WO2007108842A2 - Interpenetrating polymer network hydrogel contact lenses - Google Patents

Interpenetrating polymer network hydrogel contact lenses Download PDF

Info

Publication number
WO2007108842A2
WO2007108842A2 PCT/US2006/047170 US2006047170W WO2007108842A2 WO 2007108842 A2 WO2007108842 A2 WO 2007108842A2 US 2006047170 W US2006047170 W US 2006047170W WO 2007108842 A2 WO2007108842 A2 WO 2007108842A2
Authority
WO
WIPO (PCT)
Prior art keywords
polymer network
set forth
peg
interpenetrating
hydrogel
Prior art date
Application number
PCT/US2006/047170
Other languages
French (fr)
Other versions
WO2007108842A3 (en
Inventor
David Myung
Jaan Noolandi
Christopher Ta
Curtis W. Frank
Original Assignee
The Board Trustees Of The Leland Stanford Junior University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/409,218 external-priority patent/US20060287721A1/en
Application filed by The Board Trustees Of The Leland Stanford Junior University filed Critical The Board Trustees Of The Leland Stanford Junior University
Publication of WO2007108842A2 publication Critical patent/WO2007108842A2/en
Publication of WO2007108842A3 publication Critical patent/WO2007108842A3/en

Links

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G02B1/041Lenses
    • G02B1/043Contact lenses

Definitions

  • the present invention relates generally to vision correction. More particularly, the present invention relates to an interpenetrating network hydrogel useful as a contact lens material.
  • the present invention provides interpenetrating polymer network hydrogels that have high oxygen permeability, strength, water content, and resistance to protein adsorption.
  • the hydrogels include two interpenetrating polymer networks.
  • the first polymer network is based on a hydrophilic telechelic macromonomer.
  • the second polymer network is based on a hydrophilic monomer.
  • the hydrophilic monomer is polymerized and cross-linked to form the second polymer network in the presence of the first polymer network.
  • the first polymer contains at least about 50% by dry weight of telechelic macromonomer, more preferably at least about 75% by dry weight of telechelic macromonomer, and most preferably at least about 95% by dry weight of telechelic macromonomer.
  • the telechelic macromonomer preferably has a molecular weight of between about 575 Da and about 20,000 Da. Mixtures of molecular weights may also be used.
  • the telechelic macromonomer is poly(ethylene) glycol (PEG) diacrylate or poly(ethylene) glycol (PEG) dimethacrylate.
  • the hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2- hydroxyethyl acrylate or derivatives thereof.
  • the interpenetrating polymer network hydrogel is surface modified.
  • at least one surface is modified with a layer of poly(ethylene) glycol (PEG) macromonomers, polymerized PEG macromonomers, polymerized PEG diacrylate, or polymerized PEG dimethacrylate.
  • the interpenetrating polymer network hydrogel includes grafted polymers.
  • a hydrophilic monomer may be grafted onto the first polymer network
  • a telechelic macromonomer may be grafted onto the second polymer network, or both.
  • the interpenetrating polymer network hydrogels of the present invention have a number of desirable properties. These properties include high tensile strength (on the order of 1 MPa), high oxygen permeability (at least about 15 Barrers, preferably at least about 90 Barrers), high water content (between about 70% and about 95%), and high transparency (at least about 70%). These properties make the interpenetrating polymer network hydrogels excellent for use in ophthalmic applications. In a preferred embodiment, the interpenetrating network hydrogel is used in a contact lens.
  • FIG. 1 shows synthesis of an interpenetrating polymer network hydrogel according to the present invention.
  • FIG. 2 shows surface modification of an interpenetrating polymer network hydrogel according to the present invention.
  • FIG. 3 shows grafted interpenetrating polymer network hydrogels according to the present invention.
  • FIG. 4 shows the tensile strength of a representative interpenetrating polymer network hydrogel according to the present invention.
  • FIG. 5 shows relationship between tensile strength and PEG molecular weight for interpenetrating polymer network hydrogels according to the present invention.
  • FIG. 6 shows relationship between stress-at-break and acrylic acid precursor concentration for interpenetrating polymer network hydrogels according to the present invention.
  • FIG. 7 shows relationship between Young's modulus and acrylic acid precursor concentration for interpenetrating polymer network hydrogels according to the present invention.
  • FIG. 8 shows representative equilibrium water contents for hydrogels according to the present invention.
  • FIG. 9 shows a photograph of a hydrogel according to the present invention.
  • FIG. 10 shows resistance of an interpenetrating polymer network hydrogel to collagen type I adsorption according to the present invention as indicated by cell growth.
  • FIG. 11 shows resistance of an interpenetrating polymer network hydrogel according to the present invention to protein adsorption.
  • the present invention provides interpenetrating polymer network (IPN) hydrogels.
  • IPN interpenetrating polymer network
  • the new hydrogels have properties making them desirable as biomaterials for use, e.g., in ophthalmic applications.
  • the hydrogels are particularly well suited as a material for contact lenses.
  • FIG. 1 shows the steps required for synthesis of an IPN hydrogel according to the present invention.
  • the starting material for the hydrogel is a solution of telechelic macromonomers 110 with functional end groups 112.
  • the telechelic macromonomers are polymerized to form a first polymer network 120.
  • hydrophilic monomers 130 are added to the first polymer network 120.
  • Hydrophilic monomers 130 are then polymerized and cross-linked in the presence of first polymer network 130 to form second polymer network 140. This results in formation of an IPN hydrogel 150.
  • any hydrophilic telechelic macromonomer may be used to form, the first polymer network.
  • polymer polyethylene glycol (PEG) macromonomers are used as the basis of the first network.
  • PEG is known to be biocompatible, soluble in aqueous solution, and can be synthesized to give a wide range of molecular weights and chemical structures.
  • the hydroxyl end-groups of the bifunctional glycol can be modified into photo-crosslinkable aery late or methacrylate end-groups, converting the PEG macromonomers to PEG-diacrylate (PEG-DA) or PEG-dimethacrylate (PEG-DMA) macromonomers.
  • Adding a photoinitiator to a solution of PEG-diacrylate or PEG-dimethacrylate macromonomers in water and exposing the solution to UV light results in the crosslinking of the PEG-DA or PEG-DMA macromonomers, giving rise to a PEG-DA or PEG-DMA hydrogel.
  • Polymerizing and crosslinking a second network inside the first network will give rise to the IPN structure.
  • Preparing IPN hydrogels through firee- radical polymerization has the additional advantage that it will enable the use of molds to form contact lenses of desired shape.
  • the free-radical polymerization can be initiated through UV irradiation— in which case transparent molds can be used— or through other means such as thermal-initiation in which non-transparent molds can be used.
  • the first polymer network contains at least 50%, more preferably at least 75%, most preferably at least 95% of the telechelic macromonomer by dry weight.
  • Any hydrophilic monomer may be used to form the second polymer network according to the present invention.
  • a variety of acrylic based monomers may be used, such as acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2- hydroxyethyl methacrylate, 2-hydroxyethyl acrylate or derivatives thereof.
  • poly(acrylic acid) (PAA) hydrogel is used as the second polymer network.
  • the IPN hydrogel is synthesized by a (two-step) sequential network formation, technique based on UV initiated free radical polymerization.
  • a precursor solution for the first network is made of purified PEG-DA or PEG-DMA dissolved in phosphate buffered saline (PBS) solution with, e.g., 2,2-dimethoxy-2-phenylacetophenone (DMPA) or 2-hydroxy-2- methyl-propiophenone as the UV sensitive free radical initiator.
  • PBS phosphate buffered saline
  • DMPA 2,2-dimethoxy-2-phenylacetophenone
  • 2-hydroxy-2- methyl-propiophenone 2-hydroxy-2- methyl-propiophenone
  • the hydrogel can be synthesized by free radical polymerization initiated by other means, such as thermal-initiation and other chemistries not involving the use of ultraviolet light.
  • the precursor solution is cast in a transparent mold and reacted under a UV light source at room temperature. Upon exposure, the precursor solution undergoes a free- radical induced gelation and becomes insoluble in water.
  • the mold is fabricated in such a way that yields hydrogels at equilibrium swelling with dimensions typical of contact lenses: between 13.00 and 14.50 mm in diameter and center thickness ⁇ 30 microns.
  • the PEG-based hydrogels are removed from the mold and immersed in the second monomer solution, such as an aqueous solution of (10-100% v/v) acrylic acid containing a photo-initiator and a cross-linker, such as about 0.1 to about 10% triethylene glycol dimethacrylate (TEGDMA), for 24 hours at room temperature.
  • a cross-linker such as about 0.1 to about 10% triethylene glycol dimethacrylate (TEGDMA)
  • TEGDMA triethylene glycol dimethacrylate
  • Other cross-linkers may be used, e.g. ethylene glycol dimethacrylate, ethylene glycol diacrylate, polyethylene glycol dimethacrylate, or polyethylene glycol diacrylate.
  • the swollen gel is then exposed to the UV source and the second network is polymerized and crosslinked inside the first network to form an IPN structure.
  • the second network can be also incorporated into the PEG-based hydrogel using the same initiator, crosslinking agent and polymerization procedure.
  • the molar ratio of the first network macromonomer to the second network monomer ranges from about 1:1 to about 1 :5000.
  • the weight ratio of the first network to the second network is in the range of about 10:1 to about 1:10. All synthesized hydrogels can be stored in sterile aqueous conditions until further use.
  • UV light-absorbing monomers can be incorporated into the synthetic process by co-polymerization.
  • a benzotriazole monomer (2- (2'methacryloxy-5'-methylphenyl)-benzotriazole (Polysciences, Inc., Warrigton, PA) and a benzophenone monomer (2-hydroxy-4-acrylyloxyethoxy)-benzophenone (Cyasorb UV-2098, Cytec Industries, Inc., West Patterson, NJ) can be used.
  • a benzotriazole monomer (2- (2'methacryloxy-5'-methylphenyl)-benzotriazole (Polysciences, Inc., Warrigton, PA)
  • a benzophenone monomer (2-hydroxy-4-acrylyloxyethoxy)-benzophenone
  • These have been incorporated into (vinyl alcohol) hydrogels by Tsuk and co workers (Tsuk et al.
  • one or both surfaces of the IPN hydrogel is surface modified, e.g. to give increased resistance to protein adsorption.
  • one or both surfaces is modified with a layer of PEG macromonomers, polymerized PEG macromonomers, polymerized PEG-DA, polymerized PEG-DMA, polymerized PEG-acrylate or polymerized PEG-methacrylate.
  • the layer may be bulk polymerized on the surface of the hydrogel either as an interpenetrating network or as a network covalently anchored to the surface.
  • FIG. 2 shows a contact lens 210 with surfaces 212 and 214.
  • surface 212 is modified with PEG macromonomer layer 22O 5 although both or neither surface may be modified.
  • FIG. 3A shows a standard IPN according to the present invention, with first polymer network 310 and second polymer network 320.
  • FIG. 3B shows an IPN in which first polymer network is grafted with hydropbilic monomer 330.
  • Hydrophilic monomer 330 may be, e.g., acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2- methylpropanesulfonic acid, 2 -hydroxyethyl methacrylate, 2-hydroxyethyl aery late or derivatives thereof.
  • FIG. 3A shows a standard IPN according to the present invention, with first polymer network 310 and second polymer network 320.
  • FIG. 3B shows an IPN in which first polymer network is grafted with hydropbilic monomer 330.
  • Hydrophilic monomer 330 may be, e.g., acrylic acid, acrylamide, hydroxyethyl acrylamide
  • FIG. 3C shows an IPN in which second polymer network 320 is grafted with hydrophilic telechelic macromonomer 340.
  • Hydrophilic telechelic macromonomer 340 may be, e.g., PEG-DA or PEG-DMA.
  • FIG. 3D shows an IPN in which first polymer network 310 is grafted with hydrophilic monomer 330 and second polymer network 320 is grafted with hydrophilic telechelic macromonomer 340.
  • the grafted networks are made by polymerizing aqueous mixtures of the two components in ratios that yield a network that is predominantly made from one polymer but has grafted chains of the second polymer.
  • IPN hydrogels possess a number of important mechanical properties that make them excellent candidates for contact lenses.
  • IPN hydrogels composed of PEG-DA (50% w/v in OH 2 O) in the preparation state of the first network and polyacrylic acid (50% v/v in dH 2 O) in the preparation state of the second ' network.
  • the telechelic macromonomer PEG-DA will be referred to as simply PEG hereafter for brevity.
  • FIG. 4 shows that PEG/PAA IPNs are much stronger than either the individual polymer networks or the copolymers.
  • the effect of IPN formation on tensile strength is non-linear, as the maximum strength is many times higher than that of a PEG- PAA copolymer.
  • the elastic moduli and tensile strength of the IPNs can be modified by changing the molecular weight of the PEG macromonomer used.
  • a range of PEG/PAA IPNs with PEG molecular weights from 575 Da to 20,000 Da have been synthesized. It was found that optically clear hydrogels may be formed from any of this range of molecular weights.
  • the tensile strength of the hydrogel varies depending on the MW of PEG used.
  • FIG. 5 shows results obtained using (a) PEG(3400), (b) PEG(4600), (c) PEG(8000) and (d) PEG(14000).
  • FIG. 5 shows that use of lower molecular weight PEG results in stronger hydrogels.
  • the elastic moduli and tensile strength of the IPNs can also be modified by changing the amount of acrylic acid used in the IPN.
  • FIG. 6 shows stress-at-break values of PEG(4600)/PAA IPNs prepared from varying acrylic acid precursor solution concentrations in the preparation state of the second network. The strongest IPNs used 40% acrylic acid to prepare the second network.
  • FIG. 7 shows Young's modulus values of PEG(4600)/PAA IPNs prepared from varying acrylic acid precursor solution concentrations in the preparation state of the second network. In general, the Young's modulus increases with increasing concentrations of acrylic acid in preparation of the second network.
  • a soft contact lens with ample mechanical strength is important for enabling their daily handling, cleaning, and storage.
  • Hydrogels according to the present invention, as well as contact lenses made from these hydrogels preferably have a tensile strength on the order of 1 MPa, more preferably at least 1 MPa, most preferably between about 1 and 5 MPa.
  • IPN hydrogels composed of a PEG first network with MW 8000 and concentration of 50% w/v in dH 2 O in the preparation state, and a second network of poly aery lie acid with 50% v/v in dH2 ⁇ in the preparation state were used to test oxygen permeability.
  • the hydrogels were first rinsed in distilled water, then soaked in phosphate buffer solution for at least 24 hrs.
  • the harmonic thickness of the hydrogel was then measured using Electronic thickness gauge Model ET-3 (Rehder Development company).
  • the hydrogel was then soaked again in phosphate buffered saline solution for at least 24 hrs.
  • an electrode assembly (Rehder Development company) was attached to a polarographic cell and electrical cables were attached between the electrode assembly and a potentiostat (Gamry instruments). About 1.5L of buffer solution was then saturated with air for at least 15 minutes and preheated to 35°C. Next, the hydrogel was carefully placed onto the electrode, the gel holder was placed over the hydrogel, and a few drops of buffer solution were placed on top of the hydrogel to keep the hydrogel saturated with buffer solution. The central part of the cell was then attached onto the cell bottom and the top part of the cell, containing the stirring rod, impeller, and coupling bushing, was attached to the top part of the cell. Air saturated buffer solution at 35°C was then poured into the assembled cell and filled almost to the top.
  • Hydrogels according to the present invention preferably have an oxygen permeability of more than about 15 Barrers, more preferably at least about 60 Barrers, most preferably at least about 90 Barrers.
  • the water content of the hydrogels was evaluated in terms of the swollen- weight-to -dry- weight ratio.
  • the dry hydrogel was weighed and then immersed in water as well as phosphate buffered saline. At regular intervals, the swollen gels were lifted, patted dry, and weighed until equilibrium was attained.
  • the percentage of equilibrium water content (WC) was calculated from the swollen and dry weights of the hydrogel:
  • W s and Wj are the weights of swollen and dry hydrogel, respectively.
  • FIG. 8 shows water content data for PEG networks of varying macromonomer MW (white bars), and PEG/PAA IPNs made with PEG macromonomers of varying MW in deionized water (gray bars) and in the ionizing conditions of PBS, pH 7.4 (black bars).
  • the water content data for the PAA network alone in deionized water (gray diagonal-patterned bars) and in PBS 5 pH 7.4 (black square-patterned bars) is shown on the right as a basis for comparison.
  • Table 1 shows the effect of varying the concentration of acrylic acid monomer used to prepare the second network on the equilibrium water content of PEG/PAA IPNs. In general, lower concentrations of acrylic acid monomer leads to hydrogels with higher equilibrium water content.
  • Hydrogels according to the present invention preferably have an equilibrium water content of between about 20-95%, more preferably between about 70-90% or between about 20-60%.
  • compositions of varying weight ratios of PEG and PAA that have been made according to the present invention are shown in Table 2. The compositions in this table were all made using a starting concentration of 50% PEG macromonomers. Table 2: Compositions of PEG(8.0k)/PAA IPNs with varying preparation concentration of AA monomer
  • the percentage (%) of light transmittance of IPN hydrogels composed of PEG (50% w/v in dFfeO) in the preparation state of the first network and polyacrylic acid (50% v/v in dH 2 ⁇ ) at 550 nm was also measured using a Varian Gary lE/Cary 3E UV- Vis spectrophotometer following the method described by Saito et al (Saito et al, "Preparation and Properties of Transparent Cellulose Hydrogels", Journal of Applied Polymer Science, Vol. 90, 3020-3025 (2003)).
  • the refractive index of the PEG/PAA hydrogel was measured using an Abbe Refractometer (Geneq, Inc., Montreal, Quebec). The percentage of light transmittance was found to be 90%, and the refractive index was found to be 1.35.
  • Hydrogels according to the present invention, as well as contact lenses made from these hydrogels, are preferably at least about 70% transparent. An example of this hydrogel is shown in FIG. 9. This hydrogel had an equilibrium water content of 85% and a tensile strength of 1.1 MPa.
  • IPN hydrogels of the present invention have a high resistance to protein adsorption. This makes them especially well suited for use in extended wear contact lenses.
  • primary rabbit corneal epithelial cells was cultured and seeded at a concentration of 1 x 10 s cells/mL onto unmodified PEG/PAA hydrogels previously incubated in a 0.3% collagen type I solution and PEG/PAA hydrogels with photochemically bound collagen type I on its surface. Representative results from these experiments are shown in the photomicrographs in FIG. 10.
  • FIG. 1OA shows no cell attachment or spreading on an unmodified PEG/PAA hydrogel that was incubated in collagen type I.
  • FIG. 1OA shows no cell attachment or spreading on an unmodified PEG/PAA hydrogel that was incubated in collagen type I.
  • FIG. 11 shows results of an experiment in which MaxiSorp Polystyrene (indicated by diamonds), PEG /PAA IPN hydrogels (indicated by squares) and PHEMA (indicated by triangles) were incubated with varying concentrations of a lysozyme protein solution.
  • Lysozyme is a protein present in the tear film, and is thus an important indicator of protein adsorption for contact lenses.
  • FIG. 9 shows that PEG/PAA hydrogels show an increased resistance to lysozyme adsorption when compared to MaxiSorp, and a similar level of lysozyme adsorption to PHEMA, which is a material used in current contact lenses.
  • PEG /PAA IPN hydrogels show a high resistance to protein adsorption, making them well suited for use as contact lenses

Abstract

The present invention, provides interpenetrating polymer network hydrogels that have high oxygen permeability, strength, water content, and resistance to protein adsorption. The hydrogels include two interpenetrating polymer networks. The first polymer network is based on a hydrophilic telechelic macromonomer. The second polymer network is based on a hydrophilic monomer. The hydrophilic monomer is polymerized and cross-linked to form the second polymer network in the presence of the first polymer network. The telechelic macromonomer preferably has a molecular weight of between about 575 Da and about 20,000 Da. Mixtures of molecular weights may also be used. In a preferred embodiment, the hydrophilic telechelic macromonomer is PEG-diacrylate or PEG-dimethacrylate and the hydrophilic monomer is an acrylic-based monomer. The material is designed to serve as a contact lens.

Description

INTERPENETRATING POLYMER NETWORK HYDROGEL
CONTACT LENSES
FIELD OF THE INVENTION
The present invention relates generally to vision correction. More particularly, the present invention relates to an interpenetrating network hydrogel useful as a contact lens material.
BACKGROUND
Current contact lenses have several disadvantages, including contact lens intolerance, immune reactions to the contact lenses themselves or to the protein bound to the lenses, and infections associated with contact lens use. To overcome these disadvantages, an ideal contact lens would have high water content, oxygen permeability, mechanical strength and resistance to protein adsorption. However, current contact lenses only have a subset of these properties. For example, sϊlicone-based contact lenses offer high oxygen permeability and strength, but have a relatively high level of protein adsorption due to their hydrophobicity. Hydrophilic components such as poly(2-hydroxyethylmethacrylate) (PHEMA), poly(methacrylic acid) (PMAA), and poly(vinyl alcohol) (PVA) are often incorporated into contact lenses to increase water content and wettability. However, protein adsorption continues to be a problem with contact lenses based on these materials. Accordingly, there is a need in the art to develop materials for contact lenses that have high water content, oxygen permeability, mechanical strength and resistance to protein adsorption. SUMMARY OF THE INVENTION
The present invention provides interpenetrating polymer network hydrogels that have high oxygen permeability, strength, water content, and resistance to protein adsorption. The hydrogels include two interpenetrating polymer networks. The first polymer network is based on a hydrophilic telechelic macromonomer. The second polymer network is based on a hydrophilic monomer. The hydrophilic monomer is polymerized and cross-linked to form the second polymer network in the presence of the first polymer network. Preferably, the first polymer contains at least about 50% by dry weight of telechelic macromonomer, more preferably at least about 75% by dry weight of telechelic macromonomer, and most preferably at least about 95% by dry weight of telechelic macromonomer. The telechelic macromonomer preferably has a molecular weight of between about 575 Da and about 20,000 Da. Mixtures of molecular weights may also be used.
In a preferred embodiment, the telechelic macromonomer is poly(ethylene) glycol (PEG) diacrylate or poly(ethylene) glycol (PEG) dimethacrylate. Also preferably, the hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2- hydroxyethyl acrylate or derivatives thereof.
In one embodiment, at least one surface of the interpenetrating polymer network hydrogel is surface modified. Preferably, at least one surface is modified with a layer of poly(ethylene) glycol (PEG) macromonomers, polymerized PEG macromonomers, polymerized PEG diacrylate, or polymerized PEG dimethacrylate. In another embodiment, the interpenetrating polymer network hydrogel includes grafted polymers. For example, a hydrophilic monomer may be grafted onto the first polymer network, a telechelic macromonomer may be grafted onto the second polymer network, or both.
The interpenetrating polymer network hydrogels of the present invention have a number of desirable properties. These properties include high tensile strength (on the order of 1 MPa), high oxygen permeability (at least about 15 Barrers, preferably at least about 90 Barrers), high water content (between about 70% and about 95%), and high transparency (at least about 70%). These properties make the interpenetrating polymer network hydrogels excellent for use in ophthalmic applications. In a preferred embodiment, the interpenetrating network hydrogel is used in a contact lens.
BRIEF DESCRIPTION OF THE FIGURES
The present invention together with its objectives and advantages will be understood by reading the following description in conjunction with the drawings, in which:
FIG. 1 shows synthesis of an interpenetrating polymer network hydrogel according to the present invention. FIG. 2 shows surface modification of an interpenetrating polymer network hydrogel according to the present invention. FIG. 3 shows grafted interpenetrating polymer network hydrogels according to the present invention. FIG. 4 shows the tensile strength of a representative interpenetrating polymer network hydrogel according to the present invention. FIG. 5 shows relationship between tensile strength and PEG molecular weight for interpenetrating polymer network hydrogels according to the present invention. FIG. 6 shows relationship between stress-at-break and acrylic acid precursor concentration for interpenetrating polymer network hydrogels according to the present invention. FIG. 7 shows relationship between Young's modulus and acrylic acid precursor concentration for interpenetrating polymer network hydrogels according to the present invention. FIG. 8 shows representative equilibrium water contents for hydrogels according to the present invention.
FIG. 9 shows a photograph of a hydrogel according to the present invention.
FIG. 10 shows resistance of an interpenetrating polymer network hydrogel to collagen type I adsorption according to the present invention as indicated by cell growth. FIG. 11 shows resistance of an interpenetrating polymer network hydrogel according to the present invention to protein adsorption.
DETAILED DESCRIPTION OF THE INVENTION
Synthesis of interpenetrating network hydrogels
The present invention provides interpenetrating polymer network (IPN) hydrogels. The new hydrogels have properties making them desirable as biomaterials for use, e.g., in ophthalmic applications. The hydrogels are particularly well suited as a material for contact lenses.
FIG. 1 shows the steps required for synthesis of an IPN hydrogel according to the present invention. The starting material for the hydrogel is a solution of telechelic macromonomers 110 with functional end groups 112. The telechelic macromonomers are polymerized to form a first polymer network 120. Next, hydrophilic monomers 130 are added to the first polymer network 120. Hydrophilic monomers 130 are then polymerized and cross-linked in the presence of first polymer network 130 to form second polymer network 140. This results in formation of an IPN hydrogel 150.
Any hydrophilic telechelic macromonomer may be used to form, the first polymer network. In a preferred embodiment, polymer polyethylene glycol (PEG) macromonomers are used as the basis of the first network. PEG is known to be biocompatible, soluble in aqueous solution, and can be synthesized to give a wide range of molecular weights and chemical structures. The hydroxyl end-groups of the bifunctional glycol can be modified into photo-crosslinkable aery late or methacrylate end-groups, converting the PEG macromonomers to PEG-diacrylate (PEG-DA) or PEG-dimethacrylate (PEG-DMA) macromonomers. Adding a photoinitiator to a solution of PEG-diacrylate or PEG-dimethacrylate macromonomers in water and exposing the solution to UV light results in the crosslinking of the PEG-DA or PEG-DMA macromonomers, giving rise to a PEG-DA or PEG-DMA hydrogel. Polymerizing and crosslinking a second network inside the first network will give rise to the IPN structure. Preparing IPN hydrogels through firee- radical polymerization has the additional advantage that it will enable the use of molds to form contact lenses of desired shape. The free-radical polymerization can be initiated through UV irradiation— in which case transparent molds can be used— or through other means such as thermal-initiation in which non-transparent molds can be used. Preferably, the first polymer network contains at least 50%, more preferably at least 75%, most preferably at least 95% of the telechelic macromonomer by dry weight.
Any hydrophilic monomer may be used to form the second polymer network according to the present invention. To optimize mechanical and other properties of the IPN hydrogel, a variety of acrylic based monomers may be used, such as acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2- hydroxyethyl methacrylate, 2-hydroxyethyl acrylate or derivatives thereof. In a preferred embodiment, poly(acrylic acid) (PAA) hydrogel is used as the second polymer network.
In a preferred embodiment, the IPN hydrogel is synthesized by a (two-step) sequential network formation, technique based on UV initiated free radical polymerization. A precursor solution for the first network is made of purified PEG-DA or PEG-DMA dissolved in phosphate buffered saline (PBS) solution with, e.g., 2,2-dimethoxy-2-phenylacetophenone (DMPA) or 2-hydroxy-2- methyl-propiophenone as the UV sensitive free radical initiator. In other embodiments, the hydrogel can be synthesized by free radical polymerization initiated by other means, such as thermal-initiation and other chemistries not involving the use of ultraviolet light. In the case of UV polymerization, the precursor solution is cast in a transparent mold and reacted under a UV light source at room temperature. Upon exposure, the precursor solution undergoes a free- radical induced gelation and becomes insoluble in water. The mold is fabricated in such a way that yields hydrogels at equilibrium swelling with dimensions typical of contact lenses: between 13.00 and 14.50 mm in diameter and center thickness ~30 microns.
To incorporate the second network, the PEG-based hydrogels are removed from the mold and immersed in the second monomer solution, such as an aqueous solution of (10-100% v/v) acrylic acid containing a photo-initiator and a cross-linker, such as about 0.1 to about 10% triethylene glycol dimethacrylate (TEGDMA), for 24 hours at room temperature. Other cross-linkers may be used, e.g. ethylene glycol dimethacrylate, ethylene glycol diacrylate, polyethylene glycol dimethacrylate, or polyethylene glycol diacrylate. The swollen gel is then exposed to the UV source and the second network is polymerized and crosslinked inside the first network to form an IPN structure. Other monomer candidates for the second network, such as acrylic acid derivatives, methacrylic acid and its derivatives, acrylamide, or 2-acrylamido-2- methylpropanesulfonic acid can be also incorporated into the PEG-based hydrogel using the same initiator, crosslinking agent and polymerization procedure. Preferably, the molar ratio of the first network macromonomer to the second network monomer ranges from about 1:1 to about 1 :5000. Also preferably, the weight ratio of the first network to the second network is in the range of about 10:1 to about 1:10. All synthesized hydrogels can be stored in sterile aqueous conditions until further use.
In one embodiment of the present invention, UV light-absorbing monomers can be incorporated into the synthetic process by co-polymerization. In particular, a benzotriazole monomer (2- (2'methacryloxy-5'-methylphenyl)-benzotriazole (Polysciences, Inc., Warrigton, PA) and a benzophenone monomer (2-hydroxy-4-acrylyloxyethoxy)-benzophenone (Cyasorb UV-2098, Cytec Industries, Inc., West Patterson, NJ) can be used. These have been incorporated into (vinyl alcohol) hydrogels by Tsuk and co workers (Tsuk et al. (1997) in a paper entitled "Advances in polyvinyl alcohol hydrogel keratoprostheses: protection against ultraviolet light and fabrication by a molding process" and published in "J. Biomed. Mat. Res. 34(3): 299-304"). Once the UV-absorbing monomers have been incorporated into the materials, the light-absorbing capacity can be tested using a spectrophotometer. Finally, the refractive index of all candidate materials can be measured using an automated refractometer (CLR 12-70, Index Instruments, Cambridge, UK) or manually using an Abbe refractometer.
In one embodiment of the present invention, one or both surfaces of the IPN hydrogel (or contact lens made from the hydrogel) is surface modified, e.g. to give increased resistance to protein adsorption. In one aspect of this embodiment, one or both surfaces is modified with a layer of PEG macromonomers, polymerized PEG macromonomers, polymerized PEG-DA, polymerized PEG-DMA, polymerized PEG-acrylate or polymerized PEG-methacrylate. The layer may be bulk polymerized on the surface of the hydrogel either as an interpenetrating network or as a network covalently anchored to the surface. Alternatively, PEG chains can be covalently tethered to the surface of the hydrogel by utilizing 5-azido-2-nitrobenzoic acid N- hydroxysuccinimide ester and an amine-terminated PEG macromonomer. FIG. 2 shows a contact lens 210 with surfaces 212 and 214. In this example, surface 212 is modified with PEG macromonomer layer 22O5 although both or neither surface may be modified.
In another embodiment of the present invention, grafted polymers are used to form the IPN. FIG. 3A shows a standard IPN according to the present invention, with first polymer network 310 and second polymer network 320. FIG. 3B shows an IPN in which first polymer network is grafted with hydropbilic monomer 330. Hydrophilic monomer 330 may be, e.g., acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2- methylpropanesulfonic acid, 2 -hydroxyethyl methacrylate, 2-hydroxyethyl aery late or derivatives thereof. FIG. 3C shows an IPN in which second polymer network 320 is grafted with hydrophilic telechelic macromonomer 340. Hydrophilic telechelic macromonomer 340 may be, e.g., PEG-DA or PEG-DMA. FIG. 3D shows an IPN in which first polymer network 310 is grafted with hydrophilic monomer 330 and second polymer network 320 is grafted with hydrophilic telechelic macromonomer 340. The grafted networks are made by polymerizing aqueous mixtures of the two components in ratios that yield a network that is predominantly made from one polymer but has grafted chains of the second polymer.
Properties of interpenetrating network hydrogels
Mechanical Strength
Our extensometry studies show that IPN hydrogels possess a number of important mechanical properties that make them excellent candidates for contact lenses. We have tested IPN hydrogels composed of PEG-DA (50% w/v in OH2O) in the preparation state of the first network and polyacrylic acid (50% v/v in dH2O) in the preparation state of the second' network. The telechelic macromonomer PEG-DA will be referred to as simply PEG hereafter for brevity. We compared the strength of these IPN hydrogels to single networks of PEG or PAA3 as well as copolymers of PEG and PAA. The samples were tested on an Instron Materials Tester and normalized for thickness as well as polymer content (based on the weight fraction of polymer in the hydrogel). The calculated true stress per unit solid (megapascals) and strain (fraction of original length) data are shown in FIG. 4. FIG. 4 shows that PEG/PAA IPNs are much stronger than either the individual polymer networks or the copolymers. The effect of IPN formation on tensile strength is non-linear, as the maximum strength is many times higher than that of a PEG- PAA copolymer.
The elastic moduli and tensile strength of the IPNs can be modified by changing the molecular weight of the PEG macromonomer used. For example, a range of PEG/PAA IPNs with PEG molecular weights from 575 Da to 20,000 Da have been synthesized. It was found that optically clear hydrogels may be formed from any of this range of molecular weights. However, as shown in FIG. 5, the tensile strength of the hydrogel varies depending on the MW of PEG used. FIG. 5 shows results obtained using (a) PEG(3400), (b) PEG(4600), (c) PEG(8000) and (d) PEG(14000). FIG. 5 shows that use of lower molecular weight PEG results in stronger hydrogels.
The elastic moduli and tensile strength of the IPNs can also be modified by changing the amount of acrylic acid used in the IPN. FIG. 6 shows stress-at-break values of PEG(4600)/PAA IPNs prepared from varying acrylic acid precursor solution concentrations in the preparation state of the second network. The strongest IPNs used 40% acrylic acid to prepare the second network. FIG. 7 shows Young's modulus values of PEG(4600)/PAA IPNs prepared from varying acrylic acid precursor solution concentrations in the preparation state of the second network. In general, the Young's modulus increases with increasing concentrations of acrylic acid in preparation of the second network. A soft contact lens with ample mechanical strength is important for enabling their daily handling, cleaning, and storage. Hydrogels according to the present invention, as well as contact lenses made from these hydrogels, preferably have a tensile strength on the order of 1 MPa, more preferably at least 1 MPa, most preferably between about 1 and 5 MPa.
Oxygen Permeability
IPN hydrogels composed of a PEG first network with MW 8000 and concentration of 50% w/v in dH2O in the preparation state, and a second network of poly aery lie acid with 50% v/v in dH2θ in the preparation state were used to test oxygen permeability. The hydrogels were first rinsed in distilled water, then soaked in phosphate buffer solution for at least 24 hrs. The harmonic thickness of the hydrogel was then measured using Electronic thickness gauge Model ET-3 (Rehder Development company). The hydrogel was then soaked again in phosphate buffered saline solution for at least 24 hrs. Next, an electrode assembly (Rehder Development company) was attached to a polarographic cell and electrical cables were attached between the electrode assembly and a potentiostat (Gamry instruments). About 1.5L of buffer solution was then saturated with air for at least 15 minutes and preheated to 35°C. Next, the hydrogel was carefully placed onto the electrode, the gel holder was placed over the hydrogel, and a few drops of buffer solution were placed on top of the hydrogel to keep the hydrogel saturated with buffer solution. The central part of the cell was then attached onto the cell bottom and the top part of the cell, containing the stirring rod, impeller, and coupling bushing, was attached to the top part of the cell. Air saturated buffer solution at 35°C was then poured into the assembled cell and filled almost to the top. Next, heating coiled tubing was placed around the cell, the tubing was connected to the heating bath, insulation was wrapped around and on top of the cell, and the flow of heating fluid was turned on. The speed was then set at 400 rpm and current data was collected until the steady state was reached. The speed was then reset in 100 rpm increments up to 1200 rpm, and data was again collected. This data was then used to get the oxygen permeability by plotting the inverse of steady current versus the Reynolds number to the minus 2/3. An oxygen permeability of 95.9 + 28.5 Barrers was obtained. Hydrogels according to the present invention, as well as contact lenses made from these hydrogels, preferably have an oxygen permeability of more than about 15 Barrers, more preferably at least about 60 Barrers, most preferably at least about 90 Barrers.
Equilibrium Water Content
The water content of the hydrogels was evaluated in terms of the swollen- weight-to -dry- weight ratio. The dry hydrogel was weighed and then immersed in water as well as phosphate buffered saline. At regular intervals, the swollen gels were lifted, patted dry, and weighed until equilibrium was attained. The percentage of equilibrium water content (WC) was calculated from the swollen and dry weights of the hydrogel:
W —W
where Ws and Wj are the weights of swollen and dry hydrogel, respectively.
The parameters varied to obtain hydrogels with differing water content were the molecular weight of the PEG macronomonomer, the weight fraction of PAA in the second network, as well as the amount of crosslinking agent (e.g. triethylene glycol dimethacrylate, or low molecular weight PEG-DA) added to the first or second networks. FIG. 8 shows water content data for PEG networks of varying macromonomer MW (white bars), and PEG/PAA IPNs made with PEG macromonomers of varying MW in deionized water (gray bars) and in the ionizing conditions of PBS, pH 7.4 (black bars). The water content data for the PAA network alone in deionized water (gray diagonal-patterned bars) and in PBS5 pH 7.4 (black square-patterned bars) is shown on the right as a basis for comparison. Table 1 shows the effect of varying the concentration of acrylic acid monomer used to prepare the second network on the equilibrium water content of PEG/PAA IPNs. In general, lower concentrations of acrylic acid monomer leads to hydrogels with higher equilibrium water content.
Table 1: Equilibrium Water Content of PEG(8.0k)/PAA hydrogels with varying preparation concentration of acrylic acid (AA) monomer
Concentration of AA Equilibrium Water Content in the preparation state of PEG/PAA IPN
30% 99%
40% 91%
50% 83%
Hydrogels according to the present invention, as well as contact lenses made from these hydrogels, preferably have an equilibrium water content of between about 20-95%, more preferably between about 70-90% or between about 20-60%.
Because different MWs of PEG and different starting concentrations of acrylic acid result in different amounts of equilibrium water content, the final amount of PEG and PAA in the hydrogel varies depending on the MW of the starting PEG used and the concentration of acrylic acid used. Examples of compositions of varying weight ratios of PEG and PAA that have been made according to the present invention are shown in Table 2. The compositions in this table were all made using a starting concentration of 50% PEG macromonomers. Table 2: Compositions of PEG(8.0k)/PAA IPNs with varying preparation concentration of AA monomer
Figure imgf000014_0001
Optical clarity
The percentage (%) of light transmittance of IPN hydrogels composed of PEG (50% w/v in dFfeO) in the preparation state of the first network and polyacrylic acid (50% v/v in dH2θ) at 550 nm was also measured using a Varian Gary lE/Cary 3E UV- Vis spectrophotometer following the method described by Saito et al (Saito et al, "Preparation and Properties of Transparent Cellulose Hydrogels", Journal of Applied Polymer Science, Vol. 90, 3020-3025 (2003)). The refractive index of the PEG/PAA hydrogel (with PEG MW 8000) was measured using an Abbe Refractometer (Geneq, Inc., Montreal, Quebec). The percentage of light transmittance was found to be 90%, and the refractive index was found to be 1.35. Hydrogels according to the present invention, as well as contact lenses made from these hydrogels, are preferably at least about 70% transparent. An example of this hydrogel is shown in FIG. 9. This hydrogel had an equilibrium water content of 85% and a tensile strength of 1.1 MPa.
Protein adsorption
. i
IPN hydrogels of the present invention have a high resistance to protein adsorption. This makes them especially well suited for use in extended wear contact lenses. To demonstrate this, primary rabbit corneal epithelial cells was cultured and seeded at a concentration of 1 x 10s cells/mL onto unmodified PEG/PAA hydrogels previously incubated in a 0.3% collagen type I solution and PEG/PAA hydrogels with photochemically bound collagen type I on its surface. Representative results from these experiments are shown in the photomicrographs in FIG. 10. FIG. 1OA shows no cell attachment or spreading on an unmodified PEG/PAA hydrogel that was incubated in collagen type I. FIG. 1OB, in contrast, shows excellent cell growth and spreading upon a PEG/PAA surface that was covalently modified with collagen type I. These results show that without chemical modification of the hydrogel surfaces, collagen type I does not adsorb and, as a consequence, epithelial cells will not grow on or adhere to the PEG/PAA IPNs.
FIG. 11 shows results of an experiment in which MaxiSorp Polystyrene (indicated by diamonds), PEG /PAA IPN hydrogels (indicated by squares) and PHEMA (indicated by triangles) were incubated with varying concentrations of a lysozyme protein solution. Lysozyme is a protein present in the tear film, and is thus an important indicator of protein adsorption for contact lenses. After 1 hour at 37 degrees Celsius, the materials were washed with phosphate buffered saline (PBS) and incubated with a horse-radish-peroxidase-conjugated lysozyme primary antibody (1:4000 dilution) followed by incubation with an 2,2'-azino-bis(3- ethylbenzthiazoline-6-sulphonic acid) (ABTS) substrate. FIG.. 9 shows that PEG/PAA hydrogels show an increased resistance to lysozyme adsorption when compared to MaxiSorp, and a similar level of lysozyme adsorption to PHEMA, which is a material used in current contact lenses. Although PHEMA exhibited a lower background absorption than did PEG/PAA, both PHEMA and PEG/PAA showed little change from the baseline absorption at 405 nm with increasing Iyso2yme concentration. Thus, PEG /PAA IPN hydrogels show a high resistance to protein adsorption, making them well suited for use as contact lenses
As one of ordinary skill in the art will appreciate, various changes, substitutions, and alterations could be made or otherwise implemented without departing from the principles of the present invention. Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents.

Claims

CLAIMSWhat is claimed is:
1. A contact lens, comprising: a) a first polymer network, wherein said first polymer network is based on a hydrophilic telechelic macromonomer, and wherein said first polymer network comprises at least about 50% of said telechelic macromonomer by dry weight; and b) a second polymer network, wherein said second polymer network is based on a hydrophilic monomer; wherein said hydrophilic monomer is polymerized and cross-linked to form said second polymer network in the presence of said first polymer network, and wherein said first and second polymer networks form an interpenetrating polymer network hydrogel.
2. The contact lens as set forth in claim 1, wherein said first polymer network comprises at least about 75% of said telechelic macromonomer by dry weight.
3. The contact lens as set forth in claim 1, wherein said first polymer network comprises at least about 95% of said telechelic macromonomer by dry weight.
4. The contact lens as set forth in claim 1, wherein said hydrophilic telechelic macromonomer is poly(ethylene) glycol (PEG) diacrylate or poly(ethylene) glycol (PEG) dimethacrylate.
5. The contact lens as set forth in claim 1, wherein said hydrophilic telechelic macromonomer has a molecular weight between about 575 Da to about 20,000 Da.
6. The contact lens as set forth in claim 1, wherein said hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide5 methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2- hydroxyethyl acrylate or derivatives thereof.
7. The contact lens as set forth in claim 1. wherein at least one surface of said interpenetrating polymer network hydrogel is surface modified.
8. The contact lens as set forth in claim 7, wherein said surface is modified with a layer of poly(ethylene) glycol (PEG) macromonomers, polymerized PEG macromonomers, polymerized PEG diacrylate, polymerized PEG dimethacrylate, polymerized PEG-acrylate or polymerized PEG-methacrylate.
9. The contact lens as set forth in claim 1, wherein said first polymer network further comprises a hydrophilic monomer grafted onto said first polymer network.
10. The contact lens as set forth in claim 9, wherein said hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate or derivatives thereof.
11. The contact lens as set forth in claim 1, wherein said second polymer network further comprises a hydrophilic telechelic macromonomer grafted onto said second polymer network.
12. The contact lens as set forth in claim 11, wherein said hydrophilic telechelic macromonomer is PEG diacrylate or PEG dimethacrylate.
13. The contact lens as set forth in claim 1, wherein said interpenetrating network hydrogel has a tensile strength of at least about 1 MPa
14. The contact lens as set forth in claim 1, wherein said interpenetrating network hydrogel has an oxygen permeability of at least about 15 Barrers
15. The contact lens as set forth in claim 1, wherein said interpenetrating network hydrogel has an equilibrium water content of between about 70% and about 95%.
16. The contact lens as set forth in claim 1, wherein said interpenetrating network hydrogel is at least about 70% transparent.
17. The contact lens as set forth in claim 1, further comprising an additive for UV protection.
18. An interpenetrating polymer network hydrogel, comprising: a) a first polymer network, wherein said first polymer network is based on a hydrophilic telechelic macromonomer, and wherein said first polymer network comprises at least about 50% by dry weight of said telechelic macromonomer; and b) a second polymer network, wherein said second polymer network is based on a hydrophilic monomer;
wherein said hydrophilic monomer is polymerized and cross-linked to form said second polymer network in the presence of said first polymer network.
19. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said first polymer network comprises at least about 75% by dry weight of said telechelic macromonomer.
20. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said first polymer network comprises at least about 95% by dry weight of said telechelic macromonomer.
21. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said hydrophilic telechelic macromonomer is poly(ethylene) glycol (PEG) diacrylate or poly(ethylene) glycol (PEG) dimethacrylate.
22. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said hydrophilic telechelic macromonomer has a molecular weight between about 575 Da to about 20,000 Da.
23. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N- isopropylacrylamide, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate or derivatives thereof.
24. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein at least one surface of said interpenetrating polymer network hydrogel is surface modified.
25. The interpenetrating polymer network hydrogel as set forth in claim 24, wherein said surface is modified with a layer of poly(ethylene) glycol (PEG) macromonomers, polymerized PEG macrornonomers, polymerized PEG diacrylate, or polymerized PEG dimethacrylate.
26. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said first polymer network further comprises a hydrophilic monomer grafted onto said first polymer network.
27. The interpenetrating polymer network hydrogel as set forth in claim 26, wherein said hydrophilic monomer is acrylic acid, acrylamide, hydroxyethyl acrylamide, N-isopropylacrylamide, methacrylic acid, 2-acrylamido-2- methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate or derivatives thereof.
28. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said second polymer network further comprises a hydrophilic telechelic macromonomer grafted onto said second polymer network.
29. The interpenetrating polymer network hydrogel as set forth in claim 28, wherein said hydrophilic telechelic macromonomer is PEG diaciylate or PEG dimethacrylate.
30. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said interpenetrating network hydrogel has a tensile strength of at least about 1 MPa.
31. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said interpenetrating network hydrogel has an oxygen permeability of at least 15 Barrers.
32. The interpenetrating polymer network hydrogel as set form in claim 18, wherein said interpenetrating network hydrogel has an equilibrium water content of between about 70% and about 95%.
33. The interpenetrating polymer network hydrogel as set forth in claim 18, wherein said interpenetrating network hydrogel is at least about 70% transparent.
PCT/US2006/047170 2006-03-17 2006-12-08 Interpenetrating polymer network hydrogel contact lenses WO2007108842A2 (en)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US78330706P 2006-03-17 2006-03-17
US60/783,307 2006-03-17
US11/409,218 2006-04-20
US11/409,218 US20060287721A1 (en) 2004-10-05 2006-04-20 Artificial cornea
US84394206P 2006-09-11 2006-09-11
US60/843,942 2006-09-11
US11/636,114 2006-12-07
US11/636,114 US7857447B2 (en) 2004-10-05 2006-12-07 Interpenetrating polymer network hydrogel contact lenses

Publications (2)

Publication Number Publication Date
WO2007108842A2 true WO2007108842A2 (en) 2007-09-27
WO2007108842A3 WO2007108842A3 (en) 2008-02-28

Family

ID=38522867

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2006/047170 WO2007108842A2 (en) 2006-03-17 2006-12-08 Interpenetrating polymer network hydrogel contact lenses

Country Status (2)

Country Link
US (1) US7857447B2 (en)
WO (1) WO2007108842A2 (en)

Families Citing this family (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10344411A1 (en) * 2003-09-25 2005-04-28 Roehm Gmbh hydrogel
US8821583B2 (en) * 2004-10-05 2014-09-02 The Board Of Trustees Of The Leland Stanford Junior University Interpenetrating polymer network hydrogel
US20090088846A1 (en) 2007-04-17 2009-04-02 David Myung Hydrogel arthroplasty device
US20110166247A1 (en) * 2006-12-07 2011-07-07 David Myung Interpenetrating polymer network hydrogel contact lenses
EP2112933A4 (en) * 2007-02-16 2011-01-12 Univ Leland Stanford Junior Strain-hardened interpenetrating polymer network hydrogel
US20100280147A1 (en) * 2008-02-15 2010-11-04 Laura Hartmann High refractive index interpenetrating networks for ophthalmic applications
US20090220578A1 (en) * 2008-02-28 2009-09-03 Depuy Products, Inc. Hydrogel composition and method for making the same
US20090295004A1 (en) * 2008-06-02 2009-12-03 Pinsly Jeremy B Silicone hydrogel contact lenses displaying reduced protein uptake
US8883915B2 (en) 2008-07-07 2014-11-11 Biomimedica, Inc. Hydrophobic and hydrophilic interpenetrating polymer networks derived from hydrophobic polymers and methods of preparing the same
US20120209396A1 (en) 2008-07-07 2012-08-16 David Myung Orthopedic implants having gradient polymer alloys
JP5722773B2 (en) * 2008-08-05 2015-05-27 バイオミメディカ インコーポレイテッド Polyurethane grafted hydrogel
WO2010042943A1 (en) * 2008-10-10 2010-04-15 Massachusetts Institute Of Technology Tunable hydrogel microparticles
EP2638878B1 (en) 2010-07-30 2019-10-23 Novartis AG Silicone hydrogel lenses with water-rich surfaces
US9211256B2 (en) 2011-03-08 2015-12-15 The Johns Hopkins University Wound healing compositions comprising biocompatible cellulose hydrogel membranes and methods of use thereof
US8871016B2 (en) 2011-08-03 2014-10-28 The Johns Hopkins University Cellulose-based hydrogels and methods of making thereof
US9175153B2 (en) 2011-03-08 2015-11-03 The Johns Hopkins University Cellulose hydrogel compositions and contact lenses for corneal applications
EP3357518B1 (en) 2011-10-03 2020-12-02 Hyalex Orthopaedics, Inc. Polymeric adhesive for anchoring compliant materials to another surface
US9005700B2 (en) 2011-10-12 2015-04-14 Novartis Ag Method for making UV-absorbing ophthalmic lenses
WO2013078284A1 (en) 2011-11-21 2013-05-30 Biomimedica, Inc. Systems, devices, and methods for anchoring orthopaedic implants to bone
US9395468B2 (en) * 2012-08-27 2016-07-19 Ocular Dynamics, Llc Contact lens with a hydrophilic layer
EP2932314B1 (en) 2012-12-17 2017-02-01 Novartis AG Method for making improved uv-absorbing ophthalmic lenses
CN105917270A (en) 2013-11-15 2016-08-31 视觉力学有限责任公司 Contact lens with a hydrophilic layer
HUE038809T2 (en) 2013-12-17 2018-11-28 Novartis Ag A silicone hydrogel lens with a crosslinked hydrophilic coating
US9550845B2 (en) 2014-04-08 2017-01-24 The Board Of Trustees Of The University Of Illinois Multiple stage curable polymer with controlled transitions
WO2016032926A1 (en) 2014-08-26 2016-03-03 Novartis Ag Method for applying stable coating on silicone hydrogel contact lenses
US10525170B2 (en) 2014-12-09 2020-01-07 Tangible Science, Llc Medical device coating with a biocompatible layer
US11077228B2 (en) 2015-08-10 2021-08-03 Hyalex Orthopaedics, Inc. Interpenetrating polymer networks
CN110308570A (en) * 2015-09-15 2019-10-08 星欧光学股份有限公司 Contact lens products
CN108369291B (en) 2015-12-15 2021-07-20 爱尔康公司 Method for applying a stable coating on a silicone hydrogel contact lens
EP3724696A1 (en) 2017-12-13 2020-10-21 Alcon Inc. Weekly and monthly disposable water gradient contact lenses
US10869950B2 (en) 2018-07-17 2020-12-22 Hyalex Orthopaedics, Inc. Ionic polymer compositions
CN113926001B (en) * 2021-09-13 2023-03-07 熹微(苏州)生物医药科技有限公司 Bionic cornea and preparation method thereof
CN113735964B (en) * 2021-09-13 2023-05-05 熹微(苏州)生物医药科技有限公司 Pegylated collagen and preparation method and application thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5770669A (en) * 1994-12-05 1998-06-23 Ciba Vision Corporation Silcone-containing polymer having oxygen permeability suitable for ophalmic applications
US5962005A (en) * 1997-04-17 1999-10-05 Rengo Co., Ltd Transparent cellulose hydrogel and production process thereof
US20040138382A1 (en) * 2001-01-29 2004-07-15 Rodenstock Gmbh Photochromic plastic object
US20060008506A1 (en) * 2004-06-28 2006-01-12 Cipriano De Sousa Herminio J Method for preparing therapeutic ophthalmic articles using compressed fluids

Family Cites Families (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4973493A (en) * 1982-09-29 1990-11-27 Bio-Metric Systems, Inc. Method of improving the biocompatibility of solid surfaces
JPS6145765A (en) * 1984-08-07 1986-03-05 宇部興産株式会社 Blood vessel prosthesis and its production
US4680336A (en) * 1984-11-21 1987-07-14 Vistakon, Inc. Method of forming shaped hydrogel articles
US5030230A (en) * 1986-05-16 1991-07-09 Great Plains Eye Clinic, Ltd. Corneal implant
US4693715A (en) * 1986-06-19 1987-09-15 Abel Robert Jr Artificial cornea
US5112350A (en) * 1986-10-16 1992-05-12 Cbs Lens, A California General Partnership Method for locating on a cornea an artificial lens fabricated from a collagen-hydrogel for promoting epithelial cell growth and regeneration of the stroma
US5114627A (en) * 1986-10-16 1992-05-19 Cbs Lens Method for producing a collagen hydrogel
US5171318A (en) * 1987-11-09 1992-12-15 Chiron Ophthalmics, Inc. Treated corneal prosthetic device
US5067961A (en) * 1988-02-18 1991-11-26 Autogenesis Technologies, Inc. Non-biodegradable two phase corneal implant and method for preparing same
US4931287A (en) * 1988-06-14 1990-06-05 University Of Utah Heterogeneous interpenetrating polymer networks for the controlled release of drugs
US4978352A (en) * 1989-06-07 1990-12-18 Fedorov Svjatoslav N Process for producing collagen-based cross-linked biopolymer, an implant from said biopolymer, method for producing said implant, and method for hermetization of corneal or scleral wounds involved in eye injuries, using said implant
US5115056A (en) * 1989-06-20 1992-05-19 Ciba-Geigy Corporation Fluorine and/or silicone containing poly(alkylene-oxide)-block copolymers and contact lenses thereof
CA2101773A1 (en) 1991-01-31 1992-08-01 Toyoichi Tanaka Interpenetrating-polymer network phase-transition gels
IT1260154B (en) * 1992-07-03 1996-03-28 Lanfranco Callegaro HYALURONIC ACID AND ITS DERIVATIVES IN INTERPENETRATING POLYMERS (IPN)
US5374515A (en) * 1992-11-13 1994-12-20 Organogenesis, Inc. In vitro cornea equivalent model
US5836313A (en) * 1993-02-08 1998-11-17 Massachusetts Institute Of Technology Methods for making composite hydrogels for corneal prostheses
US5674942A (en) * 1995-03-31 1997-10-07 Johnson & Johnson Vision Products, Inc. Interpenetrating polymer networks for contact lens production
US5976648A (en) 1995-12-14 1999-11-02 Kimberly-Clark Worldwide, Inc. Synthesis and use of heterogeneous polymer gels
US6238799B1 (en) * 1996-02-09 2001-05-29 Surface Solutions Laboratories, Inc. Articles prepared from water-based hydrophilic coating compositions
US6005160A (en) * 1996-02-22 1999-12-21 National Science Council Heterobifunctional membrane in application of artificial cornea
EP0891753A4 (en) * 1996-11-13 1999-09-22 Menicon Co Ltd Artificial cornea
US5904927A (en) * 1997-03-14 1999-05-18 Northeastern University Drug delivery using pH-sensitive semi-interpenetrating network hydrogels
US6224893B1 (en) * 1997-04-11 2001-05-01 Massachusetts Institute Of Technology Semi-interpenetrating or interpenetrating polymer networks for drug delivery and tissue engineering
CA2227827A1 (en) * 1998-01-23 1999-07-23 Unknown In vitro artificial cornea and sclera
DK1062278T3 (en) * 1998-02-23 2006-09-25 Mnemoscience Gmbh Polymers with shape memory
RU2215542C2 (en) * 1998-02-23 2003-11-10 Массачусетс Инститьют Оф Текнолоджи Biodecomposing polymers able recovery of form
WO2000002937A1 (en) * 1998-07-08 2000-01-20 Sunsoft Corporation Interpenetrating polymer network hydrophilic hydrogels for contact lens
US6361560B1 (en) * 1998-12-23 2002-03-26 Anamed, Inc. Corneal implant and method of manufacture
US6086204A (en) 1999-09-20 2000-07-11 Magnante; Peter C. Methods and devices to design and fabricate surfaces on contact lenses and on corneal tissue that correct the eye's optical aberrations
EP1197782B1 (en) * 2000-03-22 2004-06-02 Menicon Co., Ltd. Material for ocular lens
US6689165B2 (en) * 2000-03-31 2004-02-10 Board Of Supervisors Of Louisana State University And Agricultural And Mechanical College Surface modifications for enhanced epithelialization
US6254637B1 (en) * 2000-04-10 2001-07-03 Lucid Korea Co., Ltd. Artificial cornea and implantation thereof
US6372815B1 (en) * 2000-04-18 2002-04-16 Ocular Sciences Inc Ophthalmic lenses and compositions, and methods for producing same
JP2004510199A (en) * 2000-09-28 2004-04-02 ノバルティス アクチエンゲゼルシャフト Perforated lens for increased tear flow and method of manufacturing the lens
WO2003093327A1 (en) * 2002-05-01 2003-11-13 Hokkaido Technology Licensing Office Co., Ltd. Gel having multiple network structure and method for preparation thereof
AU2003276137A1 (en) * 2002-06-18 2003-12-31 Board Of Trustees Of The Leland Stanford Junior University Artificial cornea
US7049351B2 (en) * 2002-11-01 2006-05-23 Novartis Ag Moldings and preparation and uses thereof
US20060127878A1 (en) * 2002-12-18 2006-06-15 Salomon David H Hydrogel preparation and process of manufacture thereof
HUE035379T2 (en) * 2003-04-24 2018-05-02 Coopervision Int Holding Co Lp Hydrogel contact lenses and package systems and production methods for same
JP4709956B2 (en) * 2004-06-18 2011-06-29 国立大学法人北海道大学 Artificial meniscus
US20070005140A1 (en) * 2005-06-29 2007-01-04 Kim Daniel H Fabrication and use of biocompatible materials for treating and repairing herniated spinal discs
SG165337A1 (en) * 2005-09-09 2010-10-28 Ottawa Hospital Res Inst Interpenetrating networks, and related methods and compositions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5770669A (en) * 1994-12-05 1998-06-23 Ciba Vision Corporation Silcone-containing polymer having oxygen permeability suitable for ophalmic applications
US5962005A (en) * 1997-04-17 1999-10-05 Rengo Co., Ltd Transparent cellulose hydrogel and production process thereof
US20040138382A1 (en) * 2001-01-29 2004-07-15 Rodenstock Gmbh Photochromic plastic object
US20060008506A1 (en) * 2004-06-28 2006-01-12 Cipriano De Sousa Herminio J Method for preparing therapeutic ophthalmic articles using compressed fluids

Also Published As

Publication number Publication date
US20070126982A1 (en) 2007-06-07
US7857447B2 (en) 2010-12-28
WO2007108842A3 (en) 2008-02-28

Similar Documents

Publication Publication Date Title
US7857447B2 (en) Interpenetrating polymer network hydrogel contact lenses
US20110166247A1 (en) Interpenetrating polymer network hydrogel contact lenses
EP1505093B1 (en) Hydrogel of (semi)interpenetrating network structure and process for producing the same
EP2222736B1 (en) High water content silicone hydrogels
TWI512017B (en) Wettable silicone hydrogel contact lenses and related compositions and methods
EP1235866B1 (en) Soft contact lenses
EP1197782B1 (en) Material for ocular lens
JP5059407B2 (en) Gel, production method thereof, water-absorbent resin, lubricant, and cell culture substrate
US20070232755A1 (en) Contact Lens
JPH07508063A (en) Surface wettable silicone hydrogel
JPH07502547A (en) Wettable silicone hydrogel compositions and methods
TW200937067A (en) Polymerizable contact lens formulations and contact lenses obtained therefrom
JPH06121826A (en) Lens material for eye
JPS6330820A (en) Polymer material for transparent hydrogel contact lens and optically transparent hydrophilic contact lens comprising the same
EP1216142A1 (en) Thermoformable ophthalmic lens
US8071661B2 (en) Biomedical devices
Yokoo et al. Smart lenses developed with high-strength and shape memory gels
JPH11287971A (en) Lens material for eye
JP2015163698A (en) Method for preparing biocompatible polymer, biocompatible polymer and use thereof
JP2006213868A (en) Gel and its manufacturing method
Liu et al. Self-healable porous polyampholyte hydrogels with higher water content as cell culture scaffolds for tissue engineering applications
JP6135896B2 (en) Polymer gel and method for producing the same
JP2002327063A (en) Hydrophilic polysiloxane monomer, contact-lens material comprising copolymer thereof, and contact-lens
WO2023209855A1 (en) Addition type polymer and silicone hydrogel lens material
KR20220114445A (en) Electric field sensitive hydrogel actuator and manufacturing method thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 06845179

Country of ref document: EP

Kind code of ref document: A2

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06845179

Country of ref document: EP

Kind code of ref document: A2