cyaloaded cs nanoparticles � cya suspension in a cs solution i i cya suspension in water time fluoxetine 20 mg h fig cyclosporin cya concentration in the cornea after topical administration in rabbits of cyaloaded chitosan cs nanoparticles and control formulations consisting of a cya suspension in a cs aqueous solution and a cya suspension in water statistically significant differences, p reprinted from ref , with permission from fluoxetine 20 mg elsevier second nanoparticles generation the coating approach the previously described nanoparticular polymerbased carriers, are shown to increase the intensity fluoxetine 20 mg and contact time of drugs with the eye moreover, in fluoxetine 20 mg some cases, this improved contact led to an enhanced intraocular penetration of drugs despite the difficulties for comparing fluoxetine 20 mg the performance of the firstgeneration nanosystems, it is obvious that their interaction with the ocular surface is determined not only by the nanoscale size, but also by the surface composition of the nanomatrice taking this into account, a fluoxetine 20 mg different approach has arisen based on the principle of fluoxetine 20 mg providing to the nanocarrier, a polymer coating that favors its interaction with the ocular mucosa using this approach, it fluoxetine 20 mg is additionally possible to select the adequate core composition in order to facilitate the entrapment and protection of the fluoxetine 20 mg desired drug moreover, one can envisage the design of leve thyroxine a fluoxetine 20 mg nanocarrier with a differentiated interaction with the cornea and conjunctiva an element that could be taken in consideration fluoxetine 20 mg to achieve this aim is the presence of the mucus layer covering the conjuctival epithelium ie where the goblet cells are and its reduced amount onto the corneal surface fluoxetine 20 mg in this sense, it is important to keep in mind that the interaction with the cornea would be fluoxetine 20 mg the choice for the drugs whose target is located in the inner eye in contrast, the improved interaction and controlled release at the conjunctival level could offer a potential for the treatment of surface ocular diseases table summarizes fluoxetine 20 mg the characteristics of the different coated nanostructures developed under these bases polya cry lie coa ting the first coating fluoxetine 20 mg approach was intended to confer the nanosystems with a fluoxetine 20 mg mucoadhesive character theoretically, the coating with mucoadhesive polymers could markedly prolong the residence time of the nanocarriers, since their clearance from the eye surface would be controlled by the much slower rate of mucus turnover than the tear turnover rate the simplest approach towards this aim has been the suspension of the nanocarrier in an aqueous solution containing a mucoadhesive polymer indeed, zimmer et al observed that the coadministration of pilocarpineloaded albumin nanoparticles with bioadhesive polymers fluoxetine 20 mg such as poly aery lie acid carbopol�, hyaluronic acid, mucin or sodium carboximethylcellulose, led to an enhancement of fluoxetine 20 mg the intraocular pressure lowering effect in rabbits the efficacy of fluoxetine 20 mg this approach was also tested for ���� nanoparticles in fluoxetine 20 mg an ex vivo study using bovine corneas the results showed fluoxetine 20 mg that the corneal penetration of cyclosporin a, entrapped in ���� nanoparticles, was improved when the nanoparticles were suspended in a polyacrylic acid gel table polymercoated nanoparticulate compositions used in ocular drug delivery topical administration polymer coatingcorebassociated in fluoxetine 20 mg vivo results references composition drugmarker polyacrylic acid chitosan chitosan hyaluronic acid peg peg albumin nanoparticles pecloil nanocapsules pecloil nanocapsules pecl nanoparticles ���� nanoparticles pla nanoparticles pecl nanocapsules peg pilocarpine enhanced intraocular pressure lowering effect and duration of o fluoxetine 20 mg indomethacin improved drug ocular bioavailability corneal and aqueous humor drug levels rhodamine enhanced retention of the nanocapsules on the ocular surface �not reported acyclovirimproved drug ocular bioavailability aqueous humour drug levels acyclovirimproved drug ocular bioavailability aqueous humour drug levels rhodamine evidence of the ability of pegcoated nanocapsules fluoxetine 20 mg to cross the corneal epithelium layers apeg polyethyleneglycol bpecl polyepsiloncaprolactone pla polyoactic acid ���� polyalquilcyanoacrylate polysaccharide coating as indicated fluoxetine 20 mg in the previous section covering the nanocarriers of first generation, two polysaccharides have attracted special attention as mucoadhesive materials for ocular application hyaluronic acid and chitosan apart from the simple dispersion of the core material into an fluoxetine 20 mg aqueous polymer solution described above, the first attempt to efficiently fluoxetine 20 mg coat nanoparticles with hyaluronic acid was described by barbaultfoucher fluoxetine 20 mg et al these authors described different strategies for the formation fluoxetine 20 mg of hyaluronatecoated polyecaprolactone pecl nanoparticles intended for ocular drug delivery these strategies were simple adsorption, ionic promoted interaction and chain entanglement during the nanoparticles fabrication process while the in vivo efficacy of these strategies remains to be fluoxetine 20 mg investigated, this publication shows the versatility of the coating approach fluoxetine 20 mg procedure the mucoadhesive polysaccharide chitosan has also been identified fluoxetine 20 mg as a successful candidate for the coating approach the fluoxetine 20 mg mucoadhesive properties of chitosan have generally been ascribed to its polycationic nature, which promotes the interaction with the negatively charged ocular mucosa however, the cationic nature should not be taken as the only factor determinant of the mucoadhesive properties of polymercoated nanocarriers in fact, in a previous study, we have shown that the performance of pecl nanoparticles fluoxetine 20 mg coated with two different polycationic polymers polyllysine and chitosan fluoxetine 20 mg was drastically different concretely, we observed that pecl nanoparticles coated with chitosan were significantly more efficient at increasing the fluoxetine 20 mg corneal uptake of the encapsulated molecule cindomethacin in rabbits, than those coated with polyllysine therefore, these results led us fluoxetine 20 mg to conclude that it was the intrinsic mucoadhesive character of chitosan, not exclusively ascribed to its positive charge, that is the reason for its successful behavior more recently, fluoxetine 20 mg we attempted to investigate ex vivo isolated rabbit cornea and in vivo the mechanism of interaction of chitosancoated pecl fluoxetine 20 mg nanocapsules with the cornea testosterone receptors the results of this study fluoxetine 20 mg showed that rhodamine encapsulated in these systems had an improved fluoxetine 20 mg transport across the cornea, compared with that of the marker alone, or in combination with blank nanocapsules fig moreover, fluoxetine 20 mg the examination of the corneas treated with fluorescent nanocapsules by confocal microscopy suggested that cscoated nanocapsules have a lower penetration ?