Volume of distribution

The volume of distribution (Vd) of a drug can be calculated by:

1: Multiplying the total amount of drug absorbed into the body by the plasma concentration of the drug.
2: Dividing the total amount of drug absorbed into the body by the plasma concentration of the drug.
3: Taking the sum of the total amount of drug absorbed into the body and the plasma concentration of the drug.
4: Dividing the plasma concentration of the drug by the total amount of drug absorbed into the body.