Contact Lens Formulation and Contact Lens

Abstract

Silicone hydrogel contact lens formulations have a silicone component and a silicone-free component. The silicone component includes compounds represented by Formula 1 and Formula 2 (and optionally Fo

Description

[0001] The present invention relates to a silicone hydrogel contact lens formulation that contains at least two benzophenone ultraviolet (UV) light absorbing compounds that result in silicone hydrogel contact lenses that have desired surface wettability and dimensional stability. Background

[0002] Silicone hydrogel contact lenses have proven to be acceptable alternatives to hydrogel contact lenses. Contact lens manufacturers are often presented with introducing new contact lenses to satisfy market demand. Thus, there is an ongoing need to develop new silicone hydrogel contact lenses to address this demand.

[0003] In the development of silicone hydrogel contact lenses, it is difficult to predict whether a new silicone hydrogel contact lens formulation will result in clinically acceptable silicone hydrogel contact lenses. Achieving a successful fit, an acceptable level of comfort, an acceptable handling experience, and an acceptable improvement in vision is impacted by various changes in lens chemistry, lens design, and manufacturing processes. In addition, as manufacturers produce an inventory of contact lenses, the shelf life becomes a critical factor, and it is important that contact lenses remain within target specifications over the shelf-life of the lenses (a typical shelf life for a silicone hydrogel contact lens may be at least 4 years, for example, from 4-8 years); otherwise, contact lenses may experience changes in properties that render them clinically unacceptable, such as by negatively impacting the fit or the comfort of the lenses. Thus, it remains a challenge when developing contact lens formulations to arrive at a contact lens with desirable properties such as lens design, shape, wettability, clarity, and shelf life, and there continues to be a need for silicone hydrogel contact lenses that remain clinically acceptable over their shelf life. Summary

[0004] The present invention addresses this ongoing need. With the understanding that it may be desirable to provide contact lenses with ultraviolet (UV) light absorbing capabilities, the present invention is based on the discovery that it is possible to produce silicone hydrogel contact lenses with a desired lens surface wettability while including more than one benzophenone UV light absorbing compounds. Generally, benzophenone UV light absorbing compounds can negatively impact the wettability of silicone hydrogel contact lenses and render them unsuitable for clinical use, such as by providing a lens surface that is not compatible with the tear film on the eye.

[0005] Silicone hydrogel contact lenses that are the reaction product of a silicone hydrogel formulation that contains a greater amount of N-vinyl pyrrolidone (NVP) than the total amount of silicone compounds have a desirable lens surface wettability. However, it has been observed that these contact lenses can exhibit changes in dimensional stability of the contact lenses over their shelf life. For example, such contact lenses can exhibit changes in lens diameter, lens base curve, or both over the shelf life of the lens. These changes in diameter or base curve, among other things, can result in silicone hydrogel contact lenses that are stored in inventory having to be rejected and discarded as they are no longer suitable for clinical wear according to the target specifications of the contact lenses. This presents a problem for contact lens manufacturers that produce large volumes of contact lenses that have to be stored prior to distribution to eye care practitioners or contact lens wearers.

[0006] The inventors have discovered that in a silicone hydrogel contact lens formulation that contains an amount of NVP that is greater than the total amount of the siloxane monomers, and that contains two different benzophenone UV light absorbing compounds, clinically acceptable lens surface wettability and acceptable dimensional stability of the resulting silicone hydrogel contact lenses can be achieved, whilst achieving the intended UV light absorbing effect. The disclosure herein describes this invention in more detail.

[0007] An embodiment of the invention is described in claim 1.

[0008] The applicant has identified that a suitable silicone hydrogel contact lens formulation can be formed using a reaction mixture comprising a silicone component and a silicone-free component. The silicone component comprises: Formula 1: Formula 2: 14 02 25 where n is an integer from 3-15 and more preferably 8-11; and optionally Formula 3: wherein m represents an integer of from 8 to 14.

[0009] In a preferred embodiment, the silicone component consists essentially of or more preferably consists of silicone compounds of Formula 1, Formula 2 and optionally Formula 3.

[0010] The silicone-free component of the present contact lens formulations comprises: a compound of Formula 4 a compound of Formula 5 a compound of Formula 6 CH3 a compound of Formula 7 CH3 14 02 25 at least two different benzophenone ultraviolet light absorbing compounds, wherein one compound is a compound of Formula 8 , and the second compound is a compound of Formula 9;

[0011] The amount of the compound of Formula 4 in the formulation is greater than the combined amounts of the compound of Formula 1 and the compound of Formula 2, and optionally Formula 3. The combined amount of the compound of Formula 5 and the compound of Formula 6 is from 5% to 15% (wt / wt) of the total composition. The compound of Formula 8 is present in an amount from 0.05% to 0.15% (wt / wt) of the total formulation. In another embodiment of the invention, a silicone hydrogel contact lens comprising the polymerized reaction product of the formulation of any embodiment is disclosed. 14 02 25 Detailed description

[0012] Silicone hydrogel contact lenses are described herein that have good UV light absorbing properties, clinically acceptable lens surface wettability and acceptable dimensional stability.

[0013] The silicone hydrogel contact lenses comprise a polymeric lens body that is the reaction product of a polymerizable composition or silicone hydrogel contact lens formulation comprising a silicone component and a silicone-free component.

[0014] Throughout this disclosure, references to ‘a total amount’ of a particular component (i.e., a combination of two or more ingredients of the same type) in a polymerizable composition refer to the sum of the amounts of all ingredients of the same type.

[0015] The following definitions for the quoted terms provided below are applicable herein unless context dictates otherwise:

[0016] A “monomer” refers to any molecule in the polymerizable composition or silicone hydrogel contact lens formulation that is capable of reacting with other molecules that are the same or different, to form a polymer or copolymer. Thus, the term encompasses polymerizable pre-polymers and macromers, there being no size-constraint of the monomer or limit on the molecular weight (however determined) unless indicated otherwise.

[0017] A “siloxane monomer” contains at least one Si—O group, and is typically either “mono-functional” or “multi-functional”, meaning that it has either one polymerizable group or two or more polymerizable groups, respectively. A “non-siloxane monomer” is a monomer that does not contain any Si—O groups.

[0018] A “silicone component” is a component or portion of the silicone hydrogel contact lens formulation which is composed of all of the siloxane monomers.

[0019] A “silicone-free component” is a component or portion of the silicone hydrogel contact lens formulation which is composed of all of the non-siloxane monomers

[0020] “Consists of” means that a formulation or component contains only the listed components, compounds, or monomers.

[0021] “Consists essentially of” means that a formulation or component contains the listed compounds or monomers but can also contain other monomers or compounds which fall within the definition of that formulation or component such as dimeric or polymeric impurities. These additional monomers or compounds can be present in an amount which does not have an impact on the final lens formulation. Additional monomers or compounds can be present in an amount of less than 5%, 2%, 1%, 0.5% or 0.1% based on the total amount of the specific formulation or component.

[0022] A “polymerizable composition” is a composition comprising polymerizable ingredients, where the composition has not yet been subjected to conditions that result in polymerization of the polymerizable ingredients. Thus, the present silicone hydrogel contact lens formulations are considered polymerizable compositions.

[0023] In the case of 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.

[0024] In the present disclosure, where a value is given for repeat groups in a structural formula, such as Formula 2 or Formula 3, it is an average value. The skilled person would understand that a complex compound of this kind contains a mixture of molecules of different molecular weight. 14 02 25

[0025] As used herein, the term “total formulation” or “total contact lens formulation” refers to all formulation ingredients, including diluents and / or solvents that are not incorporated into the final polymeric contact lens material. It can be understood that when a weight percent of an ingredient of the total formulation is provided, it refers to the weight percent of that ingredient based on the total weight of the formulation.

[0026] Throughout this disclosure, a reference to “an example” or “a specific example” or similar phrase, is intended to introduce a feature or features of the contact lens, polymerizable composition, or method of manufacture (depending on context) that can be combined with any combination of previously-described or subsequently-described examples (i.e. features), unless a particular combination of features is mutually exclusive, or if context indicates otherwise.

[0027] Throughout this disclosure, when a series of lower limit ranges and a series of upper limit ranges are provided, all combinations of the provided ranges are contemplated as if each combination were specifically listed. Also, throughout this disclosure, when a series of values is presented with a qualifier preceding the first value, the qualifier is intended to implicitly precede each value in the series unless context dictates otherwise. For example, for the values listed above, it is intended that the qualifier “from about” implicitly precedes the value of 10%, and that the qualifier “to about” implicitly precedes the value of 50%.

[0028] A silicone hydrogel contact lens formulation, comprising a silicone component; and a silicone-free component is disclosed herein.

[0029] The silicone component comprises, or consists essentially of, or in some embodiments consists of a compound of Formula 1, a compound of Formula 2 and optionally a compound of Formula 3.

[0030] The siloxane monomer of Formula 1 is:

[0031] The siloxane monomer of Formula 2 is: where n is an integer from about 3 to 15, preferably 8 to 11.

[0032] In a preferred embodiment, the combined amount of the siloxane monomers of Formula 1 and Formula 2 is from 25.0 to 40.0% (wt / wt), preferably from 25.0 to 34.9% (wt / wt) of the contact lens formulation.

[0033] In an embodiment, the silicone component comprises an additional siloxane monomer, which is a di-functional siloxane monomer of Formula 3: where m is an integer from about 8 to 14.

[0034] The value n for Formula 2 and m for Formula 3 are average values.

[0035] In a preferred embodiment, the combined amount of the siloxane monomers of Formula 1, Formula 2 and Formula 3 is from 25.0 to 40.0% (wt / wt), preferably from 25.0 to 34.9% (wt / wt) of the contact lens formulation. Where the compound of Formula 3 is present, it is preferably used in an amount of less than 1 % (wt / wt) of the total contact lens formulation.

[0036] In one preferred embodiment of the present formulations, the silicone component consists essentially of, preferably consists of Formula 1, Formula 2 and Formula 3.

[0037] The silicone-free component comprises non-ionic monomers and two benzophenone ultraviolet light absorbing compounds.

[0038] The non-ionic monomers comprise those of Formulae 4 to 7. The compound of Formula 4 is: 14 02 25

[0039] The amount of the compound of Formula 4 in the formulation is greater than the combined amounts of the compound of Formula 1 and the compound of Formula 2, and optionally Formula 3. The compound of Formula 4 is preferably present in an amount of from 35.0 to 50.0% (wt / wt) of the total contact lens formulation.

[0040] Although the upper values of the preferred ranges of siloxane monomers of Formula 1, Formula 2 and optionally Formula 3 are higher than the lowest value for the preferred amount of the compound of Formula 4, the requirement that the amount of Formula 4 is greater than the total amount of Formulae 1, 2 (and 3) takes precedence. That is, if the amount of the three siloxane monomers is in the range 35.0 to 40.0%, it is still a requirement that the amount of the compound of Formula 4 is greater than the amount of the three siloxane monomers.

[0041] In a preferred embodiment, the compound of Formula 4 is present in an amount from 35.0% to 50.0% (wt / wt) and the combined amount of the compound of Formula 1, the compound of Formula 2 and the compound of Formula 3 (when present) is from 25.0% to 34.9% (wt / wt) of the total contact lens formulation.

[0042] The compound of Formula 5 is: The compound of Formula 6 is: ch3

[0043] The combined amount of the compound of Formula 5 and the compound of Formula 6 is from 5% to 15% (wt / wt) of the total contact lens formulation.

[0044] The cross-linking compound of Formula 7 is:

[0045] The compound of Formula 7 is preferably present in an amount of from 0.5% to 1.0% (wt / wt) of the total contact lens formulation.

[0046] The benzophenone ultraviolet light absorbing compound of Formula 8 is: 14 02 25

[0047] In a preferred embodiment, the benzophenone ultraviolet light absorbing compound is that of Formula 8a, which is the 4,4’ isomer:

[0048] The compound of Formula 8, preferably 8a, is present in an amount of from 0.05 to 0.15% (wt / wt) of the total contact lens formulation, and preferably in an amount of from 0.05 to 0.1% (wt / wt).

[0049] The benzophenone ultraviolet light absorbing compound of Formula 9 is:

[0050] The compound of Formula 9 is preferably present in an amount of from 0.5% to 2.0% (wt / wt) of the total contact lens formulation. In a preferred embodiment, the compound of Formula 9 is present in an amount at least four times greater than the amount of the compound of Formula 8.

[0051] The amount of the compounds of Formula 8 and Formula 9 are expressed based on the total contact lens formulation. In a further embodiment of the present invention, the amount of the compound of Formula 8 is present in an amount of from 0.05 to 0.22% (wt / wt) of the total contact lens formulation excluding solvent. The amount of the compound of Formula 9 is preferably present in an amount at least four times greater than the amount of the compound of Formula 8.

[0052] In a preferred embodiment, the silicone hydrogel formulation further comprises a compound of Formula 10: H 14 02 25 CH3 CH3

[0053] Typically, the formulation further comprises one or more additional components which are common in contact lens formulations. Suitable additional components include a thermal polymerization initiator, an alcohol diluent and a tinting agent. It is preferred that the contact lens formulation comprises a thermal polymerization initiator. It is further preferred that the contact lens formulation comprises an alcohol diluent. The alcohol diluent is preferably present in an amount less than 30% (wt / wt), preferably from 5 to 20% (wt / wt) of the total contact lens formulation.

[0054] The composition additionally can comprise one or more tinting agents. Preferred tinting agents are reactive tinting agents and particularly tinting agents identified as “Reactive Blue” dyes. Other tinting agents may be used including non-reactive dyes and pigment dispersions including (but not limited to) phthalocyanine pigment dispersions.

[0055] Contact lenses can be made from the polymerizable compositions described herein using curing and other processing methods known in the field, such as cast molding, spin casting, injection molding, forming a polymerized rod that is subsequently lathed, etc. In a specific example, the polymerizable composition is cast molded between molds formed of a thermoplastic polymer. The thermoplastic polymer is typically a non-polar material, such as polypropylene, but polar mold materials, such as ethylene vinyl alcohol, are also used in the field. Briefly, a first mold member defining the front surface of the contact lens, referred to as a “female mold member”, is filled with an amount of the polymerizable composition sufficient to form a single polymeric lens body. A second mold member defining the back (i.e. eyecontacting) surface of the contact lens, referred to as the “male mold member”, is coupled to the female mold member to form a mold assembly having a lens-shaped cavity with the amount of polymerizable composition therebetween

[0056] The polymerizable composition within the contact lens mold assembly is polymerized using any suitable curing method. Typically, the polymerizable composition is exposed to polymerizing amounts of heat or ultraviolet light (UV). It is preferred that the polymerizable composition is heat-cured. In the case of heat-curing, also referred to as thermal curing, the polymerizable composition typically comprises a thermal initiator. Exemplary thermal initiators include 2,2'-azobis(2,4-dimethylpentanenitrile) (VAZO-52), 2,2'-Azobis(2-methylpropanenitrile) (VAZO-64), and 1,1'-azo bis(cyanocyclohexane) (VAZO-88). Peroxide initiators may also be used. The contact lens mold assemblies containing the contact lens formulations are cured by exposing the contact lens mold assemblies to heat or UV light for a time ranging from about 1 hour to about 36 hours. Additional thermal polymerization methods for contact lenses are described in US Publ. No. 2007 / 0296914 and U.S. Pat. No. 7,854,866, incorporated herein by reference.

[0057] At the completion of curing, the polymerized material between the mold members of the mold assembly has the shape of a contact lens, and is referred to herein as a “polymeric lens body”. The male and female mold members are demolded, i.e. separated from each other, and the polymeric lens body is removed from one of the separated mold 14 02 25 members, i.e. delensed, from the mold member to which it is adhered. These processes are referred to as demolding and delensing, respectively, and a variety of such methods are known to those of ordinary skill in the field. In some methods, the demolding and delensing processes can comprise a single process step, such as when the mold members are separated using a liquid which also removes the polymeric lens body from one of the mold members. In other methods, such as when a dry-demolding process is used, the polymeric lens body typically remains on one of the mold members and is delensed in a subsequent process step. Delensing can also be a wet or dry process. In one example, delensing is carried out by a “float off” method in which the mold member to which a polymeric lens body is adhered is immersed in water or other suitable liquid. Typically, the polymeric lens bodies float off of the mold members in about ten minutes or less. Dry delensing can be carried out manually, for example using tweezers to remove the polymeric lens bodies from the mold member, or they can be removed using an automated mechanical process, such as described in U.S. Pat. No. 7,811,483 (incorporated herein by reference). Additional demolding and delensing methods for silicone hydrogel contact lenses are described in US Publ No. 2007 / 0035049 (incorporated herein by reference).

[0058] After delensing, the polymeric lens body is washed to remove unreacted or partially reacted ingredients from the polymeric lens body and to hydrate the polymeric lens body. For example, the contact lenses can be exposed to organic solvents, such as ethanol, isopropyl alcohol, industrial methylated spirts, and the like, or water, or mixtures thereof. Exemplary washing methods are described in US Pat. Publ. No. 2007 / 0296914 (incorporated herein by reference).

[0059] After washing, the hydrated polymeric lens body is typically placed into a blister package, glass vial, or other appropriate container, all referred to herein as “packages.” A packaging solution is also added to the package, which is typically a buffered saline solution such as phosphate- or borate-buffered saline. The packaging solution may optionally contain additional ingredients such as a comfort agent, a hydrophilic polymer, a surfactant or other additive that prevents the lens from sticking to the package. The package is sealed, and the sealed polymeric lens body is sterilized by autoclaving. The final product is a sterile, packaged ophthalmically-acceptable contact lens.

[0060] In any of the above-described examples, the contact lens may be characterized by one or more of the following properties: wet lens diameter, wet lens base curve, contact angle, oxygen permeability, Young’s modulus, and equilibrium water content, as detailed below.

[0061] Diameter measurement is performed as per BS EN ISO 18369-3:2017, section 4.4 using a JCF Post Optimec projection comparator. The wet lens is placed into a temperature-controlled cell filled with saline and the circumference of the lens is projected onto the screen. The image is focused and calibrated, and markings give a direct read-out of the lens diameter.

[0062] The base curve is calculated from the sagittal height measurement and diameter measurement of a lens. A JOB Sag Optimec optical comparator is used to measure the sagittal height as per BS EN ISO 18369-3:2017, section 4.2.3. The wet lens is placed in a temperature-controlled cell filled with saline and the profile of the lens is projected onto a screen. A calibrated scale is used to measure the sagittal height which is defined as the distance between the vertex of the contact lens inner surface (rear surface) and a chord drawn across the surface at a known diameter.

[0063] The base curve is calculated from sagittal height measurement and diameter using the calculation: S D2 Base curve = - -I-- 2 8S 14 02 25 where S is the measured sagittal depth and D is the lens diameter.

[0064] Other methods for measuring diameter and base curve are known in the art.

[0065] To determine the shelf life of the contact lenses, contact lenses can be stored at a temperature greater than room temperature (25°C). Storing the lenses at an elevated temperature can be correlated to an extended shelf life of the lens as per ASTM F1980 Accelerated Aging of Sterile Medical Device Packages: AAR (Accelerated Aging Rate) = Q10 «Te-Ta) / io). where: Ta = Ambient Temperature (25°C) Te = Elevated Temperature Q10 = Reaction Rate = 2

[0066] In the examples herein, the lens is stored at 60°C which gives an AAR of 11.3. The diameter and base curve are measured again at two-weekly intervals. The diameter and base curve change is measured for each lens. Sets of lenses are measured and the mean values are also calculated to give an indication of the spread. A diameter and base curve change of less than 0.20mm over 10 weeks at 60°C is considered to be indicative of stability (corresponding to 26 Months at 25°C).

[0067] The contact lenses of the present invention typically and preferably have a contact angle of less than about 70°, where the contact angle is the static advancing contact angle as determined using a sessile drop method.

[0068] To determine the sessile contact angle of a contact lens surface, contact lenses to be tested are soaked in surfactant-free buffered saline prior to measurement. The surface of the contact lens is blotted to remove surface moisture. The lens is placed on a substrate with the blotted surface facing upwards, and a fixed volume drop of purified water is applied to the lens surface with a syringe. Measurements are taken promptly to ensure that the lens section does not become dry. A camera records the image of the droplet immediately after dispensing. The internal angle between the droplet and the lens is measured, generally by using curve fitting software.

[0069] For oxygen permeability, the Dk values can be determined using a Rehder 201T Oxygen Permometer / polarographic cell following the polarographic method described in ISO18369-4:2017 section 4.4.3. In preferred embodiments, the contact lens has an oxygen permeability from 50 to 90 barrers.

[0070] The contact lens preferably has 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 preferred embodiments, the contact lens has a Young’s modulus from 0.3 MPa to 1.1 MPa, and preferably from 0.4 to 0.8 MPa.

[0071] The modulus can be determined following the method described in ASTM D1708-13 using an Instron Model 3342, 3343, or 5944 mechanical testing system (Instron Corporation, Norwood, Mass., USA) and Bluehill Materials Testing Software, using a custom-built rectangular contact lens cutting die with 4 mm spacing to prepare the rectangular sample strip. Lenses are soaked in surfactant-free buffered saline prior to testing. While holding the lens concave side up, a central strip of the lens was cut using the cutting die. The thickness of the strip was determined using a calibrated gauge (Rehder electronic thickness gauge, Rehder Development Company, Castro Valley, Calif., USA). Using tweezers, the strip was loaded into the grips of the calibrated Instron apparatus, with the strip fitting over at least 75% of the grip surface of each grip. A test method designed to determine the maximum load (N), the tensile strength (MPa), the strain at maximum load (% 14 02 25 elongation) and the mean and standard deviation of the tensile modulus (MPa) can be run, and the results were recorded.

[0072] The contact lens may have an equilibrium water content (EWC) of at least about 50 wt. %, preferably at least about 56.5 wt. % and up to about 65 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. % EWC of the lens is = (weight difference / hydrated weighty 100.

[0073] Water content can also be determined from the refractive index of the contact lens. The refractive index is determined by measuring the critical angle of incidence for total internal reflection of light of wavelength using a calibrated refractometer at room temperature. Light passes from the prism surface of the refractometer into the contact lens material. The refractive index can be converted into water content by applying a previously determined calibration.

[0074] In a specific example, the contact angle is ^70° and the equilibrium water content is preferably at least 50 wt. %, most preferably at least 56.5 wt.% and up to 65 wt%.

[0075] As demonstrated by the specific examples, it has been found that combinations of the preferred siloxane monomers, non-siloxane monomers including the specific benzophenone ultraviolet light adsorbing compounds provide contact lenses of the invention with advantageous properties such as good surface lens wettability and dimensional stability. EXAMPLES

[0076] 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

[0077] The silicone hydrogel lenses of Examples 1 to 10 were produced according to the following method.

[0078] The compounds or monomers were all mixed and stirred to form a polymerizable composition or a silicone hydrogel contact lens formulation.

[0079] The formulation was put in a mold for a contact lens.

[0080] The lenses were cured using heat for about 34 hours. The skilled person is aware of suitable methods for curing contact lens formulations.

[0081] The cured polymers were removed from the contact lens molds and washed to remove unreacted materials by contacting them with water, 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. The contact lenses of the Examples also had good water wettability. 14 02 25

[0082] Table 1 Compound CAS# Formula 1 CAS# 17096-07-0 Formula 2 CAS# 308072-61-9 Formula 3 CAS# 58130-03-3 Formula 4 CAS# 88-12-0 Formula 5 CAS# 2680-03-7 Formula 6 CAS# 868-77-9 Formula 7 CAS# 109-17-1 Formula 8a CAS# 136074-26-5 Formula 9 CAS# 16432-81-8 Formula 10 CAS# 7534-94-3 AIBN initiator CAS# 78-67-1 n-propanol solvent CAS# 71-23-8

[0083] Contact lens formulations were produced using all of the components of Table 1. The same base formulation was used for all examples. In each case, the formulation contained from 25 to 34.9% of the compounds of Formulae 1 to 3, from 35 to 50% of the compound of Formula 4, from 5 to 15% of the compounds of Formulae 5 and 6, from 0.5 to 1.0% of Formula 7 and from 0.5 to 2.0% of Formula 9. The n-propanol solvent is present in the formulation in an amount of from 5 to 20%.

[0084] In the Examples, the amount of the compound of Formula 8a was varied in accordance with Table 2. Comparative Examples 1 and 6 contain 0% of the compound of Formula 8a. Comparative Example 7 contains a level of 0.03% of the compound of Formula 8a, which is below the claimed range. Comparative Examples 4 and 5 contain 0.21% and 0.28% of the compound of Formula 8a respectively, which are greater than the claimed range. Examples 1 to 5 correspond to one experimental run and Examples 6 to 10 correspond to a second experimental run.

[0085] Table 2 Example Formula 8a % (wt / wt) 1 (Comparative) 0.0 2 0.07 3 0.14 4 (Comparative) 0.21 5 (Comparative) 0.28 6 (Comparative) 0.00 7 (Comparative) 0.03 8 0.07 9 0.10 10 0.14 14 02 25

[0086] The lenses of the Examples all have a Dk of approximately 60 barrers and a Young’s modulus of 0.5 to 0.6MPa.

[0087] Other properties of the resultant contact lenses are demonstrated in Figures 1 to 7.

[0088] Figure 1 shows the variance in sessile drop contact angle for the amount of the compound of Formula 8a for Examples 1 to 5. Only comparative Example 1, and Examples 2 and 3 exhibited a sessile drop contact angle less than 70 degrees.

[0089] Figure 2 shows the variance in water content for the amount of the compound of Formula 8a for Examples 1 to 5. Although comparative Examples 4 and 5 had a reduced equilibrium water content (EWC) (less than 56.5%), the water content for all lenses was greater than 50%.

[0090] Figures 3 and 4 show the stability of the lenses of Examples 1 to 4 based on diameter and base curve, respectively. Examples 2 and 3, and Comparative Example 4 showed acceptable shelf-life stability as evident by the diameter or base curve changing less than about 0.2 mm over the testing time period. In contrast, Comparative Example 1 demonstrated a reduced shelf-life stability since the diameter or base curve changed by more than about 0.2 mm at least as early as the 4 week testing time point. However, as noted above, Comparative Example 4 had an unacceptable lens surface wettability.

[0091] Figures 5 and 6 show the stability of the lenses of Examples 6 to 10 based on diameter and base curve, respectively. Similar to the above, Examples 8, 9, and 10 showed acceptable shelf-life stability as evident by the diameter or base curve changing less than about 0.2 mm over the testing time period. Comparative Example 7 showed improved shelf life stability compared to Comparative Example 6, but the diameter changed by more than about 0.2 mm at least as early as the 10 week time point, rendering it outside the scope of the present claims.

[0092] Figure 7 shows the amount of transmissibility (%T) in the UV-visible absorption spectra for the lenses of Comparative Example 1 and Example 2, as well as other comparative examples which do not contain any of the compound of Formula 9.

[0093] Figure 7 demonstrates that the inclusion of inclusion of 0.07% of the compound of Formula 8a provides a substantial reduction in transmissibility in the region of 280 to 315 nm. The inclusion of a larger amount of Formula 9 provides a greater reduction in transmissibility as demonstrated in Comparative Example 1. Example 2 shows that a combination of both compounds provides an additive effect on reduction of transmissibility across the 280 to 380 nm range.

[0094] It would be expected that increasing the amount of Formula 8a in the lens would result in a further reduction in transmissibility. Similarly, using larger amounts of Formula 9 in the absence of Formula 8a might further reduce the transmissibility.

[0095] However, it can be seen from Figure 1 that that using levels of Formula 8a greater than the claimed level (Comparative Examples 4 and 5) results in an increase in the sessile drop contact angle indicating the lenses had undesirable surface wettabilities. This increase in contact angle results in a lens which is unsatisfactory.

[0096] Similarly, Figure 2 shows a significant drop in the water content of the lens when levels of Formula 8a are greater than the claimed level (Comparative Examples 4 and 5).

[0097] Figures 3 and 4 show that when the compound of Formula 8a is absent (Comparative Example 1), both diameter and base curve values are not stable. There is a clear change in value of both over the 10 week period of accelerated aging. Conversely, it can be seen that the level of stability is essentially the same for Examples 2 and 3 and Comparative Example 4.

[0098] Figures 5 and 6 support the data in Figures 3 and 4. Figures 5 and 6 show that the lenses of Comparative Example 6 (the same formulation as Comparative Example 1) are not sufficiently stable, showing significant decrease in measurement parameters (diameter and base curve) after two weeks of aging. The lenses of Comparative Example 7, which contains the compound of Formula 8a in a level below the claimed amount, show problematic decrease in diameter and base curve after 10 weeks of aging. Examples 8 to 10 show good diameter and base curve stability over 12 weeks of accelerated aging.

[0099] It can be appreciated that the results show that in order to provide contact lenses which show a suitable level of UV transmissibility, it is necessary to include high levels of light absorbing compounds. The skilled person can select suitable compounds. However, when using only the compound of Formula 9, the resulting lens shows poor stability. The compound of Formula 8 can be used additionally to absorb UV light and at the same time improve the stability of the lens. However, using too much of the compound of Formula 8 can adversely affect other properties, such as the sessile drop contact angle and water content. The results presented in Figures 1 to 7 therefore demonstrate that there is a window in which the compound of Formula 8 can be used to provide the benefits of UV blocking and stability without having a negative effect on the sessile contact angle and water content. 14 02 25

Claims

1. A silicone hydrogel contact lens formulation, comprising:(i) a silicone component; and(ii) a silicone-free component, whereinthe silicone component comprises:(a) a compound of Formula 1(b) a compound of Formula 216 05 24wherein n is from 3 to 15; andthe silicone-free component comprises:(a) a compound of Formula 4a compound of Formula 5a compound of Formula 6CH3a compound of Formula 7CH3at least two benzophenone ultraviolet light absorbing compounds, wherein one compound is a compound of Formula 8the second compound is a compound of Formula 916 05 24wherein the amount of the compound of Formula 4 in the formulation is greater than the combined amounts of the compound of Formula 1 and the compound of Formula 2, the combined amount of the compound of Formula 5 and the compound of Formula 6 is from 5% to 15% (wt / wt), and the compound of Formula 8 is present in an amount from 0.05% to 0.15% (wt / wt) of the total formulation.

2. The silicone hydrogel contact lens formulation of claim 1, wherein the silicone hydrogel formulation further comprises a compound of Formula 103. The silicone hydrogel contact lens formulation of any preceding claim, wherein the formulation comprises the compound of Formula 3wherein m is from 8 to 14, and wherein the amount of the compound of Formula 4 inthe formulation is greater than the combined amounts of the compound of Formula 1, the compound of Formula 2, and the compound of Formula 3.

4. The silicone hydrogel contact lens formulation of any preceding claim, wherein the compound of Formula 9 is present in an amount that is at least four times greater than the amount of the compound of Formula 8.

5. The silicone hydrogel contact lens formulation of claim 4, wherein the compound of Formula 9 is present in the formulation in an amount from 0.5% to 2.0% (wt / wt) of the total lens formulation.16 05 246. The silicone hydrogel contact lens formulation of any preceding claim, wherein the compound of Formula 4 is present in an amount from 35.0% to 50.0% (wt / wt) of the total lens formulation and the combined amount of the compound of Formula 1 and the compound of Formula 2 is from 25.0% to 40.0% (wt / wt) of the total lens formulation.

7. The silicone hydrogel contact lens formulation of any preceding claim, further comprising a thermal polymerization initiator.

8. The silicone hydrogel contact lens formulation of any preceding claim, further comprising an alcohol diluent.

9. The silicone hydrogel contact lens formulation of any preceding claim, wherein the compound of Formula 7 is present in the formulation in an amount from 0.5% to 1.0% (wt / wt) of the total lens formulation.

10. A silicone hydrogel contact lens comprising the polymerized reaction product of the formulation of any preceding claim.

11. The silicone hydrogel contact lens of claim 10, which has a chord diameter from 13.0 to 15.0 mm and a base curve from 7.5 to 9.5 mm.

12. The silicone hydrogel contact lens of claim 10 or claim 11, which has a sessile drop contact angle less than 70 degrees.

13. The silicone hydrogel contact lens of any one of claims 10-12, which has an equilibrium water content from 50 weight % to 65 weight %.

14. The silicone hydrogel contact lens of any one of claims 10-13, which has an oxygen permeability from 50 to 90 barrers.

15. The silicone hydrogel contact lens of any one of claims 10-14, which has a Young's modulus from 0.3 MPa to 1.1 MPa.16 05 24

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