vinylamide component is substantially composed of VMA or is composed of VMA, the weight percentage of the N-vinylamide component is greater than 35% or 38%. The weight percentage of the N-vinylamide component is less than 40% or 39%. In some embodiments, any of the lower limits of the weight percentage of the N-vinylamide component is combined with any of the upper limits of the weight percentage of the N-vinylamide component. In some embodiments, the weight percentage of the N-vinylamide component is between 38% and 39%.

[0100] In another specific example, the total amount of the compound of formula 2 and the N-vinylamide component is at least 47% by weight, preferably at least 50% by weight. The total amount of the compound of formula 2 and the N-vinylamide component is less than 70% by weight, preferably less than 60% by weight.

[0101] The methacrylate component comprises hydroxybutyl methacrylate (HOB) and isobornyl methacrylate (IBM). It is crucial that HOB and IBM are present in the formulation at an amount ranging from 8.5% to 16% by weight, with the total amount of IBM being less than 5% by weight. Preferably, HOB and IBM are present in the formulation at a ratio ranging from 70:30 to 90:10.

[0102] The methacrylate component (d) comprises hydroxybutyl methacrylate (HOB) and isobornyl methacrylate (IBM), and is substantially composed of them in some embodiments, and is composed of them in others. In some embodiments, the ratio of HOB to IBM is greater than 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, or 87:13. In some embodiments, the ratio of HOB to IBM is less than 90:10, 89.5:10.5, 89:11, or 88.5:11.5. In some embodiments, any of the lower limits of the HOB to IBM ratio is combined with any of the upper limits of the HOB to IBM ratio. In some embodiments, the HOB to IBM ratio is between 85:15 and 90:10 or about 88:12. In some embodiments, the hydroxybutyl methacrylate and isobornyl methacrylate are present in the formulation at a weight percentage greater than 11, 12, or 13%. In some embodiments, the hydroxybutyl methacrylate and isobornyl methacrylate are present in the formulation at less than 16% by weight. In some embodiments, either the lower limit of HOB and IBM is combined with either the upper limit of HOB and IBM. Preferably, the total amount of HOB and IBM is from 13.6% to 16% by weight.

[0103] In an alternative embodiment, the weight ratio of HOB to IBM is preferably from 75:25 to 80:20, more preferably about 77:23. In this embodiment, the total amount of HOB and IBM is preferably less than 10% by weight.

[0104] Other silicone-free methacrylate monomers are known in the art and can be present in contact lens formulations. Exemplary silicone-free methacrylate monomers include methyl methacrylate (MMA), tert-butyl methacrylate (tBMA), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol methyl ether methacrylate (EGMA), and combinations thereof. Preferably, the additional silicone-free methacrylate monomer is methyl methacrylate (MMA).

[0105] Preferably, these additional methacrylate-containing monomers are present in a contact lens formulation at a total amount of less than 5% by weight, more preferably less than 3% by weight, and even more preferably less than 1% by weight, and even more preferably, in the case where the methacrylate component is substantially composed of HOB and IBM, at the minimum amount defined above. Particularly preferably, no other methacrylate-containing monomers are present.

[0106] In a particular instance, the polymerizable composition may have a weight ratio of the compound of Formula 2 to the total amount of nonsiloxane-containing methacrylate monomers greater than 0.9:1, preferably greater than 1:1.

[0107] In another specific instance, the total amount of non-polysiloxane and siloxane monomers containing monofunctional methacrylates is generally greater than 26% by weight, and preferably greater than 30% by weight.

[0108] Typically, the formulation also includes one or more additional components commonly found in contact lens formulations. Suitable additional components include photoinitiators, thermal initiators, crosslinking agents, UV blockers, and colorants.

[0109] The polymerizable composition may additionally contain at least one non-siloxane crosslinking agent. As used herein, "crosslinking agent" is any compound having a molecular weight of less than about 2,000 Da and two or more olefinically unsaturated groups. Therefore, the crosslinking agent can react with functional groups on two or more polymer chains to bridge one polymer to another. TAIC is particularly preferred as a crosslinking agent in the formulations of this invention.

[0110] The crosslinking agent is preferably used in an amount of 0.03 to 0.2% by weight of the contact lens formulation.

[0111] The composition may further contain one or more colorants. Preferably, the colorant is a reactive colorant, and in particular a colorant identified as a "Reactive Blue" dye.

[0112] The composition may additionally contain one or more UV blockers.

[0113] Contact lenses can be prepared from the polymerizable composition described herein using curing and other processing methods known in the art (such as casting, rotational molding, injection molding, forming polymeric rods that are subsequently machined, etc.). In a particular example, the polymerizable composition is cast between molds formed of a thermoplastic polymer. Thermoplastic polymers are typically nonpolar materials, such as polypropylene, but polar mold materials (such as vinyl alcohol) are also used in the art. Briefly, a first mold component (referred to as the “female mold component”) defining the front of the contact lens is filled with a certain amount of polymerizable composition sufficient to form a single polymeric lens body. A second mold component (referred to as the “male mold component”) defining the back of the contact lens (i.e., the eye contact surface) is joined to the female mold component to form a mold assembly having a lens-shaped cavity therebetween, with the aforementioned amount of polymerizable composition present.

[0114] The polymerizable composition within the contact lens mold assembly is polymerized using any suitable curing method. Typically, the polymerizable composition is exposed to heat or ultraviolet (UV) light of a polymerizable amount. In the case of UV curing (also known as photopolymerization), the polymerizable composition typically contains a photoinitiator such as benzoin methyl ether, 1-hydroxycyclohexylphenyl ketone, Darocur, or Irgacur (available from Ciba Specialty Chemicals). Photopolymerization methods for contact lenses are described in U.S. Patent No. 5,760,100 (which is incorporated herein by reference). In the case of heat-curing (also known as thermal curing), the polymerizable composition typically contains a thermal initiator. Exemplary thermal initiators include 2,2′-azobis(2,4-dimethylpentanonitrile) (VAZO-52), 2,2′-azobis(2-methylpropionitrile) (VAZO-64), and 1,1′-azobis(cyanocyclohexane) (VAZO-88). A contact lens mold assembly containing a contact lens formulation is cured by exposing the contact lens mold assembly to heat or UV light for a duration ranging from about 1 hour to about 5 hours. Additional thermal polymerization methods for contact lenses are described in U.S. Publication No. 2007 / 0296914 and U.S. Patent No. 7,854,866, which are incorporated herein by reference.

[0115] Upon completion of curing, the polymeric material between the mold components of the mold assembly has the shape of a contact lens, referred to herein as the "polymer lens body". Demolding, i.e., separating, and removing the polymer lens body from the mold components to which it is attached, i.e., lens removal, are processes collectively referred to as demolding and lens removal, and various such methods are known to those skilled in the art. In some methods, the demolding and lens removal process may comprise a single process step, such as when using a liquid separation mold, where the liquid also removes the polymer lens body from the mold. In other methods, such as when using a dry demolding process, the polymer lens body typically remains on one of the mold components and is removed in a subsequent process step. Lens removal can also be a wet or dry process. In one example, lens removal is performed by a "floating" method, wherein the mold component to which the polymer lens body is attached is immersed in water. Optionally, the water may be heated (e.g., up to about 100°C). Typically, the polymer lens body floats from the mold component within about 10 minutes. Dry lens removal can be performed manually, for example, using tweezers to remove the polymer lens body from the mold component, or it can be done using automated mechanical processes, such as those described in U.S. Patent No. 7,811,483 (which is incorporated herein by reference). Additional mold and lens removal methods for silicone hydrogel contact lenses are described in U.S. Publication No. 2007 / 0035049 (which is incorporated herein by reference).

[0116] After removal of the contact lens, the polymer lens body is washed to remove unreacted or partially reacted components and to hydrate the polymer lens body. For example, the contact lens may be exposed to organic solvents such as ethanol, isopropanol, industrial methylated spirits, or water, or mixtures thereof. Exemplary washing methods are described in U.S. Patent Publication No. 2007 / 0296914 (which is incorporated herein by reference) and in Example 1 below.

[0117] After washing, the hydrated polymer lens body is typically placed in a blister pack, glass vial, or other suitable container (referred to herein as a "packaging"). A packaging solution, typically a buffered saline solution such as phosphate or borate buffered saline, is also added to the container. The packaging solution may optionally contain additional ingredients such as comfort agents, hydrophilic polymers, surfactants, or other additives to prevent lens adhesion to the container. The packaging is then sealed, and the sealed polymer lens body is sterilized by autoclaving. The final product is a sterile, packaged, ophthalmologically acceptable contact lens.

[0118] In any of the above examples, the contact lens can be characterized by one or more of the following properties: contact angle, oxygen permeability, tensile strength, Young's modulus, and equilibrium water content, as detailed below.

[0119] In any of the following examples, the contact lens may have a contact angle of less than about 30° or 25°, wherein the contact angle is the static advancing contact angle, as determined using the seated drop method. To determine the contact angle of the contact lens surface, the contact lens to be tested is immersed in phosphate-buffered saline (PBS) for at least 12 hours. Using rubber-tipped tweezers, the lens is removed from the PBS and agitated to remove excess water. A 4 mm diameter segment is cut from each lens using a lens cutter. The surface of the contact lens segment to be tested is blotted dry by placing it face down on a microscope lens cleaning cloth and gently dragging the segment through the cloth using rubber-tipped tweezers until no liquid is observed being absorbed into the cloth. The segment is placed on a microscope slide, ensuring it is flat with the blotted surface facing up. Measurements are taken promptly to ensure the segment does not dry out (as demonstrated by deformation of the segment). In the Krüss DSA-100, start the droplet shape analysis program and select the "VCA eq" method using the following settings: camera tilt = +2; 100 μl syringe with straight needle; dispensing solution = purified water; dispensing volume = 0.75 μl; dispensing speed = 7.5 μl / min; and dispensing mode = volume. Place the microscope slide on the sample stage so that the longer side of the lens segment is perpendicular to the camera. Move the syringe to fit the viewing screen and adjust the image until it reaches its maximum value in the middle window. Dispense water onto the lens. Capture an image of the droplet between 10 and 15 seconds after dispensing the water. Select the calculation method based on the contact angle as follows: <30° = circle fitting method; 30° to 130° = tangent method −1; >130° = tangent method −2. Take the average contact angle measurement of the 5 lens segments as the contact angle of a specific surface of the contact lens (i.e., the back or front).

[0120] For oxygen permeability, the Dk values ​​provided in the following examples were determined using a Rehder 201T oxygen permeability meter / polarograph according to the polarographic method described in section 4.4.3 of ISO 18369-4:2017.

[0121] In any of the examples described below, the contact lens may have a Young's modulus (i.e., tensile modulus) of at least 0.3 MPa or 0.5 MPa to 0.95 MPa, 1.0 MPa or 1.1 MPa. In a preferred embodiment, the contact lens has a Young's modulus of from 0.3 MPa to 1.1 MPa, and preferably from 0.5 to 0.95 MPa.

[0122] The contact lens has a tensile strength of less than or equal to 1.0 MPa, preferably less than or equal to 0.9 MPa. The contact lens typically has a tensile strength of at least 0.4 MPa, more preferably at least 0.5 MPa. A preferred embodiment of the contact lens of the present invention has a tensile strength from 0.5 MPa to 0.9 MPa.

[0123] The modulus, elongation, and tensile strength values ​​reported in this paper were determined using an Instron Model 3342, 3343, or 5944 mechanical testing system (Instron Corporation, Norwood, Mass., USA) and Bluehill Materials testing software, using a custom rectangular contact lens cutting mandrel with 4 mm spacing to prepare rectangular sample strips. Modulus was determined in an indoor environment with at least 70% relative humidity. Lenses were immersed in phosphate-buffered saline (PBS) for at least 10 minutes prior to testing. The center strip of the lens was cut using the cutting mandrel while the concave side of the lens was facing upwards. Strip thickness was determined using a calibrated metrology instrument (Rehder Electronics Thickness Gauge, Rehder Development Company, Castro Valley, California, USA). Strips were loaded into the fixtures of the calibrated Instron device using tweezers, with the strips mounted on at least 75% of the fixture surface. Run a test method designed to determine the mean and standard deviation of maximum load (N), tensile strength (MPa), strain (elongation %) at maximum load, and tensile modulus (MPa), and record the results.

[0124] In any of the above examples, the contact lens may have an equilibrium water content (EWC) of at least about 30%, 40%, or 45% by weight and up to about 50%, 55%, 60%, or 70% by weight. For example, the contact lens may have an EWC of from 40% to 60% by weight. To measure the EWC, excess surface water is wiped off the lens and the lens is weighed to obtain the hydrated weight. The lens is dried in an oven at 105°C and weighed. The weight difference is determined by subtracting the weight of the dry lens from the weight of the hydrated lens. Lens weight % EWC = (weight difference / hydrated weight) × 100. In certain examples, the contact angle is ≤30° and the equilibrium water content is most preferably at least 45% by weight and up to 55% by weight.

[0125] As will be apparent from the disclosure of this application as a whole (including the technical solution structure and specific examples), exemplary components of the polymerizable compositions disclosed herein are typically combined in embodiments of the invention. For example, those skilled in the art will recognize that the polymerizable compositions of the invention advantageously comprise combinations of exemplary monofunctional (meth)acrylate-containing siloxane monomers disclosed herein with exemplary difunctional (meth)acrylate-containing siloxane monomers disclosed herein, combinations of exemplary N-vinylamide components disclosed herein, and combinations of exemplary (meth)acrylate components disclosed herein.

[0126] As demonstrated by specific examples, it has been found that the preferred combination of the present invention, comprising a siloxane monomer containing a monofunctional methacrylate, a siloxane monomer containing a difunctional (meth)acrylate, an N-vinylamide component, and a methacrylate-containing monomer, provides the contact lenses of the present invention with advantageous properties (such as reduced tensile strength).

[0127] Example

[0128] The following examples illustrate certain aspects and advantages of the invention, but it should be understood that the invention is not limited thereto. Table 1 details the reactants used in the examples, Table 2 describes the specific amounts of each component used in the total formulation as a percentage by weight, Table 3 presents the ratios and totals of the components, and Table 4 presents the properties.

[0129] Silicone hydrogel lenses of Examples 1 to 3 and Comparative Examples were produced according to the following methods.

[0130] All compounds or monomers are mixed and stirred to form a polymerizable composition or a silicone hydrogel contact lens formulation.

[0131] The preparation is placed into the mold of the contact lens.

[0132] The lenses were cured with ultraviolet light for approximately 1 hour (Examples 1 and 2 and Comparative Examples) or with heat for approximately 5 hours (Example 3). Skilled technicians know the appropriate methods for curing contact lens formulations.

[0133] The cured polymer is removed from the contact lens mold and washed by contact with an organic solvent, water, or a combination thereof to remove unreacted material. The washed contact lenses are then placed in packaging and sterilized in an autoclave to obtain sterilized packaged contact lenses. All example and comparative contact lenses are transparent and flexible, and also have good water wettability.

[0134] Table 1

[0135]

[0136] Table 2

[0137]

[0138] Table 3

[0139]

[0140] Table 4

[0141]

[0142] In Table 3, “(Formula 2)” refers to the general structure of the compound of Formula 2 in this description, and Si-2 is a specific embodiment of Formula 2.

[0143] Surprisingly, a specific choice of the ratio of non-silicone monomers and HOB to IBM can cause this significant reduction in the tensile strength of the resulting lens. The lenses of this invention retain other advantageous features seen in prior art lenses formed using the same combination of siloxane monomers, such as high Dk and good seat drop contact angle.

[0144] While certain illustrative examples are mentioned in the disclosure herein, it should be understood that these examples are illustrative and not intended to be limiting. Although exemplary examples are discussed, the above embodiments are intended to be construed as covering all modifications, substitutions, and equivalents that fall within the spirit and scope of the invention as defined by the appended disclosure.

[0145] Numerous publications and patents have been cited above. The full text of each of the cited publications and patents is incorporated herein by reference.

Claims

1. A silicone hydrogel contact lens formulation comprising: (i) Silicone components; and (ii) Silicone-free, wherein The silicone component comprises: (a) Compound of Formula 1 Where R1 is selected from hydrogen or methyl; R2 is selected from hydrogen or C 1-4 Hydrocarbon group; m represents an integer from 0 to 10; n represents an integer from 4 to 100; a and b represent integers of 1 or greater; a+b is from 20 to 500; b / (a+b) is from 0.01 to 0.22, and the configuration of the siloxane unit includes random configuration; and (b) Compound 2 Wherein n is 10 to 25, and the compound of formula 1 and the compound of formula 2 are present in the formulation in a ratio of 50:50 to 77:23 and in a combined amount of 45 to 55% by weight; and The silicone-free component comprises an N-vinylamide component (c); and a methacrylate component (d), wherein The N-vinylamide component (c) comprises N-vinyl-N-methylacetamide (VMA); and The methacrylate component (d) comprises hydroxybutyl methacrylate (HOB) and isobornyl methacrylate (IBM), wherein the hydroxybutyl methacrylate and isobornyl methacrylate are present in the formulation in an amount from 8.5 to 16% by weight and the total amount of IBM is less than 5% by weight.

2. The formulation according to claim 1, wherein the total amount of the compound of formula 2, VMA and HOB is greater than 28 by weight.

3. The formulation according to claim 1 or 2, further comprising at least one of the following: a photoinitiator, a thermal initiator, a crosslinking monomer, a UV blocker, and a colorant.

4. The formulation according to any of the preceding claims, wherein the N-vinylamide component (c) comprises VMA and N-vinylpyrrolidone (NVP).

5. The formulation according to any of the preceding claims, wherein the N-vinylamide component is present in an amount from 33 to 39% by weight.

6. The formulation according to any of the preceding claims, wherein the ratio of HOB to IBM is 85:15 to 90:

10.

7. The formulation according to any of the preceding claims, wherein the ratio of the compound of formula 1 to the compound of formula 2 is from 55:45 to 75:

25.

8. The formulation according to any of the preceding claims, wherein the ratio of HOB to IBM is approximately 88:

12.

9. The formulation according to claim 1, wherein: The ratio of Equation 1 to Equation 2 is from 53:47 to 57:43; The N-vinylamide component is essentially composed of NVP and VMA, wherein the NVP:VMA ratio is from 68:32 to 72:28; and The methacrylate component is essentially composed of HOB and IBM, wherein the ratio of HOB to IBM is from 85:15 to 90:

10.

10. The formulation according to claim 1, wherein: The silicone component is essentially composed of Formula 1, Formula 2 and Formula 3: In equation 3, m represents an integer from 3 to 12, n represents an integer from 1 to 10, and R... 1 Selected from alkyl groups having 1 to 4 carbon atoms, and R 2 and R 3 Each is independently selected from hydrogen atoms or methyl groups, wherein Formula 3 is present in an amount of less than 0.6% by weight of the formulation; The ratio of Equation 1 to Equation 2 is from 60:40 to 65:35; The N-vinylamide component is essentially composed of VMA; and The methacrylate component is essentially composed of HOB and IBM, wherein the ratio of HOB to IBM is from 75:25 to 80:

20.

11. A silicone hydrogel contact lens comprising a polymerization product of a formulation according to any one of the preceding claims.

12. The silicone hydrogel contact lens according to claim 11, having a tensile strength from 0.4 MPa to 1 MPa.

13. The silicone hydrogel contact lens according to claim 11 or 12, having a droplet contact angle of less than 30°.

14. The silicone hydrogel contact lens according to any one of claims 11 to 13, having a balanced water content of from 45% by weight to 55% by weight.

15. The silicone hydrogel contact lens according to any one of claims 11 to 14, having an oxygen permeability of 110 to 140 barrers.

16. The silicone hydrogel contact lens according to any one of claims 11 to 15, having a Young's modulus from 0.3 MPa to 1.1 MPa.

17. The silicone hydrogel contact lens according to any one of claims 11 to 16, having a chord diameter of 13.5 to 15.5 mm and a base curve of 7.5 to 9.5 mm.

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