Drug Delivery | Controlled and on target

Micro medical robots, many shaped like little beetles, are designed to travel inside the body in order to treat infected areas and thus minimize the need for surgery. Photo by Yoshikazu Tsuno/Getty Images.

Drugs have traditionally been delivered to patients by mouth or by injection. Working together to increase both the efficacy and safety of drug delivery, chemical and biomedical engineers have devised a variety of improved delivery techniques. These new methods also provide the added benefit of enhanced comfort and convenience for the patient.

Early drug-delivery breakthroughs using chemical principles include

  • Nasal sprays that deliver finely atomized amounts of a drug via inhalation,
  • Transdermal patches that deliver controlled doses through the skin, and
  • Controlled-release capsules and wafers that deliver drugs over an extended period.

Targeted delivery

In recent years targeted drug-delivery methods have been an important area for chemical and biomedical engineers. Novel vehicles are being designed that deliver a drug precisely to the targeted organ, tissue, or tumor. The drug payload is then released in response to an internal or external trigger and in the amount required at the site.

Such delivery systems have the advantage of being able to

  • Reduce or delay premature degradation of a drug once it is in the body,
  • Maximize the ability of a drug to travel through the body to the target site without affecting healthy tissue and organs,
  • Minimize the total amount of the drug that must be administered, and
  • Reduce potential side effects that often result when healthy tissue and organs are exposed to a drug.