Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F30/00—Homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal
  • C08F30/04—Homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal containing a metal
  • C08F30/08—Homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal containing a metal containing silicon
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses
  • G02B1/043—Contact lenses

Definitions

• the present invention relates to contact lenses, and more particularly to hydrophilic soft gas permeable contact lenses having improved clinical performance.
• DK substantial permeability to oxygen
• HGP hard gas permeable
• hydrophilic soft gas permeable (SGP) lenses have been developed based upon compositions contain ⁇ ing, e.g., a polymerizable vinylic siloxane monomer and a hydrophilic vinylic monomer. See, e.g., U.S. Patent Nos. 4,136,250; 4,182,822; 4,261,875; 4,343,927; 4,426,389; 4,486,577; 4,605,712; 4,711,943 and 4,837,289.
• the SGP lenses of this type which generally have a water content of from about 25 to 75% by weight, have excellent oxygen permeability and hydrophilicity.
• the clinical performance of SGP lenses including functional (i.e., on the eye) wettability, deposition resistance, dehydration resistance and/or comfort, is very poor, making such lenses unsuitable for extended wear.
• a soft gas permeable contact lens composed of the polymerization product of composi ⁇ tions containing a polymerizable vinylic siloxane monomer and a hydrophilic vinylic monomer, having on the lens surface a proportion of hydroxy acrylic monomer units to silicon units sufficient to provide an SGP lens having the requisite high DK, softness and rebound elasticity, and which at the same time possess a high degree of clinical performance, thus rendering the lenses eminently suitable for long-term extended wear.
• the requisite sufficient proportion of hydroxy acrylic monomer units to silicon units on the lens surface can be attained by surface treatment of the lens in order to increase hydroxy acrylic monomer units and/or to reduce the silicon units on the surface.
• the surface treatment is carried out either by reaction on the lens surface with a polyhyd- ric alcohol (polyol) and/or base or acid, or by radiation treatment of the lens to graft, deposit or coat hydroxy acrylic monomer units on the surface thereof.
• polyol polyhyd- ric alcohol
• the present invention differs significantly from prior art practices related to the provision, or attempted provision, of a hydrophilic surface on a hydrophobic lens.
• hydrophobic lenses are known in the art which are made of silicone rubber, a cross-linked polysiloxane, such as illustrated in U.S. Patent No. 3,228,741. These hydrophobic lenses are highly oxygen permeable but are extremely poor in functional wettability, deposition resistance and comfort, and also exhibit a mysterious tight lens syndrome. It is known in the art to seek to improve the functional wettability of such lenses by provision of an ultrathin coating of hydro ⁇ philic polymer. See, e.g., U.S. Patent Nos. 3,854,982; 3,916,033; 3,925,178; and 4,143,949. Generally these efforts have not in any event proven successful.
• the lens per se is a hydrophilic SGP lens containing a substantial amount of water (e.g., generally at least 25% by weight) such that its surface, in contrast to the silicone rubber lenses, is already highly hydrophilic and no apparent need would exist to provide a hydrophilic polymeric surface coating thereon as is taught with respect to hydrophobic lens materials.
• a hydrophilic SGP lens containing a substantial amount of water (e.g., generally at least 25% by weight) such that its surface, in contrast to the silicone rubber lenses, is already highly hydrophilic and no apparent need would exist to provide a hydrophilic polymeric surface coating thereon as is taught with respect to hydrophobic lens materials.
• the SGP lens is formed from the polymeriza ⁇ tion product of compositions containing at least one poly- merizable vinylic siloxane (PVS) monomer, and at least one hydrophilic vinylic monomer.
• PVS poly- merizable vinylic siloxane
• the polymerizable vinylic siloxane monomer contains at least one polymerizable vinylic group such as acrylic, styrenyl or vinylic group, at least one polysiloxanyl group, and at least one linkage connecting these two groups; thus, for example:
• CH 2 CCH 3 COO(CH 2 ) 2 OCH 2 CHOHCH 2 0(CH 2 ) 3 Si(OSi I-CH 3 ) 3 ;
• TSM CH 3 y-tris(trimethylsiloxy)silylpropyl methacrylate
• Hydrophilic vinylic monomers suitable for use in SGP lens compositions along with the PVS include, for example, N,N-dimethylacrylamide (NNDMA) , 2-hydroxyethyl methacrylate (HEMA), glyceryl methacrylate (GMA), N-vinyl pyrrolidone and the like.
• NMDMA N,N-dimethylacrylamide
• HEMA 2-hydroxyethyl methacrylate
• GMA glyceryl methacrylate
• N-vinyl pyrrolidone N-vinyl pyrrolidone
• the lenses per se are formed by lathe cutting, cast molding, spin casting, or other like known techniques.
• SGP lenses made according to the known formulations possess a high oxygen permeability but exhibit poor clinical performance.
• HAM hydroxy acrylic monomer
• HEMA hydroxy acrylic monomer
• GMA hydroxy acrylic monomer
• the units referred to are the structural monomeric units or the number of silicon atoms, including those as part of an overall copolymeric structure.
• HAM Hydroxy acrylic monomer
• R is H or a substituted or unsubstituted alkyl, such as methyl or CH 2 COOH; and X is a radical selected from the group consisting of hydroxyalkyloxy, hydroxy- alkyl amine, and hydroxy; with the alkyl being substituted or unsubstituted, and preferably selected from C x to C 10 alkyls, most preferably C 2 and C 3 alkyls; and with the hydroxy on the alkyl being either a single hydroxy (e.g., as in 2-hydroxyethyl methacrylate) or multiple hydroxy (e.g., as in glyceryl methacrylate) .
• exemplary and preferred hydroxy acrylic monomers are:
• the SGP lens of the invention is made from the known SGP lens compositions and, after lens formation, the lens is then treated to provide on its surface a pro ⁇ portion of HAM units to silicon units (e.g., by increase of HAM units and/or by decrease of silicon units) suffi ⁇ cient to provide improved clinical performance of the lens, such as functional wettability, deposition resist ⁇ ance, dehydration resistance and comfort.
• One means for achieving the requisite surface proportion of HAM to silicon units is by reaction of the lens surface, preferably in the dehydrated state, with a polyol of the formula R (OH) n where R x is a substituted or unsubstituted alkyl, preferably a C 2 to C 5 alkyl, and n is an integer of at least 2, such as glyceryl methacrylate, ethylene glycol, glycerine, glycerine-glycerine, polyglycerine, or the like.
• the reaction is preferably carried out in the presence of a base, such as sodium hydroxide, preferably in a concentration of 0.1 to 10 mole percent based on the polyol, or an acid or acid-containing mixture, such as ethanol/sulfuric acid, the reaction being conducted to the extent that the physical properties of the base lens (e.g., strength, oxygen permeability, softness, rebound elasticity, etc.) are essentially unaffected.
• a base such as sodium hydroxide
• an acid or acid-containing mixture such as ethanol/sulfuric acid
• the core lens can be treated with a HAM, preferably 2-hydroxyethyl acrylate or methacrylate, by grafting, deposition or coating to the lens surface so as. to provide a sufficient proportion of HAM units to silicon units at the lens surface.
• the grafting, deposi ⁇ tion or coating can be carried out using known radiation- induced reactions, including reactions induced by UV, x-ray, ⁇ -ray, and other electromagnetic radiation, such as radio frequency, microwave and the like, electron beam radiation, including electrical discharge, and the like, with reactions induced by UV, ⁇ -ray or electron beam radiation being preferred.
• the treating techniques per se that can be used in the practice of this invention are well known in the art, such as the grafting, deposition or coating cured by UV, y-ray or electron beam, illustrated in U.S. Patent Nos. 3,916,033 and 3,854,982; coating by spin casting or cast molding of the lenses cured by radia ⁇ tion; or plasma treating techniques, such as those dis ⁇ closed in U.S. Patent Nos. 3,925,178 and 4,143,949, as is well known in the art.
• the disclosures of these prior art patents are expressly incorporated herein by reference.
• the surface treatment produces on the lens surface a thin coating consisting essentially of poly(hydroxy alkyl acrylate and/or methacrylate), more preferably poly(2-hydroxyethyl acrylate and/or methacrylate).
• the required sufficient proportion of HAM units to silicon units on the lens surface that produces the desir ⁇ able clinical performance will vary primarily depending upon the type and amount of particular PVS and hydrophilic monomer employed. However, the sufficient proportion in the surface layer will, at any proportion, be higher than that existing in the lens body or core. Preferably, the proportion of HAM units to silicon units in the surface layer is at least 0.5. Generally, the higher the propor ⁇ tion the better the clinical performance of the lens, and the thicker the treated surface layer the better the durability of the lens wettability. However, the treated layer can not be so thick that the desired properties of the lens are adversely affected.
• HAM units can easily be determined by those skilled in the art.
• the improvement in the clini ⁇ cal performance of the lens comes about, at least in part, by virtue of establishment of compatibility between the delicate corneal wetting mechanism of the eye and the composition and structure of the lens surface.
• the known SGP lens having insufficient proportion of HAM units to silicon units or containing too high a level of silicon units on the surface are too hydrophobic for the spreading and binding of mucin to the lens surface.
• Mucin is the excellent wetting agent used in the cornea and contains a certain proportion of hydrophilic sites to hydrophobic sites.
• SGP lenses were fabricated from buttons which were made according to the formulations and procedures set forth in U.S. Patent No. 4,182,822, the starting formu ⁇ lation consisting of 36% (by weight), V-tris(trimethyl ⁇ siloxy) silylpropyl methacrylate (TSM) prepared according to Example 1 of the above patent, 59% N,N-dimethylacryl- amide (NNDMA), and 5% methyl methacrylate (MMA) with 0.3% t-butylperoxypyvalate included as a catalyst.
• TSM V-tris(trimethyl ⁇ siloxy) silylpropyl methacrylate
• NMDMA N,N-dimethylacryl- amide
• MMA methyl methacrylate
• the formu ⁇ lation was placed in a Teflon tube.
• buttons cut from the rods were post-cured at 110°C under high vacuum (0.5 Torr) for six hours.
• the lens can be made by the lathe technique known in the art.
• the hydrated lenses were extracted and condition ⁇ ed in physiological saline solution for a time sufficient to insure no substantial irritation.
• the lens thus made has high DK, about 4 to 5 times higher than that of the conventional poly HEMA soft lens, and contains about 50% by weight of water, and thus has softness, rebound elasticity and a highly hydrophilic lens surface.
• the proportion HAM units to silicon units on the lens surface is equal to zero.
• the lenses were very poor in performance such as functional wettabi ⁇ lity, deposition resistance and comfort, making the lens unsuitable for extended wear.
• Provision of 6% by weight HEMA in the formulation such that the formulation comprised 36% TSM, 58% NNDMA and 6% HEMA, results in a lens having high DK, softness, rebound elasticity, a highly hydrophilic surface and a proportion of HAM to silicon units equal to 0.15, and thus an improved SGP lens having improved clinical performance, such as functional wettability, deposition resistance and comfort as compared to the control lens above.
• Clinical ⁇ ly, the lenses could be worn for up to several hours by test patients.
• the lens formulation contains 36% TSM, 44% NNDMA and 20% HEMA
• the lenses could be worn continuously for up to several days by test patients, with wettability marginally unacceptable in certain circumstances.
• HAM to silicon proportion by increase of the amount of HEMA in the composition is at the expense of TSM, and thus reduces the oxygen permeabi ⁇ lity of the lens and/or causes the formation of opaque material.
• further increase of the HAM to silicon proportion can be achieved by surface treatment.
• the strength of the lens after the treatment was not significantly affected.
• the result ⁇ ing lens could be used for at least weekly extended wear by the test patients.
• the clinical of long term wearing on one patient showed that the lenses could indeed con ⁇ tinuously be worn for up to 3 months for at least certain patients.
• the surface treatment resulted in sub ⁇ stantially improved clinical performance.
• a SGP lens comprising 47% (by weight) TSM, 45% NNDMA and 8% HEMA, having 38% water content, high DK, softness, highly hydrophilic lens surface and a proportion of HAM units to silicon units equal to about 0.15, was found to be unsuitable for extended wear. Clinically, the lens produced poor vision, discomfort and encountered serious deposition problems within less than four hours of wear.
• ESCA data is the average value of the treated surface with 100 A° depth. Thus, the value right at the surface is substantially higher than those reported above.
• An unhydrated optically polished lens button was made according to U.S. Patent No. 4,182,822 employing 36% (by weight) TSM, 42% NNDMA and 22% HEMA, and glycerine surface treated as set forth in Example 3 herein.
• the button was fully hydrated in physiological saline solu ⁇ tion, and its surface was subjected to a number of simulated cleaning cycles, each cycle involving thumb- rubbing 10 times in tap water, followed by wetting in physiological saline solution.
• the surface wettability to the physiological saline solution was substantially the same based on visual inspection after sixty (60) cleaning cycles, equivalent to about one years service life of the lens in weekly extended wear.
• the surface of the untreated button was substan ⁇ tially not wettable by physiological saline solution under the same testing condition.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Medicinal Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Optics & Photonics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Physics & Mathematics (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Eyeglasses (AREA)
• Coating Of Shaped Articles Made Of Macromolecular Substances (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1990
  • 1990-09-07 KR KR1019910700493A patent/KR920701271A/ko not_active Withdrawn
  • 1990-09-07 JP JP2512563A patent/JPH04501882A/ja active Pending
  • 1990-09-07 EP EP19900913584 patent/EP0443005A4/en not_active Ceased
  • 1990-09-07 WO PCT/US1990/005032 patent/WO1991004283A1/en not_active Ceased
• 1991
  • 1991-03-13 CN CN91101622A patent/CN1064752A/zh active Pending

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