nanocapsules emulsion h nanoparticles t �� microparticles fig indomethacin concentrations attained in the aqueous humor following the topical application, in rabbits, of indomethacinloaded carriers and a control drug solution mean values � sd, n = , p compared with indocollyre p compared with colloidal suspensions reprinted from ref , with permission from pharmaceutical press immunosuppressive peptide cyclosporin a interestingly, following topical claritin and itchy ears administration of pecl nanocapsules containing cyclosporin a, we observed corneal levels of the drug which were five times higher than those provided claritin and itchy ears by an oily solution topical formulation of cyclosporin typically used these high levels were not, however, translated risperdal autism into high drug concentrations in the aqueous humor a result that was attributed to the important hydrophobicity of this peptide and claritin and itchy ears its tendency to associate with lypophylic components claritin and itchy ears therefore, at present, there is a proofofconcept of claritin and itchy ears the efficacy of polyester nanocapsules for enhancing the concentration of topically applied drugs in the corneal epithelium whether this enhanced concentration may claritin and itchy ears or may not lead to a favored accumulation of the drug in the inner eye claritin and itchy ears is expected to be largely dependent on the physicochemical characteristics of the drug polysaccharidebased nanoparticles the polyester polymers described above are hydrophobic polymers that need to be biodegraded into hydrophilic claritin and itchy ears oligomers in order to be eliminated from the body a very different class of polymers, which has only received attention in the last few years, is the one represented by claritin and itchy ears the hydrophilic polysaccharides hyaluronic acid and chitosan are two types of polysaccharides which have opened new prospects in the ocular drug delivery area the choice of hyaluronic acid has been justified by its bioadhesive character, but also by its well known safety profile in fact, hyaluronic acid is already being used as a substitute for vitreous humor in intraocular surgery, claritin and itchy ears since it constitutes a basic component of the vitreous body on the other hand, chitosan claritin and itchy ears is a polycationic biopolymer which exhibits several favorable biological properties for ocular drug administration these properties include mucoadhesiveness biodegradability in the rich lysozyme containing mucus ie ocular mucosa, and also wound healing and antimicrobial activity despite the number claritin and itchy ears of articles showing the efficacy of hyaluronic acid solutions for improving the retention of drugs applied topically onto the eye, the only particulate formulation that has been tested in vivo was composed of microparticles zm rather than nanoparticles claritin and itchy ears these hyaluronate microparticles were shown to increase the residence time of the model drug methylprednisolone at the ocular surface of the rabbit claritin and itchy ears eye taking into account the reported influence of the size on the interaction of particles with the ocular mucosa, we have recently designed claritin and itchy ears nanoparticles consisting of hyaluronic acid and chitosan at present, we know that these nanoparticles are stable upon incubation in simulated lachrymal fluids and in vivo studies are in progress in order to evaluate their mechanism of interaction with the ocular mucosa chitosan has also received significant attention in the ophthalmic field one of the chitosanbased systems that has exhibited an claritin and itchy ears interesting behavior following topical ocular administration, is the one consisting of chitosan nanoparticles these nanoparticles have been tested on the rabbit model claritin and itchy ears for their ability to enhance the concentration of cyclosporin a at the level of the claritin and itchy ears ocular mucosa as expected, the results showed that the chitosan nanoparticles were able to increase claritin and itchy ears the concentrations of cyclosporin a in the external claritin and itchy ears ocular tissues cornea and conjunctiva significantly for up to hr postinstillation fig despite this enhanced retention of the drug in the external tissues, the levels attained in the internal ocular structures ie aqueous humor, iris and ciliary body and in the blood were negligible consequently, these results suggested the utility of this new formulation for the treatment of surface eye diseases, ie dry eye or inflammatory diseases these high drug concentrations restricted to the periocular tissues were later explained by a high corneal and conjunctival surface retention of chitosan nanoparticles indeed, in a study consisting of evaluating the concentration of fluorescent chitosan, either in the form of nanoparticles or as a solution, in cornea and conjunctiva, we could conclude that the affinity of chitosan for the ocular surface is greater when it is in a particulate form this conclusion invites interesting prospects with regard to the potential of chitosan nanoparticles as drug carriers for topical ocular administration keeping this in mind, we tested the acute claritin and itchy ears tolerance of chitosan nanoparticles following topical instillation to rabbits very recently the results gave evidence of an excellent tolerance, without any sign claritin and itchy ears of irritation or damage of the ocular surface claritin and itchy ears structures cya concentration in the cornea ng cyag cornea ?