Scientists in Japan are reporting an advance toward using a natural disease-fighting protein in pills or syrups that patients can take by mouth rather than injection. Their study is the first to show that coating the protein with a polymer material already in wide medical use can increase its absorption by the intestine.
In the study, Atsushi Sato and colleagues note that the protein — lactoferrin (LF) — occurs in saliva, breast milk and other body fluids, where it has powerful effects in fighting bacteria, viruses, and inflammation. LF is sparking excitement as a potential treatment for cancer, gangrene, hepatitis, and a host of other diseases. Although LF is available as a dietary supplement and as an experimental oral drug, acid in the stomach quickly destroys existing forms of LF, reducing the protein's effects.
The scientists found that laboratory rats absorbed 10 times more LF if the protein is coated with the polymer, called polyethylene glycol (PEG). In addition, the coated PEG remained active in the bloodstream longer than the uncoated protein. The scientists also showed that the coated drug retained most of its disease-fighting potency, including antibacterial, antioxidative and anti-inflammatory activity, compared to the uncoated drug. The PEG-coating technique not only is a promising advance toward making lactoferrin an oral drug, but also may be used to convert other healthful food proteins into useful drugs, the researchers note.
- Nojima et al. Development of Poly(ethylene glycol) Conjugated Lactoferrin for Oral Administration. Bioconjugate Chemistry, 2008; 19 (11): 2253 DOI: 10.1021/bc800258v
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