In vitro permeability of round window membrane to transforming dexamethasone with delivery vehicles——a dosage estimation

Background In recent years the interest of sustained drug delivery into inner ear is promising,at the same time a greatdeal of novel oral drugs using biodegradable vehicles have been produced to achieve sustained drug release.The aim ofthis study was to use biodegradable vehicles to release dexamethasone in the round window membrane application.Methods Dexamethasone gels composed of alginate and chitin were prepared and the release-permeating profileswere studied using a reproducible in vitro apparatus.A longer-period time course was simulated using the parametersacquired in this study.The data obtained in this study was compared with those of other studies in intratympanic drugdelivery,and an appropriate initial dosage was extrapolated.Results The combination of alginate and chitin could efficiently restrict dexamethasone diffusion and the time coursesuggested a sustained drug concentration within 24 hours.A higher initial dosage was estimated to achieve a stabletherapeutic concentration in vivo.Conclusion The combination of alginate and chitin could be used as vehicle for sustained release of dexamethasone inintratympanic application.