Patent ID: 6200589
Filing Date: 2001-03-13
Classification: A61K,A61L

Abstract:
A semipermeable biological implant comprising:a semipermeable polymeric network formed into a geometric shape having an inner volume, said implant having cells encapsulated within said inner volume and capable of immununoisolating said encapsulated cells when said inplant is implanted into a biological medium, said semipermeable polymer network comprising the polymerization product of acryloyl or methacryoyl capped polyisobutylene and mixtures thereof, wherein said polyisobutylene is formed by cationic polymerization, and a hydrophilic segment derived from an acrylate selected from the group consisting of formulas (II), (III) and (IV) ##STR6##where R.sub.2 is hydrogen or methyl, R.sub.3 is an alkylene group having from about 2 to about 4 carbon atoms, and R.sub.4 and R.sub.5 may be the same or different and are selected from the group consisting of hydrogen and alkyl groups having from 1 to about 4 carbon atoms;wherein the ratio of capped polyisobutylene to said hydrophilic segments is from about 50:50 parts by weight to about 30:70 parts by weight; andwherein the polymeric network allows the passage of glucose and insulin and prevents the passage of molecules having a molecular weight of greater than 50,000 daltons.