Volume of Distribution in pharmacokinetics is typically abbreviated Vd, Vz, or Varea. Vd in pharmacokinetics reflects the reversible uptake of drugs by tissues from the blood. It is thought of as a fictitious volume that a drug occupies in the body as a uniform sack relative to the drug concentration in blood. Large Volumes of Distribution indicates more significant levels of the drug, reaching tissues relative to measured plasma concentrations and can show the compound’s potential for achieving the desired target. We calculate Vd in pharmacokinetics by dividing the measured Clearance (CL) with the elimination rate constant (λz). Volumes of distribution can be calculated following IV doses. Similarly, the apparent Volume of Distribution (Vd/F) may be determined for extravascular doses and includes a bioavailability correction factor to account for the compound’s absorption. Volume of distribution at steady-state (Vss) is another useful PK parameter for predicting tissue distribution and is calculated as mean residence time (MRT) times clearance (CL) following IV dosing.