Recombinant human growth hormone (rhGH) has been widely used in children to treat growth retardation and applied in growth hormone replacement therapy for adults. Unfortunately, rhGH therapy still suffers the poor patient compliance due to daily injection. Additionally, rhGH sustained delivery system related research area was still in its infancy. In this respect, development of a sustained-release rhGH formulation over a period of 1 week to 1 month would be a significant improvement of the current daily treatment.

Prof. MA Guanghui and her group from Institute of Process Engineering, Chinese Academy of Sciences presented a new method to prepare amphiphilic poly (monomethoxypolyethylene glycol-co-D,L-lactide) (mPEG-PLA, PELA) microspheres with narrow size distribution for sustained release of rhGH. The method combined premix membrane emulsification and double emulsion technique without any exogenous stabilizing excipients. They focused on investigating the microcosmic mechanisms responsible for rhGH encapsulation and rhGH stability.

The key factor for protein stabilization is that mPEG-PLA block copolymer possessed the function similar to surfactants, thus can minimize the contact of protein with the oil/water interface. It was showed that PELA microspheres exhibited an lower initial burst release of 14.2% rhGH, a more constant release of 78.3% after a 45-days period and much better integrity of rhGH than conventional microspheres.The research is promising for construction of sustained release system for rhGH by PELA microspheres.

This work was supported byPfizer and National Natural Science Foundation of China (20706053). The research results were published on Journal of Materials Chemistry, 2011, 21, 12691

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)