shows the results of 13 experimental runs carried out using the design protocol. The data obtained was analyzed and fitted into various polynomial models. It was observed that the response Y1 (particle size) fitted best into the quadratic response surface model with backward elimination after natural logarithmic transformations of the data. On the other hand response Y2 (% encapsulation efficiency) fitted best into the quadratic response surface model after square root transformation of the data.
The polynomial models showing the relationship between the independent variables and the responses Y1 and Y2 can be expressed by the following Eqs. (3) and (4):