Similar attempts to guide pills magnetically have been made in recent years, but the latest system uses a feedback loop that can control the pill’s position more precisely in three dimensions.
The pill itself is a conventional-looking gelatin capsule containing a tiny magnet that is swallowed and eventually excreted by the patient.
Along its journey, the pill is controlled by an external magnet, which is actually a modified materials-testing system (MTS) that has a force sensor mounted to a motorised uniaxial arm under computer control.
Using a feedback loop, the external magnet senses the force between it and the pill, varying that force as needed to hold the pill in place with the minimum force.
Edith Mathiowitz, lead on the project and professor of medical science and engineering at Brown University in the US, said: ’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.’
Mathiowitz added that many therapeutics currently on the market could potentially benefit by prolonged localisation, either at the site of action or at the point of optimal absorption.
’Ultimately we could envision our system being of great use in targeting GI cancers, other GI diseases [such as irritable bowel syndrome], and being used to administer drugs orally that currently suffer from poor oral absorption.’
Feasibility tests have now been carried out on rats, showing that the system exerted a pressure on the intestinal wall that was less than 1/60th of what would be damaging.
’We also see our system being used to investigate the absorption of new drugs in various locations to determine where they are best absorbed. This information could be extremely useful for then designing the optimal drug-delivery system for the novel compound,’ said Mathiowitz.