AU718546B2 - Biocompatible optically transparent polymeric material based upon collagen and method of making - Google Patents

Description

WO 96/40818 PCT/US96/10013 Title of the Invention Biocompatible Optically Transparent Polymeric Material Based Upon Collagen and Method of Making Related Application This application is a continuation-in-part application of U.S. patent application Serial No.

08/279,303, filed July 22, 1994, which application is incorporated by reference in its entirety.

Field of the Invention This invention relates to a biocompatible polymer containing the copolymerization product of a mixture of hydrophobic and hydrophilic acrylic and/or allelic monomers, and telo-collagen preliminarily purified from glucoproteins and proteoglucanes. The material is useful for the production of soft intraocular lenses, refractive intraocular contact lenses, and standard contact lenses useful for example, in correcting aphekia, myopia and hypermetropia.

Background of the Invention Ordinary polymers, based upon pure non-polyenic acrylates or allelic monomers, do not have on their surfaces water-solvent ionic layers on their surfaces which are buffered against the WO 96/40818 PCT/US96/10013 -2sorption of proteins. Providing water-solvent ionic layers on the surface of the polymer is desirable because such layers will greatly improve the bio-compatibility of the lens with cell membranes of the recipient's eye.

Polyenic water-solvent ionic monomers may be used in order to produce a water-solvent layer. However, this decreases the resistance of such copolymers against swelling. For example, the system of polyenic copolymers, based upon acrylamid or acrylic acid with HEMA has a tendency towards excessive swelling beyond all bounds. This happens because pure homopolymers, polyacrylamide or polyacrylic acid, contained in this system, dissolve in water.

Therefore, it is an advantage to produce a polymer which would be able to form such a vital water-solvent layer, and would not affect the polymer resistance against swelling.

References concerning graft-copolymers of collagen include U.S. Patent No. 4,388,428 (June 14, 1983) and U.S. Patent No. 4,452,925 (June 5, 1994). In these patents, a system of water-soluble monomers and A telo-collagen is used. However, this system is not hydrolytically stable and is not sufficiently optically transparent. In U.S. Patent No. 4,452,925, nothing is mentioned of special optical conditions needed for transparent polymer production. The watersolvent A telo-collagen disclosed in this patent does not have the capacity to form a gel in the organic monomer solution, and therefore the collagen precipitates or coagulates.

According to one aspect of the invention there is provided a biocompatible, optically transparent, polymeric material based on collagen, comprising: one or more hydrophilic acrylic or allelic monomers, and one or more hydrophobic acrylic or allelic monomers; and telo-collagen containing telo-peptides, wherein said one or more hydrophillic acrylic or allelic monomers and said one or more hydrophobic acrylic or allelic monomers, are graftpolymerized with said telo-collagen to form a biocompatible, optically transparent, polymeric material based on collagen.

According to another aspect of the invention there is provided a method for producing a biocompatible, optically transparent, polymeric material, comprising: dissolving an acid-telo-collagen solution in one or more hydrophilic monomers to form a collagen/hydrophilic solution; dissolving one or more hydrophobic monomers in one or more hydrophilic monomers to form a hydrophobic/hydrophilic solution; combining said collagen/hydrophillic and said hydrophobic/hydrophilic solution to form a resultant solution; and 20 graft-polymerizing said resultant solution to form the present biocompatible, optically transparent, polymeric material based on collagen.

The preset invention also provides a deformable lens comprised of the above described optically transparent, biocompatible, polymeric material.

The present invention is also directed to methods for correcting aphekia (absence of the lens of the eye), myopia or hypermetropia in a patient by surgically implanting in the eye of the patient, the deformable lens as described above.

14/02/2000 The biocompatible polymeric material according to the present invention is preferably made as a copolymerization product of a mixture of hydrophobic and hydrophilic acrylic and/or allelic monomers graft polymerized witrh telocollagen. For example, one or more hydrophobic acrylic and/or allelic monomers are mixed with one or more hydrophilic acrylic and/or allelic monomers, and the resultant solution is then mixed with telo-collagen dissolved in one or more hydrophillic acrylic and/or allelic monomers. The resulting material is then irradiated to form the present biocompatible optically transparent polymeric material.

Preferably the telo-collagen used in the present invention is essentially type IV collagen obtained from pig's eye sclera or cornea. The collagen is a .naturally stable polyenic, which comprises hydrophobic, hydroxylic and polarized amino-acids (Matsumura, Relationship Between Amino-Acid Composition and Differentiation of Collagen, Lut. J. Biochem. 3(15):265-274 14/02/2000 WO 96/40818 PCT/US96/10013 (1972), and Traub and Piez The Chemistry and Structure of Collagen, Advances in Protein Chem 25:243-352, (1971). It is not advisable to use a modified collagen in the system according to the present invention since this collagen biodegrades with time Patent No.

4,978,352, December 18, 1990).

The resulting biocompatible polymeric material is an elastic biopolymer, based upon the mixture of the hydrophobic and hydrophilic monomers and telo-collagen. The product of the hydrophobic and hydrophilic monomer copolymerization exhibits an elevated hydrolytic stability and a much higher index of refraction, if compared with a polymer which is based upon hydrophilic monomers alone.

The high molecular mass of telo-collagen molecules (320,000D), their size (up to 1000A), the disorientation of molecules in space, the refraction index 1.47 (Hogan J. J. et. al., Histology of Human Eyes, An Atlas and Textbook, Philadelphia, London, Toronto, (1971)), and other characteristics of collagen make it impossible to produce optically transparent hydrogel implants made of collagen alone. The refraction index of the hydrogel base substance, the aqueous number is equal to 1.336, which is substantially different from the refractive index of collagen 1.47, resulting in opacification of the gel, if a suspension of collagen in aqueous monomer is made.

WO 96/40818 PCTfUS96/10013 -6- In order to produce an optically homogeneous gel in the mixture of organic monomers it is necessary to utilize telo-collagen containing telo-peptide. Telo-peptide is the basic element of interaction among collagen molecules. This produces a stable gel in the mixture of hydrophobic and hydrophilic monomers, and this gel neither precipitates nor coagulates.

For the purpose of increasing the optical transparency and homogeneity in this system, the refraction index of polymer and of telo-collagen should be approximately equal, so that the intensity of light diffusion is close to zero, in accordance with Reley's equation Frolof, Course of Colidle Chemistry, Moskva Chemia, 1989):

N,

2

N

2 C* V 2 WHEREAS, I I 24 (1 COS 2 w) NZ 2N XP, I is intensity of incident light; I is the intensity of diffused light as a unit of radiation volume; P, distance to detector; w light diffusion angle; WO 96/40818 PCT/US96/10013 -7- C concentration of particles per volume unit; X length of incident light wave; N, refraction index of particles; N. refraction index of basal substance; and V volume of particles.

If N, then I, O. Thus, the intensity of light diffusion is zero.

A preferred hydrophilic acrylic monomer for use in the present invention is 2hydroxyethyl methacrylate (HEMA), and a preferred hydrophobic monomer for use in the present invention is 4-metharyloxy-2-hydroxybenzophenone. The telo-collagen is preferably produced from pig's eye sclera or cornea.

WO 96/40818 PCT/US96/10013 -8- Detailed Description of the Preferred Embodiments I. Definitions: The below definitions serve to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms.

Telo-collagen. By the term "telo-collagen" is intended for the purposes of this invention a naturally stable polyenic, that contains hydrophobic, hydroxylic and polarized amino-acids (Matsumura, Relationship Between Amino-Acid Composition and Differentiation of Collagen Lut. J. Biochem 3(15):265-274 (1972).

The present telo-collagen is essentially type IV telo-collagen preferably made from pig's eye sclera or cornea, and has a viscosity of greater than or equal to 1000cPs. The present telocollagen retains the telo-peptides and has a refractive index of about 1.44 to 1.48.

Biocompatible polymeric material. By the terminology "biocompatible polymeric material" is intended a material which is made by combining or mixing one or more hydrophobic monomers (acrylic and/or allelic monomers), and one or more hydrophilic monomers (acrylic WO 96/40818 PCT/US96/10013 -9and/or allelic monomers), and graft-copolymerizing the resultant mixture with a telo-collagen/hydrophilic monomer/acid solution.

Monomer. By the term "monomer" denotes the molecular unit that by repetition, constitutes a large structure or polymer. For example ethylene CH 2 =CH, is the monomer of polyethylene, H(CH,)NH.

Allyl.

CH

2

CHCH

2 By the term "allyl" is intended 2-propenyl, the monovalent radical, Organic Acid. By the term "organic acid" is intended an acid made up of molecules containing organic radicals. Such acids include for example, formic acid (H-COOH), acetic acid

(CH

3 COOH) and citric acid all of which contain the ionizable -COOH group.

Acrylic. By the term "acrylic" is intended synthetic plastic resins derived from acrylic acids.

Optically Transparent. By the terminology "optically transparent" is intended the property of a polymeric material to allow the passage of light at or above the threshold of visual sensation the minimum amount of light intensity invoking a visual sensation). Preferably, WO 96/40818 PCT/US96/10013 the present biocompatible polymeric material including COLLAMER has a refractive index in the range of 1.44 to 1.48, more preferably 1.45 to 1.47, and most preferably 1.45 to 1.46. The best mode of the present invention is the biocompatible polymeric material COLLAMER.

Polymerization. By the term "polymerization" is intended a process in which monomers combine to form polymers. Such polymerization can include "addition polymerization" where monomers combine and no other products are produced, and "condensation polymerization" where a by-product water) is also formed. Known suitable polymerization processes can be readily selected and employed for the production of the present biocompatible polymeric material by those of ordinary skill in the art to which the present invention pertains.

Polyene. By the term "polyene" is intended a chemical compound having a series of conjugated (alternating) double bonds, the carotenoids.

Refractive Index. By the terminology "refractive index" is intended a measurement of the degree of refraction in translucent/transparent substances, especially the ocular media. The "refractive index" is measured as the relative velocity of light in another medium (such as the WO 96/40818 PCT/US96/10013 11 present polymeric material) as compared to the velocity of light in air. For example, in the case of air to crown glass the refractive index(n) is 1.52, in the case of air to water n=1.33.

Tensile Strength. By the terminology "tensile strength" is intended the maximal stress or load that a material is capable of sustaining expressed in kPa. The present biocompatible polymeric material including COLLAMER has a tensile strength in the range of about 391-1778 kPa, preferably 591-1578 kPa, more preferably 791-1378 kPa, and most preferably in the range of from 991 kPa to 1178 kPa. The present material "COLLAMER" has a tensile strength of preferably 1085 493 kPa. The tensile strength of a polymeric material can be readily determined using known methods, by those of ordinary skill in the art.

Hypennetropia. By the term "hypermetropia" is intended farsightedness/longsightedness, long or far sight which is an optical condition in which only convergent rays can be brought to focus on the retina. Such conditions include: absolute that cannot be overcome by an effort of accommodation; axial that is due to shortening of the anteroposterior diameter of the globe of the eye; curvature which is due to the decreased refraction of the anterior diameter of the globe of the eye; manifest.--h. that can be compensated by accommodation; facultative manifest latent the difference WO 96/40818 PCT/US96/10013 12between total and manifest and total that which can be determined after complete paralysis of accommodation by means of a cycloplegic; index arising from decreased refractivity of the lens.

Myopia. By the term "myopia" is intended "shortsightedness; nearsightedness; near or short sight; that optical condition in which only rays a finite distance from the eye focus on the retina. Such conditions include: axial due to elongation of the globe of the eye; curvature.-- m. due to refractive errors resulting from excessive corneal curvature; (3) degenerative.--pathologic index arising from increased refractivity of the lens, as in nuclear sclerosis; malignant.--pathologic night.--m. occurring in a normally emmetropic eye because long light rays focus in front of the retina; pathologic.--degenerative or malignant., progressive, marked by fundus changes, posterior staphyloma and subnormal corrected acuity; prematurity observed in infants of low birth weight or in association with retrolental fibroplasia; senile lenticular.--second sight; (10) simple arising from failure of correlation of the refractive power of the anterior segment and the length of the eyeball; (11) space.--a type of m. arising when no contour is imaged on the retina; and (12) transient.--m. observed in accommodative spasm secondary to iridocyclitis or ocular contusion.

WO 96/40818 PCT/US96/10013 13- Ilydrophilic allelic monomer. By the term "hydrophilic allelic monomer" is intended for the purposes of the present invention any monomer containing an allyl group which monomer is soluble in water.

Hydrophilic acrylic monomer. By the terminology "hydrophilic acrylic monomer" is intended any monomer containing an acrylic group which monomer is soluble in water. For example, HEMA is a hydrophilic acrylic monomer because it is soluble in water even though it contains both hydrophilic groups and hydrophobic groups.

Hydrophobic allelic monomer. By the term "hydrophobic allelic monomer" is intended for the purposes of the present invention, any monomer contaifiing an allyl group, which monomer is not soluble in water.

Hydrophobic acrylic monomer. By the term "hydrophobic acrylic monomer" is intended for the purposes of the present invention, any monomer containing an acrylic group, which monomer is not soluble in water.

Deformnable lens. By the term "deformable lens" is intended any type of deformable lens, for example, for correcting hypermetropia or myopia, where the lens comprises the present material. Such lenses include those disclosed in U.S. Patent Application Serial Nos. 08/318,991 WO 96/40818 PCT/US96/10013 14 and 08/225,060. All of the foregoing are hereby incorporated by reference herein. Such lenses include: intraocular lenses for implantation into a patient's eye, for example, into the anterior chamber, in the bag or in the sulcas; refractive intraocular lenses for implantation into a patient's eye, for example, into the anterior chamber or in the sulcas; and standard soft contact lenses.

Implant. By the term "implant" is intended the surgical method of introducing the present lens into the eye of a patient, for example, into the anterior chamber, in the bag or in the sulcas, by the methods described in U.S. Patent Application Serial Nos. 08/195,717, 08/318,991, and 08/220,999 using for example, surgical devices disclosed in U.S. Patent Application Serial Nos. 08/197,604, 08/196,855, 08/345,360, and 08/221,013. All of the foregoing are hereby incorporated by reference.

The present hydrophilic monomers and hydrophobic monomers must be selected such that the hydrophobic monomer(s) is soluble in the hydrophilic monomer(s). The hydrophilic monomer acts as a solvent for the hydrophobic monomer. Suitable monomers can be readily selected by those of ordinary skill in the art to which the present invention pertains.

Examples of suitable hydrophobic monomers, include: 1) 4-methacryloxy-2-hydroxybenzophenone (acrylic); WO 96/40818 PCT/US96/10013 2) ethyl-3 benzoil acrylate (acrylic); 3) 3-allyl-4-hydroxyacetoplienone (allelic); 4) 2-(2 '-liydroxy-3 '-allyl-5 '-mielhiylpheiiyl)-2H-benzotriazole (allelic); N-propyl metliacrylate (acrylic); 6) allyl benzene (allelic); 7) allyl butyrate (allelic); 8) allylanisole (allelic); 9) N-propyl inethacrylate (acrylic); ethyl-methacrylate (acrylic); 11) methyl methacrylate (acrylic); 12) n-hieptyl methacrylate (acrylic).

Various examples of suitable hydr-ophilic monomers, include: 1) 2-hydroxyethyl inethacrylate (JIEMA) (acrylic); 2) hydroxypropyl methacrylate (acrylic); 3) 2-hydroxyethiyl methacrylate (acrylic); 4) hydroxypropyl. methacrylate (acrylic); allyl alcohiol (allelic); 6) poly(ethylene glycol)n monomethacrylate (acrylic); WO 96/40818 PCT/US96/10013 16- 4-hydroxybutyl methacrylate (acrylic); allyl glucol carbonate (allelic).

II. Method of Making the Present Polymeric Material Based on Collagen The following is a description of a preferred method of making the biocompatible polymeric material according to the present invention.

Step 1: The hydrophilic monomer is mixed with an acid, in particular formic acid. The weight ratio of hydrophilic monomer to acid is preferably in the range of about 5:1 to about 50:1, preferably 14:1 to 20:1, and most preferably, 14:1. This solution is preferably filtered through a 0.2 microfilter.

Step 2: In an independent step, an acidic telo-collagen solution is prepared by mixing telo-collagen with organic acid (preferably formic acid). The solution is preferably 2 by weight telo-collagen in 1 M formic acid.

WO 96/40818 PCT/US96/10013 17- Step 3: The solutions resulting from steps 1 and 2 are then mixed together. The resultant solution is preferably mixed from about 10 minutes to 60 minutes, most preferably 20 minutes at a temperature of 15-30*C. The ratio of telo-collagen to hydrophilic monomer is about 1:2 to about 1:7, preferably 1:3 to 1:6, and most preferably 1:4.

Step 4: In an independent step, the hydrophobic monomer and hydrophilic monomer are mixed together in a weight ratio of about 10:1 to 1:1, preferably 8: 'to 3:1, and most preferably 5:1. The monomers are mixed with stirring for about 30 to 90 minutes, preferably 60 minutes at 70 to 95 0 C, preferably 80-95*C, and most preferably 80-92*C. The resulting solution is preferably filtered through a 0.2 micron filter.

Step The solutions from steps 3 and 4 are mixed together in a weight ratio in the range of about 1:1 to 50:1, preferably 2:1 to 5:1, and most preferably 3:1. The solution is preferably WO 96/40818 PCT/US96/10013 -18mixed 20 minutes with no heating at a temperature of 25-40 0 C. Mixing is preferably performed with a homogenizer.

Step 6: The resulting material from Step 5 is then preferably degassed using centrifugation or other means well-known to those of ordinary skill in the art to which the present invention applies).

Step 7: The resulting material from Step 6 is irradiated to form a final product that can be dried, and stored, stored in a desiccator due to its hydroscopic nature). The material from Step 6 can also be stored in a refrigerator, for example at 5"C to 10*C, prior to irradiation.

A polymeric material according to the present invention is obtained from an interaction between a solution of telo-collagen complex, and the hydrophilic and the hydrophobic monomers under radiation of 1Mrad/hr for a total dose of from 0.20 to 0.80Mrad, preferably 0.30 to 0.60Mrad, and most preferably from 0.35 to 0.50Mrad (IMrad 10 Kgray).

WO 96/40818 PCT/US96/10013 19- A turbo-type mixer such as a homogenizer, is preferably employed for mixing the solutions of at least Steps 3 and 5, and the mixing times set forth above are based on using a turbo-type mixer. Those of ordinary skill in the art can readily select and employ other known mixers and methods, as well as time ranges.

In a preferred embodiment the present polymeric material is made by mixing the hydrophobic monomer in two stages to increase the solution viscosity, where in stage one the telo-collagen complex and a mixture of formic acid with 2-hydroxyethyl-methacrylate are used as a stabilizer of ultra-colloidal state solution and in stage two a hydrophobic blend of at least one monomer is introduced into the gel produced.

III. Standardized Method for the Compounding of the present COLLAMER A. Preparation of Acidic Collagen Solution A IM acid solution, preferably IM formic acid is prepared. The quantity of acid solution required for dissolution of the swollen tissue is calculated using a ratio of swollen collagen tissue: (sclera or cornea) acid solution of about 40:0.5 to 55:2, preferably about 45:1 to about 52:1.5, most preferably about 50:1.

WO 96/40818 PCT/US96/10013 The swollen tissue is then dispensed in a homogenizer for about 10 to 20 minutes, preferably about 15 minutes at 2 to 10 RPM, preferably 4-5 RPM, at room temperature. The produced solution is then filtered through a funnel glass filter with a pore size of 100-150 microns, the filtrate is then filtered through a second funnel glass filter with a pore size of 75-100 microns. The produced homogenic solution is then transferred into a container.

B. lydrophobic and Hydrophilic Solution Prepatation 1. The hydrophilic monomer, preferably HEMA is mixed with the hydrophobic monomer, preferably MHBPH in a weight ratio of about 5:1 and heated for one hour at to 92 0 C with stirring using a stirrer hot plate). The heated solution is then filtered through micron filter.

2. HEMA is mixed with an organic acid (preferably formic acid), preferably in a weight ratio of about 14:1. This mixture is added to the collagen solution produced in a weight ratio of HEMA solution:collagen solution of about 1:3, and mixed for about 20 minutes at room temperature. The mixing is preferably performed using a homogenizer at a rate of 6000

RPM.

WO 96/40818 PCT/US96/10013 -21 3. The HEMA MHBPH solution of is then mixed in small portions with the HEMA telo-collagen solution of The mixing is preferably performed in a homogenizer for 10 minutes at room temperature.

C. Production of COLLAMER Glass vials are then coated with approximately 7mm of paraffin wax. The solution of B(3) is then poured into the glass vials and degassed centrifuged for 15 minutes to remove air). The vials are subsequently irradiated at 5 Kgray. (Note: prior to irradiation the vials can be stored in a refrigerator, for example at 5"C to IV. Guidance for Selecting the Present Monomers The following equation can be used to aid in the selection of the appropriate concentration of monomer necessary to result in the present polymeric material having an index of refraction in the present desired range (1.44 to 1.48, preferably 1.45 to 1.47, and most preferably 1.45 to 1.46).

WO 96/40818 PCT/US96/10013 -22- The monomer of copolymerization with telo-collagen complex is selected such that: N N) (1 K,)Np N, 0.02 K, coefficient of swelling N, refractive index of water (1.336) Np refractive index of dry polymer N, refractive index of telo-collagen (about 1.45 to 1.46) i=n where Np A E Ni C i=n N, refractive index of i-monomer Ci concentration of i-monomer A coefficient of increase in refractive index due to polymerization n number of monomers WO 96/40818 PCT/US96/10013 -23 i monomer number The hydrophobic and hydrophilic monomers must be selected such that the hydrophilic monomer is a solvent for the hydrophobic monomer, the hydrophobic monomer is soluble in the hydrophilic monomer.

The manner and method of carrying out the present invention may be more fully understood by those of skill in the art to which the present invention pertains by reference to the following examples, which examples are not intended in any manner to limit the scope of the present invention or of the claims directed thereto.

Examples Example I: Compounding COLLAMER A. Preparation of acidic collagen solution Under an exhaust hood, 1 liter of distilled water was measured into a 3 liter glass beaker.

52 grams of formic acid was then added to the beaker and mixed until dissolved. Swollen WO 96/40818 PCT/US96/10013 -24 collagen containing tissue (from pig's eyes) was then added to the acid solution in the below ratios of swollen tissue:acid solution.

Swollen Tissue 517.00 grams 50.64 grams Acid Solution 10.21 grams 1.00 grams The mixture was tlen stored in a refrigerator at a temperature of 5"C, and was thereafter dispersed in a homogenizer for 15 minutes at 4-5 RPM at room temperature.

The produced solution was then filtered through a funnel glass filter with a pore size of 100-150 microns. Thereafter, the filtrate was filtered through a funnel glass filter with a pore size of 75-100 microns. The final homogenic solution was then transferred into a 250ml container.

B. MIIBI'II and IIEMA solution prepamlion 1. 527.4g of HEMA was mixed with 106.2g of MHBPH and heated for one hour at 80"C using a stirrer hot plate. The heated solution was filtered through an Acro 50-5.0 micron filter.

WO 96/40818 PCT/US96/10013 2. 1415.6g of HEMA was then mixed with 99.4g of formic acid in a hermetic glass container with a Teflon lid. 100g portions of the IIEMA/acid solution were added into 333g of telo-collagen solution and mixed for 20 minutes at room temperature. The mixing was performed in a homogenizer at a rate of 6000 RPM.

3. The HEMA/MHBPHI solution was then added in small portions to the HEMA telo-collagen solution. The mixing was performed in a homogenizer for 10 minutes at room temperature.

C. Production of COLLAMER Glass vials were coated with approximately 7mmn of paraffin wax. The resultant solution of Step B(3) was then poured into the glass vials and centrifuged for 15 minutes to remove air.

The vials were then irradiated at 5Kgray to polymerize and cross-link the present material.

Example 2: Preparation of a Biocomipatible Polymeric Optically Transparent Material In this example, pig's eye sclera was used. 300g of 2-hydroxyethyl methacrylate was mixed with 16g of formic acid. 50g of telo-collagen was filtered purified from sclera using alkaline hydrolysis with 200g NaOH and 200g of NaSO, in 2.5 liters of water, and filtered WO 96/40818 PCT/US96/10013 -26through a 100 micron filter. The telo-collagen was mixed with 2-hydroxyethyl methacrylate and the formic acid solution containing 2-hydroxyethyl methacrylale. 20g of 4-methacryloxy-2hydroxybenzophenone (MHBPH) dissolved in HEMA was then added. This mixture was radiated with gamma radiation in the range of 3.5-5.0 Kgray to polymerize and cross-link all the components.

Hydrophobic monomers were used in this system to reduce the absorption of water and swelling of the polymerized material when introduced into the aqueous media of the eye. In addition, the hydrophobic monomer was chosen so that the refractive index of the resultant polymer increased to be approximately equal to the refractive index of telo-collagen.

Example 3: The same procedure in Example 2 can be utilized, except the following monomers can be substituted: 1) ethyl-3-benzoilacrylate (hydrophobic acrylic monomer), plus 2) 2-hydroxyethyl melhacrylate (HEMA), (hydrophilic acrylic monomer).

WO 96/40818PCIS6 01 PCT/US96/10013 27 Example 4: The samne procedure in Example 2 can be utilized, except the following monomers can be substituted: 1) 3-al-4-hlyd roxyacetolphenione (hydrophobic al lel ic monomer), plus 2) 2-hydroxyethyl methacrylatc (III3MA), (hiydrophilic acrylic monomer).

Examnple The same procedure in Example 2 can be utilized, except the following monomers can be substituted: 1) 2-(2'-hydroxy-3' -allyl-5 '-mtethiylphecnyl)-2H-benzotriazole (hydrophobic allelic monomer), plus 2) hydroxypropyl methacrylate, (hydrophuilic acrylic mnonomner), WO 96/40818 WO 9640818PCT/US96/1 0013 28 Example 6: The same procedure in Example 2 can be utilized, except the following monomers can be substituted: 1) methyl niethacrylate (hydrophobic acrylic monomer), plus 2) hydroxypropyl miethacrylate (hydrophilic acrylic monomer).

Example 7:- The same procedure in Example 2 can be utilized, except the following monomers can be substituted: 1) 2-(2 '-hiydroxy-3'-ally1-5 '-miethiylphlenyl)-21 I-benizotriazole (hydrophobic allelic monomner), plus 2) hydroxypropyl methacrylate (hyd rophilic acrylic monomer).

WO 96/40818 PCT/US96/10013 -29- Example 8: A. Tensile Strength Testing of COLLAMER Material The purpose of this test was to determine the tensile properties of the present collamer material. This includes tensile strength, Young's modulus, and percent elongation at failure.

The data collected was used to construct standards for inspection. The tensile test is similar to the silicone tensile test. The sample geometry is different but the stress fundamentals remain the same.

B. Materials COLLAMER samples Instron tensile tester (Model 1122) forceps log book WO 96/40818 PCT/US96/10013 C. Procedure 1. Sample Preparation a. The dry material samples were cut into rings. Tie dimensions are: Outside diameter 10 .1 mm, inside diameter 8 .1 mm, thickness 1.0 .01 mm. The material was prepared following the procedures used to manufacture lenses. Lenses were hydrated following MSOP #113AG.

2. Testing a. The instron tester was set up for tensile specimens, following ESOP 202, RMX-3 Slab Pull Test, Rev B. The fixtures were placed into the jaws and the fixtures were brought together so that the top and bottom portion touched, by moving the crosshead up or down. When the fixtures were touching, there was WO 96/40818 PCTIUS96/1 0013 -31 approximately 8 mmn between the two pins. This was the starting position of jaw separation, so the Instron position coordinates were set to zero.

b. The load dial was set to 2 kg full scale output, the crosshead speed to 500 mmn/min and the chart recorder to 500 mm/nin. The chart speed corresponded to and recorded jaw separation. The chart buttons marked "PEN" and "TIME" were depressed.

c. The wet test sample was removed from its vial and placed so it was almost stretched between the two pins. When the sample was in place, the "UP" button on the crosshead control panel was immediately pressed. This sample was then loaded to failure.

d. When the sample failed, the "STOP" button on the crosshead control panel was pressed. The chart buttons marked "PEN" and "TIME" were then depressed so that they were in the up position.

the return on the crosshead control panel was then pressed to return the crosshead to starting position.

WO 96/40818 PCT/US96/10013 -32e. The failure point in the chart was then marked by noting the load at failure (in kg) and jaw separation.

f. Steps 2a through 2e were repealed until all samples were all tested.

C. Data Calculation for Ultimate Tensile Strength a F/A Where: S= Ultimate Tensile Strength, Pascals, (Pa).

F Force required to break the test specimen, Newtons, (N) A Hydrated cross sectional area of specimen, square meters, (m2).

Swell Factor, 1.17 w= width, mm t thickness, mm WO 96/40818 PCTIUS96/10013 33 Giveni: F .29 kg x 9.81 in/s 2 2.84 N A 2[6(w) x =2[(1.17 x 1.0) x 17 x 2.74 mm' Conversion from min' to 1112: 2.74 mm 2 2.74 x 101 M 2 A 2.74 x 10'6 m' Find: Ultimate Tensile Strength, or Solution: a F/A 2.84N/2.74 x 10-611m2 1038.3 kPa To convert kPa to psi, multiply by 145.04 x 1038.3 kiPa x 145.04 x 10-' 150.6 psi ar 1038.3 kPa or or 150.6 psi WO 96/40818 WO 9640818PCTIUS96/1 0013 34 Calculation for P'ercentl E longation 6 200[L/MCars)] Where: elongation (specified), percent, L increase in jaw separation at specified elongation, (mmn), and MCus) mean circumference of test specimen, mmn, circumference 7rd Giveni: L =41.5 min MC(Trs) wid2)/2 (v x 10 mim w x 8 rnrn)/2 28.27 mm Fhaid: Elongation, WO 96/40818 WO 9640818PCTIUS96/10013 35 Solution: 2OOIUMC(Ts)] 200[4 1.5 inin/28.27 mmn] 293.6% 6 293.6 Calculation for Younig's Alodulshi E PI/Ae Where: 13E Young's Modulus, Pascals, (Pa) P Force, Newtons, (N) 1I length of sample, meters (in) A =Cross Sectional Area, square meters, (in 2 e =Gross Longitudinal Deformation, meters, (in).

WO 96/40818 WO 9640818PCTIUS96/10013 36 Giveni: P =.29 kg x 9.81 in/s 2 2.84 N 1 .008 i A A 2[6(w) x =2 [(1.17 x 1.0) x 17 x =2.74 mm 2 Conversion front mm 2 to til 2 2.74 im 2 2.74 x 10-6 M 2 A =2.74 x 10" in 2 e =.0415 i Find: Young's Modulus, 1E Solution: E PI/Ae (2.84 N x .008 i)I(.0415 in x 2.74 x 101 Mn 2 =200.2 kPa To convert kPa to psi, multiply by 145.04 x 199.8 kPa x 145.04 x 10' 29.0 psi E 199.8 kPa or 29.0 psi WO 96/40818 PCT/US96/10013 -37- E. Discussion Tile Instron was set up and calibrated according to ESOP #202. The testing fixtures were brought together so the centerlines were aligned and there was approximately 8 mm between the posts. This was designated zero and the fixtures returned to this position every time after the test. Crosshead speed and the chart recorder speed were set to 500 mm/min.

The chart recorder was set at zero load and deflection before every test. The chart recorder recorded kilograms-force load and jaw separation. Load is used to determine the ultimate tensile strength (see formula 1, Test Data Section), the stress at which the sample fails.

The sample was not set up to test elongation using a standard gage length but a formula in the ASTM D412 standard is used to calculate the elongation (see formula 2, Data Section).

The performance of the specimen proved the material to be elastic and with the stress increasing at a linear rate until failure. The linear increase can be one of two things: it is possible the specimens have stress risers on the inside diameter. Stress risers would be caused by the milling process, because/it doesn't have the surface finish of the lathe-turned outer diameter; this may not allow the material to neck down during the plastic deformation stage of the test. The majority of the stress is concentrated on the internal circumference, which loads the stress risers more than if they were on the outside circumference; the material may not WO 96/40818 PCT/US96/10013 38 neck down (plastic deformation) as do other plastic materials such as Kapton film. It reacts like RMX-3, with the cross sectional area getting smaller as elongation increases, which is indicative of Hooke's law.

The present material showed COLLAMER good resistance to tear propagation, which would happen at any stress risers. The cross sectional area of the failed part was flat, which was indicative of elastic failure.

E. Conclusion The combined data from the present COLLAMER samples gave an average tensile strength of 1084.6 kilopascals (kPa), and an average elongation of 324.9 percent The tolerance for average tensile strength was calculated as 3 times the standard deviation, giving an upper tolerance of 1578 kPa (229 psi) and a lower tolerance of 591 kPa (86 psi). The tolerance for the elongation is calculated in the same manner. The upper tolerance is 395 elongation and the lower tolerance is calculated as 255 elongation. See Appendix 3 for the calculations. The tensile strength standard is 1085 493 kPa (157 71 psi) and the elongation is 325% 70. Young's modulus standard is 189 25 kPa (27 11 psi).

WO 96/40818 PCT/US96/10013 -39- F. References ASTM D412 Properties of Rubber in Tension ESOP 202 RMX-3 Slab Pull Test, Rev B.

Mark's Standard Handbookfor Mechanical Engineers, Ninth Edition All references cited are hereby incorporated by reference. Now having fully described this invention, it will be understood by those of skill in the art that the scope may be performed within a wide and equivalent range of conditions, parameters, and the like, without affecting the spirit or scope of the invention or of any embodiment thereof.

Claims (15)

1. A biocompatible, optically transparent, polymeric material based on collagen, comprising: one or more hydrophilic acrylic or allelic monomers, and one or more hydrophobic acrylic or allelic monomers; and telo-collagen containing telo-peptides, wherein said one or more hydrophilic acrylic or allelic monomers and said one or more hydrophobic acrylic or allelic monomers, are graft-polymerized with said telo-collagen to form a biocompatible, optically transparent, polymeric material based on collagen.

2. The polymeric material of claim 1, wherein said telo-collagen has a viscosity of greater than or equal to 1000cPs.

3. The polymeric material of claim 1, wherein said one or more hydrophilic acrylic or allelic monomers are selected from the group consisting of: IIEMA (acrylic); 2-hydroxyethyl methacrylate (HEMA) (acrylic); hydroxypropyl nethacrylate (acrylic); 2- h y d r o x y e t h y methacrylate (acrylic); hydroxypropyl methacrylate (acrylic); allyl alcohol (allelic); poly(ethylene A A WO 96/40818 PCT/US96/1 0013 41 glycol)n nionomethacrylate (acrylic); 4-hydrox ybutyl metliacrylate (acrylic); allyl glucol carbonate (allelic); said one or more hydrophobic acrylic or allelic monomers are selected from the group consisting of: 4-niethiacryloxy-2-hiydroxybenizoplhenone (MIIBH3P) (acrylic); allyl benzene (allelic); allyl butyrate (allelic); 4-allylanisole (al lelic); 3-aIlyl-4 -hydroxyacetophienone (allelic); 2-(2 '-hiydroxy-3 '-allyl-5' -me(hylphienone-2f1-benzotriazol) (allelic); N-propyl methacrylate (acrylic); ethyl-niethacrylate (acrylic); methyl iethacrylate (acrylic); ethyl-3-benzoil acrylate (acrylic); and n-heptyl methacrylate (acrylic); and wherein said one or more hydrophobic monomers are soinbie in said one or more hydrophilic monomers.

4. The polymeric material of claim 3, wherein said hydrophilic monomer is HEMA and said hydrophobic monomer is MI-IBPII. The polymeric material of claim 1, wherein said biocompatible, optically transparent, polymeric material has an index of refraction in the range of from 1.44 to 1.48. WO 96/40818 PCT/US96/10013 -42-

6. The polymeric material of claim 5, wherein said index of refraction in the range of from 1.45 to 1.47.

7. The polymeric material of any one of claims 1 or 4, wherein said biocompatible, optically transparent, polymeric material has an index of refraction in the range of from 1.45 to 1.46.

8. The polymeric material of claim 1, produced by the process comprising: 0 dissolving an acid-telo-collagen solution in one or more hydrophilic monomers to form a collagen/hydrophilic solution; dissolving one or more hydrophobic monomers in one or more hydrophilic monomers to form a hydrophobic/hydrophilic solution; combining said collagen/hydrophilic and said hydrophobic/hydrophilic solution to form a resultant solution; and graft-polymerizing said resultant solution to form the present biocompatible, optically transparent, polymeric material based on collagen. WO 96/40818 PCT/US96/10013 -43-

9. A method for producing a biocompatible, optically transparent, polymeric material, comprising: dissolving an acid-telo-collagen solution in one or more hydroplilic monomers to form a collagen/hydrophilic solution; dissolving one or more hydrophobic monomers in one or more hydrophilic monomers to form a hydroplobic/hydrophilic solution; combining said collagen/hydrophilic and said hydrophobic/hydrophilic solution to form a resultant solution; and graft-polymerizing said resultant solution to form the present biocompatible, optically transparent, polymeric material based on collagen. The method of claim 9, wherein said step of graft-polymerizing comprises irradiating said resultant solution. d I WO 96/40818 PCT/US96/10013 -44-

11. A deformable lens comprising: the biocompatible, optically transparent, polymeric material based on collagen of claim 1.

12. The deformable lens of claim 11, wherein said deformable lens is a contact lens.

13. The deformable lens of claim 11, wherein said deformable lens is a soft intraocular lens.

14. lens. The deformable lens of claim 11, wherein said deformable lens is a refractive intraocular A method for correcting aphekia, myopia or hypermetropia in a patient suffering therefrom, comprising: implanting in the eye of said patient, the intraocular lens of any one of claims 13 or 14.

16. The polymeric material of claim 1, wherein said polymeric material has a tensile strength of from about 591 kPa to about 1578 kPa. t a k WO 96/40818 PCT/US96/l 0013 45

17. The deformable lens of claim 11, wherein said deforniable lens has a tensile strength of from about 591 kPa to about 1578 kPa.

18. A deformable lens comprising: the biocompatible, optically transparent polymeric material of claim 4.