Dorzolamide Cyclodextrin Nanoparticle Suspension Eye Drops and Trusopt in Rabbit

PURPOSE: Dorzolamide nanoparticle γ-cyclodextrin eye drops may prolong the effect of dorzolamide on intraocular pressure. We test whether the nanoparticle drops have an irritating or toxic effect on the eye in an in vivo rabbit model. METHODS: Eighteen pigmented rabbits were divided into 4 groups receiving dorzolamide nanoparticle γ-cyclodextrin eye drops×1/day or×2/day, Trusopt® (dorzolamide HCl)×3/day, and untreated controls that received no drops. The rabbits received treatment for 1 month. After sacrifice, 33 eyes and 25 Harderian glands were evaluated for histopathology in a masked way. RESULTS: Mild inflammation was seen in 19/31 eyes and 13/23 Harderian glands. The difference in inflammation (n=eyes/n=glands)between the γ-cyclodextrin nanoparticle eye drops×1/day (n=5/5),×2/day (n=5/3), Trusopt (n=7/4), or untreated control (n=2/0) groups was nonsignificant in both eyes and glands (P=0.87 and P=0.92) Acute inflammation was seen in 1 Harderian gland that received γ-cyclodextrin nanoparticle eye drops×2/day. The difference in conjunctival injection between the groups was nonsignificant (P=0.30). CONCLUSIONS: Dorzolamide γ-cyclodextrin nanoparticle eye drops are no more locally toxic or irritating to the eye than Trusopt.