Preparation and properties of methotrexate loaded chitosan microspheres for the intranasal administration

Objective To study the preparation of methotrexate loaded chitosan microspheres for nasal administration.Methods The chitosan microspheres loaded with methotrexate were prepared by a spray-drying method and orthogonal design was introduced to select optimum preparation condition.Characteristics of the microspheres,such as the entrapment efficiencies,product yield and size distributions were investigated in detail.The in vitro released studies and nasal cilia toxicity were also observed.Results The average diameter of the microspheres was(4.0-5.0)μm with narrow size distribution.The drug release rate from the microspheres can be controlled by modifying the polymer/drug ratios and the cilia irritation of the microsphers was found to be minor.Conclusions Spray drying method is suitable for preparing chitosan microspheres loaded with methotrexate,and chitosan could be considered as a good carrier for the nasal delivery system for the brain targeting.