In the field of biomaterial, amphiphilic co-polymer is considered as an exploring-worthy biodegrade polymer for drug delivery due to its advantages that maintaining the proteins stability and increasing the protein loading efficiency. However, amphiphilic microcapsules exhibit broad size distributions prepared by conventional methods, such like mechanical stirring and spray-drying methods. The broad size distribution would lead to poor reproducibility. Therefore, it is necessary to develop a novel method in order to provide amphiphilic microcapsules with narrow size distribution.

Prof. MA Guanghui and her group from Institute of Process Engineering, Chinese Academy of Sciences presented a new method to prepare amphiphilic microcapsules with narrow size distribution and regular sphericity. The method is combining premix membrane emulsification and double emulsion technique. They focused on investigating the process parameters and mechanisms by using Poly (monomethoxypoly ethylene glycol-co-D,L-lactide) (mPEG-PLA, PELA), one of common amphiphilic polymers as model. It was showed that the key factors for preparing smooth-surface microcapsules were: internal water phase with less volume, slower stirring rate during solidification and using ethyl acetate as oil phase. It was also found that the significant factors affecting narrow size distribution of microcapsule: intrinsic viscosity of polymer, PVA concentration in external water phase and transmembrane pressures.PELA microcapsules with CV value under 15% were successfully obtained by manipulating the preparation conditions. The research would motivate the investigating of other amphiphilic polymer formulations when premix membrane emulsification technique is employed. 

This work was supported byNational Natural Science Foundation of China (20706053), the Funds for Creative Research Groups of China (112022160303), Major International Joint Research Program of China (20820102036) and Significant Creation of New Drugs (20092x09503-027). The research results were published in Colloids and Surface B: Biointerfaces, 87 (2011) 399-408.

Corresponding author: Wang Yuxia, Ma Guanghui

Tel.: 86 10 82544937(Y. Wang), 86 10 82627072 (G. Ma)

E-mail addresses: yxwang@home.ipe.ac.cn (Y. Wang), ghma@home.ipe.ac.cn (G. Ma)