Design, development and evaluation of PEGylated rhGH with preserving its bioactivity at highest level after modification.

Modification of recombinant proteins with polyethylene-glycol (PEG) can improve their pharmacokinetic properties, although their bioactivity may be reduced after PEGylation due to structural changes. In this study, simultaneous optimization of PEGylation efficiency and preserved bioactivity of recombinant human growth hormone (rhGH) was investigated. In this regard, experiments were designed by the response surface methodology (RSM)-central composite design (CCD) utilizing design expert software.