Today we are witnessing a revolution in what medicines are able to do for patients. But along with that progress, we are seeing parallel advancements in getting these novel molecules where they need to go. Because if a medicine can’t reach its target inside a person, it doesn’t matter how well it works in the lab.
“You have to think of delivery as part and parcel of your discovery process,” says Karthik Nagapudi, Principal Scientist, Small Molecule Pharmaceutics. “The entire industry faces this kind of challenge because we see the potential of these molecules, but we don’t always know how to get them to the right place in the body.”
Traditionally, drug delivery has focused on improving the performance of existing medicines, perhaps to extend their efficacy or reduce side effects. Even though these improvements have been very successful, delivery has often been more of an afterthought in the development process. More recently, the biological challenges of reaching the target have become a central issue for promising molecules. We need to create a delivery vehicle that is sturdy enough to reach its intended destination, can get the medicine into the cells where it is needed and will direct its function only to its intended target.
“It can be a great molecule, but that doesn’t make it a medicine,” says Charles Yang, Director and Department Head, Small Molecule Pharmaceutics.
We’re working to overcome these challenges through different approaches. Take antibody-drug conjugates, which are like homing devices—they combine a medicine with an antibody that binds specifically to its target, carrying it exactly where it needs to go. We can also modify the packaging of a medicine to either protect its integrity or direct it to specific locations in the body. For example, therapies can be formulated to be administered as an injection to bypass the harsh journey an oral drug takes through the digestive tract, and packaged into lipid or polymer nanoparticles for protection and targeted delivery. Novel devices can also be developed to deliver medicines to specific target tissues, such as one that can deliver treatment directly into the vitreous fluid of the eye.
An overarching goal is to create platforms that can be adapted to different modalities. Much as a wide variety of today’s small molecules can be packaged into a pill, we’re working to create flexible delivery platforms to accommodate many novel modalities. “We’re building platforms now with the idea that no matter what molecule our chemists make, we can more or less fit it in,” Nagapudi says.