For example, you could inject a drug into the target area, but it won't last long--only minutes to hours--because it is removed by the body's highly efficient lymphatic system. What about implantable drug-delivery devices? Most of these are composed of stiff materials that in a dynamic environment like a joint can rub and cause inflammation on their own. Further, most of these devices release medicine continuously--even when it's not needed. Arthritis, for example, occurs in cycles characterized by flare-ups then remission.
Toward the Holy Grail
"The Holy Grail of drug delivery is an autonomous system that [meters] the amount of drug released in response to a biological stimulus, ensuring that the drug is released only when needed at a therapeutically relevant concentration," Karp and colleagues write in JBMR. His coauthors are Praveen Kumar Vemula, Nathaniel Campbell, and Abdullah Syed of BWH, HMS and HSCI; Eric Boilard (now at Universit Laval), Melaku Muluneh, and David Weitz of Harvard University; and David Lee of BWH, currently at Novartis. Karp notes the key involvement of Lee, a doctor who is "treating patients with the problem we're trying to solve."
The researchers tackled the problem by first determining the key criteria for a successful locally administered arthritis treatment. In addition to having the ability to release drug on demand, for example, the delivery vehicle should be injectable through a small needle and allow high concentrations of the drug. The team ultimately determined that an injectable gel seemed most promising.
Next step: what would the gel be made of? To cut the time involved in bringing a new technology to market, the team focused only on materials already designated by the Food and Drug Administration as being generally recognized as safe (GRAS) for use in humans.
|Contact: Holly Brown-Ayers|
Brigham and Women's Hospital