Factors affecting drug transport include the degree of dissociation of the drug and the pH of the body fluid, the difference in drug concentration, as well as the permeability and area and thickness of the cell membrane, the amount and function of cell membrane transporter proteins, blood flow, etc. The pH of the body fluid in which fifty percent of the drug is dissociated is the pH of the body fluid in which it is found. 1. The degree of drug dissociation refers to the pH value of the body fluid where the drug is located when it is dissociated by fifty percent. Since most of the drugs belong to the weakly acidic or weakly alkaline drugs, the acidity and alkalinity of body fluid and the degree of drug dissociation can affect the drug transportation. 2. Some drugs pass through the cell membrane by simple diffusion, and the difference in drug concentration between the two sides of the membrane, as well as the permeability, area and thickness of the cell membrane have a great influence on drug transportation. 3. Changes in blood flow can also affect the difference in drug concentration between the two sides of the cell membrane, and the speed of blood flow, the richness of blood flow can affect the speed of the drug taken away by the blood flow, which further affects the concentration of the drug on one side of the membrane. 4. The amount and function of cell membrane transporter proteins can also affect the transmembrane transport of drugs.