This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Drug distribution is influenced by: 
Select and explain. 
A. Plasma protein binding, B. Lipid solubility, C. Degree of blood flow, D. All of these
D: All of these
Answer: D: All of these 
Explanation: - Factors affecting drug distribution

 Lipid solubility - Higher the solubility, higher the distribution
 Ionization at physiological pH - Higher the ionization, lower the distribution
The degree of plasma protein binding - More the binding, less the distribution
 Affinity for different tissues - Higher affinity, higher distribution
 Regional blood flow - More the flow, more the distribution
 Fat: lean body mass ratio (changes with age) - Increases with age
 Disease like CHF, uremia, cirrhosis