الفهرس 
A pharmaceutical study on vesicular systems for ocular drug deliveryOnly 14 pages are availabe for public view
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Abstract
Niosomes are a novel vesicular drug delivery system formed from the self-build of non-ionic surfactants in aqueous media which can encapsulate hydrophilic and lipophilic drugs in an aqueous layer or in vesicular lipid membrane. Niosomes are unilamellar or multilamellar vesicles which improve the drug bioavailability and therapeutic performance by enclosing the drug molecule and limiting its effect to target cells.They also have much more stable structure than liposomes, require no special conditions for dealing and storage. Materials needed in the preparation of niosomes are low cost and available, also surfactants used are biocompatible and non-immunogenic. Non-ionic surfactants are main component in niosomes preparation, such as, alkylglycerol ethers, alkyl glycosides, polyoxyethylene alkyl ethers, sucrose esters, alkyl amides and sorbitan fatty acid esters which are most frequently used in literature. Several methods are used to prepare niosomes, including lipid film hydration, ether injection method, reverse phase evaporation method and bubble method.Separation of unentrapped drug from the formed vesicles can be performed by centrifugation, ultracentrifugation, dialysis and gel filtration. characterization of niosomes include measurement of encapsulation efficiency, vesicle size and zeta potential. Assessment of shape and morphology of the vesicles can be performed using transmission electron microscopy (TEM).Clotrimazole (CLT) is an azole-type antifungal drug with a topical activity against pathogenic dermatophytes and yeasts. CLT binds to cytochrome P-450 dependent enzyme lanosterol 14-a-demethylase heme moiety of the fungus, inhibits 14-a-demethylase, then blocks ergosterol formation causing the accumulation of toxic methylated 14-a-sterols