How the octopus inspired a new method of drug delivery

The rubber suction cup, just slightly smaller than a 1 cent (euro) coin, is filled with medication and then stuck to the inner cheek for the drug to release. — ETH Zurich/TNS

Not all medications are effective if taken in pill form.

For example, large-molecule drugs made of peptides or proteins, such as insulin, have to be administered via injections because of this.

Researchers have long sought a better way to deliver these medications, such as patches that stick to the inside of your cheek.

But according to science journal Nature, “getting substances to stick to wet cheeks without damaging the tissues can be difficult”.

Swiss Federal Institute of Technology pharmacist Jean-Christophe Leroux and his colleagues have found inspiration from an unlikely source, however: an octopus.

“The suction cup in the octopus is made in such a way that you really have a very strong suction as soon as you apply it to the wet tissue,” Leroux said.

The rubber dispensers are about 1.1 centimetres across and 0.6cm high, and can hold more than 50 milligrammes of a drug.

Their design stops the medication from being diluted by saliva or other fluids, said study co- author and China’s Southern University of Science and Technology materials scientist Luo Zhi.

According to Nature, the researchers tested the patches in beagles, which have a cheek lining similar to humans.

They loaded the cups with desmopressin – a peptide drug that is administered orally – and a chemical that makes drugs pass more easily through tissue.

The researchers found oral bioavailability – the amount of the medicine taken by mouth that reaches the bloodstream – using the suction cup was 16.4%, compared to just 0.12% with a tablet.

After three hours, the dogs who used the suction cups had a blood plasma concentration of the drug 150 times higher than in those who took tablets.

The study was published in the journal Science Translational Medicine.

This is an “unprecedented increase in bioavailability,” Canada’s University of Montreal clinical pharmacist Simon Matoori said.

The researchers also tested the suction cups with semaglutide, which is used to treat diabetes and has molecules four times larger than desmopressin.

The patch’s bioavailability was similar to the tablet after 30 minutes.

“This clever way of overcoming biological barriers will inspire other drug-delivery scientists to improve further so that someday, we can deliver insulin non-invasively,” United States’ Purdue University pharmacist Park Kinam said. – By Nancy Clanton/The Atlanta Journal-Constitution/Tribune News Service