Kp is Ct/Cv. If Kp > 1, what does this indicate about drug distribution?

• A. More drug in plasma than in tissue.
• B. More drug in tissue than in plasma.
• C. Equal distribution between tissue and plasma.
• D. No distribution occurs.

Answer: (D)

The main idea is how a drug partitions between tissue and plasma, described by the distribution ratio Kp = Ct/Cv. If this ratio is greater than one, the tissue concentration is higher than the plasma concentration, meaning the drug distributes preferentially into tissues rather than remaining in the blood. This often reflects high lipophilicity or strong tissue binding and is typically associated with a larger apparent volume of distribution.

So, a Kp > 1 indicates more drug in tissue than in plasma. If the drug had more in plasma, Kp would be less than one; if distribution were equal, Kp would be around one; the statement that no distribution occurs isn’t consistent with a Kp > 1.