An experimental ultrafast-acting insulin could work four times quicker than current fast-acting formulas, researchers say.
For the study, the researchers focused on a form of insulin called monomeric insulin. Though its structure should, in theory, allow it to act faster, monomeric insulin is too unstable for practical use, so the Stanford University team had to find a way around that problem.
"The insulin molecules themselves are fine, so we wanted to develop a 'magic fairy dust' that you add into a vial that would help to fix the stability problem," said senior author Eric Appel, assistant professor of materials science and engineering.
"People often focus on the therapeutic agents in a drug formulation but, by focusing only on the performance additives -- parts that were once referred to as 'inactive ingredients' -- we can achieve really big advancements in the overall efficacy of the drug," Appel added in a university news release.
His team identified an additive polymer that could stabilize monomeric insulin for more than 24 hours in stressed conditions. Current commercial fast-acting insulin stays stable for six to 10 hours under the same conditions.
The researchers confirmed the ultrafast action of their formulation in pigs with diabetes, the most advanced non-human animal model. Their results were published July 1 in the journal Science Translational Medicine.
In the pigs, the experimental insulin reached 90% of its peak activity within 5 minutes of injection, while commercial fast-acting insulin began showing significant activity only after 10 minutes.
The experimental insulin's activity peaked at about 10 minutes; commercial insulin required 25 minutes.
Though results of animal experiments are not always the same in humans, the researchers said the difference could be significant. It could translate to a fourfold decrease in the time insulin takes to reach peak activity in people.
"It's really unprecedented," Appel said. "This has been a major target for many big pharmaceutical companies for decades."
Additional tests are underway with an eye to applying for U.S. Food and Drug Administration approval for clinical trials in humans.
The American Academy of Family Physicians has more on insulin.