25 March 1994
Vol 263, Issue 5154

About The Cover

A polyanhydride film viewed under cross-polarized light microscopy. Polyanhydrides can be designed to degrade within any length of time ranging from 1 day to 6 years by the alteration of their chemical composition. These bioerodible polymers are currently used in drug delivery devices for the treatment of brain cancer and other diseases. See page 1715. These polymers are among the materials discussed in the special section on Materials Science beginning on page 1698. [Photograph: E. Mathiowitz, J. Jacob, and D. Chickering]