Trimming Down the Medicine Cabinet

 

 

The next item to join the miniaturization trend may soon be the medicine cabinet. Weizmann scientists have found a way to prolong the effect of medication; instead of taking a medicine tablet, say, four times a day, you'll only need to gulp it down once.

 

For example, the method, developed by Prof. Matityahu Fridkin of the Organic Chemistry Department, Prof. Yoram Shechter of the Biological Chemistry Department and Dr. Eytan Gershonov, who worked with both departments, has reduced the number of insulin injections needed in diabetic rats to a fourth. Instead of requiring two injections a day to keep glucose levels at a normal level, once in two days was sufficient.

 

Normally, when medication is taken, its level in the blood surges -- sometimes up to one hundred times more than what is needed for effective action. These high levels often produce damaging side effects, but are necessary to keep the drug in the bloodstream long enough to do its job. Then, within minutes to several hours, the drug is cleared from the circulation and a new dose is needed.

 

For several decades, scientists have been trying to invent a way of releasing drugs into the blood in a more even manner while prolonging the time the medication actively circulates in the body. However, this goal was achieved for only a very limited number of drugs.

 

Fridkin and Shechter's new technique may affect how numerous categories of drugs, including antibiotics and cancer medications, are released into the body. They devised several kinds of molecular "corks," each with a different tendency to disintegrate in the bloodstream, and attached them to the medicine's molecules. According to the scientists, the corks prevent the medicine's active ingredients from seeping into the bloodstream in large quantities. Corks more prone to disintegration come off first, releasing the active medicine ingredients, while those less prone to disintegration hold out longer. Thus, the corks release relatively low but steady quantities of the drug into the patient's bloodstream over a longer period of time.

 

The cork is a small organic molecule. In a test tube study, the Weizmann Institute scientists found that it slowly disconnects from the drug under the temperature and pH conditions equivalent to those in human blood.

 

By altering the molecule's chemical features, the scientists created different versions of the molecular cork that can be disconnected at different rates, so that the speed of the drug's release into the circulation can be more precisely controlled.