Smaller is Better

Oct 01, 2006

Everybody has heard about using nanotechnology in drug delivery,but not many people—even specialists in drug development—know quite where the new technology fits in. In some ways, this puts pharma in the same league with other everyday industries undergoing major changes, albeit invisible ones, when technologists alter products at the microscopic level. Marketers trumpet nanotech progress in fields from stain-resistant clothing and sports equipment to computer parts and car accessories. Of course, they rarely share details about how the new technology works.

In pharma, nanotech usually creates or "packages" microscopic doses to deliver medication more effectively. These doses are very small. The width of a human hair is approximately 50,000 nanometers, while the width of a DNA strand is 2.5 nanometers. FDA has no definition of (or budget for) nanotechnology, but along with 22 other agencies, it participates in the National Nanotech Initiative (NNI), which was formed in 2001. NNI sets the scale of nanotechnology at about one to 100 nanometers. Many nanobiotech devices are a bit larger, but a recent Google search did not find the word "nanobiotechnology" on When technology in this size range modifies a drug, it generally alters fundamental molecular or biological properties, so that a drug can enter a cell by activating or disabling a particular receptor—or change a key property like solubility.

Nanobiotechnology and the Drug Lifecycle

Elan Corporation estimates that solubility issues slow the development of 40 percent of new drug compounds, often preventing them from entering trials at all. Other drugs lose revenue when the delivery platform proves to be less than patient-friendly or limits its success. If patients are not comfortable taking a drug with a certain delivery, they are more likely to switch to a different drug or not comply with their therapy. More convenient drug delivery increases patient compliance. In addition, new delivery systems keep a drug competitive after patent expiration, even when generics using the old delivery method cut the manufacturer's price by 90 percent. So nanobiotechnological drug delivery can reduce or eliminate revenue losses throughout the drug lifecycle.

Drug Delivery Creates a Market

When most individuals envision drug delivery, they see injections, pills and capsules, inhalation systems, transdermal patches, and so on. Nanobiotechnology differs in that it enhances drug delivery at the molecular level. Some of the first nanobiotechnology products were produced using liposomes and their phospholipid bilayer. These substances—something like little envelopes—encapsulate a small molecule, making it water soluble so that it can more easily enter specific cells. Many companies are developing this technology to aid the delivery of chemotherapy agents directly to cancer cells.

The first compound advertised as a nanobiotechnology drug was Abraxane from Abraxis Oncology. This company attached paclitaxel, one of the most popular chemotherapy drugs, to an albumin nanoparticle. Adding the nanoparticle enabled the manufacturer to eliminate the toxic solvent traditionally used to deliver paclitaxel. Abraxane requires no premedication, has a better toxicity profile, and improves quality of life during treatment for breast cancer. The current success of Abraxane—and the company's nanoparticle albumin—was affirmed when AstraZeneca agreed to co-promote the drug. The enhanced molecule breathes new life into a market once dominated by an inexpensive and patient-unfriendly therapy.

NanoBio Corporation is developing its NanoStat platform for use in a variety of therapeutic treatments, including vaccine delivery. The NanoStat platform is a nanoemulsion created by immersing nanoparticles in oil and water to disrupt membranes on organisms like viruses, bacteria, and fungi. The company has products in clinical trials for herpes simplex I and II, shingles, and onchomyosis. In addition, the platform is being developed for nasal delivery of vaccines and has received funding from the United States government for potential bioterrorism applications.

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