If a hemophiliac patient injects his factor 8 through the veins directly into the bloodstream to provide the body with clotting factor... Why don't they just make the drug as a pill and have the liver do its job with extracting protein and dumping it into the bloodstream?
Proteins will be digested through a number of proteases in the stomach and intestines (pepsin, trypsin, etc) into their constituent amino acids. The amino acids are then absorbed in the small intestine. So any specific proteins you try to put into a pill will be digested into amino acids before being absorbed. If you somehow manage to defeat the digestive enzymes, the protein will simply pass through the digestive tract without being absorbed--the intestines don't have the capability to allow larger polypeptides through.
If you think about it, this is probably a good thing. We don't want random proteins from our food running around in our bodies. It would likely kill us in short order.