One in ten people in the UK have a needle phobia so serious it means they frequently miss out on vital treatments such as vaccines and biopsies.
Help, however, could soon be at hand – in the form of an ‘exploding’ capsule that, once swallowed, releases its cargo of medicine precisely where it is needed.
The technology is inspired by the way squid squirt ink underwater when they are angry or frightened, by filling their body with water then expelling it (and the ink) rapidly. This jet-propulsion system also helps them move rapidly around the ocean.
Preliminary studies suggest the capsule (the size of a blueberry) not only avoids the need for needle jabs but also reduces the risk of side-effects (caused as the injected drugs have to circulate around the bloodstream before reaching their target).
Experts behind this approach predict it could one day do away with the need to regularly inject drugs, such as Ozempic for weight loss, cancer-fighting medication or insulin for diabetes.
The technology was developed initially for people with diabetes, both type 1 and type 2 (the vast majority of those with type 1 need to inject themselves with insulin four or five times a day, while about 50 per cent of those in the UK with type 2 need insulin injections within six to ten years of diagnosis).
Around three-quarters of people with diabetes would prefer to swallow a pill daily than have regular injections, reported the journal Diabetes, Obesity and Metabolism in 2020.
But while many medications can be swallowed because they are made up of small molecules that pass through the lining of the stomach easily, others – including insulin – consist of large molecules that cannot easily pass through the stomach or intestinal lining, and are destroyed by the harsh acidic environment of the stomach. That is why they must be injected directly into the bloodstream.
The ‘exploding’ capsule that, once swallowed, releases its cargo of medicine precisely where it is needed
It is inspired by the way squid squirt ink underwater when they are frightened
And even medications made up of small molecules often have to be given in significantly higher doses than needed, to compensate for any stomach acid attack.
Yet high dosing is not possible if the drugs can build up to toxic levels, are too sensitive to the acidity of the stomach or are expensive.
‘We want to make it easier for patients to receive medication,’ says Professor Giovanni Traverso, a gastroenterologist at Brigham and Women’s Hospital in the US and one of the scientists behind the new squid-inspired capsule.
He added: ‘The challenge with drugs such as insulin and monoclonal antibodies [targeted treatments used to boost the immune system to treat conditions including cancer] is that they require an injection – that can be a barrier for receiving medication. This work represents one of the next major advances in that progression.’
The new drug delivery system, which comes in different versions depending on where it will deliver its payload, uses either carbon dioxide or tightly coiled springs to propel liquid drugs out of the capsule.
The gas or spring is kept compressed by a carbohydrate plug which is gradually broken down by the stomach acid over a pre-determined period of time. It’s a bit like releasing the top off a bottle of fizzy pop; the gas or spring expands, propelling a jet of drugs out of the capsule.
It produces enough force to fire the medicine into the sub-mucosal space, a thin layer of tissue under the mucous lining of the stomach that has lots of blood vessels. This means the drug can be quickly carried into the bloodstream. The empty capsule then passes through the rest of the digestive tract before being excreted.
In the latest squid ink study, published in Nature, pig studies showed the capsules were as effective at delivering insulin as injections without causing any obvious side-effects. The researchers also showed the capsule worked with an Ozempic-like weight-loss drug that’s normally injected, as well as short interfering RNA (siRNA) – a treatment which can silence certain genes, making it potentially useful in tackling many genetic disorders.
They found the concentration of the drugs in the animals’ bloodstream reached similar levels as when they were injected.
There is even hope this method of delivery may be better than injecting into the skin, as it allows the drugs to take effect much more rapidly – important when it comes to insulin. Injected insulin through the skin can take up to 30 minutes to work, compared with ten minutes for the capsule.
Professor Traverso said: ‘To be able to do this with a device that is administered orally is remarkable.’
One in ten people in the UK have a needle phobia so serious it means they frequently miss out on vital treatments such as vaccines and biopsies.
The researchers now plan to further develop the capsules, in hopes of testing them in humans.
Commenting on the technology, Simon Heller, a professor of clinical diabetes at the University of Sheffield, says: ‘The capsule which mimics the mechanism of squid propulsion is very clever technology and seems to work in early trials on animals.
‘As well as helping people who don’t like needles, it could mean that drug doses can be kept to a minimum [since the capsule protects drugs from gastric acid in the stomach], and it could help deliver insulin more quickly.
‘It is certainly interesting in principle – but there are hurdles to jump to make it a major step forward for people with diabetes. We also need to know more about the potential downsides of using ingested devices like these.’
