Gainesville, FL—Patients can have confidence in the insulin purchased at U.S. pharmacies, according to a study examining the consistency and potency of insulin available there.

The Diabetes Care article reports that all human and analog insulins measured contained the expected quantity of active insulin, despite past questions raised about the integrity of insulin purchased from United States retail pharmacies.

A 2017 article in the Journal of Diabetes Science & Technology put a spotlight on that issue, stating that cold supply chain apparently impacted insulin concentrations to a larger extent than anticipated, concluding, “Quality of a critical care biologic product, such as insulin, is difficult to determine prior to dispensing by the pharmacist or at home before administration by the patient. If the results presented here can be repeated by others (with additional analysis of insulin analogs/biosimilar insulins, and other biologics shipped through the cold supply chain), we see the need to evaluate during which step in the cold chain the observed massive reductions in insulin concentration are taking place and how this can be avoided. Patients are paying high prices for insulin and should expect to receive insulin vials with adequate insulin content in return.”

In response, University of Florida–led researchers sought to independently validate the method used, isotope dilution solid-phase extraction (SPE) liquid chromatography mass spectrometry (LC-MS), and expand analysis to two U.S. Pharmacopeia (USP) methods (high-performance LC with ultraviolet detection and LC-MS).

The study team used each method to evaluate nine insulin formulations, purchased at four pharmacies, within five geographic locations in the United States. The authors report that all 174 human and analog insulins measured by the USP methods contained the expected quantity of active insulin (100 ± 5 units/mL), adding, “When using isotope dilution SPE-LC-MS, units-per-milliliter values were well below product labeling due to unequal recovery of the internal standard compared with target insulin.”

The study concludes, “Insulin purchased from U.S. pharmacies is consistent with product labeling.”

The research was funded by the JDRF, the American Diabetes Association (ADA), and The Leona M. and Harry B. Helmsley Charitable Trust.

“During such an unprecedented time it’s more important than ever for people with T1D to feel safe. This study reaffirms our confidence in the safety and effectiveness of insulin products,” said Aaron Kowalski, PhD, president and CEO of JDRF. “As JDRF, our partners, and the type 1 diabetes community pursue cures and support the development of better insulins, we must also work together to make these safe and effective insulin products affordable and accessible to everyone who needs them.”

The associations note that the 2017 study did not use a research method approved by USP and was inconsistent with data from previous regulatory audits. USP and the FDA require insulin vials and cartridges to contain 100 U/mL (± 5 U/mL).

The sponsors advise that the research will be expanded during a second study phase to measure any potential seasonal variations in reported insulin activity.

 « Click here to return to Weekly News Update.