Drugs delivered by nanoparticles hold promise for targeted treatment
of many diseases, including cancer. However, the particles have to be
injected into patients, which has limited their usefulness so far.
Now, researchers from MIT and Brigham and Women’s Hospital (BWH) have
developed a new type of nanoparticle that can be delivered orally and
absorbed through the digestive tract, allowing patients to simply take a
pill instead of receiving injections.
In a paper appearing in the Nov. 27 online edition of Science
Translational Medicine, the researchers used the particles to
demonstrate oral delivery of insulin in mice, but they say the particles
could be used to carry any kind of drug that can be encapsulated in a
nanoparticle. The new nanoparticles are coated with antibodies that act
as a key to unlock receptors found on the surfaces of cells that line
the intestine, allowing the nanoparticles to break through the
intestinal walls and enter the bloodstream.
This type of drug delivery could be especially useful in developing new
treatments for conditions such as high cholesterol or arthritis.
Patients with those diseases would be much more likely to take pills
regularly than to make frequent visits to a doctor’s office to receive
nanoparticle injections, say the researchers.
“If you were a patient and you had a choice, there’s just no question:
Patients would always prefer drugs they can take orally,” says Robert
Langer, the David H. Koch Institute Professor at MIT, a member of MIT’s
Koch Institute for Integrative Cancer Research, and an author of the
Science Translational Medicine paper.
Lead authors of the paper are former MIT grad student Eric Pridgen and
former BWH postdoc Frank Alexis, and the senior author is Omid
Farokhzad, director of the Laboratory of Nanomedicine and Biomaterials
at BWH. Other authors are Timothy Kuo, a gastroenterologist at BWH;
Etgar Levy-Nissenbaum, a former BWH postdoc; Rohit Karnik, an MIT
associate professor of mechanical engineering; and Richard Blumberg,
co-director of BWH’s Biomedical Research Institute.
No more injections
Several types of nanoparticles carrying chemotherapy drugs or short
interfering
RNA,
which can turn off selected genes, are now in clinical trials to treat
cancer and other diseases. These particles exploit the fact that tumors
and other diseased tissues are surrounded by leaky blood vessels. After
the particles are intravenously injected into patients, they seep
through those leaky vessels and release their payload at the tumor site.
For nanoparticles to be taken orally, they need to be able to get
through the intestinal lining, which is made of a layer of epithelial
cells that join together to form impenetrable barriers called tight
junctions.
--------------------------
---------------------------