부산대학교 도서관

Background: Acanthamoeba keratitis (AK) is a corneal sight-threatening infection caused by the free-living amoebae of the genus Acanthamoeba. Early and appropriate treatment significantly impacts visual outcomes. Mucoadhesive polymers such as chitosan are a potential strategy to prolong the residence time and bioavailability of the encapsulated drugs in the cornea. Regarding the recent administration of miltefosine (MF) for treating resistant AK, in the present study, we synthesized miltefosine-loaded chitosan nanoparticles (MF-CS-NPs) and evaluated them against Acanthamoeba. Methodology/Principal findings: Chitosan nanoparticles (CNPs) were prepared using the ionic gelation method with negatively charged tripolyphosphate (TPP). The zeta-potential (ZP) and the particle size of MF-CS-NPs were 21.8±3.2 mV and 46.61±18.16 nm, respectively. The release profile of MF-CS-NPs indicated linearity with sustained drug release. The cytotoxicity of MF-CS-NPs on the Vero cell line was 2.67 and 1.64 times lower than free MF at 24 and 48 hours. This formulation exhibited no hemolytic activity in vitro and ocular irritation in rabbit eyes. The IC50 of MF-CS-NPs showed a significant reduction by 2.06 and 1.69-fold in trophozoites at 24 and 48 hours compared to free MF. Also, the MF-CS-NPs IC50 in the cysts form was slightly decreased by 1.26 and 1.21-fold at 24 and 48 hours compared to free MF. Conclusions: The MF-CS-NPs were more effective against the trophozoites and cysts than free MF. The nano-chitosan formulation was more effective on trophozoites than the cysts form. MF-CS-NPs reduced toxicity and improved the amoebicidal effect of MF. Nano-chitosan could be an ideal carrier that decreases the cytotoxicity of miltefosine. Further analysis in animal settings is needed to evaluate this nano-formulation for clinical ocular drug delivery. Author summary: Acanthamoeba keratitis (AK) is a painful corneal disease that causes vision loss if not treated promptly. AK incidence is increasing worldwide, especially among those who wear contact lenses. Prompt and proper treatment is essential for complete recovery of vision. The successful treatment has been complicated due to low efficacy, toxicity, and ineffectual ocular drug delivery. Mucoadhesive polymers, like chitosan nanoparticles, are a promising approach to enhancing drug residence time and transcorneal permeation. Miltefosine (MF) is an effective medication for treating refractory AK. In the present study, miltefosine-loaded chitosan nanoparticles were prepared, and their therapeutic effect and cytotoxicity were compared with free miltefosine. The MF-CS-NPs demonstrated a significant decrease in the viability of trophozoite forms compared to free miltefosine. The nano-chitosan formulation was more effective toward trophozoites than the cysts form. Overall, the chitosan nanoparticles improved the effectiveness of miltefosine against Acanthamoeba. Besides, this formulation notably reduced toxicity compared to free MF, exhibiting no in-vivo irritation. The nano-chitosan carrier can be proposed as an ideal nanocarrier for future evaluation in AK treatment. [ABSTRACT FROM AUTHOR]