Porous hydrophilic materials, chambers therefrom, and devices comprising such chambers and biologically active tissue and methods of preparation

Claim 1

A synthetic, hydrophilic, polymeric material of a polymer of at least one monomer from the group consisting of a monoalkylene glycol monoester of methacrylic acid, a polyalkylene glycol monester of methacrylic acid, a monoalkylene glycol monoester of crylic acid, a polyalkylene glycol monoester, a N-alkyl substituted acrylamide, a N,N-dialkyl substituted acrylamide, a N-alkyl substituted methacrylamide, a N,N-dialkyl substituted methacrylamide, N-vinylpyrrolidone, an alkyl substituted N-vinylpyrrolidone, and vicinal epoxy alkyl 2-alkenoate, characterized by: water-insolubility; water-swellability; biological inertness; non-toxicity to and compatibility with living tissue; retention of structural integrity over long periods of time in contact with body fluids; a water-uptake capability when in osmotic equilibrium with water of from 5 to 4000 weight percent based on the weight of said hydrophilic material to form a hydrogel; an ultimate strength of about 3 g/mm 2 to 200 g/mm 2 , an initial tear strength of 0.1 g/mm 2 to 20 g/mm 2 , and a progagation tear strength of 0.5 g/mm to 10 g/mm; and 3-dimensional, reticulum-like porosity in which at least about 75 percent of the remaining pores, as determined under a scanning electron microscope, are characterized by an average diameter, not exceeding about 10 microns and in which below about 25 percent of the pores are characterized by an average diameter generally sufficiently small so as to prevent an immune rejection when said hydrophilic material containing biologically active tissue therein is in contact with living tissue environment, the geometry of such permitting the ingress or egress of a steroid.