A higher Kp suggests high tissue affinity, while a lower Kp suggests greater plasma protein affinity. Complete the statement: A higher Kp indicates high tissue affinity, while a lower Kp indicates greater plasma protein affinity.

• A. Higher, Lower
• B. Lower, Higher
• C. Not applicable
• D. The same

Answer: (A)

Kp is the tissue-to-plasma partition coefficient, a ratio that describes how much drug is found in tissue relative to plasma at steady state. A higher Kp means more drug in tissue compared to plasma, which reflects greater tissue affinity. A lower Kp means more of the drug remains in plasma, often because it is bound to plasma proteins, which keeps it circulating in the blood and limits its distribution into tissues. So the statement completes naturally as: a higher Kp indicates high tissue affinity, while a lower Kp indicates greater plasma protein affinity. This relationship helps explain how binding in plasma versus tissue distribution shapes overall drug distribution and the apparent volume of distribution.