Objective:To prepare fluorouracil(FU)hollow microspheres

and to evaluate its in vitro release behavior. Methods:On the basis of single-factor test

three factors[FU

ethyl cellulose(EC)and polyvinylpyrrolidone(PVP)] three-leveled orthogonal experimental design L9(33)was carried out with the in vitro release as marker for optimization. Results:The optimization formulation composed of FU:EC:PVP(0.6:1.0:0.1

w/w)was obtained based on the orthogonal experiment with comprehensive score of the in vitro release.Mean cumulative in vitro release of three batches of FU hollow microspheres prepared using the optimization formulation at 0.5

1

2

4

8

12

24 h was(9.88±0.38)%

(14.64±0.09)%

(23.94±0.67)%

(39.21±0.36)%

(57.53±0.83)%

(67.99±0.58)%

(80.34±0.39)%

respectively(P=0.001). The in vitro release models at 0-8 h and 8-24 h were prescribed by the one-level equation[Ln(1-Q)=-0.072 1 t-0.563 7

r =0.997 3

P =0.001] and Higuchi equation(Q =0.102 3t1/2+0.398 7

r =0.999 9

P =0.001)

respectively.Conclusion:Perfect sustained release effect is obtained for fluorouracil hollow microspheres in this study. This study would lay the foundation for the development of fluorouracil prolonged action preparation.