Novel Polymers Help Oral Medications Reach the Bloodstream

All too often, when a person takes a pill full of a potent and effective drug, the drug passes straight through the body, not reaching the organ where it is needed — a waste of money and inconvenient if it is a cold medicine, but potentially dire if it is a treatment for a serious illness.

Professor Kevin Edgar of the Department of Sustainable Biomaterials has teamed up with Professor Lynne Taylor of Purdue University to identify, understand, and create new polymer additives that enhance the ability of orally administered drugs to reach the bloodstream.

The all-natural polymers can be used with a range of medicines to prevent crystallization — which limits drug bioavailability — during transport and storage. The polymer then traverses the digestive tract until the still fully potent medicine is released in the small intestine, where it is best absorbed into the bloodstream.

“Improved bioavailability means a scarce and expensive drug can be used to treat more patients and with fewer side effects,” said Taylor. “Fewer doses will be required, making it easier for patients to take their drugs on time every day — nothing is more important for vanquishing disease and preventing the development of resistant organisms.”

“No polymers work in every drug formulation, but these are some of the most broadly effective bioavailability enhancement polymers we’ve seen,” Edgar explained. “We have already found that they enhance the stability and solubility of three HIV drugs, a pain reliever, two antibiotics, and five flavonoids, which are potent, drug-like molecules that occur naturally in nuts, fruits, and vegetables.”

The final trick, after creating a polymer that binds the medicines so they cannot crystallize, is to make sure that polymer knows when to let go.

“The small intestine is where many medicines have the best chance to enter the bloodstream,” said Taylor, “so often the ideal polymer will hang onto the drug through the acidic environment of the stomach and then release the medicine in the benign environment of the small intestine.”

“Most of the polymer just passes through the body unchanged and unabsorbed,” Edgar noted. “If any of it breaks down in the gastrointestinal tract, it breaks down into things that are part of our diet anyway.”