Evaluation and Determination of the Safety Dose for Subconjunctival Injection of Doxycycline in Rabbit Eye

Purpose: To evaluate the safety and determining safe dose of subconjunctival injection of Doxycycline in an animal model. Methods: Eight white New Zealand rabbits were randomly classified to four groups of two. Different dosages of 250, 500, 1000 and 2000 ug/cc of Doxycycline was injected in the right eye of all rabbits in each group and the left eye of normal controls remained with no injection while that of the other one received Normal Saline in 0.1 cc in each group. All rabbits underwent the total eye examination in the first, third and thirtieth day of injection and after that the total globe was sent for complete histopathological examination. Results: No clinical significance was detected in all four groups from the first to third day of examination in terms of change in tearing, hyperemia and chemosis. There was also no approved sign of inflammation, necrosis and scar or any histological change in both clinical and histopathological examinations. Conclusion: Subconjunctival injection of Doxycycline with various dosages from 500 to 2000ug in 0.1cc in this animal model was safe and no sign of clinical or histological changes was detected in this duration of thirty-dayobservation.