Formula optimization of clothianidin 300SC based on the combination of uniform design and response surface method

The formula of clothianidin 300SC was optimized by combining the uniform design and the response surface method. Partial least squares quadratic polynomial and stepwise regression quadratic polynomial model were used to analyze the results about the effect of the wetting-suspending agent and the viscosity modifier on the thermal stability. It was indicated that both the two models were capable of predicting the aqueous separation rate after hot storage(ASRHS) with the R2 of 0.9411 and 0.9999, respectively. The two formulas proposed by predicting models for ASRHS were both favorable formulas, of which the ASRHS were lower than 5% and the suspensibilities before and after the hot storage were higher than 92%. Besides, stepwise regression quadratic polynomial model was the better one, along with the average relative errors of predicted values of-4.85%. The optimal conditions were adding T2700, NR1602, xanthan gum and veegum at mass fraction of 3%, 0.4%, 0.22% and 2%. Under the optimal conditions the minimum value of ASRHS was 2.27%±0.08% and the suspensibility before and after hot storage were 92.51%±0.25% and 92.02%±0.46%. Furthermore, favorable dispersibility and flowability were observed under those conditions. Fortunately, no flocculation, agglomerate or knot at the bottom was observed even after hot storage. The ASRHS of samples remained lower than 5% and other performance was also qualified even when the dosage of T2700 was appropriately reduced according to the response surface results. The combination of uniform design and response surface method demonstrated favorable adaptability in the optimization of SC formula.