Chewable time-release pills on way.

Researchers at Oregon State University, Corvallis, have developed the first delivery system for sustained or "time-release" drugs that can be chewed, crushed, or compacted into tablets, According to James Ayres, professor of pharmacy, "There are a lot of elderly people in nursing homes who can not swallow time-release capsules. So they are forced to take medicine four to six times a day, which is not only inconvenient, it results in an uneven delivery of the drug product."

Chewable time-release products never have worked because the polymer coating around the drugs that controls their release is broken down when cracked by chewing or crushing. Likewise, chewing the tiny pellets inside time-release capsules is ineffective because it immediately activates the drug agent. The researchers solved the problem through a combination of alternating polymer coatings that surround inner cores of sugar and the drug. Ethylcellulose--the same coating used on bowling pins--is utilized to control the release rate of the drug. A second polymer, polyethylene oxide, forms a gel-like substance that acts like a glue when combined with fluids from the intestinal tract.

When the tablet is chewed, cracks form around the ethylcellulose polymers, then gastric juices inside the body combine with the polyethylene oxide to form the glue-like substance to seal the cracks. The rate of release can be controlled by the number and thickness of the polymer layers. In fact, the technology works so well that the time-release mechanisms are effective...