Preparation of gastrodin-chitosan microspheres by spray-drying method

Objective To prepare gastrodin-chitosan microspheres and study the characteristics of microspheres.Methods The chitosan microspheres loaded with gastrodin were prepared by using the spray-drying method.The formulation and preparation condition were optimized by L9(34) orthogonal design with inlet temperature,pump speed,chitosan concentration and ratio of gastrodin to chitosan as factors,the entrapment efficiency and product yield as index. The characteristics of the microspheres were investigated in detail. Results The optimal formulation and the preparation conditions were as follows: Q-flow 40 m3/ h,Aspiration 100%,inlet temperature110 ℃,pump speed 15%,chitosan concentration 1%,ratio of gastrodin to chitosan 1 ∶ 3. The optimized microspheres were spherical with the drug loading efficiency,entrapment efficiency,yield and average diameter as(23. 10 ± 0. 38) %,(92. 41 ± 0. 96) %,(71. 32 ± 0. 93) % and(5. 38 ± 1. 09) μm,respectively,and the in vitro release of the microspheres had sustained release characteristics. Conclusion Spray-drying method for preparing gastrodin loaded chitosan microspheres is simple and rapid. The microspheres with high entrapment efficiency and uniform particle size conform to the nasal drug delivery requirements.