A transparent, biocompatible, non-resorbable, homogenous hydrogel containing 97.5% apyrogenic water and 2.5% of the cross-linked, synthetic polyacrylamide. Upon injection into the urethral submucosal tissue, the polyacrylamide hydrogel serves as a bulk forming agent and may possibly increase the strength of the urethral sphincter and thereby prevent or decrease stress-induced urinary incontinence. Check for active clinical trialsusing this agent.