MXPA97004139A - Polymer containing suitable silicon for ophthalmology applications - Google Patents

Abstract

Copolymers formed from polyalkylene glycol dimethacrylates and vinyl reactive silicones are described which have up to 20 silicon atoms in the substantial absence of additional crosslinking agents. The copolymers can include a monomer with a hydrophilicity modifier. The preferred silicone is TRIS (ie, 3-methacryloxypropyltris (trimethylsiloxy) -silane), while the preferred polyalkylene glycol is polypropylene glycol dimethacrylate. The copolymers are especially suitable for use in the manufacture of soft contact lenses because of their good durability and high oxygen permeability.

Description

POLYMER CONTAINING SUITABLE SILICON FOR OPHTHALMOLOGICAL APPLICATIONS FIELD OF THE INVENTION This invention relates to polymers suitable for the formation of a contact lens. More specifically, this invention relates to organosilicon-polyalkylene glycol copolymers suitable for use in the manufacture of soft contact lenses.

BACKGROUND OF THE INVENTION Contact lenses can be classified in general into two categories. The first category, hard contact lenses, developed significantly in the 1940s with the appearance of poly (methyl methacrylate) lenses. Hard contact lenses have certain advantageous properties but are generally less comfortable for the consumer. The second category, soft contact lenses, were first developed as a result of the discovery of poly-HEMA or poly (2-hydroxyethyl-methacrylate). Although soft contact lenses REF: 24623 provide comfort to the patient, these lenses suffer from durability problems. In addition, soft lenses in general require a high water content in order to achieve sufficient oxygen permeability to maintain the health of the cornea during long periods of use. One objective of soft contact lenses is the high oxygen permeability. The high oxygen permeability is required because the cornea is filled with spent oxygen by absorbing oxygen from the tear film, whose oxygen originates from the surrounding air. A contact lens that covers the cornea reduces the availability of oxygen to the cornea, unless the lenses are sufficiently oxygen-permeable. Thus, substantial efforts have been devoted to the production of contact lenses, which are soft and have a high oxygen permeability. Improvements in oxygen permeability have been achieved with the use of polysiloxane materials, especially polydimethylsiloxanes. However, these materials are inherently non-wettable, or hydrophobic. The polysiloxanes have been copolymerized with hydrophilic materials to produce contact lenses, because the hydrophobic nature of the polysiloxanes adversely affects the patient's comfort. An example of a polysiloxane copolymer material suitable for the formation of hard contact lenses is described in EP-A2-108, 886 by the inventors Leboeuf and Singer. This reference describes a material for hard contact lenses which is a copolymer of (a) 15-40% of tris (trimethylsiloxy) methacryloxypropylsilane (ie, TRIS), (b) 10-80% of a crosslinking agent, ( c) up to 60% of an alkanol ester and / or a hydrophilic monomer. An example of a polysiloxane copolymer material suitable for the fabrication of soft contact lenses is described in EP-A2-493, 320 by the inventors Mueller and Plankl. This reference discloses a material for soft contact lenses which is the product of the copolymerization of (a) 15-69.9% of a polyether vinyltelequélico, (b) 30-84.9% of a fluorinated monomer, an ethylenically unsaturated monomer, an ethylenically monomer unsaturated which contains silicone, or a mixture thereof, (c) up to 40% of another ethylenically unsaturated monomer, and (d) 0.1 to 10% of a polyethylenically unsaturated comonomer (i.e., a crosslinking agent). The vinyltelequinic polyether may include a polyethylene oxide or a polypropylene oxide. One of the preferred monomers (b) is tris (trimethylsiloxysilyl) -propyl methacrylate (i.e., TRIS). One problem that is created with the use of siloxanes (e.g., TRIS) in the manufacture of soft contact lenses is that the polymeric material includes crosslinking agents to increase the durability of the polymer. The addition of any of the crosslinking agents decreases the oxygen permeability (Dk) of the lenses. Thus, this leads to a continuing need for a soft contact lens that has an increased oxygen permeability and provides good patient comfort.

DESCRIPTION OF THE INVENTION An object of this invention is to provide a polymeric material suitable for the formation of soft contact lenses having high oxygen permeability, good hydrophilicity, good durability, good visual clarity and patient comfort. Another object of the invention is to provide a process for producing soft contact lenses in the substantial absence of crosslinking agents, while maintaining high oxygen permeability and good durability. One embodiment of the invention is a copolymer having good durability, high oxygen permeability, ocular biocompatibility, good optical clarity, and good hydrophilicity. The copolymer is formed from a mixture of monomer which has (a) from 50 to 95 weight percent of a vinyl reactive silicone having up to 20 silicon atoms and (b) from 5 to 50 weight percent of a diviny polyalkylene glycol in the absence or substantial absence of additional crosslinking agents. The term "additional crosslinking agents" in this context is to be understood in a manner that refers to other crosslinking agents other than vinyl reactive silicone and divinyl polyalkylene glycols. The copolymer can include a hydrophilicity modifier, which is hydrophobic or hydrophilic, to properly attenuate the hydrophilicity to the desired level. Preferably, the vinyl reactive silicone is 3-methacryloxypropyltris (trimethylsiloxy) -silane, while the polyalkylene glycol divinyl is the polypropylene glycol dimethacrylate. Another embodiment of the invention is a soft, hydrophilic contact lens made from the aforementioned copolymer. The contact lens preferably contains 10 to 15 weight percent water. However, another embodiment of the invention is a process for making a soft contact lens in the substantial absence of a crosslinking agent. The process first involves the formation of a mixture of a vinyl reactive silicone which has up to 20 silicon atoms, with a diviny polyalkylene glycol in the substantial absence of cross-linking agents. The mixture is placed in a contact lens mold under conditions sufficient to polymerize the silicone and polyalkylene glycol monomers, thereby forming a soft contact lens. One embodiment of the invention is a copolymer which has an advantageous balance of mechanical durability, oxygen permeability, and visual clarity. This polymeric material is useful in the formation of mechanisms for visual correction, preferably in contact lenses, due to its advantageous properties. Another embodiment of the invention is a soft contact lens formed from a silicone / polyalkylene glycol copolymer. The polymeric materials or contact lenses of the present invention preferably have a Dk of at least 70, more preferably a Dk of at least 75, even preferably a Dk of at least 78, and more preferably a Dk of at least 80. A third embodiment of the invention is a process for forming contact lenses having high oxygen permeability. The monomers required in the preparation of the copolymers of the present invention include (a) one or more vinyl reactive silicones having up to 20 silicon atoms and (b) one or more difunctional polyalkylene glycol monomers. The monomeric weight percentage of the vinyl reactive silicone can vary from about 50 to 95 percent, more preferably from about 60 to 80 percent, while the weight percent of the polyalkylene glycol can vary from about 5 to 50 percent , more preferably from about 20 to 40 percent. In one embodiment, the copolymer includes one or more hydrophilicity modifiers, which are described in US-A-4, 921, 956 (Molock et al.), Which are incorporated by reference. The copolymer can include about 0.5 to 40, more preferably around 1 to 40, even more preferably about 1 to 30, weight percent of the hydrophilic modifier. In case any modifier is present, the high limitation of the polyalkylene glycol divinyl monomer is about 49.5 weight percent, more preferably about 49 weight percent. Advantageously, the copolymerization of the silicone-containing monomer and the polyalkylene glycol is carried out in the absence of crosslinking agents. Although the difunctional polyalkylene glycol can function as a crosslinking agent, the polyalkylene glycol is proposed primarily to copolymerize with the vinyl reactive silicone. By polymerizing in the substantial absence of additional crosslinking agents, the present invention produces contact lenses having increased oxygen permeability (Dk) without adversely affecting durability as compared to prior art processes, in which addition was required of crosslinking agents. Preferably, the present process is completely free of additional crosslinking agents.

MONOMER CONTAINING SILICONE (a): "Vinyl reactive silicones", as mentioned herein, refer to monomers, oligomers, or macromers having siloxane groups and vinyl groups (unsaturated carbon-carbon double bonds) capable of reacting with other groups reactive to form a chemical bond with one of the carbon atoms. Useful vinyl reactive silicones according to the present invention include those having less than about 20 silicon atoms, more preferably with less than about 10 silicon atoms, and even more preferably less than 7 silicon atoms. Examples of such vinyl reactive silicones include, without limitation, 3-methacryloxypropyltris (trimethylsiloxy) -silane; 3-methacryloxypropyl-bis (trimethylsiloxy) -methylsilane; and 3-methacryloxypropyl-pentamethyldisiloxane; and mixtures thereof. A particularly preferred vinyl reactive silicone is 3-methacryloxypropyltris (trimethylsiloxy) -silane (CAS No. 17096-07-0), also known as TRIS.

DIFFUNTIONAL POLYALYKYLGLENOLIC MONOMER (b): Polyalkylene glycol (or divinyl) difunctional monomers useful in accordance with the present invention include, without limitation, polyethylene glycol dimethacrylates, polypropylene glycols dimethacrylates, diethyrnically-terminated polyethylene glycols, diethyrically capped polypropylene glycols, tetramethylene glycol dimethacrylates. and combinations thereof. Preferably the range of the average molecular weight of the polyalkylene glycol ranges from about 425 to about 4000. Specifically, the polypropylene glycol, and even more preferably the POLYPROPYLENGLICOL 4000, available from DOW CHEMICAL (Midland, Mi), is. a particularly preferred polyalkylene glycol. It is also preferred that the dimethacrylate of a polyalkylene glycol also consists of one or more urethane linkages. A dimethacrylate of a polyalkylene glycol can be prepared by mixing a methacrylate with the polyalkylene glycol in the presence of a catalyst at room temperature. This dimethacrylate can be obtained, for example, by reacting a polyalkylene glycol with a vinyl monoisocyanate. For example, polypropylene glycol can be mixed with isocyanatoethyl methacrylate in the presence of about 0.01 to 0.05 weight percent dibutyltin dilaurate as the catalyst. The resulting polypropylene glycol contains methacrylate end groups which impart polymerization reactivity of free radical addition to the adduct.

HYDROFILICITY MODIFIERS: The hydrophilicity modifiers useful in accordance with the present invention include hydrophobic and hydrophilic, the latter being preferred. A preferred group of hydrophilicity modifiers includes those defined by the formula X-T-G wherein the hydrophilic group G typically has one or more etherified or free hydroxy groups, amino groups, amides, urethanes and / or other typical hydrophilic groups; X is a polymerizable or reactive portion selected from ethylenically unsaturated radicals, preferably vinyl, 1 or 2-lower alkylvinyl, more preferably 1-methylvinyl, or 2-methylvinyl, or allyl; and T is in general a divalent linking group which can be selected from a wide variety of divalent groups which can be linked both to G and X. These hydrophilicity modifiers are described more fully in US-A-4, 921 , 956, which is incorporated by reference at this point. Other hydrophilic compounds useful in accordance with the present invention, without limitation to these, are monomers selected from groups consisting of dimethylacrylamide, 2-hydroxyethyl methacrylate, N-vinylpyrrolidone, monomethacrylated polyethylene glycols, monometacrylated polypropylene glycols, and mixtures thereof. Other hydrophobes useful in accordance with the present invention include, without limitation, monomers selected from groups consisting of methyl methacrylate, fluorinated reactive vinyl monomers, such as hexafluoroisopropyl methacrylate, styrenic monomers, isobornyl methacrylate, and mixtures thereof. same.

ELABORATION PROCESS OF CONTACT LENSES: Contact lenses can be made from the aforementioned monomers by a variety of processes. Preferably, the contact lenses are made by polymerizing a prepolymerization mixture including the silicone, polyalkylene glycol, and an optional hydrophilic modifier, in contact with a lens mold, which is preferably a double-sided lens mold. Polymerization can be initiated with the addition of a polymerization initiator, such as DAROCUR 1173, available from EM Chemicals (Hawthorne, NJ). The prepolymerization mixture can be prepared by mixing together the desired monomers with a solvent, such as, without limitation, isopropyl alcohol. Prior to the molding process of the lenses, the monomer solution will be prepared and preserved under adverse conditions for polymerization. Preferably, the monomer solution is briefly polymerized for later application to the lens molding device. The monomer solution can be prepared by mixing about 50 to 95 weight percent of the vinyl reactive silicone with 5 to 50 weight percent of the diviny polyalkylene glycol, based on the weight of the monomers, in the presence of a solvent. The concentration of the solvent should be high enough to produce a monomer solution that has a sufficiently low viscosity to allow sufficient flow, while not too high that problems with subsequent solvent extraction processes result. The monomer solution may have about one or ten percent by weight of the solvent, more preferably two to five percent, based on the total weight of the solution. Suitable solvents include isopropyl alcohol and methyl ethyl ketone. A polymerization initiator, such as DAROCUR 1173 can be added to the monomer mixture to initiate the polymerization. The polymerization initiator is preferably added in an amount of up to about 0.05 grams per gram of total monomer, more preferably about 0.003 grams / gram of monomer. Thus, the preparation of a contact lens according to the present invention can occur by the following processes. First, a vinyl reactive silicone which has up to 20 silicon atoms is contacted with a diviny polyalkylene glycol in the presence of a solvent and a polymerization initiator, thereby forming a prepolymerization mixture. The prepolymerization mixture is placed in a contact lens mold, preferably double-sided, under conditions sufficient to cause copolymerization of the polyalkylene glycol with the silicone in the substantial absence of cross-linking agents. Ultraviolet light is applied to the mixture at a sufficient intensity to initiate the polymerization process. The copolymerization process is allowed to continue with the conclusion in the substantial absence of additional crosslinking agents, thereby producing soft contact lenses that actually have a shape defined by the mold. The foregoing descriptions will allow one of ordinary skill in the art to practice the invention. In order to allow the reader to understand the specific modalities and advantages of it, reference to the following examples is suggested. The temperatures are given in degrees Celsius.

EXAMPLE 1: In order to impart reactivity, the isocyanatoethyl methacrylate end groups are attached to the propylene glycols which they have. a range of molecular weights of about 425 to 4000. While anhydrous conditions are maintained, about 20 grams (about 0.05 gram-mol) of POLYPROPYLENGLICOL 4000 (available from DOW CHEMICAL Co., Midland MI) are added to the 3-flask. collars 500 ml dried to the flame, cooled to around 23 ° C. About 1.55 grams (about 0.01 grams mol) of isocyanatoethyl methacrylate (available from MONOMER POLYMER, INC., Windham, NH) and about 0.004 grams (about 0.02 weight percent) of dibutyltin dilaurate as catalyst (available from PHALTZ BAUER, Waterbury, CT) are added to the flask. The flask is gently shaken manually, then covered with a metal foil to reduce contact with the fire and stirring slowly and mechanically at room temperature in a nitrogen atmosphere at night. The resulting polypropylene glycols contain methacrylate end groups, (polypropylene glycol dimethacrylate) which has an average molecular weight of about 425 to 4000. Polyethylene glycol dimethacrylates having an average molecular weight of about 200, 400 and 600 are commercially available of Monomer Polymer Labs (Windham, NH).

EXAMPLE 2: The polypropylene glycol dimethacrylate ("PPG") which has a molecular weight of about 4000 is substantially prepared as described in Example 1. About 0.80 grams of the polypropylene glycol dimethacrylate are added to about 1.2 grams of 3- methacryloxypropyltris (trimethylsiloxy) -silane (ie TRIS, available from GELESTE, Tullytown, PA), and about 0.05 cubic centimeters (ce) from the DAROCURR 1173 initiator. The resulting solution is mixed perfectly and transferred to the double polypropylene molds face for contact lenses. The solution is polymerized, or cured, in a nitrogen atmosphere by applying an ultraviolet (UV) light with sufficient intensity to lead to the actual termination of the copolymerization after an application period of about 3 hours. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and actually made according to the previously described procedure, are evaluated for oxygen permeability. Oxygen flows (J) are measured at 34 ° C in a humid cell (ie gaseous streams are maintained at around 100% relative humidity) using a DklOOO instrument (available from Applied Design and Development Co., Norcross, Georgia). A stream of oxygen is passed through one side of the face of the lenses, with a speed of about 20 cm / min., While a stream of nitrogen is passed on the opposite side of the face of the lenses with a speed around cm / min. The concentration of oxygen in the nitrogen stream (ie, oxygen that diffuses through the lens) is measured under equilibrium conditions.

Dk, a measure of the oxygen permeability of a material, is then determined from the following formula: Dk = Jt / (Poxiqeno) 2 where J = oxygen flow (microliters 02 / cm -minute) ^ oxygen- ^ measured - "water vapor \ t¡'- 'TL ßl aS Qβ test) [mm Hg] Measured = barometric pressure [mm Hg] Water pressure = 0 mm Hg at 34 ° C (in a dry cell) [mm Hg] Water vapor = 40 +/1 mm Hg at 34 ° C (in a wet cell) [mm Hg] t = thickness lens material [mm] where Dk as here is reported, has units of ((ce 2 -10 of 02) (mm / cm) (cm / sec) (mm Hg) x 10) Contact lenses, fully hydrated, prepared according to the procedures of Example 1, have a Dk of about 87 and a modulus of elasticity of about 1.6 megaPascals (MPa).

EXAMPLE 3 (COMPARATIVE): The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is substantially prepared as described in example 1. About 0.80 gr. of polypropylene glycol dimethacrylate (PPG) are added to about 1.1 gr. of TRIS, at about 0.10 gr. of ethylene glycol dimethacrylate ("EGDMA", available from Sartomer, West Chester, PA) and about 0.05 ce of the initiator. DAROCUR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is polymerized, or cured, in a nitrogen atmosphere by applying an ultraviolet (UV) light with sufficient intensity to lead to the substantial completion of the copolymerization after an application period of about three hours. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the procedures of Comparative Example 3, have a Dk of about 70 and a modulus of elasticity of about 10.9 MPa.

EXAMPLE 4 (COMPARATIVE): The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially as described in Example 1. About 0.70 gr. of polypropylene glycol dimethacrylate (PPG) are added to about 1.2 gr. of TRIS, about 0.10 gr. of EGDMA, and about 0.05 ce of initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided propylene molds for contact lenses. The solution is polymerized or cured in a nitrogen atmosphere by applying an ultraviolet (UV) light with sufficient intensity to lead to the actual termination of the copolymerization after an application period of about 3 hrs. The resulting contact lenses are removed from the mold and hydrated. The contact lenses, completely hydrated and made substantially in accordance with the procedures of Comparative Example 4, have a Dk of about 45 and a modulus of elasticity of about 13.8 MPa. Table 1 summarizes the characteristics of contact lenses made according to the procedures of Examples 2 and Comparatives 3 and 4.

TABLE 1 Example 2 describes the preparation of contact lenses based on a copolymer of polypropylene glycol-TRIS which have a Dk of about 87. Examples 3 and 4 describe the preparation of similar contact lenses with the addition of dimethacrylate of ethylene glycol as a crosslinking agent which increases the mechanical properties. The Dk achieved with the addition of a crosslinking agent is advantageously reduced in both Examples (3 and 4), as compared to Example 2. However, the moduli of elasticity of the contact lenses of Example 2 remain acceptable in absence of additional crosslinking agents. Thus, Example 2 and Comparative Examples 3 and 4 illustrate that contact lenses have a high oxygen permeability (Dk) and acceptable mechanical properties which can be achieved by copolymerization of polyalkylene glycol dimethacrylates with TRIS in the absence of conventional additional crosslinking, such as ethylene glycol dimethacrylate (EGDMA).

EXAMPLE 5: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially as described in Example 1. About 0.59 gr. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.01 gr. of the hydrophobic monomer hexafluoroisopropylmethacrylate (ie, "HFIM", available from Polysciences, Warrington, PA), and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed thoroughly and transferred to the double-sided polypropylene molds for the Contact. The solution is polymerized, or cured, in a nitrogen atmosphere by applying an ultraviolet (UV) light with sufficient intensity to lead to the substantial completion of the copolymerization after a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the procedures of Example 5, have a DK of about 87.

EXAMPLE 6: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.29 gr. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.01 gr. of HFIM. and about 0.05 ce of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. The resulting contact lenses completely hydrated and made substantially in accordance with the previously described procedure, have a Dk of about 88.

EXAMPLE 7: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.28 g. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.02 gr. of HFIM, and about 0.05 ce of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. The resulting contact lenses completely hydrated and made substantially in accordance with the previously described procedure, have a Dk of about 85.

EXAMPLE 8: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.30 gr. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, about 0.02 gr. of the hydrophobic isobornyl methacrylate monomer (Sartomer, West Chester, Pa). at about 0.03 gr. of isopropyl alcohol (JT Baker, Phillipsburg, NJ), and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed thoroughly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. The resulting contact lenses completely hydrated and made substantially in accordance with the previously described procedure, have a Dk of about 85.

EXAMPLE 9: About 0.85 gr. of the polyethylene glycol dimethacrylate, which has a molecular weight of about 200, are added to about 0.15 gr. of TRIS, at about 0.10 gr, of the hydrophobic methyl methacrylate monomer (Aldrich Chemical, Milwaukee, Wl) and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for the lenses contact. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 10: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.20 g of the polypropylene glycol dimethacrylate are added to about 0.70 g. of TRIS, at about 0.10 gr. of the hydrophilic monomer N-vinylpyrrolidone, and about 0.05 ce of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by application of UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 11; The polypropylene glycol dimethacrylate which has a molecular weight of about 400.0 is prepared substantially in accordance with the procedure described in Example 1. About 0.24 g. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.02 gr. of N-vinylpyrrolidone, at 0.04 gr. of isopropyl alcohol (Aldrich Chemical Co.) as a solvent, and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed thoroughly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The material is cured an additional hour at a temperature of 60 ° C. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the previously described procedure have a Dk of about 78.

EXAMPLE 12: The polypropylene glycol dimethacrylate which has a molecular weight of about 1200 is prepared substantially according to the procedure described in Example 1. About 0.18 g. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.12 gr. of the hydrophilic hydroxyethyl methacrylate monomer, and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. The contact lenses completely hydrated and elaborated substantially in accordance with the previously described procedure, have a Dk of about 58.

EXAMPLE 13: The polypropylene glycol dimethacrylate which has a molecular weight of about 1200 is prepared substantially according to the procedure described in Example 1. About 0.10 gr. of polypropylene glycol dimethacrylate are added to about 1.0 gr. of TRIS, at about 0.10 gr. of hydroxyethyl methacrylate, and at about 0.10 gr. of the solvent methyl ethyl ketone, and about 0.05 ce of the DAROCURR 1173 initiator. The solution is perfectly mixed and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. EXAMPLE 14: About 0.10 gr. of the polyethylene glycol dimethacrylate which has a molecular weight of about 600 are added to about 1.0 g. of TRIS, about 0.60 gr. of the hydrophilic monomer dimethylacrylamide (Alcolac, Baltimore, MD). and about 0.05 ce of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. Fully hydrated contact lenses, made substantially in accordance with the previously described procedure, have a Dk of about 96.

EXAMPLE 15: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.30 gr. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.025 gr. of the hydrophilic monomer dimethylacrylamide, at about 0.025 gr. of solvent isopropyl alcohol, and about 0.05 ce of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. Contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the previously described procedure have a Dk of about 98.

EXAMPLE 16: Around 0.15 gr. of the polyethylene glycol dimethacrylate which has a molecular weight of about 200, are added to about 0.85 g. of TRIS, at about 0.10 gr. of the solvent methyl ethyl ketone, and about 0.05 ce of the DAROCURR 1173 initiator. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by the application of a UV light for a period of about 3 hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 17: The polypropylene glycol dimethacrylate which has a molecular weight of about 1200 is prepared substantially according to the procedure described in Example 1. About 0.30 gr. of polypropylene glycol dimethacrylate are added to about 1.0 gr. of TRIS, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 18: About 0.04 of polytetramethylene glycol dimethacrylate, which has a molecular weight of about 1000, is added to about 1.40 g. of TRIS, at about 0.40 gr. of dimethylacrylamide, about 1.0 gr. of the solvent isopropyl alcohol, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided propylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by the application of UV light for a period of about three hours. A special curing is performed at about 60 ° C for about an hour. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and processed substantially in accordance with the previously described procedure have a Dk of about 47.

EXAMPLE 19: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 0.26 gr. of polypropylene glycol 4000 dimethacrylate are added to about 0.040 gr. of polyethylene glycol dimethacrylate which has a molecular weight of about 600, at about 0.70 gr. of TRIS, at about 0.02 gr. of solvent isopropyl alcohol, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the previously described procedure have a Dk of about 52.

EXAMPLE 20: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially according to the procedure described in Example 1. About 3.0 gr. of polypropylene glycol dimethacrylate are added to about 7.0 gr. of TRIS, about 0.05 gr. of solvent isopropyl alcohol, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by the application of UV light for a period of about three hours. An additional curing is performed at about 60 ° C for about an hour. Contact lenses are removed from the mold and hydrated. The contact lenses completely hydrated and elaborated substantially in accordance with the previously described procedure, have a Dk of about 58.

EXAMPLE 21: Around 0.85 gr. of polyethylene glycol dimethacrylate, which has a molecular weight of about 400, are added to about 0.15 gr. of TRIS, at about 0.10 gr. of the hydrophobic methyl methacrylate monomer, at about 0.05 gr. of methyl ethyl ketone, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed thoroughly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by the application of UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 22: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially in accordance with the procedure described in Example 1. About 0.30 gr. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, about 0.05 gr. of the solvent isopropyl alcohol, and about 0.05 cc of the DAROCURR 1173 initiator. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. An additional curing is performed at about 60 ° C for about an hour. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the previously described procedure have a Dk of about 93.

EXAMPLE 23: Around 0.30 gr. of polyethylene glycol dimethacrylate which has a molecular weight of about 200 are added to about 1.0 gr. of TRIS, at about 0.10 gr. of the hydrophobic monomer methyl methacrylate, at about 0.30 gr. of the hydrophilic monomer dimethylacrylamide, and about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed thoroughly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated.

EXAMPLE 24: The polypropylene glycol dimethacrylate which has a molecular weight of about 4000 is prepared substantially in accordance with the procedure described in Example 1. About 0.18 g. of polypropylene glycol dimethacrylate are added to about 0.70 gr. of TRIS, at about 0.02 gr. of the hydrophilic hydrophilic methacrylate monomer, at about 0.10 gr. of the hydrophilic monomer dimethylacrylamide, at about 0.05 cc of the initiator DAROCURR 1173. The resulting solution is mixed perfectly and transferred to the double-sided polypropylene molds for contact lenses. The solution is cured in a nitrogen atmosphere by applying a UV light for a period of about three hours. The resulting contact lenses are removed from the mold and hydrated. Contact lenses completely hydrated and made substantially in accordance with the previously described procedure have a Dk of about 32.

Table 2 summarizes the results of oxygen permeability described in Examples 5-24.

Table 2 Examples 5-24 illustrate variations in formulations which may be executed in accordance with the present invention. Those of ordinary skill in the art of making hydrophilic contact lenses will be able to formulate numerous other compositions without departing from the scope of the present invention.

The invention has been described in detail, with regard to certain preferred embodiments, in order to allow the reader to practice the invention without undue experimentation. Either way, a person having ordinary skill in the art will readily recognize that many of the previous parameters and components can be varied or modified to a certain extent without departing from the spirit and scope of the invention. In addition, titles, headings or whatever, are provided to increase the understanding of this document to the readers, and that it is not read as a restrictive in the field of application of the present invention. Accordingly, the intellectual property rights to this invention are defined only by the following claims. It is noted that in relation to this date, the best method known by the applicant to carry out the present invention is that which is clear from the present description of the invention. The invention having been described as follows, the content of the following is claimed as property:

Claims (23)

1. A copolymer having high oxygen permeability, ocular biocompatibility, and visual clarity, the copolymer which is formed of monomers, characterized in that it comprises: (a) from 50 to 95% by weight of the vinyl reactive silicone which has up to 20 silicon atoms; and (b) from 5 to 50% by weight of the diviny polyalkylene glycol, wherein the copolymer is formed in the substantial absence of additional crosslinking agents.

2. A copolymer according to claim 1, characterized in that the vinyl reactive silicone has less than 10 silicon atoms.

3. A copolymer according to claim 1, characterized in that the vinyl reactive silicone has less than 7 silicon atoms.

4. A copolymer according to claim 3, characterized in that the vinyl reactive silicone is selected from the group consisting of 3-methacryloxypropyltris (trimethylsiloxy) -silane; 3-methacryloxypropyl-bis (trimethylsiloxy) methyl silane; 3-methacryloxypropyl-pentamethyldisiloxane; and mixtures thereof.

5. A copolymer according to claim 4, characterized in that the vinyl reactive silicone is 3-methacryloxypropyltris (trimethylsiloxy) -silane (TRIS).

6. A copolymer according to claim 1, characterized in that the polyalkylene glycol divinyl is selected from the group consisting of dimethylacrylates of polyethylene glycols, dimethacrylates of polypropylene glycols, diethyrically capped polyethylene glycols, diethyrically capped polypropylene glycols, tetramethylene glycol dimethacrylates and combinations thereof.

7. A copolymer according to claim 6, characterized in that the polyalkylene glycol divinyl is a polypropylene glycol dimethacrylate.

8. A copolymer according to claim 6, characterized in that the polyalkylene glycol divinyl has an average molecular weight of 425 to 4000.

9. A copolymer according to claim 1, characterized in that it comprises: (a) from 50 to 95% by weight of the vinyl reactive silicone which has up to 20 silicon atoms; (b) from 5 to 49% by weight of the diviny polyalkylene glycol, and from 1 to 40% by weight of a hydrophilic monomer.

10. A copolymer according to claim 9, characterized in that the hydrophilic monomer is selected from the group consisting of dimethylacrylamide, 2-hydroxyethyl methacrylate, N-vinylpyrrolidone, monomethacrylated polyethylene glycols, monomethacrylated polypropylene glycols, and mixtures thereof.

11. A copolymer according to claim 1, characterized in that it comprises: (a) from 50 to 95% by weight of the vinyl reactive silicone which has up to 20 silicon atoms; (b) from 5 to 49% by weight of the diviny polyalkylene glycol, and from 1 to 40% by weight of a hydrophobic monomer.

12. A copolymer according to claim 11, characterized in that the hydrophobic monomer is selected from the group consisting of methyl methacrylate, reactive, vinyl, fluorinated monomers, styrenic monomers, isobornyl methacrylate, and mixtures thereof.

13. A copolymer according to claim 1, characterized by 60 to 80% by weight of the vinyl silicone and 20 to 40% by weight of the polyalkylene glycol divinyl.

14. A hydrophilic contact lens made from the monomers comprising: (a) from 50 to 95% by weight of the vinyl reactive silicone which has up to 20 silicon atoms; and (b) from 5 to 50% by weight of the diviny polyalkylene glycol characterized in that the contact lens is made in the substantial absence of additional crosslinking agents.

15. A contact lens according to claim 14, made from the monomers, characterized in that it comprises: (a) from 50 to 95% by weight of 3-methacryloxypropyltris (tri-ethylsiloxy) silane; and (b) 5 to 50% by weight of polypropylene glycol dimethacrylate.

16. A contact lens according to claim 14, characterized in that it consists essentially of: (a) from 50 to 95% by weight of a vinyl reactive silicone which has up to 20 silicon atoms; (b) from 5 to 49% by weight of the diviny polyalkylene glycol; and (c) from 1 to 40% by weight of the hydrophilicity modifier.

17. A process for making a soft contact lens in the substantial absence of added crosslinking agents, characterized by the steps: (a) contacting the vinyl reactive silicone which has up to 20 silicon atoms, with a diviny polyalkylene glycol in the substantial absence of additional crosslinking agents, thereby forming a prepolymerization mixture; (b) placing the prepolymerization mixture and the polymerization initiator in contact with the lens mold under conditions sufficient to cause copolymerization of the polyalkylene glycol with the silicone in the substantial absence of crosslinking agents; and (c) copolymerizing the polyalkylene glycol and the silicone and allowing the copolymerization to continue in the substantial absence of crosslinking agents for a period sufficient to produce contact lenses.

18. A process according to claim 17, characterized in that the vinyl reactive silicone includes less than 10 silicon atoms.

19. A process according to claim 18, characterized in that the vinyl reactive silicone includes less than 7 silicon atoms.

20. A process according to claim 19, characterized in that the vinyl reactive silicone is selected from the group consisting of 3-methacryloxypropyltris (trimethylsiloxy) -silane; 3-methacryloxypropyl-bis (trimethylsiloxy) methylsilane; and 3-methacryloxypropyl-pentamethyldisiloxane and mixtures thereof, and the polyalkylene glycol is selected from the group consisting of dimethylacrylates of polyethylene glycols, dimethacrylates of polypropylene glycols, diethyrnically capped polyethylene glycols, diethyrnically capped polypropylene glycols, tetramethylene glycol dimethacrylates, and combinations thereof.

21. A process of compliance with. claim 20, characterized in that the vinyl reactive silicone is 3-methacryloxypropyltris (trimethylsiloxy) silane > (TRIS) and the polyalkylene glycol is polypropylene glycol.

22. A process according to claim 17, characterized in that the product of the copolymerization comprises: (a) from 50 to 95% by weight of the vinyl-reactive silicone which has up to 10 silicon atoms; (b) 5 to 50% by weight of the diviny polyalkylene glycol.

23. A process according to claim 17, characterized by the step of adding a hydrophilic or hydrophobic monomer to the prepolymerization mixture, in order to modify the hydrophilic nature of the contact lenses.