Drug delivery

I've just come across a very interesting paper in the Proceedings for the National Academy of Sciences. There are many different therapeutic proteins and peptides on the market, the most famous of which is probably insulin. However, because they are degraded within the gastrointestinal system they can't be given orally and are delivered via injection. However, groups are now looking at needle-free protein delivery.

This group demonstrate the oral delivery of granulocyte colony-stimulation factor (GCSF), which is used to hasten the recovery of cells in the immune system after chemotherapy. Bai and friends did this by using the protein carrier transferrin as a carrier. Transferrin is resistant to gastrointestinal digestion, and when the group expressed active GCSF as a recombinant fusion protein with transferrin and gave this orally, an increase in neutrophil count was observed. However, if GCSF was given alone no neutrophil increase was noted. When free transferrin was delivered with the transferrin-GCSF fusion protein no increase in neutrophil count was seen, which suggests that the fusion protein is taken up by a transferrin receptor-mediated process. As a review of the paper concludes,
"these results show that a transferrin-based recombinant fusion protein is a promising approach for future development of orally active protein and peptide drugs."
The days of daily injections for insulin-dependent diabetics could well be numbered.