Objective: To optimize the formulations of vinorelbine intravenous emulsion by a central composite design methodology. Method: Independent variables were investigated which included the oil concentration

the soybean phospholipid concentration and the content of poloxamer with the parameter of stability and mean particle size. Linear or nonlinear mathematic models were used to estimate the relationship between independent and dependent variables. Response surfaces were delineated according to best-fit mathematic models

and optimum formulations were selected. Prediction was carried out through comparing the observed and predicted values. Result: Regression coefficients of the parameter of stability and mean particle size were as high as 0.987 6 and 0.983 7 respectively in nonlinear mathematic models. Optimum formulation was proposed to contain oil 9.0%

soybean phospholipid 2.2% and poloxamer 1.51%. Conclusion: The optimum mathematic model established was highly predictive.