Some medications -- particularly those to treat cancer -- have been derided for years for destroying healthy cells along with those they are trying to eradicate. Sometimes they cause more harm than good to the patients receiving them. This scenario has inspired researchers to develop more targeted drugs to affect only diseased cells or areas of the body, rather than the body as a whole.
Medical experts believe these so-called intelligent drug delivery systems -- still mainly in the research and clinical trial stages -- will be the standard of care one day for things like cancer, diabetes, and gastrointestinal disorders.
"When we administer something intravenously, the entire body is being exposed to this drug," Mary Caldorera-Moore, an assistant professor of biomedical engineering at Louisiana Technical University researching intelligent drug delivery, told us. "For example, with chemotherapy drugs, they are very harsh" on the body. Moreover, research has shown that many times only about 20% of a drug administered is effective at treating a condition; a lot of the medication that goes into someone's body is wasted or misused.
Intelligent drug delivery -- which can target an area of the body and administer only the needed dosage -- can change all this. "We can improve the efficiency of the drug if we can get it locally to where we need it -- where the disease is. We can use less of the drug, driving the cost down, and the patient won't have as many side effects."
Caldorera-Moore previously worked at the University of Texas under Nicholas Peppas, a prominent biomedical and chemical engineer who has been working for about 30 years on an intelligent drug delivery system based on hydrogels. Peppas is seen as a leader and authority in drug delivery research.
The idea is to design materials to respond to environmental cues inside the human body to target the diseased areas without harming other parts of the body, Caldorera-Moore said. "We are developing these materials to be pH responsive, temperature responsive, or biomolecule responsive. What we mainly focus on is molding them into nanoparticles or microparticles so they can taken orally or injected." pH refers to the level of acidity in an aqueous solution or environment -- in this case, the human body. These medications would replace intravenous drugs that are still widely used to treat things like diabetes and cancer, making the treatments more tolerable and effective. "The entire goal is to increase patient compliance and success."
For example, biomolecule-responsive hydrogels can be loaded with drugs that would not be released until they come into contact with "markers that let them know they are in a tumor environment," such as enzymes associated with cancerous cells.