Hydrogel Extends Drug Shelf Life Beyond Refrigeration

Many medicines need to be kept refrigerated or they become ineffective, but a new way of packaging protein-based drugs into a stiff gel could potentially extend their shelf life at room temperature.

If medicines are not stored properly, they can break down and become unsafe to use. For example, exposure to high temperatures can break down the chemical bonds that keep the medicine’s molecules in place, impairing their function. Shaking some medicines can cause the molecules to clump together, making them less effective. Matthew Gibson Researchers at the University of Manchester in the UK have been working to solve these challenges for almost 15 years.

He and his colleagues have developed a method to make working with protein-based drugs simpler and more practical. He said the new advances are Dave Adams Hydrogel-making researchers at the University of Glasgow in Scotland have found a way to mix proteins with gel ingredients to create hard, white structures that can be packed into a syringe. In this form, the proteins, which normally must be refrigerated at minus 20 degrees Celsius (minus 4 degrees Fahrenheit), can withstand temperatures of up to 50 degrees Celsius (122 degrees Fahrenheit) and remain functional under those conditions for up to four weeks.

Hydrogels get their stiffness from small molecules bound together in large chains that break when force is applied. In a syringe, pushing down on the plunger breaks the molecular bonds, turning the gel-protein mixture into a liquid. The hydrogel remains too large to fit through the needle, so only the drug comes out.

The team tested the method with several compounds, including bovine insulin and beta-galactosidase, an enzyme commonly used in genetic biology, and mailed themselves boxes filled with tubs of hydrogel packed with the proteins, finding that the proteins could withstand the temperature and jolts that come with going through the postal system.

There are laboratory methods that can keep proteins stable for longer, but this approach may be better suited to leaving the lab and going into the clinic, he said. Alex Brogan The King’s College London researcher says the method would be most useful in countries and regions where refrigeration is scarce and prohibitively expensive. If the new method works for protein-based vaccines, it could make disease prevention more equitable, he says.

Gibson says he and his team are confident they can produce the hydrogel on an industrial scale, but want to study its longevity and safety further. Using it in a vaccine is on their wish list, but in the short term the method could also be used to store, transport and administer the diabetes and obesity drug semaglutide.