Identification of Volume of Distribution for 239Pu in Rats

The work within identifies the volume of distribution (VD) of plutonium using data from studies in which rats were administered an intravenous bolus injection of 239Pu4+-citrate. The research investigated two separate datasets. Data published by Durbin and colleagues in "Plutonium Deposition Kinetics in Rats" and studies conducted by Lovelace Respiratory Research Institute (LRRI) were examined. The goal of this research was to identify a value of VD consistent with the known biological behavior of plutonium. The identified VD is necessary to develop a physiologically-based pharmacokinetic (PBPK) model. The creation of a PBPK model describing the behavior of plutonium in the body enables the comparison of transfer rates to validate the biokinetic models currently in use for internal dosimetry purposes. The VD of a substance describes the distribution between intracellular and extracellular fluid compartments, providing information such as cellular uptake and protein binding. The VD time profiles and values found using the Durbin data were consistent with known behavior of plutonium. The VD values found using data provided by LRRI were not consistent with known behavior of plutonium; however, the VD time profiles generated may still be of use for PBPK modeling.