cyaloaded cs nanoparticles � cya suspension in a cs solution i i cya suspension in water time medicaid prevacid preferred drug 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 elsevier second nanoparticles generation the coating approach the previously described nanoparticular polymerbased carriers, are shown to increase the intensity and contact time of drugs with the eye moreover, in some cases, this improved contact led to an enhanced intraocular penetration of drugs despite the difficulties for comparing 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 medicaid prevacid preferred drug composition of the nanomatrice taking this into account, a different approach has arisen based on the principle of providing to the nanocarrier, a polymer coating that favors its medicaid prevacid preferred drug interaction with the ocular mucosa using this approach, it is additionally possible to select the adequate core composition in medicaid prevacid preferred drug order to facilitate the entrapment and protection of the desired drug moreover, one can envisage the design of a medicaid prevacid preferred drug nanocarrier with a differentiated interaction with the cornea and medicaid prevacid preferred drug conjunctiva an element that could be taken in consideration to achieve this aim is the presence of the mucus layer covering the conjuctival epithelium ie where the goblet medicaid prevacid preferred drug cells are and its reduced amount onto the corneal surface medicaid prevacid preferred drug in this sense, it is important to keep in mind that the interaction with the cornea would be medicaid prevacid preferred drug 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 the characteristics of the different coated nanostructures developed under these bases polya cry lie coa ting the first coating approach was intended to confer the nanosystems with a mucoadhesive character theoretically, the coating with mucoadhesive polymers could markedly medicaid prevacid preferred drug prolong the residence time of the nanocarriers, since their clearance from the eye surface would be controlled by medicaid prevacid preferred drug 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 such as poly aery lie acid carbopol�, hyaluronic acid, medicaid prevacid preferred drug mucin or sodium carboximethylcellulose, led to an enhancement of medicaid prevacid preferred drug the intraocular pressure lowering effect in rabbits the efficacy of this approach was also tested for ���� nanoparticles in an ex vivo study using bovine corneas the results showed that the corneal penetration of cyclosporin a, entrapped in medicaid prevacid preferred drug ���� 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 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 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 to cross the corneal epithelium layers apeg polyethyleneglycol bpecl medicaid prevacid preferred drug polyepsiloncaprolactone pla polyoactic acid ���� polyalquilcyanoacrylate polysaccharide coating as indicated medicaid prevacid preferred drug 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 aqueous polymer solution described above, the first attempt to efficiently coat nanoparticles with hyaluronic acid was described by barbaultfoucher medicaid prevacid preferred drug et al these authors described different strategies for the formation medicaid prevacid preferred drug 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 investigated, this publication shows the versatility of the coating approach procedure the mucoadhesive polysaccharide chitosan has also been identified as a successful candidate for the coating approach the medicaid prevacid preferred drug 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 medicaid prevacid preferred drug coated asprin facial with two different polycationic polymers polyllysine and chitosan was drastically different concretely, we observed that pecl nanoparticles coated with chitosan were significantly more efficient at increasing the medicaid prevacid preferred drug corneal uptake of the encapsulated molecule cindomethacin in rabbits, than those coated with polyllysine therefore, these results led us 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, medicaid prevacid preferred drug we attempted to investigate ex vivo isolated rabbit cornea and in vivo the mechanism of interaction of chitosancoated pecl medicaid prevacid preferred drug nanocapsules with the cornea the results of this study medicaid prevacid preferred drug showed that rhodamine encapsulated in these systems had an improved transport across the cornea, compared with that of the medicaid prevacid preferred drug marker alone, or in combination with blank nanocapsules fig moreover, medicaid prevacid preferred drug the examination of the corneas treated with fluorescent nanocapsules by confocal microscopy suggested that cscoated nanocapsules have a lower penetration ?