Drug Delivery System Breaks the 'Mucus Barrier'
"We studied the properties of disease-causing viruses that evolved to infect mucosal surfaces to engineer a coating that enables our drug delivery particles to penetrate mucus layers in minutes. In our new work, we have improved the coatings considerably to allow faster penetration for a wider array of particle sizes," says lead presenter Samuel K. Lai, Ph.D.
"Mucus has evolved to be a highly efficient barrier," says Justin Hanes, professor of chemical & biomolecular engineering at Johns Hopkins University, the lead investigator of the study. “For example, we constantly inhale particles into our lungs, but they typically stick to mucus rather than penetrate it. Particles that stick are removed rapidly from the lungs on a mucus ‘conveyor belt,’ and are swallowed and sterilized in the gut. Mucus barriers protect us from constant infection, as well as everyday things like the millions of particles in the black cloud emitted from a bus when it takes off from a stop.”
Unfortunately, mucus also prevents the passage of many beneficial drugs. And when the mucus gets thicker—most notably in diseases like chronic sinusitis, cystic fibrosis and chronic obstructive pulmonary disorder—drug treatment of the lungs and other mucus-lined areas becomes more difficult.
Lai explained that coating drug-loaded nanoparticles with an inexpensive polymer material allows particles to pass through the mucus linings. With this mucus-penetrating mechanism, drugs could be delivered locally and with enhanced durations to treat diseases at mucosal surfaces. In collaboration with Richard Cone, professor of biophysics at Johns Hopkins, the work also opens the door to more targeted drug delivery, including improved chemotherapy for cervical and lung cancer patients.
Release Date: August 20, 2008
Source: American Chemical Society