Mucoadhesive microspheres containing gentamicin sulfate for nasal administration: preparation and in vitro characterization.

In this study, suitable microsphere formulations were designed in order to provide the absorption of a high polar drug through nasal mucosa. For this purpose, gentamicin sulfate (GS) was chosen as a model drug and used at different drug/polymer ratios in the microsphere formulations. The microspheres were prepared by spray drying technique. Hydroxypropyl methylcellulose was used as a mucoadhesive polymer in the formulations to increase the residence time of the microspheres on the mucosa. Sodium cholate was added into the formulations for increasing the absorption of GS through nasal mucosa. The in vitro characteristics of the microspheres were determined. The microspheres were evaluated with respect to the particle size, production yield, encapsulation efficiency, shape and surface properties, drug-polymer interaction, mucoadhesive property, in vitro drug release and suitability for nasal drug delivery.