Hydrogel Targets Inflammatory Bowel Disease

Drug-infused enemas are important but imperfect weapons in the fight against inflammatory bowel disease, including Crohn’s disease and ulcerative colitis. They deliver drugs directly into a patient’s gastrointestinal tract, but their payloads work slowly and are unable to selectively treat diseased tissue. Patients can require frequent, even daily, enemas loaded with chemicals capable of affecting healthy cells to ensure that inflamed tissues receive sufficient medication. A hydrogel developed by a multi-institutional research team led by Jeffrey M. Karp of Brigham & Women’s Hospital, in Boston, appears to address the shortcomings of conventional enemas (Sci. Transl. Med. 2015, DOI: 10.1126/scitranslmed.aaa5657). The hydrogel relies on ascorbyl palmitate molecules—which FDA already recognizes as safe—that self-assemble into a nanofibrous network. Researchers can readily load the network with medicine, making the hydrogel a simple and scalable drug delivery platform, Karp says. Using animal models and human tissue samples, the team has shown that the hydrogel’s negative electrostatic charge quickly anchors it to positive surface charges prevalent at inflammation sites. Enzymes near these sites then cleave bonds within the network, freeing the encapsulated drug. The system still needs clinical evaluation, notes pharmaceutical scientist Abraham Rubinstein of Hebrew University of Jerusalem. But Rubinstein adds that the team’s study “is elegant and interesting” and shows how a simple approach can work in a complex biological environment.