Patent ID: 8231890

Claim:
A method for implanting a hydrogel polymer at an implantation site within the body of a human or animal subject, said method comprising: providing a hydrogel formed from one or more ethylenically unsaturated monomers at least some of which have ionizable functional groups, a crosslinker and an initiator; providing a catheter having a lumen, said catheter being insertable into the subject's body and advanceable to the implantation site; contacting the hydrogel with a treatment solution having a low pH at a predetermined temperature and for a predetermined time so that the protonation state of the hydrogel is altered in a predetermined fashion; drying the hydrogel to form a dried hydrogel mass; placing the dried hydrogel mass within a catheter lumen; and delivering the dried hydrogel mass out of the catheter lumen to the implantation site such that the pH present at the implantation site changes the protonation of the dried hydrogel mass such that the hydrogel expands at a predetermined rate.