Mucoadhesive cellulosic derivative sponges as drug delivery system for vaginal application

Vaginal delivery of active drugs has been largely studied for local and systemic applications. It is well known that vagina is a complex route, due to physiological and non-physiological changes. Therefore, in order to achieve a prolonged local effect, these variations have to be considered. The aim of this study was to formulate and to characterize a solid system, called sponges, obtained by lyophilization of cellulosic derivative (HEC 250M) hydrogels. These sponges have to meet particular criteria to be adapted for vaginal application: they have to adhere to the vaginal cavity and to be rehydrated by the small amount of vaginal fluids. Moreover, they have to be easily manipulated and to be stable. Three freezing temperatures have been tested to prepare sponges (-15°C, -25°C, -35°C). By SEM analyzes, it was observed that the pores into the sponges were smaller and numerous as the freezing temperature decreases. However, this temperature did not have any influence on the rehydration speed that was rather influenced by the HEC concentration. Viscosity and mucoadhesive strength of hydrogels and corresponding sponges were also measured. It appeared that these parameters are mainly dependent on the HEC concentration. These mucoadhesive sponges can be considered as potential drug delivery systems intended for vaginal application.