Alan Carter didn’t start his recent research with any deep doubts about the insulin that people buy in pharmacies. He just wanted to find out how different kinds of insulin compared.
“We thought, well, if we can figure out if there’s very subtle differences between the two manufacturing processes, then maybe we can help determine if there is a significant issue for patients who switch back and forth because of insurance formulary restrictions and costs,” Carter says.
Daily insulin injections can be the difference between life and death for many people with diabetes. But their efficacy at managing blood sugar levels can be frustratingly unpredictable.
Doctors often blame changes in patients’ diet or exercise, but Carter, who’s an adjunct clinical faculty member at the University of Missouri-Kansas City School of Pharmacy, thinks he may have stumbled on a different reason for why insulin injections don’t always work as they should.
While working at MRIGlobal, a contract research organization based in Kansas City, Carter used data from a cutting-edge technique called quadrupole-time-of-flight spectrometry to analyze 18 insulin samples purchased from various Kansas City-area pharmacies and other suppliers.
Instead of seeing what he expected to be minor differences, he was shocked to see that few of the samples appeared to come close to having the insulin concentrations they were supposed to have.
“We were really confused to see why those numbers were so low,” Carter says.
Some of the vials, which were expected to have 95 units per milliliter of intact insulin, were found to have less than half that.
Carter doesn’t think there’s a problem with insulin manufacturing. After all, it’s made, tested and stored under strict rules.
He suspects there may be a previously undetected problem with insulin that occurs once it reaches patients. Maybe it gets exposed to temperature extremes that make it break down. Or maybe it’s clumping or clinging to the insides of the vials.
“Everybody’s doing what we know to do correctly. Why is it not giving us the quantity per milliliter that we would expect?” Carter asks.
Carter’s research – which is slated for publication in the peer-reviewed Journal of Diabetes Science and Technology – has concerned some diabetes patient groups, but Washington University professor of medicine Richard Ostlund says he’s not alarmed.
“This is quite preliminary, this particular study,” Ostlund says.
Ostlund, who specializes in diabetes and insulin research, says that the cutting-edge method that Carter used may turn out to be useful, but it’s still too new to be reliable.
“I would call this sort of a Lamborghini method,” Ostlund says. “It’s a very fancy instrument, but it isn’t necessarily any better, and it might actually be worse than some other standard methods.”
Even if the methods Carter used are reliable, the 18 samples he tested are far too few to tell scientists anything definitive about the insulin supply around the world.
Still, Ostlund says that Carter’s research raises an important point. Even though insulin is well-tested when it’s made, drug makers, academic researchers and the Food and Drug Administration have not shown much interest in evaluating how it might change before it gets used.
“In terms of subtle changes, that’s something that we would have to look at with a future study,” Ostlund says.
In the meantime, Ostlund says, patients with diabetes should not make any changes to their insulin treatment routines based on the study.
Carter acknowledges his study is, at most, a first step. But he’s hopeful that upcoming research in this area from the American Diabetes Association and the JDRF, formerly known as the Juvenile Diabetes Research Foundation will shed further light on the mystery.
“The question I have is, what if we did happen to see something that does impact patients with diabetes and we know we haven’t really looked at it very deeply?” he asks.
Editor's note: KCUR is licensed to the University of Missouri Board of Curators and is an editorially independent community service of the University of Missouri-Kansas City.
Alex Smith is a health reporter for KCUR. You can reach him on Twitter @AlexSmithKCUR