Helical intravitreal triamcinolone acetonide implant: a 6-month surgical feasibility study in rabbits

Ophthalmic Surg Lasers Imaging. 2009 Mar-Apr;40(2):160-8. doi: 10.3928/15428877-20090301-17.

Abstract

Background and objective: To investigate the surgical feasibility and safety of a long-term intravitreal triamcinolone acetonide (TA) sustained delivery system.

Materials and methods: Pigmented rabbits were implanted with sustained-release formulations containing 925 microg of TA within a non-biodegradable polymer coating: Dose A (n = 15) with a slow delivery rate of 1 to 2 microg/day and Dose B (n = 15) releasing 3 to 5 microg/day. Additionally, a control group (n = 10) using a device coated with polymer only was implanted. The devices were surgically implanted through a 30-gauge sclerotomy into the vitreous cavity. The animals were clinically observed for up to 6 months after the surgery with complete ophthalmologic examinations. Histologic evaluation of a subset of eyes was performed at the conclusion of the study.

Results: Implants were successfully implanted in all 40 eyes. Ocular examinations revealed excellent implant tolerability. In all eyes, there was no significant postoperative inflammation at 1 week of follow-up. There was no increase in intraocular pressure during the follow-up period and histologic evaluation demonstrated no significant abnormalities. Minimal and localized vitreous hemorrhage was observed in 22.5% of implanted eyes and mostly cleared at 1 month after surgery. During the 6 months of follow up, localized lens opacities associated with physical implant contact developed in 66.6% of eyes.

Conclusion: The surgical procedure using the intravitreal TA sustained delivery device is feasible. Surgical complications were generally mild, with lens opacities attributable to unique anatomical features of the rabbit eye. Long-term follow-up and histology revealed excellent implant tolerability.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Drug Implants*
  • Feasibility Studies
  • Follow-Up Studies
  • Glucocorticoids / administration & dosage*
  • Glucocorticoids / adverse effects
  • Intraoperative Complications
  • Postoperative Complications
  • Rabbits
  • Retina / drug effects
  • Retina / pathology
  • Sclerostomy / methods
  • Triamcinolone Acetonide / administration & dosage*
  • Triamcinolone Acetonide / adverse effects
  • Vitreous Body / drug effects*

Substances

  • Drug Implants
  • Glucocorticoids
  • Triamcinolone Acetonide