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