الفهرس 
Chapter 1يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
This thesis included two parts: First part was concerned with preparing levofloxacin (LF) loaded spanlastic nanovesicles using Span 60 and edge activators by thin film hydration technique to provide sustained release and overcome the frequent administration. Depending on the results, F5 (composed of Span 60 and Tween 60 as edge activator at weight ratio of 8:2, respectively) was selected as the optimum formula according to 32 factorial design and exhibited EE% = 59.7±4.2%, PS = 177.6±1.8 nm, PDI = 0.27 ± 0.022, ZP = -40.6 ± 0.68 mV and sustained release where only 39.37±0.72% of LF amount was released after 4 h compared to complete release from the drug solution. Both Sodium carboxy methyl cellulose (NaCMC) gel and gelrite in situ gel systems were selected to incorporate the optimum spanlastic formula to overcome the rapid drainage from the ocular surface. F5 suspension was found to be stable at different storage conditions over three months. An in vitro microbiological study indicated that; loading of LF into spanlastic particles enhanced its antibacterial effectiveness compared to marketed product. Additionally, confocal laser scanning microscopy determined 300% enhancement in the penetration ability of SL into cornea. Second part was concerned with formulation and characterization of phenytoin (PT) loaded ocular delivery systems. PT-loaded nanoemulsions were prepared by phase inversion method using capryol 90, tween 80 and transcutol P as oil, surfactant and cosurfactant respectively at Smix (2:1). The optimum formula F6 (composing of 5% capryol 90, 30% tween 80, 15% transcutol and 50% deionized water) was incorporated into either sodium alginate in situ gel (NEIG) or mucoadhesive chitosan eyedrops (MCNE) and fully characterized. In-vivo safety study was conducted and indicated the safety of formulations compared to phenytoin suspension. Finally, corneal debridement model was used to investigate the healing effect of the developed PT loaded NEIG and MCNE systems in comparison to the drug suspension and untreated animals. According to the study results, animals treated with PT loaded NEIG and MCNE showed significantly higher healing rate and lower expression of inflammatory mediators than those treated with PT suspension and un treated animals indicating that PT was more effective when incorporated in nanoemulgels, than its free form in promoting corneal wound healing.”