Drug delivery right on target

One of the challenges in treating cancerous tumors with chemotherapy and medical isotopes is maximizing the treatment of cancer cells while minimizing the potential for harming healthy tissue. With materials being developed at Pacific Northwest National Laboratory, however, a more targeted approach might be on the way.

Researchers Anna Gutowska and Byeongmoon Jeong are working with stimuli-sensitive polymers that can change immediately from a liquid into a gel in response to an increase in temperature or other stimuli. This unique feature would enable physicians to inject a mixture of the polymer and a therapeutic agent directly into a specific target, where it would warm, harden and deliver localized treatment.

The gels show promise in treating inoperable and difficult-to-treat solid tumors in the liver, pancreas, brain, breast and prostrate. "While much more research remains to be done before this becomes an accepted medical procedure, we are very excited about its potential," said Gutowska, a senior research scientist.

After initial research funded by the U.S. Department of Energy, the Laboratory is applying National Institutes of Health funds to optimize the materials and investigate the long-term effects of leaving them in the body.

Jeong is exploring the use of biodegradable gels that would serve as a delivery system for protein drugs such as insulin. Protein and peptide drugs are typically injected daily because they break down in the stomach if given in a pill form. As an alternative, the gels would form a reservoir under the skin and slowly release the drugs directly into the bloodstream over a week or even several months.

In related research, the Laboratory is collaborating with the Medical University of South Carolina on an approach to repair articular cartilage—the durable cartilage that cushions joints.

First, researchers are developing a three-dimensional cell culture system that would support in-laboratory growth of the cells that generate articular cartilage. They also are developing a biodegradable polymer gel that could be injected at the site of the injury. The gel would serve as a temporary synthetic "scaffold," supporting the growth of injected cartilage-forming cells.

Researchers are conducting preliminary studies on the gels' biocompatibility and efficacy as a drug delivery system.

As development continues, Pacific Northwest is seeking research and clinical partners to move the technology into real-world applications.