Objective: To optimize formulation of Platycodonis Radix effervescent tablets. Method: On the basis of single-factor tests

taking effervescent acid-base ratio

the amount of mannitol and effervescent as independent variables

disintegration time and pH as dependent variables. Experiments were based on central composite design

mathematical models were simulated by multiple-linear equation

second-order polynomial equation and triple-order polynomial equation. Optimal formulation of Platycodonis Radix effervescent tablets was predicted by response surface methodology. Result: Optimum formula was as follows:acid-base ratio of 1:1.25 (tartaric acid-NaHCO3)

mannitol amount of 52% and effervescent amount of 100% to extract powder. Under these conditions

disintegration time of Platycodonis Radix effervescent tablets was 224 s and pH was 5.32. Conclusion: Platycodonis Radix effervescent tablets can be obtained with good taste

rapidly disintegration and convenience in using. Central composite design-response surface methodology is successfully used to optimize formulation of this preparation with good predictability.