Researchers have developed a new silk-based stabilizer that shows benefit for keeping vaccines and antibiotics stable up to temperatures of 140 degrees Fahrenheit. The development could prove to enhance delivery and storage of a wide variety of medical countermeasures that currently require refrigeration to prevent changes to their chemical structures.
In a study published in this week’s online issue of Proceedings of the National Academy of Sciences, the researchers demonstrate they were able to protect and stabilize both live vaccines and antibiotics when stored at higher than recommended temperatures for periods far longer than recommended. All of this was accomplished by immobilizing the bioactive molecules of the drugs using silk protein matrices.
The research is led by grantees of NIH’s National Institute of Biomedical Imaging and Bioengineering (NIBIB), David Kaplan, Ph.D., and Jeney Zhang, Ph.D. candidate, at Tufts University School of Engineering in Medford, Mass. The National Eye Institute and the National Institute of Dental and Craniofacial Research at NIH also contributed to this research.
“This truly exciting development is the culmination of years of creative exploration and research focused on a major problem in the delivery of health care. Dr. Kaplan and his team have done a masterful job at both understanding the key properties of silk, and applying these insights to a global medical challenge,” said NIBIB Director Roderic I. Pettigrew, Ph.D., M.D.
Silk is a protein polymer with a chemistry, structure, and assembly that can generate a unique environment, making it an attractive candidate for the stabilization of bioactive molecules over extended periods of time. The team used silk films that essentially wrap up the live bioactive molecules present in the drugs. This protects these essential bioactive elements, greatly extending the shelf-life of the medication. Kaplan’s group found that these silk films had the added benefit of protecting one antibiotic against the detrimental effects of light exposure.
The need for a cold chain has been a decades-long obstacle for the health care providers, aid organizations, military forces, scientists and pharmaceutical companies, especially in settings where electricity is limited. The ability to do away with cold storage requirements could save billions of dollars and ease logistical burdens on drug delivery to third world regions.
“New studies are already under way,” says Dr. Kaplan. “We have already begun trying to broaden the impact of what we’re doing to apply to all vaccines. Based on what we’ve seen with other proteins, peptides, and enzymes, there’s no reason to believe that this wouldn’t be universal. This could potentially eliminate the need for a cold-chain system, greatly decreasing costs and enabling more widespread availability of these life-saving drugs.”