Synergetic Protein Factors That Improve rhGM-CSF Absorption via an Oral Route Exist in Silkworm Pupae.

Recent studies have demonstrated that recombinant human granulocyte macrophage colony-stimulating factor (rhGM-CSF) produced by the silkworm pupae bioreactor is absorbed into blood through oral administration and functions as an active cytokine. The aim of this study was to further examine and identify synergetic protein factors in silkworm pupae that improve rhGM-CSF absorption via an oral route. The concentrations of rhGM-CSF in serum were evaluated in mice after oral administration of rhGM-CSF using different chemical compositions of silkworm pupae as pharmaceutical excipients. The experimental data revealed that the supernatant lyophilized powder (SLP) of a homogenized slurry of silkworm pupae caused a significant increase in the rhGM-CSF level in blood when rhGM-CSF was orally administered with SLP, suggesting that synergetic protein factors that improve the oral absorption of rhGM-CSF primarily exist in SLP. As shown by scanning electron microscopy, microspheres were formed when rhGM-CSF was coated ...