- Fifty:fifty poly (DL glycolic acid-lactic acid) copolymer (PGLA) is a potentially useful depot drug delivery system for 5-fluorouracil (5-FU). The purpose of this study was to evaluate the fibroinflammatory reaction induced by this polymer. Polymer discs without 5-FU were inserted subconjunctivally in one eye of each of two guinea pigs and four pigmented rabbits (control group), and discs containing 20% 5-FU were inserted subconjunctivally in both eyes of nine pigmented rabbits (study group). The tissue reaction to the copolymer did not differ between rabbits and guinea pigs, with a mild mixed inflammatory reaction 1 week after implantation. At 2 weeks a thin fibrous capsule surrounded the discs, with no change in the amount of inflammation. At 4 weeks the disc had disintegrated, but residual polymer was seen within multinucleated giant cells in the episcleral tissue. Granulation tissue and inflammatory responses were mild. Less inflammation and fibrosis occurred in the study eyes, although the pattern of response was similar in the two groups. The inflammatory response to PGLA was markedly less than that to implanted collagen shields, and our findings suggest that PGLA implant is a promising ocular drug delivery system for 5-FU after filtration surgery.