Medicines are a cornerstone of modern healthcare, helping us manage everything from a minor headache to more severe conditions like infections or chronic illnesses. Over the years, the field of drug development has evolved, and today, medicines typically fall into two broad categories: small-molecule drugs and large-molecule drugs, also known as biologics.
When an octopus touches something with its sucker, it creates a seal, and then by contracting its muscles, it creates a suction effect. This action enables the octopus to grip the object tightly (Getty Images/iStockphoto/Representative image)
When you think of conventional medicines, like aspirin, antihistamines, or antibiotics, you're thinking of small-molecule drugs. These drugs are chemically synthesized in laboratories and have a simple structure, making them relatively straightforward to produce. Their size and design enable them to easily enter cells, where they can interact with the body's molecules to exert their therapeutic effects. For instance, if you've ever taken paracetamol for pain relief or amoxicillin for an infection, you've benefited from small-molecule drugs.
One of the main advantages of small-molecule drugs is their ease of administration. They can be formulated into pills, injections, and even inhalers. Their predictability, stability, and affordability make them common in modern medicine.
On the other end of the spectrum are biologics. These drugs are derived from living organisms and are more complex than their small-molecule counterparts. Unlike small molecule drugs that have a broad effect on the body, biologics and other large molecules are more targeted. This precision means they can be used to treat specific conditions with fewer side effects.
Biologics have transformed medicine. They're instrumental in managing various conditions ranging from diabetes, and heart diseases, to cancer. For example, drugs like Herceptin have become vital in treating certain types of cancer.
The challenge with biologics and other large molecules is that they aren’t easily absorbed by our body when taken in the form of a pill or capsule. Imagine trying to push a large bead through a fine mesh; it's not going to pass through easily. That's essentially the problem with large molecules. Our body's natural filters, like the gastrointestinal tract, block out large molecules. This means that they usually need to be directly injected into our system. This can be problematic, especially for children and those who need to take these drugs regularly.
Researchers have been hard at work trying to find a way around this. In the past, there have been attempts to develop oral forms of large-molecule drugs, by mixing them with certain substances that help them pass through our body's barriers. Yet very few have made it to clinical trials. Some have even suggested devices that can directly inject these drugs into our gut lining. However, there are questions about the safety and practicality of this approach.
Why not use other systems like patches that deliver the drug through the skin? While these systems can be effective, they come with their own set of challenges. Manufacturing is complex and applying them can be tricky. Researchers have also looked into methods like nasal delivery for biologics. Still, there's a long-standing interest in finding new ways to improve their delivery in pharmaceutical studies.
Interestingly, the inside of the mouth, known as the buccal mucosa, presents a promising site for drug delivery. It's easily accessible, can handle some disruption, and, crucially, avoids some of the typical barriers that large molecules face in our bodies. However, the lining of the mouth is thick, making it hard for large-molecule drugs to pass through, even with the help of chemicals designed to enhance absorption.
Now, a recent study in Science Translational Medicine provides an innovative solution that draws inspiration from nature. Researchers, led by Zhi Luo and David Klein Cerrejon, looked at how octopuses use their suckers.
When an octopus touches something with its sucker, it creates a seal, and then by contracting its muscles, it creates a suction effect. This action enables the octopus to grip the object tightly. The researchers hypothesized that a similar design might help biologics enter our body.
Using this concept, the team developed a special suction patch. This suction patch, made using 3D printing, was designed to be small and comfortable for patients. It comes with a chamber that holds the drug, protecting it from dilution by saliva. Most importantly, it carries a substantial amount of the drug, ensuring effective delivery.
The patch, when applied to the inside of the mouth, works like an octopus sucker. It stretches the tissue inside the mouth, making it easier for the drug to pass through and enter the bloodstream.
Here's the clever part: The team combined the stretching action with substances that help drugs pass through barriers. In tests on dogs, which have cheek linings similar to that of humans, the patch resulted in greater absorption of a drug called desmopressin (known for being hard to absorb orally) than when taken in its tablet form. This wasn't just a small improvement; the absorption of the drug was significantly higher.
The team didn't stop there. They also tested their patch on humans using a drug used for diabetes and weight loss. In the human trial involving 40 participants, the majority expressed a preference for these patches over injections, especially for daily and weekly use. This is an important step since it suggests that not only is the delivery system effective, but also that it is user-friendly.
The potential applications of this technology are vast. Many biologics and large-molecule drugs that currently require injections could be administered using these patches. This includes a range of medications being developed for conditions like diabetes or obesity. Additionally, drugs that often degrade the digestive system, like insulin, could see increased effectiveness with this method.
The team has patented the suction cup prototype and is seeking partners and funding to ensure it meets pharmaceutical standards before running clinical trials
In short, this study presents a promising way to take large-molecule drugs without the need for injections. By mimicking the octopus' sucker mechanism, we have a simple yet powerful tool to revolutionize drug delivery. While more research is needed to fully appreciate its potential and limitations, the future looks promising for patients who rely on biological and large-molecule treatments.
Anirban Mahapatra is a scientist by training and the author of a popular science book on COVID-19. The views expressed are personal
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