Hydrogel foams can deliver drugs for 6 months

Imagine only having to inject insulin once every 6 months rather than every day. Researchers at the University of Cambridge in the U.K. are working toward this with biodegradable polymer sponges that can release drugs over long periods to treat diabetes, cancer and other chronic diseases such as HIV/AIDS, or act as templates for tissue regeneration after surgery or injury.

The team used synthetic biodegradable polymers and forced high-pressure carbon dioxide through to create injectable, reformable and spreadable hydrogel foams with pores that can be loaded with protein drugs or transplanted cells. Tweaking the formulation can control the rate of release. Because the hydrogels are up to 99.7% water with no organic solvents, they should be more effective and better tolerated than current hydrogels. The research is published in Biomaterials.

"The hydrogels protect the proteins so that they remain bio-active for long periods, and allow the proteins to remain in their native state," says Dr. Oren Scherman of the Department of Chemistry, who led the research. "Importantly, all the components can be incorporated at room temperature, which is key when dealing with proteins which denature when exposed to high heat."

This delivery system could be especially useful in areas where patients do not have regular access to doctors, such as rural Africa, or to improve compliance in long-term treatment of infectious diseases such as HIV/AIDS and tuberculosis.

"There's been a lot of research that shows patients who need to take a pill each day for the rest of their lives, especially HIV patients in Africa who do not show any obvious symptoms, will take the pills for a maximum of 6 months before they stop, negating the point of taking the medication in the first place," says researcher Eric Appel. "If patients only have to take one shot, which will give them 6 month's worth of medication, we'll have a much greater chance of affecting an entire population and slowing or stopping the progression of a disease."

Studies of the hydrogel delivering drugs in brain cancer are under way.

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