Compositions capable of forming hydrogels in the eye

An aqueous composition of water soluble polymer and a polymeric water-soluble photoinitiator, the composition having a coherency effective to substantially prevent dispersion when the composition is injected into an aqueous environment to undergo a crosslinking reaction into a hydrogel,

• wherein the water soluble polymer is free of photoinitiator groups, has free acrylic or other vinylic groups capable of facile free radical reaction with the polymeric water-soluble photoinitiator, and is capable of being crosslinked when irradiated with light of wavelengths greater than about 305 nm to form the hydro gel,
• wherein the water soluble polymeric photoinitiator has the formula:
• (A)m(B)n(D)q
• in which A, B and D are each are vinyl groups (—CH2—CH—) to which a pyrrolidone group (A), a hydroxyl or acetate group (B), and a photoinitiator group (D), respectively, is attached;
• and where the respective mole fractions of the monomer units is:
• m=0.1 to 0.5;
• n=0.1 to 0.5;
• and q=0.05 to 0.25, and
• wherein the photoinitiator group comprises a phosphine oxide moiety linked to the main polymer chain by a urethane bond.

An aqueous composition of water soluble polymer and a polymeric water-soluble photoinitiator, the composition having a coherency effective to substantially prevent dispersion when the composition is injected into an aqueous environment to undergo a crosslinking reaction into a hydrogel,

• wherein the water soluble polymer is free of photoinitiator groups, has free acrylic or other vinylic groups capable of facile free radical reaction with the polymeric water-soluble photoinitiator, is a copolymer of vinylpyrrolidone and vinyl alcohol having a fraction of its hydroxyl groups modified with a functional acryl group for crosslinking, and is capable of being crosslinked when irradiated with light of wavelengths greater than about 305 nm to form the hydrogel, and
• wherein the water soluble polymeric photoinitiator has the formula:
• (A)m(B)n(D)q
• in which A, B and D are each are vinyl groups (—CH2—CH—) to which a pyrrolidone group (A), a hydroxyl or acetate group (B), and a photoinitiator group (D), respectively, is attached;
• and where the respective mole fractions of the monomer units is:
• m=0.1 to 0.5;
• n=0.1 to 0.5;
• and q=0.05 to 0.25.

A method of forming a dimensionally stable, clear hydrogel, comprising the steps of

• (i) providing a vinyl alcohol monomer-containing polymer having a refractive index of at least 1.41;
• (ii) chemically modifying a sufficient amount of a first part of vinyl alcohol monomers in said vinyl alcohol monomer-containing polymer so as to obtain a hydrophilic water soluble polymer having functional acrylic groups for crosslinking;
• (iii) chemically modifying a second part of said vinyl alcohol monomer-containing polymer by attaching a blue light activated photoactive group comprising a phosphine oxide moiety by means of an urethane bond to obtain a polymeric water soluble photoinitiator;
• (iv) providing an injectable aqueous composition of said first and second parts, said composition having a refractive index of about 1.36 to 1.45;
• and
• (v) irradiating said aqueous composition with light of a wavelength exceeding about 400 nm, to form a hydrogel by means of crosslinking.