Contact lenses that facilitate the spreading of liquid

Abstract

A silicon hydrogel contact lens which comprises all of (i) at least 10% by weight of a monofunctional siloxane monomer comprising a (meth)acrylate group, a polysiloxane linked by a urethane linkage, (

Description

FIELD

[001] The present invention relates to smooth surfaced contact lenses that facilitate the spreading of liquid across the surface of the lens. BACKGROUND

[002] A healthy tear film is important for ocular comfort. Contact lens wear disrupts the tear film into thinner pre- and post-lens tear films. A thin pre-lens tear film can break-up more quickly between blinks than the tear film of a non-lens wearer, which can expose the contact lens to surface air and cause lens dehydration which can in turn result in ocular discomfort. Additionally, a thin post-lens tear film can result in a reduced flow of nutrient-ladened tears to the cornea, which can adversely impact ocular health and / or lead to discomfort.

[003] Commercially and clinically, silicone hydrogel contact lenses are a popular alternative to conventional hydrogel contact lenses (i.e., hydrogel contact lenses that do not contain silicone or silicone-containing ingredients). The presence of siloxanes in silicone hydrogel contact lens formulations is believed to affect the properties of silicone hydrogel contact lenses obtained therefrom. For example, it is believed that the presence of a siloxane component in a contact lens results in a relatively higher oxygen permeability compared to a conventional hydrogel contact lens without a siloxane component. However, the presence of a silicone component increases the likelihood of hydrophobic domains being present on the lens surface of a silicone hydrogel contact lens as compared to a conventional hydrogel contact lens without a silicone component. The presence of hydrophobic domains on the surface of a silicone hydrogel contact lens can negatively impact the surface wettability of silicone hydrogel contact lenses. The first generation of silicone hydrogel contact lenses provided high levels of oxygen, even though the wettability of the lenses tended to be lower than might be desired. Techniques have been developed to overcome the hydrophobicity issues of silicone hydrogel contact lens surfaces. For example, silicone hydrogel contact lenses may be surface coated with a hydrophilic film or treated (e.g. plasma treated) to enhance the polarity and hence wettability of a surface. Based on the popularity of silicone hydrogel contact lenses, there continues to be a need for new silicone hydrogel contact lenses having wettable lens surfaces, especially without the need for a surface treatment or surface coating. In particular, there is a need for silicone hydrogel lenses that are highly wettable despite including significant quantities of siloxane monomers. The inclusion of high levels of siloxane monomers, such as at levels of at least 40% (wt / wt) of the polymerizable composition from which the polymeric lens body is formed, especially significant quantities of high molecular weight (> 5000 daltons) difunctional monomers, such as at levels of at least 15% (wt / wt) of the polymerizable composition from which the polymeric lens body is formed, may be desirable in contact lens formulations to impart desirable properties to the lens. However, rendering lenses with such levels of siloxanes monomers wettable has been found to present a challenge.

[004] Previously it has been found that the provision of a plurality of micropillars on a surface of a contact lens, including silicone hydrogel contact lenses, can result in a lens surface having a very rapid drop spread, which may improve the tear film quality of a lens wearer. It would be desirable to provide silicone hydrogel contact lenses having front and / or back surfaces that function to improve the tear film quality of a lens wearer without the need for micropillars or other topographic features on the lens surface. SUMMARY

[005] A feature of the present invention is to provide a contact lens that facilitate the spreading of liquid, especially water or an aqueous solution such as human tears, across the surface of the lens.

[006] Additional features and advantages of the present invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.

[007] To achieve these and other advantages, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates to a silicone hydrogel contact lens. The silicone hydrogel contact lens includes an optic zone, a peripheral zone, and a circumferential edge. At least 90% of the area of the anterior surface or at least 90% of the area of the posterior surface or at least 90% of the area of both the anterior surface and posterior surface have a smooth surface. Preferably, at least 95% of the area of the anterior surface or at least 95% of the area of the posterior surface or at least 95% of the area of both the anterior surface and posterior surface have a smooth surface. A smooth surface is a surface that lacks features that facilitate wicking of liquid. In particular, a smooth surface lacks features that project above the surface. In some examples the surface lacks features that project more than 100 nm above the surface. In some examples, the surface lacks features that are indented more than 200 nm below the surface. The contact lens comprises a polymeric lens body that is the reaction product of a polymerizable composition, said polymerizable composition comprising: (a) at least 40% (wt / wt) of polymerizable siloxane compounds, including (i) at least 10% (wt / wt) of monofunctional siloxane monomers comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, and including (ii) at least 15% (wt / wt) of difunctional siloxane monomers having a molecular weight of at least 5,000 daltons; and (b) at least 30% (wt / wt) hydrophilic N-vinyl amide monomer. The above amounts are all based on the total weight of the constituents present in the polymerizable composition that together become bound into the polymer matrix on polymerization. After having been dried at 70 °C in an oven for 16 hours, the silicone hydrogel contact lens advantageously has an enthalpy of melting of bound water of at least 90 J / g as determined by Differential Scanning Calorimetry (DSC) using a heating rate of 20 °C / min. The silicone hydrogel contact lens preferably has an enthalpy of melting of bound water of at least 95 J / g as determined by Differential Scanning Calorimetry (DSC) using a heating rate of 20 °C / min. The melting bound water produces the characteristic endothermic curve observed in the range of 0 to 120 °C shown in FIG. 3. Optionally, the percentage hydration of the lens at 40% RH and 25 °C is at least 8.5%, preferably at least 9.1%, of the equilibrium water content (EWC) of the fully hydrated contact lenses measured using the BS EN ISO18369-4: Section 4.2 test method; and / or optionally, the mass of the silicone hydrogel contact lens decreases by less than 2.3% when a lens that has already been air dried at 20 °C, for example in a desiccator (e.g. at 15% relative humidity (RH)), to a steady mass, is further dried in an oven at 105 °C to a steady mass. A steady mass is a mass that does not change (i.e. remains within +1- 0.01%) for at least 5 minutes when the conditions remain constant. The loss of mass on oven drying an air dried silicone hydrogel contact lens is believed to remove residual water that is present in the polymer matrix.

[008] It has surprisingly been found that a silicone hydrogel contact lens having a large siloxane component content, i.e. of at least 40% (wt / wt), can exhibit very rapid liquid spreading even when lacking surface topographic features and when lacking a surface coating or surface treatment, if the polymerizable composition from which the polymeric lens body is formed includes at least 30 wt% N-vinyl amide monomers and the siloxane component includes a substantial proportion of monofunctional siloxane monomers comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, and if the silicone hydrogel lens has an enthalpy of melting of at least 90 J / g, optionally coupled with either (i) a percentage hydration at 40% RH and 25 °C that is at least 8.5 %, preferably at least 9.1%, of the EWC of the fully hydrated lens, or (ii) a loss of mass on oven drying of less than 2.3% after having previously been air dried, or both (i) and (ii).

[009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

[010] The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate some of the features of the present invention and together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [Oil] FIG. 1 depicts the anterior and posterior surfaces of a contact lens.

[012] FIG. 2 depicts the optic zone and peripheral zone of a contact lens.

[013] FIG. 3 depicts a DSC Thermogram of contact lenses. DETAILED DESCRIPTION

[014] Silicone hydrogel contact lenses that improve the spreading of liquid, such as tears or eye drops, across the lens surface are described herein.

[015] FIG. 1 depicts a perspective view of a contact lens, 1, comprising a concave posterior surface, 12, a convex anterior surface, 10, and a peripheral edge, 11. Referring to FIG. 2, which depicts a top view of a contact lens, 1, the contact lens additionally comprises an inner optic zone, 14, as defined by the dashed circle, and a peripheral zone, 13, which is depicted by the annulus region defined by the boundary of the optical zone and the peripheral edge, 11.

[016] A conventional soft contact lens typically has a diameter of about 14 mm and an optic zone having a diameter of about 7 to 9 mm, such as about 8 mm. None of the figures herein depicting contact lenses is to be construed as having been drawn to scale.

[017] The contact lens of the invention includes a smooth surface on either the anterior surface the posterior surface or, preferably, both the anterior and posterior surfaces. A smooth surface lacks surface features, such as protrusions or depressions, projecting from or indented into the lens surface, especially features that project than 100 nm above the surface or are indented more than 200 nm below the surface. Surface features are typically features having a width of at least 50 nm. Examples of protrusions are pillars and ridges molded at or added onto to the surface of a lens. Examples of depressions are dimples or trenches molded at or cut into a lens surface. Preferably, a smooth lens surface lacks surface features on at least 90% of the area of the surface lacks, ideally at least 95% of the area of the surface.

[018] The height of a protruding feature (e.g. a micropillar or ridge height) is the perpendicular distance from the base of the feature (i.e., in contact at the surface of the contact lens) to the opposing top of the protruding feature at the highest point of the protruding feature. Likewise, the depth of a depressed feature (e.g. a dimple or trench depth) is the perpendicular distance from the lip of the feature (i.e., in contact at the surface of the contact lens) to the opposing bottom of the depressed feature at the deepest point of the depressed feature.

[019] The width of a feature, as defined herein, is the largest distance connecting any two points along the perimeter of the feature in a direction parallel to the surface of the lens at 10% of its height from its base or 10% of its depth from the top.

[020] The smooth surface may only be present in the at least the anterior surface or at least the posterior surface or both the anterior surface and the posterior surface. Preferably both the anterior surface optic zone and posterior surface optic zone have a smooth surface. One or both of the peripheral zones of the anterior and posterior surfaces of the lens, preferably both, may also have a smooth surface. Preparing lenses with smooth surfaces has been found to be more straightforward than preparing lenses with complicated surface features. Incorporating surface feature during cost molding required the use of precision molds which can be difficult to manufacture and may be costly. Separating contact lenses having surface features from molding surfaces may also be challenging, requiring larger separation forces or requiring precautions to be taken not to inflict damage on the surface feature during separation from the mold. Adding surface features to lenses once the lens body has been formed, e.g. by cast molding or lathing, requires the use of precision tools and adds an additional step to the manufacturing process. At least 70% of the anterior or posterior surface of the contact lens may have a smooth surface, such as at least 80%, at least 90%, or at least 99% of the anterior or posterior surface of the contact lens, or both the anterior and posterior surfaces of the contact lens.

[021] With the contact lens of the present invention, drop spread rate across the surface is increased compared to a control lens made from an identical process and polymerizable composition except that the polymerizable composition from which the control lens is made contains 9% (wt / wt) of the monofunctional siloxane monomers comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, based on the total weight of the polymerizable components of the polymerizable composition. Additionally or alternatively, with the contact lens of the present invention, drop spread rate across the surface is increased compared to a control lens made from an identical process, except that the control lens has an enthalpy of melting of bound water (e.g. in the range of 0 to 120 °C) of at least 90 J / g as determined by Differential Scanning Calorimetry (DSC) performed on a lens that has been dried at 70 °C in an oven for 16 hours. Additionally or alternatively, with the contact lens of the present invention, drop spread rate across the surface is increased compared to a control lens made from an identical process, except that the percentage hydration at 40% RH and 25 °C of the control lens is less than 8%, for example 7%, of the EWC of the fully hydrated lens. Additionally or alternatively, with the contact lens of the present invention, drop spread rate across the surface is increased compared to a control lens made from an identical process, except that the mass of the control lens decreases by more than 2.3% when a lens that has been air dried at 20 °C, for example in a desiccator (at 15% RH), to a steady mass is further dried in an oven at 105 °C to a steady mass. The control lens may be a lens made from an identical process but from the comparative formulation 9 disclosed below. The increase in drop spread rate is surprising given the lack of surface features that can provide capillary forces resulting in hemi-wicking. A rapid drop spread could potentially help stabilization of pre-lens tear film by quickly re-distributing pre-lens tear in the event of tear film evaporation drying the pre-lens surface during interblink cycle. The improvement in drop spread rate of a smooth contact lens surface can be demonstrated by video capture analysis using the method described in Example 2 and characterised by a drop spread ratio. Briefly, a drop of liquid is dropped onto the lens surface and using video capture system software a plot of the height of the drop on the surface versus time is generated. The drop width at 100 ms (microseconds) after impact with the lens surface is divided by the width of the falling drop to give a drop spread ratio. The higher the drop spread ratio, the more rapidly the liquid spreads across the surface. A surface with a water drop spread ratio of more than 2.00 is considered to be rapidly wettable, whereas a drop spread ratio of more than 2.30 especially more than 2.35 allow for extremely rapid distribution of water across the lens. Lenses having a drop spread ratio of more than 2.40 are very highly wettable.

[022] The surface of the contact lens that has a high drop spread ratio can be the posterior surface of the contact lens. When the posterior surface has a high drop spread ratio, post lens tear film thickness may be increased and improve wearer comfort. Advantageously, the posterior surface of the contact lenses of the invention has a water drop spread ratio of more than 2.00, preferably a drop spread ratio of more than 2.30 especially more than 2.35, such as more than 2.40.

[023] The surface of the contact lens that has a high drop spread ratio can be both the posterior surface and anterior surface of the contact lens. Advantageously, both the posterior surface and the anterior surface of the contact lenses of the invention has a water drop spread ratio of more than 2.00, preferably a drop spread ratio of more than 2.30 especially more than 2.35, such as more than 2.40.

[024] The contact lens typically has an equilibrium water content (EWC) of at least about 40% (wt / wt) or 45% (wt / wt) and up to about 55% (wt / wt), 60% (wt / wt) or 70% (wt / wt). For example, the contact lens may have an EWC from 40 to 60% (wt / wt), especially from 45% to 55% (wt / wt). To measure 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. The % (wt / wt) EWC of the lens is = (weight difference / hydrated weight) X 100. EWC is measured using the BS ENISO18369-4: Section 4.2 test method. Silicone hydrogel contact lenses that both contain a high proportion of siloxane monomers, i.e. are formed from polymerizable compositions comprising 40% (wt / wt) of a polymerizable siloxane, and which have a very high water content, e.g. in excess of 60% (wt / wt), are challenging to formulate and even if successfully produced may have undesirable physical or mechanical properties.

[025] The contact lens of the present invention advantageously has a percentage hydration at 40% RH and 25 °C of at least 8.5%, for example at least 9.1%, of the EWC of the fully hydrated lens. While EWC is a measure of the total amount of water that a lens can hold (e.g. at 100% RH), when the lens is worn on the eye it is exposed to the atmosphere. Contact lenses rapidly loose water content when exposed to the air. Even at 97.5% RH humidity, the water content of a lens stabilises at substantially less than the EWC, for example around 50 to 55% of the EWC. The anterior surface of the lens is typically being exposed to air that has a RH of about 40 % at 25 °C. The percentage hydration of a lens at 40% RH and 25 °C is a measure of how well the lens retains its water content during wear. Ideally the lens of the invention has an EWC of at least 40% (wt / wt), preferably at least 45% (wt / wt), for example from 40 to 55 % (wt / wt), coupled with a percentage hydration at 40% RH and 25 °C of at least 8.5%, for example at least 9.1%, of the EWC of the fully hydrated lens. It has been found that lenses of the invention that retain a relatively high proportion of water at 40% RH and 25 °C typically have a high drop spread rate, even at moderately high EWC, such as in the range of 40 to 60 % (wt / wt),

[026] The contact lens of the present invention includes a polymeric lens body of silicone hydrogel lens material formed from the curing of a polymerizable composition. A “polymerizable composition” is a composition comprising polymerizable ingredients, where the composition has not yet been subjected to curing conditions that result in polymerization of the polymerizable ingredients to form a matrix of a polymeric material. The silicone hydrogel material is formed by curing a polymerizable composition (i.e., a monomer mixture) comprising at least 40% (wt / wt) of a polymerizable siloxane component based on the total amount of polymerizable constituents present in the polymerizable composition. The polymerizable siloxane component includes at least one monofunctional siloxane monomer comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage and at least one difunctional siloxane monomer having a molecular weight of at least 5000 daltons, for example at least 8000 daltons. In the case of polyorganosiloxane prepolymers, and other polydisperse monomers, the term “molecular weight”, as used herein, refers to the absolute number average molecular weight Mn (in units of daltons (Da) or g / mol) of the monomer. The number average molecular weight is typically determined using GPC, using polystyrene standards. In addition, the number average molecular weight may be determined by identification of the number average molecular weight on a technical data sheet or specification sheet provided by a chemical supplier to a contact lens manufacturer. The monofunctional siloxane monomer or monomers comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage constitutes at least 10% (wt / wt) of the total amount of polymerizable constituents present in the polymerizable composition. The difunctional siloxane monomer or monomers having a molecular weight of at least 5000 daltons constitutes at least 10% (wt / wt) of the total amount of polymerizable constituents present in the polymerizable composition. A “monomer” refers to a molecule comprising a polymerizable carbon-carbon double bond (i.e., a polymerizable group) capable of reacting with other polymerizable group-containing molecules that are the same or different, to form a polymer or copolymer. As used herein, the term “siloxane monomer” is a monomer that contains at least one Si-0 group. Siloxane monomers useful in contact lens compositions are well-known in the art (see, e.g., US Pat No. 8,658,747 and US Pat No. 6,867,245). (All patents and publications mentioned here and throughout are incorporated in their entirety by reference.) The term “siloxane monomer” encompasses polymerizable pre-polymers and macromers having a siloxane chain (-Si-O-), there being no size constraint of the monomer unless indicated otherwise. The monomer (including the siloxane monomer) may comprise a single polymerizable carboncarbon double bond, or more than one polymerizable group, and thus have cross-linking functionality.

[027] In some examples, the polymerizable composition comprises a siloxane component content of at least 40% (wt / wt) such as at least 45% or 46% (wt / wt). The “silicone component” is a portion of the silicone hydrogel contact lens formulation which is composed of all siloxane monomers. Unless specified otherwise, as used herein, a given weight percentage (% wt / wt) of a component of the polymerizable composition is relative to the total weight of all polymerizable ingredients and IPN polymers (as described further below) in the polymerizable composition that together become bound into the polymer matrix on polymerization. The weight of the polymerizable composition contributed by components, such as diluents, that do not incorporate into the final contact lens product are not included in the wt.% calculation of the polymerizable composition. The weight percent of the silicone component is typically greater than 47% or 48% (wt / wt). The weight percent of the silicone component is typically less than 55%, especially less than 53%. The silicone component may, for example, be present in the formulation from 47% to 55%, such as from 48% to 53%, preferably from 48% to 51% (wt / wt).

[028] The polymerizable composition comprises at least 30% (wt / wt) hydrophilic N-vinyl amide monomer. The polymerizable composition may further comprise additional hydrophilic monomers, such as further hydrophilic vinyl monomers. As used-herein, a “hydrophilic vinyl monomer” is any siloxane-free (i.e., contains no Si-0 groups) hydrophilic monomer having a polymerizable carbon-carbon double bond (i.e., a vinyl group) present in its molecular structure that is not part of an acryl group, where the carbon-carbon double bond of the vinyl group is less reactive than the carbon-carbon double bond present in a polymerizable methacrylate group under free radical polymerization. Likewise, the “hydrophilic N-vinyl amide monomer” is any siloxane-free hydrophilic monomer having a polymerizable vinyl group bound directly to the nitrogen atom of an amide group. As used herein, the term “acryl group” refers to the polymerizable group present in acrylate, methacrylates, acrylamides, etc. Thus, while carbon-carbon double bonds are present in acrylate and methacrylate groups, as used herein, such polymerizable groups are not considered to be vinyl groups. A “(meth)acrylate-containing monomer” is any non-siloxane monomer that has a single polymerizable (meth)acrylate group (e.g., methyl methacrylate, etc.). A siloxane monomer having at least one polymerizable (meth)acrylate group is referred to herein as a “(meth)acrylate-containing siloxane monomer”. “(Meth)acrylate” covers both methacrylate groups and acrylate groups. Further, as used herein, a monomer is “hydrophilic” if at least 50 grams of the monomer are fully soluble in 1 litre of water at 20 °C (i.e., ~ 5% soluble in water) as determined visibly using a standard shake flask method.

[029] The hydrophilic N-vinyl amide monomer may be selected from N-vinyl-N-methylacetamide (VMA), N-vinyl pyrrolidone (NVP) or a combination of VMA and NVP. Additional hydrophilic vinyl monomers present in the polymerizable composition may include 1,4-butanediol vinyl ether (BVE), or ethylene glycol vinyl ether (EGVE), or di ethylene glycol vinyl ether (DEGVE), or any combination thereof. As used herein, a given weight percentage of a particular class of component (e.g., hydrophilic vinyl monomer, siloxane monomer, or the like) in the polymerizable composition equals the sum of the wt.% of each ingredient in the composition that falls within the class. Thus, for example, a polymerizable composition that comprises 10% VMA and 25% (wt / wt) NVP and no other hydrophilic vinyl monomer, is said to comprise 35% (wt / wt) hydrophilic vinyl monomer. In a specific example, the polymerizable composition comprises from 30% (wt / wt) up to about 45% or 40% (wt / wt) of VMA or NVP, or a combination thereof. Additional hydrophilic monomers that may be included in the polymerizable composition are N,N-dimethylacrylamide (DMA), 2-hydroxyethyl methacrylate (HEMA), ethoxyethyl methacrylamide (EOEMA), ethylene glycol methyl ether methacrylate (EGMA), and combinations thereof.

[030] A specific example of a hydrogel contact lens of the present invention is one that is based on a polymerizable composition comprising from 40% (wt / wt) to 55% (wt / wt) of siloxane monomer, from 30 wt.% to 55 wt.% of a vinyl monomer selected from NVP, VMA, or combinations thereof, and optionally from about 1 wt.% to about 20 wt.% of a hydrophobic monomer selected from methyl methacrylate (MMA), isobornyl methacrylate (IBM), or 2-hydroxybutyl methacrylate (HOB) or any combination thereof.

[031] The polymerisable composition includes at least 10% (wt / wt) monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage. An example of a suitable monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage is that having a structure represented by Formula (I), Formula (I) wherein n is 10 to 25. A compound of formula (I) where n is 16 and having a molecular weight of approximately 1500 daltons, is commercially available as FMM from Shin-Etsu Silicones of America, Akron, Ohio, USA (CAS number 697234-76-7). It is preferred that the amount of monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage is greater than 11.5% especially greater than 12% (wt / wt) of the total polymerizable composition. It is preferred that the amount of monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage is less than 25 weight percent. For example, monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage can be present in the formulation from 12 to 25 % (wt / wt). It is preferred that the amount of the compound of Formula (I) is greater than 12% (wt / wt) of the total composition. It is further preferred that the amount of the compound of Formula (I) is less than 25% (wt / wt). For example, the compound of Formula (I) can be present in the formulation from 12 to 25 % (wt / wt).

[032] Optionally, the majority of the monofunctional siloxane monomer(s) of the polymerizable composition comprise a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage. Advantageously, all or substantially all the monofunctional siloxane monomer(s) of the polymerizable composition comprise a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage. The polymerizable composition may comprise no more than 5% (wt / wt) of monofunctional siloxane monomers other than those that comprise a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, such as no more than 3% (wt / wt) or nor more than 1% (wt / wt) of monofunctional siloxane monomers other than those that comprise a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage. The polymerizable composition may comprise no monofunctional siloxane monomers other than those that comprise a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage. Advantageously the ratio of total monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage to total monofunctional siloxane monomer(s) not comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via urethane linkage (if present) in the polymerizable composition is at least 1.5:1, such as at least 5:1, preferably at least 8:1, especially at least 15:1.

[033] The polymerisable composition includes at least 15% (wt / wt) difunctional siloxane monomer(s) having a molecular weight of at least 5,000 daltons, for example, at least 25% (wt / wt) of such a monomer. The difunctional siloxane monomer(s) having a molecular weight of at least 5,000 daltons is preferably non-fluorinated. A non-fluorinated monomer includes no fluorine atoms. The difunctional (meth)acrylate-containing siloxane monomer may be a compound represented by Formula (II): 4 C H H xO 4"" &* S> S' x ■> * >V- Formula (II) wherein Ri is selected from either hydrogen or a methyl group; R2 is selected from either hydrogen or a Ci-4 hydrocarbon group; m represents an integer of from 0 to 10; n represents an integer of from 4 to 100; a and b represent integers of 1 or more; a+b is from 20-500; b / (a+b) is from 0.01-0.22, and the configuration of siloxane units includes a random configuration. An example of a suitable difunctional siloxane monomer(s) having a molecular weight of at least 5,000 daltons is M5A, a monomer of Formula (II) above wherein Ri is a methyl group, R2 is a methyl group, m is 0, a is 60-100, b is 4-7, n is 6-8. A further example of a suitable difunctional siloxane monomer is M4U, which is a monomer of the Formula (II) above wherein Ri is a methyl group, R2 is a methyl group, m is 0, a is 120-230, b is 6-15, and n is 6-8. The polymerizable composition optionally includes at least 15% (wt / wt) of compounds of formula (II), such as monomers M5A and M4U, for example at least 25% (wt / wt) of compounds of formula (II), such as monomers M5A and M4U. It is preferred that the total amount of compounds of Formula (II) is less than 38% (wt / wt). It is further preferred that the amount of compounds of Formula (II) is greater than 26% (wt / wt). For example, compounds of Formula (II) can be present in the formulation from 26 to 38% (wt / wt). It is preferred that the amount of the compound of Formula (I) is greater than 12% (wt / wt) and the amount of the compound of Formula (II) is less than 38% (wt / wt). The amount of the compounds of Formula (I) is optionally from 12 to 25 % (wt / wt) and the amount of the compound of Formula (II) is optionally from 26 to 38% (wt / wt).

[034] The polymerizable composition may additionally comprise further monofunctional siloxane monomer(s). Suitable further monofunctional siloxane monomer include those comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via an ether linkage. An example of a suitable further monofunctional siloxane monomer is that having a structure represented by Formula (III), Formula (III).

[035] An example of a suitable commercially available mono-functional siloxane monomers having a structure represented by the formula (III) is 2-propenoic acid, 2-methyl-,2-[3-(9-butyl-l,l,3,3,5,5,7,7,9,9-decamethylpentasiloxane-l-yl)propoxy]ethyl ester, X-22-1622 available from Shin-Etsu Chemical Co., Ltd., Tokyo, Japan (CAS # 1052075-57-6). Advantageously the ratio of total monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage to total monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via an ether linkage (if present) in the polymerizable composition is at least 1.5:1, such as at least 5:1, preferably at least 8:1, especially at least 15:1.

[036] The polymerizable composition may additionally comprise at least one cross-linking agent. As used herein, a “cross-linking agent” is a monomer having at least two polymerizable groups. Thus, a cross-linking agent can react with functional groups on two or more polymer chains so as to bridge one polymer to another. The cross-linking agent may comprise an acryl group or a vinyl group, or both an acryl group and a vinyl group. In certain examples, the cross-linking agent is free of siloxane moieties, i.e., it is a non-siloxane cross-linking agent. A variety of cross-linking agents suitable for use in silicone hydrogel polymerizable compositions are known in the field (see, e.g., U.S. Pat. No. 8,231,218, incorporated herein by reference). Examples of suitable crosslinking agents include, without limitation, lower alkylene glycol di(meth)acrylates such as triethylene glycol dimethacrylate and diethylene glycol dimethacrylate; poly(lower alkylene) glycol di(meth)acrylates; lower alkylene di(meth)acrylates; divinyl ethers such as triethyleneglycol divinyl ether, diethyleneglycol divinyl ether, 1,4-butanediol divinyl ether and 1,4-cyclohexanedimethanol divinyl ether; divinyl sulfone; di- and trivinylbenzene; trimethylolpropane tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; bisphenol A di(meth)acrylate; methylenebis(meth)acrylamide; triallyl phthalate; 1,3-Bis(3-methacryloxypropyl)tetramethyldisiloxane; diallyl phthalate; and combinations thereof.

[037] As will be appreciated by those skilled in the art, the polymerizable composition may comprise additional polymerizable or non-polymerizable ingredients conventionally used in contact lens formulations such as one or more of a polymerization initiator, a UV absorbing agent, a tinting agent, an oxygen scavenger, a chain transfer agent, or the like. Constituents that are intended to form a part of the polymeric lens body, i.e. remain present in the lens following extraction and washing steps, typically comprise polymerizable groups to enable them to become chemically bound into the polymeric lens body. Thus, for example, tinting agents, UV blockers and the like that form part of the lens body typically comprise polymerizable groups such as vinyl and acrylate groups. However, it is also possible for the polymeric lens body to include constituents, typically high molecular weight (e.g. having a Mn of 10,000 Da or more) and polymeric constituents that are physically entrapped in the polymeric matrix without being chemically bound to the polymeric matrix. Examples include polymeric wetting agent can be present in the polymeric lens body as part of an interpenetrating polymer network (IPN) or a semi-IPN. An interpenetrating polymer network is formed by at least two polymers, each of which is crosslinked to itself, but none of which are crosslinked to each other. Similarly, a semi-IPN is formed by at least two polymers, at least one of which is crosslinked to itself but not to the other polymer, and the other of which is not crosslinked either to itself or the other polymer. Consistently that become physically bound into the polymeric matrix are considered to be constituents of the polymerizable composition that become part of the polymeric lens body. The contact lens of the present invention advantageously has a polymeric lens body that has less than 5% (wt / wt) of constituents that are not chemically bound into the polymeric matrix, especially less than 1% (wt / wt) of such constituents. The contact lens of the present invention advantageously has a polymeric lens body that is free of an internal polymeric wetting agent present in the lens body as an IPN or a semi-IPN. In one example, the contact lens of the present disclosure can have ophthalmically acceptably wettable lens surfaces and / or good drop spreading characteristics when the polymeric lens body is free of an internal polymeric wetting agent present in the lens body as an IPN or a semi-IPN.

[038] In some examples, the polymerizable composition may include an organic diluent in an amount to prevent or minimize phase separation between the hydrophilic and hydrophobic components of the polymerizable composition, so that an optically clear lens is obtained. Diluents commonly used in contact lens formulations include hexanol, ethanol, and / or other alcohols. In other examples, the polymerizable composition is free or substantially free (e.g., less than 500 ppm) of an organic diluent. In such examples, the use of siloxane monomers containing hydrophilic moieties such as polyethylene oxide groups, pendant hydroxyl groups, or other hydrophilic groups, may make it unnecessary to include a diluent in the polymerizable composition. Non-limiting examples of these and additional ingredients that may be included in the polymerizable composition are provided in U.S. Pat. No. 8,231,218. Constituents of the polymerizable composition that do not become physically or chemically bound into the polymeric matrix are not included in the total mass of the polymerizable composition used to calculate % (wt / wt) of constituents of the polymerizable composition.

[039] The polymerizable formulation used to form the silicone hydrogel contact lens of the invention may, for example, comprise: (i) a silicone component; and (ii) a silicone-free component, wherein the silicone component comprises: (a) a compound of Formula (II) as defined herein; and (b) a compound of Formula (I) as defined herein, and the compound of Formula (II) and the compound of Formula (I) are present in the formulation at a weight ratio from 50:50 to 80:20; and the silicone-free component comprises: (c) an N-vinyl amide component; and (d) a methacrylate component, wherein the N-vinyl amide component (c) comprises N-vinyl N-methyl acetamide (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 at a weight ratio from 60:40 to 90:10. In some embodiments, if the hydroxybutyl methacrylate to isobornyl methacrylate weight ratio is 60:40 to 65:35, one or more of: (i) the weight ratio of the compound of Formula (II) to the compound of Formula (I) is from 50:50 to 75:25, preferably from 65:35 to 70:30; (ii) the compound of Formula (I) is present in an amount of at least 12% (wt / wt); (iii) the compound of Formula (II) is present in an amount of less than 38% (wt / wt); (iv) the weight ratio of the compound of Formula (I) to the total of the methacrylate component is greater than 0.9:1; (v) the weight ratio of compound of Formula (II) to the compound of Formula (I) is less than 3:1; and (vi) the total amount of mono(meth)acrylate compounds in the composition is greater than 26% (wt / wt). In other embodiments, if the total amount of IBM in the contact lens formulation is greater than 5% (wt / wt), one or more of: (i) the weight ratio of the compound of Formula (II) to the compound of Formula (I) is from 50:50 to 75:25, preferably from 65:35 to 70:30; (ii) the compound of Formula (I) is present in an amount of at least 12% (wt / wt); (iii) the compound of Formula (II) is present in an amount of less than 38% (wt / wt); (iv) the weight ratio of the compound of Formula (I) to the total of the methacrylate component is greater than 0.9:1; (v) the weight ratio of compound of Formula (II) to the compound of Formula (I) is less than 3:1; and (vi) the total amount of mono(meth)acrylate compounds in the composition is greater than 26% (wt / wt).

[040] The polymerizable formulation used to form the silicone hydrogel contact lens of the invention may, for example, comprise: (i) a silicone component; and (ii) a silicone-free component, wherein the silicone component comprises: (a) a compound of Formula (II) as defined herein; and (b) a compound of Formula (I) as defined herein, and the compound of Formula (II) and the compound of Formula (I) are present in the formulation at a weight ratio from 50:50 to 77:23; and the silicone-free component comprises: (c) an N-vinyl amide component; and (d) a methacrylate component, wherein the N-vinyl amide component (c) comprises N-vinyl N-methyl acetamide (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 at a weight ratio from 70:30 to 90:10, for example from 85:15 to 90:10.

[041] The polymerizable formulation used to form the silicone hydrogel contact lens of the invention may, for example, comprise: (i) a silicone component; and (ii) a silicone-free component, wherein the silicone component comprises: (a) a compound of Formula (II) as defined herein; and (b) a compound of Formula (I) as defined herein, and the compound of Formula (II) and the compound of Formula (I) are present in the formulation at a weight ratio from 50:50 to 77:23 and in a combined amount of from 45 to 55% (wt / wt); and the silicone-free component comprises: (c) an N-vinyl amide component; and (d) a methacrylate component, wherein the N-vinyl amide component (c) comprises N-vinyl N-methyl acetamide (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 of from 8.5 to 16% (wt / wt) and the total amount of IBM is less than 5% (wt / wt). In some embodiments, the total amount of the compound of Formula (I), VMA and HOB is greater than 28% (wt / wt).

[042] The polymerizable formulation used to form the silicone hydrogel contact lens of the invention may, for example, comprise: (i) a silicone component; and (ii) a silicone-free component, wherein the silicone component comprises: (a) a compound of Formula (II) as defined herein; and (b) a compound of Formula (I) as defined herein, and the compound of Formula (II) and the compound of Formula (I) are present in the formulation at a weight ratio from 50:50 to 80:20 and in a combined amount of from 45 to 55% (wt / wt); and the silicone-free component comprises: (c) an N-vinyl amide component; and (d) a methacrylate component, wherein the N-vinyl amide component (c) comprises N-vinyl N-methyl acetamide (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 of from 8.5 to 16% (wt / wt). In some embodiments, the total amount of the compound of Formula (I), VMA and HOB is greater than 28% (wt / wt). In other embodiments, if the total amount of IBM in the contact lens formulation is greater than 5% (wt / wt), one or more of: (i) the weight ratio of the compound of Formula (II) to the compound of Formula (I) is from 50:50 to 75:25, preferably from 65:35 to 70:30; (ii) the compound of Formula (I) is present in an amount of at least 12% (wt / wt); (iii) the compound of Formula (II) is present in an amount of less than 38% (wt / wt); (iv) the weight ratio of the compound of Formula (I) to the total of the methacrylate component is greater than 0.9:1; (v) the weight ratio of compound of Formula (II) to the compound of Formula (I) is less than 3:1; and (vi) the total amount of mono(meth)acrylate compounds in the composition is greater than 26% (wt / wt). In other embodiments, the total amount of the compound of Formula (I), VMA and HOB is greater than 28% (wt / wt) and if the total amount of IBM in the contact lens formulation is greater than 5% (wt / wt), one or more of: (i) the weight ratio of the compound of Formula (II) to the compound of Formula (I) is from 50:50 to 75:25, preferably from 65:35 to 70:30; (ii) the compound of Formula (I) is present in an amount of at least 12% (wt / wt); (iii) the compound of Formula (II) is present in an amount of less than 38% (wt / wt); (iv) the weight ratio of the compound of Formula (I) to the total of the methacrylate component is greater than 0.9:1; (v) the weight ratio of compound of Formula (II) to the compound of Formula (I) is less than 3:1; and (vi) the total amount of mono(meth)acrylate compounds in the composition is greater than 26% (wt / wt).

[043] As part of the present invention, the contact lens can be sealed in a contact lens package. The packaging solution sealed within the contact lens package may be any conventional contactlens compatible solution. In one example, the packaging solution comprises, consists, or consists essentially, of an aqueous solution of a buffer, and / or a tonicity agent. In another example, the packaging solution contains additional agents such as one or more additional antimicrobial agents, and / or a comfort agent, and / or a hydrophilic polymer, and / or a surfactant and / or other beneficial agent. In some examples, the packaging solution may comprise polysaccharides (e.g., hyaluronic acid, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxy ethyl cellulose, etc.) or other high molecular weight polymers, such as polyvinyl pyrrolidone, which are commonly used as comfort polymers or thickening agents in ophthalmic solutions and contact lens packaging solutions. In other examples, the packaging solution may comprise an ophthalmic drug. The packaging solution can have a pH in the range of about 6.8 or 7.0 up to about 7.8 or 8.0. In one example, the packaging solution comprises phosphate buffer or borate buffer. In another example, the packaging solution comprises a tonicity agent selected from sodium chloride or sorbitol in an amount to maintain osmolality in the range of about 200 to 400 mOsm / kg, and typically from about 270 mOsm / kg up to about 310 mOsm / kg.

[044] With respect to the contact lens package, this package can include or comprise a plastic base member comprising a cavity configured to retain the contact lens and packaging solution and a flange region extending outwardly around the cavity. A removable foil is attached to the flange region to provide a sealed contact lens package. Such contact lens packages, which are commonly referred to as “blister packs,” are well-known in the art (see e.g., U.S. Pat. No. 7,426,993).

[045] It will be appreciated that conventional manufacturing methods can be used to manufacture the sealed contact lens package. In a method of manufacturing a contact lens package, the method can include the step of placing an unworn contact lens and a contact lens packaging solution in a receptacle, placing a cover on the receptacle, and sealing the cover on the receptacle. Generally, the receptacle is configured to receive a single contact lens and an amount of packaging solution sufficient to completely cover the contact lens, typically about 0.5-1.5 ml. The receptacle may be made from any suitable material, such as glass or plastic. In one example, the receptacle comprises a plastic base member comprising a cavity configured to retain the contact lens and packaging solution and a flange region extending outwardly around the cavity, and the cover comprises a removable foil attached to the flange region to provide the sealed contact lens package. The removable foil may be sealed by any conventional means such as heat sealing or gluing. In another example, the receptacle is in the form of a plastic base member comprising a plurality of threads and the cover comprises a plastic cap member comprising a compatible set of thread for engagement with the threads of the base member thereby providing a resealable cover. It will be appreciated that other types of packaging can also be used to provide a resealable package. For example, the contact lens package may comprise a plastic cover comprising features that engage with compatible features of the receptacle to form an interference fit. The method of manufacturing the sealed contact lens package may further comprise sterilizing the unworn contact lens by autoclaving the sealed contact lens package. Autoclaving generally involves subjecting the sealed contact lens package to temperatures of at least 121° C for at least 20 minutes.

[046] The contact lens can be provided unworn (i.e., a new contact lens, not having been previously used by a patient), immersed in the packaging solution and sealed in a package. The package may be a blister package, glass vial, or other appropriate container. The package comprises a base member having a cavity for accommodating a packaging solution and an unworn contact lens. The sealed package may be sterilized by sterilizing amounts of radiation, including heat or steam, such as by autoclaving, or by gamma radiation, e-beam radiation, ultraviolet radiation, etc. In a specific example, the packaged contact lens is sterilized by autoclaving.

[047] The final product can be a sterile, packaged contact lens (e.g., silicone hydrogel contact lens) having ophthalmically-acceptable surface wettability.

[048] The contact lens may be manufactured by a cast molding technique. An exemplary cast molding technique involves dispensing a polymerizable composition into a mold assembly having a molding surface formed of a non-polar thermoplastic polymer to form the polymeric lens body. The mold assembly may comprise a female mold member having a concave surface that defines the anterior surface of the contact lens and a male mold member having a convex surface that defines the posterior surface of the contact lens, both mold members having molding surfaces formed of a non-polar thermoplastic polymer that form the polymeric lens body. The polymerizable composition is typically dispensed into the female mold member and the male mold member is combined with the female mold member to form a contact lens mold assembly. The contact mold assembly is subjected to curing conditions, such as UV or thermal curing conditions, under which the curable composition is formed into a polymeric lens body. The molding surfaces of the molds that defines the posterior and anterior surfaces of the contact lens are preferably smooth. The mold is disassembled (i.e., demolded) and the polymeric lens body is removed from the mold and contacted with an organic solvent, such as ethanol, to extract unreacted components from the lens body. After extraction, the lens body is hydrated in an aqueous solution. Exemplary methods of manufacturing silicone hydrogel contact lenses are described in U.S. Pat. No. 8,865,789.

[049] The following Examples illustrate certain aspects and advantages of the present invention, which should be understood not to be limited thereby.

[050] The following chemicals are referred to in formulations 1-9, and may be referred to by their abbreviations. FMM: a monomer of Formula (I) above, wherein n is 16 and having a molecular weight of approximately 1500 daltons (CAS number 697234-76-7) obtainable from Shin-Etsu Silicones of America, Akron, Ohio, USA X-22-1622: 2-propenoic acid, 2-methyl-, 2-[3-(9-butyl-l,l,3,3,5,5,7,7,9,9-decamethylpentasiloxane-l-yl)propoxy] ethyl ester (CAS number of 1052075-57-6) obtainable from Shin-Etsu Chemical Co., Ltd., Tokyo, Japan (KF-1622) M5A: a monomer of Formula (II) above, wherein Ri is a methyl group, R2 is a methyl group, m is 0, a is 60-100, b is 4-7, n is 6-8. M4U: a monomer of the Formula (II) above wherein Ri is a methyl group, R2 is a methyl group, m is 0, a is 120-230, b is 6-15, and n is 6-8 (also referred to KF-1625). M3U: a,co-bis(methacryloyloxyethyliminocarboxyethyloxy-propy 1)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane)-poly (co-methoxy-poly(ethyleneglycol)propylmeth-ylsiloxane) having a molecular weight about 12,800 daltons (CAS number 697234-74-5) M3U blue: is a suspension of phthalocyanine blue in M3U VMA: N-vinyl-N-methylacetamide (CAS number 3195-78-6) NVP: N-vinyl pyrrolidone (CAS number 88-12-0) DMA: N,N-dimethylacrylamide (CAS number 2680-03-7) EGMA: Ethylene glycol methyl ether methacrylate (CAS number 6976-93-8) MMA: Methyl methacrylate (CAS number 80-62-6) EGDMA: Ethylene glycol dimethacrylate (CAS number 97-90-5) TEGDMA: triethylene glycol dimethacrylate (CAS number 109-16-0) DEGVE: diethylene glycol vinyl ether (CAS number 929-37-3) TEGDVE: triethylene glycol divinyl ether (CAS number 765-12-8) AE: 2-Allyloxy ethanol (CAS number 111-45-5) TPP: Triphenyl phosphine (CAS number 603-35-0) TPO: Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (CAS number 75980-60-8) IBM: isobornyl methacrylate (CAS number 7534-94-3) HOB: 2-hydroxybutyl methacrylate (CAS number 29008-35-3). AOT: Sodium bis(2-ethylhexyl)sulfosuccinate (sodium dioctyl sulfosuccinate) (CAS number 577-11-7) IBM: Isobornyl methacrylate (CAS number 7534-94-3) TAIC: Triallyl isocyanurate (CAS number 1025-15-6) AIBN: Azobisisobutyronitrile (CAS number 78-67-1) Example 1. Silicone hydrogel contact lenses.

[051] The following Examples illustrate certain aspects and advantages of the present invention, which should be understood not to be limited thereby. The reactants used in the Examples are detailed in Table 1, the particular amounts of each component used are set out parts by weight of the total formulation. The silicone hydrogel lenses of Formulations 1, 2 and 4 of the invention and the comparative silicone hydrogel lenses of Formulations 3, 5, 6, 7, 8 and 9 were produced according to the following method: The compounds or monomers were all mixed and stirred to form a polymerizable composition or a silicone hydrogel contact lens formulation. The formulation was put in a mold for a contact lens having smooth molding surfaces. The lenses were cured using ultraviolet light for about 1 hour (Examples 1 and 2 and Comparative Examples). The skilled person is aware of suitable methods for curing contact lens formulations. The cured polymers were removed from the contact lens molds and washed to remove unreacted materials by contacting them with organic solvent, water, or combinations thereof, and then the washed contact lenses were placed in a package and sterilized in an autoclave to provide a sterilized packaged contact lens. The contact lenses of all Examples and Comparative Examples were transparent and flexible, and also had good water wettability. Table 1 Formulation 1 2 3* 4 5* 6* 7* 8* 9* TAIC 0.090 0.090 0.10 0.045 0.090 IBM 1.872 1.650 5.40 2.080 5.410 HOB 13.726 12.070 9.00 6.924 9.020 VMA 10.415 24.700 9.00 38.718 48.00 48.00 48.00 43.050 9.020 NVP 24.303 10.580 27.10 27.080 FMM 22.070 12.590 9.00 17.990 15.00 30.00 9.020 X-22-1622 0.486 30.00 15.00 26.906 M5A 26.974 37.760 30.145 10.00 10.00 10.00 8.968 M4U 39.801 M3U 39.720 M3U Blue 0.100 EGMA 7.00 7.00 7.00 6.278 MMA 15.00 15.00 15.00 13.453 TEGDVE 0.10 0.10 0.10 0.090 EGDMA 0.50 0.50 0.50 0.448 AE 0.630 1.15 1.15 1.15 1.123 Tint 0.009 0.009 0.009 0.14 0.010 0.010 0.010 0.009 TPP 0.403 0.45 0.45 0.45 0.448 AIBN 0.450 0.50 0.50 0.50 0.448 TPO 0.090 0.090 0.09 0.090 AOT / SDS 0.450 0.450 0.50 0.450 UV blockers 2.115 0.90 0.90 0.90 0.807 Total 99.999 99.989 100.000 100.000 113.61 113.61 113.61 102.028 100.000 Formulation 1 2 3* 4 5* 6* 7* 8* 9* Drop spread ratio 2.50 2.63 2.31 2.63 2.09 2.20 2.45 2.05 2.19 * denotes a comparative example Example 2. Drop spreading behavior of silicone hydrogel contact lenses.

[052] A video capture system was used to analyze drop spreading on silicone hydrogel contact lenses. The tip of a drop dispensing needle was positioned 10 mm above the center of the anterior side of each sample lens. A 5.5 pl drop of water was dropped onto the center of the lens and the spreading of the droplet onto the surface was captured by video (1000 fps). Video capture system software generated plots showing the height of the drop on the surface of the lens versus time elapse. The width of the droplet on the surface is measured 100 ms after the drop has touched the surface and is divided by the diameter of the spherical droplet before it touches the surface to give a drop spread ratio. This non-dimensional drop spread ratio is used instead of absolute drop width to make the data independent of the liquid drop volume used for the measurement. The drop spread ratio for lenses of formulations 1 to 9 is shown in Table 1 above. The drop spread ratio for commercially available Dailies Total 1™ lenses (available from Alcon Inc.) which have a crosslinked hydrogel coating on the lens surface and Acuvue Oasys Max 1 -Day™ lenses (available from Johnson &Johnson Vision) is shown in Table 2 below. Example 3. Enthalpy of melting

[053] Differential Scanning Calorimetry (DSC) involves measuring the change in heat flow as a material is heated in a controlled atmosphere. The thermogram produced can be used to characterize a material based on physical and chemical changes that occur within the sample. In this instance DSC was used to observe differences in water content based on the melting of the bound water in the sample. Prior to analysis the contact lenses were rinsed with ultrapure water to remove the buffer solution. The samples were then dried at 70 °C overnight in an oven for at least 16 hours, to remove any free water, whilst avoiding chemically altering the lens. The enthalpy of melting was determined under nitrogen using a TA Instruments (New Castle, DE USA) DSC 2920 Differential Scanning Calorimeter according to the following procedure: Equilibrate at -20 °C, Heat 20 °C / min to 300 °C. The enthalpy of melting of contact lenses of Formulations 2, 4, 8 and 9 and commercially available Dailies Total 1™ lenses and Acuvue Oasys Max 1-Day™ lenses is shown in Table 2 below.

[054] FIG. 3 shows the DSC thermograms of contact lenses of formulations 2 and 4 as a well as those of comparative formulations 8 and 9 plus comparative commercially available Dailies Total 1TM lenses (available from Alcon Inc.) and Acuvue Oasys Max 1-DayTM lenses (available from Johnson &Johnson Vision). The first endothermic peak between -20 °C and +10 °C is believed to relate to the removal of residual free water whereas the main endothermic peak between 0 °C and 120 °C relates to the bound water content. Example 4. Loss on drying

[055] The samples were rinsed thoroughly with ultrapure water to remove the buffer solution. They were then left to air dry to remove excess water and weighed. Air drying may be performed at 20 °C in a desiccator (at 15% RH) to a steady mass The lenses were then dried in an oven at 105 °C to a steady mass to determine the water content of the samples. A steady mass is a mass that does not change (i.e. remains within +1- 0.01%) for at least 5 minutes when the conditions remain constant. The loss on drying of contact lenses of Formulations 2, 4, 8 and 9 and commercially available Dailies Total 1™ lenses and Acuvue Oasys Max 1-Day™ lenses is shown in Table 2 below. Example 5. Water contents.

[056] The Equilibrium Water Content (EWC) of the fully hydrated contact lenses produced from formulations 2, 4 8 and 9 and of commercially available Dailies Total 1™ lenses and Acuvue Oasys Max 1-Day™ lenses was measured using the BS ENIS018369-4: Section 4.2 test method. The hydration (%) of the lens materials at 40% RH was calculated by comparing the equilibrium weight of the lenses at 40% RH and 25 °C with the EWC of fully hydrated lenses. The EWC and hydration (%) at 40% RH and 25 °C of contact lenses of Formulations 2, 4, 8 and 9 and commercially available Dailies Total 1™ lenses and Acuvue Oasys Max 1-Day™ lenses is shown in Table 2 below. Table 2 Formulation: 2 4 8* 9* Dailies Total 1 Acuvue Oasys Max 1 -Day Drop spread ratio 2.63 2.63 2.05 2.19 1.90 1.79 Loss on drying (%) 1.55 2.03 9.46 2.56 3,21 4,73 Enthalpy of melting (J / g) 126.6 102.5 131.4 137.5 83.2 72.5 Equilibrium water content (%) 48.1 51.9 55.8 47.2 33.2 37.8 % hydration at 40% RH 9.3 9.7 7.5 10.6 9.0 7.5

[057] Smooth surfaced contact lenses meeting the enthalpy of melting, loss on drying and water content criteria set out for lenses of the present invention were all found to have a drop spread ratio of greater than 2.30 despite including at least 40% siloxane monomers in the polymerizable composition, including greater than 15% (wt / wt) of the polymerizable composition of di-functional siloxane having a molecular weight of at least 5000 daltons.

[058] A comparison of the drop spread ratios of the comparative example lenses produced from formulations 5, 6 and 7 in which the relative proportions of FMM, a monofunctional siloxane monomer comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, and KF-1622, a monofunctional siloxane monomer comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via an ether linkage, are altered indicates that increasing the level of monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, such as FMM, increases the ability of a lens to facilitate the spreading of water across the surface of the lens. It should be noted that while a lens prepared from formulation 7 has an advantageously high drop spread ratio of 2.45, that formulation lacks substantial amounts (>15% (wt / wt)) of high molecular weight (>5000 Da) difunctional siloxane monomer(s).

[059] The disclosure herein refers to certain illustrated examples, it is to be understood that these examples are presented by way of example and not by way of limitation. The intent of the foregoing detailed description, although discussing exemplary examples, is to be construed to cover all modifications, alternatives, and equivalents of the examples as may fall within the spirit and scope of the invention as defined by the additional disclosure.

[060] References herein to “an example” or “a specific example” or “an aspect” or “an embodiment” or similar phrase, are intended to introduce a feature or features of the contact lens with surface pillars or components thereof, the sealed contact lens package or components thereof, or method of manufacturing the contact lens with surface pillars (depending on context) that can be combined with any combination of previously-described or subsequently-described examples, aspects, embodiments (i.e. features), unless a particular combination of features is mutually exclusive, or if context indicates otherwise. Further, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents (e.g., at least one or more) unless the context clearly dictates otherwise. Thus, for example, reference to a “contact lens” includes a single lens as well as two or more of the same or different lenses.

[061] The entire contents of all cited references in this disclosure, to the extent that they are not inconsistent with the present disclosure, are incorporated herein by reference.

[062] The present invention can include any combination of the various features or embodiments described above and / or in the claims below as set forth in sentences and / or paragraphs. Any combination of disclosed features herein is considered part of the present invention and no limitation is intended with respect to combinable features.

[063] Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.

Claims

1. A silicone hydrogel contact lens having an anterior surface and a posterior surface, wherein at least the anterior surface or at least the posterior surface or both have a smooth surface, wherein the contact lens comprises a polymeric lens body that is the reaction product of a polymerizable composition, said polymerizable composition comprising:(a) at least 40% (wt / wt) of a polymerizable siloxane component, including (i) at least 10% (wt / wt) monofunctional siloxane monomer(s) comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage, and including (ii) at least 15% (wt / wt) difunctional siloxane monomer(s) having a molecular weight of at least 5000 daltons; and(b) at least 30% (wt / wt) hydrophilic N-vinyl amide monomer;wherein the silicone hydrogel contact lens that has been dried at 70 °C in an oven for 16 hours has an enthalpy of melting in the range of 0 to 120 °C of at least 90 J / g as determined by Differential Scanning Calorimetry (DSC) at 20 °C / min.

2. The contact lens of claim 1, wherein the percentage hydration of the lens at 40% RH and 25 °C is at least 8.5%, preferably at least 9.1%, of the equilibrium water content (EWC) of the fully hydrated contact lenses.

3. The contact lens of claim 1 or claim 2, having an equilibrium water content (EWC) of from 40 to 60% (wt / wt), especially from 45% to 55% (wt / wt).

4. The contact lens of any one of the preceding claims, wherein the mass of the silicone hydrogel contact lens that has been air dried at 20 °C in a desiccator to a steady mass, decreases by less than 2.3% when further dried in an oven at 105 °C to a steady mass.

5. The contact lens of any one of the preceding claims, wherein the polymerizable composition including at least 11.5% (wt / wt) based on the total weight of the polymerizablecomponents of the polymerizable composition of monofunctional siloxane monomers comprisinga (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage.

6. The contact lens of any one of the preceding claims, wherein the monofunctional siloxane monomers comprising a (meth)acrylate polymerizable group and a polysiloxane moiety linked to each other via a urethane linkage include or consist of a compound of Formula (I):wherein n is 10 to 25.

7. The contact lens of any one of the preceding claims, wherein the at least 30% (wt / wt) hydrophilic N-vinyl amide monomer present in polymerizable composition comprises N-vinyl N-methyl acetamide (VMA).

8. The contact lens of claim 7, wherein polymerizable composition comprises at least 10% (wt / wt) N-vinyl N-methyl acetamide (VMA).

9. The contact lens of claim 7 or claim 8, wherein the at least 30% (wt / wt) hydrophilic N-vinyl amide monomer presenting in polymerizable composition further comprises N-vinyl pyrrolidone (NVP).

10. The contact lens of any one of the preceding claims, wherein the polymerisable composition includes at least 15% (wt / wt) of a non-fluorinated difunctional monomer having a molecular weight of at least 5000 daltons.

11. The contact lens of claim 10, wherein the non-fluorinated difunctional monomer has a structure represented by Formula (II),Formula (II)wherein Ri is selected from either hydrogen or a methyl group; R2 is selected from either hydrogen or a Ci-4 hydrocarbon group; m represents an integer of from 0 to 10; n represents an integer of from 4 to 100; a and b represent integers of 1 or more; a+b is from 20-500; b / (a+b) is from 0.01-0.22, and the configuration of siloxane units includes a random configuration.

12. The contact lens of any one of the preceding claims, which lacks a surface coating or treatment.T +44(0)30 0300 2000A

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