https://www.selleckchem.com/pr....oducts/Rapamycin.htm
The oral bioavailability of hydrophilic and macromolecular drugs is generally poor owing to their poor membrane permeability. For example, peptide and protein drugs are poorly absorbed because of their low stability and poor membrane permeability in the gastrointestinal tract. Consequently, these drugs can be clinically administered only via injection. However, such frequent administration of injections subjects the patients to considerable pain, along with increasing the possibility of serious side effects. Several approaches have be