nanocapsules emulsion h nanoparticles t �� microparticles fig indomethacin concentrations attained in the aqueous altace kidney humor following the topical application, in rabbits, altace kidney 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 altace kidney press immunosuppressive peptide cyclosporin a interestingly, following topical altace kidney administration of pecl nanocapsules containing cyclosporin a, we observed corneal levels of the drug which were five times higher than those provided altace kidney by an oily solution topical formulation of cyclosporin typically used these high levels were not, however, translated into high drug concentrations in the aqueous humor a result that was attributed altace kidney to the important hydrophobicity of this peptide and altace kidney its tendency to associate with lypophylic components altace kidney therefore, at present, there is a proofofconcept of altace kidney the efficacy of polyester nanocapsules for enhancing the concentration of topically applied drugs in the corneal epithelium whether this enhanced concentration may 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 altace kidney body a very different class of polymers, which has only received attention in the last few years, is the one represented by altace kidney the hydrophilic polysaccharides hyaluronic acid and chitosan are altace kidney two types of polysaccharides which have opened altace kidney new prospects in the ocular drug delivery area altace kidney the choice of hyaluronic acid has been altace kidney justified by its bioadhesive character, but also by its well known safety profile in fact, hyaluronic acid is already being used as a altace kidney substitute for vitreous humor in intraocular surgery, since it constitutes a basic component of the vitreous body on the other hand, chitosan is a polycationic biopolymer which exhibits several favorable altace kidney biological properties for ocular drug administration these properties include mucoadhesiveness biodegradability in the rich lysozyme altace kidney containing mucus ie ocular mucosa, and also altace kidney wound healing and antimicrobial activity despite the number of articles showing the efficacy of hyaluronic acid solutions for improving the retention of drugs altace kidney applied topically onto the eye, the only particulate formulation that has been tested in vivo altace kidney was composed of microparticles zm rather than nanoparticles altace kidney these hyaluronate microparticles were shown to increase altace kidney the residence time of the model drug methylprednisolone at the ocular surface of the rabbit altace kidney eye taking into account the reported influence of altace kidney the size on the interaction of particles altace kidney 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 altace kidney and in vivo studies are in progress in order to evaluate their mechanism of interaction altace kidney with the ocular mucosa chitosan has also received altace kidney significant attention in the ophthalmic field one of the chitosanbased systems that has exhibited an interesting behavior following topical ocular administration, is altace kidney the one consisting of chitosan nanoparticles these nanoparticles altace kidney have been tested on the rabbit model altace kidney for their ability to enhance the concentration of altace kidney cyclosporin a at the level of the altace kidney ocular mucosa as expected, the results showed that altace kidney the chitosan nanoparticles were able to increase the concentrations of cyclosporin a in the external 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 altace kidney structures ie aqueous humor, iris and ciliary altace kidney body and in the blood were negligible consequently, altace kidney these results suggested the utility of this altace kidney new formulation for the treatment of surface eye altace kidney diseases, ie dry eye or inflammatory diseases these high drug concentrations restricted to the periocular altace kidney 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 will motrin alleviate rectocele discomfort altace kidney with regard to the potential of chitosan nanoparticles altace kidney as drug carriers for topical ocular administration keeping this in mind, we tested the acute tolerance of chitosan nanoparticles following topical instillation altace kidney to rabbits very recently the results gave evidence of an excellent tolerance, without any sign altace kidney of irritation or damage of the ocular surface structures cya concentration in the cornea ng cyag cornea ?