Zirgan Ganciclovir Ophthalmic Gel 0.15% Sterile, 5 Gram Tube (RX)Zirgan is a brand name for Ganciclovir ophthalmic gel, a medication used for the treatment of certain viral eye infections. It is a sterile gel formulation that contains 0. 15% ganciclovir as the active ingredient. Ganciclovir is an antiviral medication that works by preventing the replication of certain viruses, including herpes simplex virus type 1 and 2, and cytomegalovirus. Zirgan is specifically indicated for the treatment of herpes simplex