Suction Cup Delivers Drugs Through Cheek

Researchers at ETH Zurich in Switzerland have developed an alternative to injections as a way to deliver large drugs, such as peptides, minimally invasively into the blood stream. The suction cup created by these researchers is inspired by octopus suckers, and it affixes to the mucosal lining of the inside of the cheek. The cup stays in place because a vacuum is drawn when the patient presses it onto their cheek lining. This vacuum helps to stretch the tissue, making it more permeable to drugs. The suction cup also exposes the mucosal lining to an additional reagent called a permeability enhancer, which fluidizes the cell membranes of the mucosa, allowing peptides to traverse the lining more easily. In tests so far, the suction cups have produced successful delivery of medication to the blood stream, and have been described by volunteers as preferable to injections.

No one enjoys injections, but for some people they are a source of terror. This is more common with children, but many adults also have a fear of needles. Moreover, for people who need to take a drug regularly, getting repeat injections is no fun, with repeated trauma at the injection sites. However, there is often no easy replacement for injections, particularly for drugs that are not usually suitable for oral, inhalational ,or transdermal administration, such as peptides.

This latest invention is an attempt to deliver such drugs in a minimally invasive fashion, through the inside wall of the cheek. The concept was born when one of the researchers noticed a half peppercorn stuck to the inside of his cheek during a meal, which resonated with him as a way to affix a drug-filled container to the slippery oral mucosa. However, the oral mucosa itself is not particularly amenable to drug delivery, with its dense nature providing a barrier.

To circumvent this, the researchers combined the suction effect of the cup, which stretches the tissue somewhat, potentially increasing its permeability, with an additional substance called a permeability enhancer that makes the treated cell membranes more permeable. This combination resulted in the successful delivery of drugs through mucosa.

However, the technology did require some fine-tuning, which the researchers performed using a post-mortem pig mucosa as a testing bed. “We had to find out what geometry and how much of a vacuum were required to hold the suction cup in place on the mucosal lining of the cheek and to stretch it sufficiently without causing any damage,” said Klein Cerrejon, a researcher involved in the study.