A tiny magnet inside a gelatin capsule allows researchers to hold medicine at an exact place in the intestine where it is best absorbed. Credit: Mathiowitz Lab/Brown Univ. |
Most patients never have that choice. The problem with
administering many medications orally is that a pill often will not dissolve at
exactly the right site in the gastrointestinal tract where the medicine can be
absorbed into the bloodstream. A new magnetic pill system developed by Brown Univ.
researchers could solve the problem by safely holding a pill in place in the
intestine wherever it needs to be.
The scientists describe the harmless operation of their
magnetic pill system in rats online in the Proceedings of the National Academy of Sciences. Applied to
people in the future, said senior author Edith Mathiowitz, the technology could
provide a new way to deliver many drugs to patients, including those with
cancer or diabetes. It could also act as a powerful research tool to help
scientists understand exactly where in the intestine different drugs are best
absorbed.
“With this technology you can now tell where the pill is
placed, take some blood samples and know exactly if the pill being in this
region really enhances the bioavailability of the medicine in the body,” said
Mathiowitz, professor of medical science in Brown’s Department of Molecular
Pharmacology, Physiology, and Biotechnology. “It’s a completely new way to
design a drug delivery system.”
The two main components of the system are
conventional-looking gelatin capsules that contain a tiny magnet, and an
external magnet that can precisely sense the force between it and the pill and
vary that force, as needed, to hold the pill in place. The external magnet can
sense the pill’s position, but because the pill is opaque to x-rays, the
researchers were also able to see the pill in the rat’s bodies during their
studies.
Safety first
The system is not the first attempt to guide pills magnetically, but it is the
first one in which scientists can control the forces on a pill so that it’s
safe to use in the body. They designed their system to sense the position of
pills and hold them there with a minimum of force.
“The most important thing is to be able to monitor the
forces that you exert on the pill in order to avoid damage to the surrounding
tissue,” said Mathiowitz. “If you apply a little more than necessary force,
your pill will be pulled to the external magnet, and this is a problem.”
To accomplish this, the team including lead author and
former graduate student Bryan Laulicht took careful measurements and built an
external magnet system with sophisticated computer control and feedback
mechanisms.
“The greatest challenges were quantifying the required
force range for maintaining a magnetic pill in the small intestines and
constructing a device that could maintain intermagnetic forces within that
range,” said Laulicht, who is now a postdoctoral scholar at MIT.
Even after holding a pill in place for 12 hours in the
rats, the system applied a pressure on the intestinal wall that was less than
1/60th of what would be damaging.
The next step in the research is to begin delivering
drugs using the system and testing their absorption, Mathiowitz and Laulicht
said.
“Then it will move to larger animal models and ultimately
into the clinic,” Laulicht said. “It is my hope that magnetic pill retention
will be used to enable oral drug delivery solutions to previously unmet medical
needs.”
In addition to Mathiowitz and Laulicht, authors on the
paper include Brown researchers Nicholas Gidmark and Anubhav Tripathi. Brown Univ.
funded the research.
Filed Under: Drug Discovery
