Abstract
Abstract: :
Purpose: Azithromycin has the characteristic feature of having high and sustained concentrations in tissue and a long half–life. Several factors may influence ocular tissue absorption of topical antibiotics. The main purpose of this study is to assess the corneal tissue absorption of azithromycin in normal and dry eyes. Methods: A total of 25 New Zealand Albino rabbits weighing 2–3 kilograms each were included in this study. One eye of each rabbit was kept open for 10 minutes with a lid speculum preventing the rabbit from blinking. The other eye was left as control. The room temperature and humidity were monitored. Azithromycin 1.5% topical eye drops were instilled in both eyes at a dosage level of one drop every minute for 5 minutes. Five rabbits were sacrificed following the instilling of topical eyedrops at the following time points: 30 minutes, 3 hours, 6 hours, and 12 hours. The corneal tissues were harvested from the right and left eyes. Specimens were placed in pre–weighed vials and subjected to analysis by High Performance Liquid Chromatography (HPLC) Mask Spectrometry. Results: The mean corneal tissue levels of azithromycin was 66.38 ng/microliter, 92.60 ng/microliter,117.54 ng/microliter, and 179.90 ng/microliter at 30 minutes, 3 hours, 6 hours and 12 hours respectively. On the other hand, the mean azithromycin concentration in the normal eyes that were not desiccated was 41.98 ng/microliter, 43.36 ng/microliter, 43.32 ng/microliter, and 79.98 ng/microliter at 30 minutes, 3 hours, 6 hours and 12 hours respectively. There was statistically significant increase in the corneal tissue absorption of azithromycin in the desiccated eyes compared to the normal eyes (p < 0.0001). Conclusions: This study demonstrated that corneas exposed to dryness showed statistically significant increase in the azithromycin level compared to normal eyes following topical azithromycin. This study may have important clinical application in the management of ocular surface infections.
Keywords: antibiotics/antifungals/antiparasitics • cornea: tears/tear film/dry eye • keratitis