Scientists formulate means of delivering cancer drug

New Materials Asia, Oct, 2006

A joint research team from Kyoto University and the Kanagawa Academy of Science and Technology, both Japan, has developed a way to encapsulate the cancer drug retinoic acid, making it last longer in the body.

Retinoic acid is used in the treatment of acute promyelocytic leukaemia, but in vitro tests have suggested that it might also be used on solid tumours. However, the body eliminates the compound so quickly from the bloodstream that a delivery system must be developed if the drug is to find practical applications.

The research group has devised a means of encapsulating retinoic acid in a micelle of polymer molecules suspended in water. The polymer capsules are less than 100 nm in diameter, which is small enough to pass through capillaries to reach the site of a solid tumour.

Because the polymer capsules resemble biological molecules, they are not eliminated by the kidneys, liver and white blood cells, the researchers say.

In animal tests, when retinoic acid was administered without encapsulation, its concentration within the bloodstream dropped below 1% after four hours. With encapsulation, it remained at 40%.

The next step is to conduct animal tests to see if the encapsulated drug can effectively treat a solid tumour.

For further information, contact: Kyoto University, Graduate School and Faculty of Medicine, Yoshida, Konoe-cho, Sakyoku, Kyoto 606-8501, Japan; Internet: www.kyoto-u.ac.jp; or contact: Kanagawa Academy of Science and Technology, Kanagawa Science Park, 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa, Japan; Internet: www.newkast.or.jp