Objective: To optimize formulation of breviscapine gastric-floating tablets by central composite design-response surface methodology. Method: Based on single factor tests

with amounts of hydroxypropyl methyl cellulose K4M(HPMC K4M) and lactose as independent variables

synthesized estimated value which was calculated by release of breviscapine at 2

6 and 12 h as dependent variable

formulation of breviscapine gastric-floating tablets was optimized by central composite design

SAS software was adopted to process experimental data in order to choose optimum mathematical mode

Statistica 6.0 software was employed to draw 3D surface plot and contour plot for determination of optimum formulation. Result: Optimum formulation was:breviscapine 10 mg

HPMC K4M(hydrophilic gel matrix) 20 mg

lactose(porogenic agent) 10 mg

NaHCO3(frothing agent) 15 mg

octadecanol(floating assistant)10 mg

microcrystalline cellulose(filler) 35 mg;and amounts of HPMC K4M and lactose were 20% and 10%

respectively.Cumulative release of breviscapine gastric-floating tablets at 2

6 and 10 h were 19.2%

39.7% and 81.5%

respectively.Breviscapine gastric-floating tablets could float in 5 s with duration of floating was more than 10 h. Conclusion: This established mathematical model had high predictability

which could be used to optimize formulation of breviscapine gastric-floating tablets.These prepared gastric-floating tablets had good release requirements and floating properties.