Scientists have developed a drug capsule that allows the oral delivery of insulin, meaning patients with diabetes that are reliant on insulin therapy could soon have an alternative to subcutaneous injections.
What is insulin?
Insulin is a peptide hormone produced by the β-cells of the pancreas. This hormone enables the body to regulate the amount of glucose in the blood.
In healthy individuals insulin (circled) is produced by the pancreas.
The team designed a capsule that contains an ingestible microneedle capable of injecting insulin into the stomach lining. Using a large animal model, the researchers were able to deliver enough insulin to lower blood glucose levels which were comparable to levels achieved by subcutaneous injection. The pill could also be adapted to deliver other protein drugs. Study findings are published in Science.
Robert S. Langer, senior study author commented on the impact of the findings in a recent press release:
"We are really hopeful that this new type of capsule could someday help diabetic patients and perhaps anyone who requires therapies that can now only be given by injection or infusion,”
The microneedle within the capsule is composed of compressed, freeze-dried insulin and a biodegradable material, and is designed to always land in the stomach in the same orientation.
Video credit: Diana Saville
"If a person were to move around or the stomach were to growl, the device would not move from its preferred orientation," said Giovanni Traverso, also senior study author.
Once in the stomach the microneedle is decompressed causing the insulin to be injected into the lining of the stomach. The mechanism works by releasing a spring which is freed by dissolving a supporting sugar disk (water within the stomach causes the sugar disk to dissolve).
As the stomach wall does not possess pain receptors the researchers are hopeful that this could be a preferable method of administration compared to traditional injection.
After the capsule releases its contents, it moves harmlessly through the digestive system. The team reported no adverse effects from the capsule.
The team are now working to further optimize the technology and manufacturing of the capsule.
"Our motivation is to make it easier for patients to take medication, particularly medications that require an injection," explained Traverso.
"The classic one is insulin, but there are many others."
Type 1 diabetes
Type 1 diabetes (T1D) is typically caused by an autoimmune reaction whereby the body attacks the cells that produce insulin. Patients with T1D produce very little or no insulin meaning they require insulin to be administered every day to allow them to regulate the levels of glucose in their bloodstream.
Type 2 diabetes
Type 2 diabetes (T2D) is a chronic condition that accounts for ~90% of diabetes cases. Patients with T2D are either:
- resistant to insulin (their body resists the effects of the hormone) or
- have a relative insulin deficiency (their body doesn’t produce enough insulin to allow them to regulate glucose levels efficiently)
affecting their ability to metabolize glucose.
T2D is often linked to being overweight or obese. In some cases it is possible to manage the condition by losing weight, adjusting dietary habits, and exercising. However, some patients do require insulin therapy and/or other medications to help them regulate their blood glucose.