Whether it's one pill several times a day or a self-administered injection, taking medicine frequently can be a major nuisance. Now Weizmann Institute scientists have developed a new approach that may prolong the action of many drugs, making it possible to administer them at much greater intervals without jeopardizing their effectiveness.

Immediately after it's taken, the medication's levels in the blood normally surge -- sometimes up to 100 times more than what is needed. Such high levels often produce damaging side effects, but they are necessary to keep the drug in the blood long enough to do its job. Then,within minutes to several hours, the drug is cleared from the circulation, creating the need for a new dose.

For several decades, scientists have exerted major efforts to invent a way of releasing drugs into the blood in a more balanced manner while prolonging the time a medication actively circulates in the body. Unfortunately, this goal has been achieved for only a very limited number of drugs.

Prof. Mati Fridkin of the Organic Chemistry Department and Prof. Yoram Shechter of the Biological Chemistry Department have designed a new technique that can affect how numerous categories of drugs, including antibiotics and cancer medications, are released into the body. The technique is based on a molecular "plug" that attaches to and temporarily blocks the action of the drug. Once the medication enters the circulation, the "plug" is gradually disconnected. This, the scientists believe, releases relatively low but steady quantities of the drug into the patient's blood over a long period of time.

This approach may make it possible to administer a drug less frequently in significantly larger doses than usual without causing side effects. Contributing to the drug's prolonged action is the fact that medications modified with the "plug" are less susceptible to breakdown by enzymes than their unmodified counterparts.

In an animal study to be publ
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Contact: Julie Osler
JOsler@CompuServe.com
212-779-2500
American Committee for the Weizmann Institute of Science
15-Mar-1999