Preclinical Studies of Microparticulate Formulations for Treating the Ophthalmic Disease
Microparticulate ophthalmic formulations of Cyclosporin A were studied for acute eye irritation in healthy adult albino rabbits as per OECD guidelines. The therapeutic efficacy was also evaluated using Wistar rats as animal models in treatment of keratoconjunctivitossicca (dry eyes). No ocular reactions were observed at intervals of 1,6,8,24,48 and 72 hrs after instillation of test substances, indicating safety of of the different excipients incorporated in nanoformulations. Topical application of 0.2% Benzalkonium chloride b.i. d. for 8-10 days produced a significant decrease in aqueous tear production and induced dry eyes. in all groups except normal group. The STT wetting length was measured after 2,4,7,10,14 and 20 days of instillation of cyclosporine nanoemulgels and placebo. Statistical analysis of STT data obtained after 15 days showed that p value is less than 0.05, indicating significantly better recovery of dry eyes, however no significant difference was observed after 7 days when compared with marketed product. Statistical evaluation of goblet cell count data obtained after 7 days demonstrated that p value is less than 0.05 and nanoemulgels are significantly more effective than marketed eye drops after 7 days period. This indicated that microparticulatenanoemulgel systems by virtue of small size and gel consistency play important role in enhancing bioavailability and therapeutic efficacy of CsA drug.
Keywords - Keratoconjunctivitissicca, Microparticulate Systems, Efficacy Testing