The distribution of a drug around the body may be affected by the degree to which it binds to plasma proteins. Prednisone and eteplirsen are both drugs used for treatment of Duchenne muscular dystrophy. Prednisone has a high affinity for plasma proteins whereas eteplirsen has a low affinity for plasma proteins. Based on this differing affinity for plasma proteins, a fraction of prednisone will move into the non-vascular compartments in the body, as only drug can leave the circulation.