Autoclavable highly cross-linked polyurethane networks in ophthalmology

doi:10.1016/0142-9612(93)90210-S

Biomaterials

Volume 14, Issue 14, November 1993, Pages 1089-1097

https://doi.org/10.1016/0142-9612(93)90210-S Get rights and content

Abstract

Highly cross-linked aliphatic polyurethane networks have been prepared by the bulk step reaction of low molecular weight polyols and hexamethylenediisocyanate (HDI). These polyurethane networks are optically transparent, colourless and autoclavable amorphous glassy thermosets, which are suited for use in ophthalmic applications such as intraocular lenses and keratoprostheses. The properties of these glassy polyurethanes, obtained from the reaction of the low molecular weight polyols triisopropanolamine (TIPA) or tetrakis(2-hydroxypropyl)ethylenediamine (Quadrol) and HDI in stoichiometric proportions, have been investigated in more detail. The glassy Quadrol/HDI-based polyurethane exhibits a reduction in ultimate glass transition temperature from 85 to 48 C by uptake of 1% of water, and good ultimate mechanical properties (tensile strength 80–85 MPa, elongation at break ca 15%, modulus ca 1.5 GPa). IR spectra of these hydrophobic polyurethane networks revealed the absence of an isocyanate absorption, indicating that all isocyanates, apparently, had reacted during the crosslinking reaction. The biocompatibility could be increased by grafting tethered polyacrylamide chains onto the surface during network formation. These transparent cross-linked polyurethanes did not transmit UV light up to 400 nm, by incorporation of a small amount of the UV absorbing chromophore Coumarin 102, and could be sterilized simply by autoclaving. They were implanted in rabbit eyes, either in the form of small circular disks or in the form of a keratoprosthesis (artificial cornea). It was shown that the material was well tolerated by the rabbit eyes. Serious opacification of the cornea, a direct result of an adverse reaction to the implant, was never seen. Even 1 yr after implantation of a polyurethane keratoprosthesis the eye was still ‘quiet’.

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Autoclavable highly cross-linked polyurethane networks in ophthalmology

Abstract

Ophthalmol.

J. Cataract. Refract. Surg.

J. Cataract Refract. Surg.

J. Cataract Refract. Surg.

J. Cataract. Refract. Surg.

J. Cataract Refract. Surg.

Polymer

Eur. Polym. J.

Physica

Polymer

Polymer

Biomaterials

Am. Intra-ocular Implant Soc. J.

J. Cataract Refract. Surg.

Cataract: Biochemistry, Epidemiology and Pharmacology

Magnitude and causes of blindness in the developing world

Int. Ophthalmol.

High volume efficient cataract surgery in developing countries

Int. Ophthalmol.

Cataract blindness in Africa

Ophthal. Surg.

Who develops cataracts?

Arch. Opthalmol.

The lens opacities case — control study. Risk factors for cataract

Arch. Ophthalmol.

Fechner's Intraocular Lenses

Intraocular lens implantation: a review

Artif. Organs.

Lens implantation, 30 years of progress

Changing trends in intraocular lens implantation

Arch. Ophthalmol.

Neue Materialien bei Intraokularlinsen

Fortschr. Ophthalmol.

Corneal endothelium damage with intraocular lenses: contact adhesion between surgical materials and tissue

Science

Hydrophilic gels for biological use

Nature

A randomized prospective clinical comparison of hema (IOGEL) and PMMA intraocular lenses

Acta Ophthalmol.

Intraocular biocompatibility of hydroxyethylmethacrylate and methacrylic acid copolymer/partially hydrolyzed poly(2-hydroxyethylmethacrylate)

J. Biomed. Mater. Res.

Synthetic hydrogels for biomedical applications

Keratoprostheses

Polyurethanes in Medicine