The chitosanmicrospheres were prepared by the O/W/O combined with multiple emulsification chemical crosslink technique.Quadratic polynomial equation and linear regression equation were fitted by the statisticsoftware,and the resulting equations were used to produce response surface graphs.The best experiment conditions were screened by central composite design(CCD)using drug load,encapsulation efficiency,and the proportions of microspheres(with diameter of 40-60 ?m)as variables.The shape of microspheres was observed by scanning electron microscope.
Results:
The best ranges of the prescription includeddrug to carrier material ratio0.4-0.5;organic phase and water phase ratio0.4-0.6;and first emulsion and oil phase ratio0.13-0.17.The 3 batches of microspheres prepared according to the above condition were well-shaped(full sphere),with the mean drug loading capacity being(10.25?0.08)% and the encapsulation efficiency being(30.61?1.46)%.