Having delivered promising pre-clinical results from trials with insulin, researchers from RMIT University (Royal Melbourne Institute of Technology) in Australia hope to move into clinical trials as soon as possible.
The technology could also be used to deliver other protein drugs orally, such as monoclonal antibodies.
An international patent application has been filed for the technology.
The challenge with delivering protein drugs orally is that the drugs degrade very quickly in the stomach before they can reach their target.
The new capsule, however, protects the drug so it can pass safely through the stomach to the small intestine. It can withstand the low pH environment in the stomach, before dissolving in the higher pH levels of the small intestine.
The insulin is packaged in a fatty nanomaterial within the capsule that helps ‘camouflage’ the insulin so it can cross the intestinal walls – in a similar fashion to mRNA vaccines which package the mRNA in fats.
Most diabetics take a combination of both fast-acting insulin (a fast response to control blood-sugar when eating a meal) and slow-acting insulin (which keeps insulin in the body steady over a longer time frame).
A study, published in the journal Biomaterials Advances, assessed the performance of the oral capsules with both fast-acting and slow-acting insulin.
The capsule showed ‘excellent absorption’ results for the slow-acting form: in fact around 50% better than injection delivery for the same quantity of insulin.
While the capsule also achieved good absorption results for fast-acting insulin, the significant lag in the insulin taking effect via oral delivery compared with injection delivery appears to be a less practical option.
“Our results show there is real promise for using these oral capsules for slow-acting insulin, which diabetics could one day take in addition to having fast-acting insulin injections,” said co-lead researcher Professor Charlotte Conn, a biophysical chemist from RMIT University.
“The oral capsules could potentially be designed to allow dosing over specific time periods, similar to injection delivery. We need to investigate this further, develop a way of doing so and undergo rigorous testing as part of future human trials.”
The same amount of insulin was used in oral capsules as in injection delivery, showing another advantage to this capsule design.
“For many pre-clinical trials the oral formulations by necessity contain much higher levels of insulin to achieve the same response as the injection delivery. This is not a very cost-effective way to deliver protein drugs which tend to be expensive,” said Dr Céline Valéry, a pharmaceutical scientist from RMIT and study co-author.
Study: 'A promising new oral delivery mode for insulin using lipid-filled enteric-coated capsules', Biomaterials Advances, March 6, 2023. DOI: 10.1016/j.bioadv.2023.213368