Formula and process optimization of controlled‐release microcapsules prepared using a coordination assembly and the response surface methodology

Abstract

ABSTRACTA model chlorpyrifos microcapsule was prepared using coordination assembly between Fe3+ and tannic acid (TA). The influence of independent variables such as the dropping rate of TA (X1) and Fe3+ (X3), the concentration of TA (X2) and Fe3+ (X4), and the reaction temperature (X5) on the encapsulation efficiency (R1) and release characteristics (R2) of the microcapsule had been investigated, based on a central composite design with five factors and five levels. The results showed that the main factors influencing R1 and R2 were X4 and X2, then the interaction between X2 and X4, followed by X5 and X3. The optimal formula mainly based on higher R1 and lower R2 were determined and then tested. The optimized conditions led to an encapsulation efficiency and cumulative release proportion of 97.12% ± 0.72% and 40.07% ± 0.53%, along with the average relative errors of predicted values being 1.78% and −1.60%, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42865.