Preparation of ligustrazine-chitosan microspheres by spray drying method

Objective To prepare ligustrazine-chitosan microspheres and to investigate the drug release behavior in vitro. Methods Microspheres were prepared using the spray drying method.The encapsulation efficiency was used to evaluate the influence of different formulation and preparation factors,the formulation was optimized by L9(34) orthogonal design.Results The optimal formulation and preparation factors were as follows: chitosan concentration(0.01 g/mL),ratio of chitosan to ligustrazine(1∶4),inlet temperature(120 ℃),air flow rate(500 L/h).The optimized microspheres had a spherical shape,the loading capacity was(18.60±0.15)%,entrapment efficiency was(93.01±0.76)%,the average diameter was(10.69±0.64) μm.The drug release profile in vitro could be described by Higuchi equation Q=19.798 t1/2+25.209(r=0.997) at 1-15 h,which showed the prepared microspheres obviously had the sustained release effect.Conclusion The encapsulation efficiency of ligustrazine-chitosan microspheres is higher,the preparation method is simple,and the process is stable.It will provide the basis for realizing the industrialization in Chinese materia medica microspheres.