Welcome to the brave new world of nanomedicine. In this Health Alert, Johns Hopkins specialists explain how drugs called nanopharmaceuticals are changing the treatment of cancer.
Q. What are nanopharmaceuticals? Are they safe?
A. Nanopharmaceuticals are drugs designed using extremely small materials -- a billionth of a meter, or a nanometer, in size. For comparison, the width of a strand of hair is 100,000 nanometers, and a nanometer is smaller than a single cell in your body.
At this tiny scale, materials have novel and often useful properties. For example, drugs packaged in nanoscale particles can enter hard-to-reach parts of the body, or nanoparticles themselves may be used as a medicine.
Nanopharmaceuticals show the most promise for the treatment of cancer. One such product called Doxil contains the chemotherapy drug doxorubicin encapsulated in liposomes -- tiny fat bubbles less than 200 nanometers in diameter. These liposomes target tumor cells, penetrating the altered and often damaged blood vessels of the tumor and slowly releasing doxorubicin. This drug-delivery system allows doctors to administer larger amounts of the drug, while sparing healthy tissue and thus reducing the typical toxic side effects of chemotherapy.
Some experts have raised concerns about possible hazards of nanoparticles. Because these particles have a large surface area relative to their size, they are highly chemically reactive. Their small size also means they could escape to unintended parts of the body, penetrating the membranes of healthy cells and interfering with cell processes or causing DNA damage.
