If you could watch what happens to a typical drug in your body, you'd probably see its ingredients spread quickly, even to places where they are not needed. The drug doesn't always arrive at the right place at the right time or stick around long enough to have its full benefit. So drug developers often combine medicines with other compounds to maximize benefits and minimize side effects. Indeed, researchers are always looking for ways to more precisely control the timing, targeting, and dosage of drugs.

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