Efficacy of localised DTPA treatment for decorporation of Np injected intramuscularly as Np(IV) or Np(V)

The efficacy of DTPA treatment for intramuscularly administered Np(IV) citrate and Np(V) in 0.1 M HNO3 was investigated in rats. Chelation treatment was performed near the site of the Np injection, at different post-injection times. For wounds contaminated with Np(IV) citrate, significant Np decorporation was obtained when treatment was performed at 2 min. Treatment efficacy gradually decreased with treatment delay and no decorporation was observed if treatment was delayed by I h. All other treatments were performed 20 min after the i.m. Np injection. Similar decorporation, 20 to 30% of administered Np(IV), was observed over range of Np mass from 10(-4) to 10 mu g, but no decorporation of Np(V) was observed. Taking account of the biokinetics of Np(IV) and Np(V), it seems that most of the present results can be explained by the kinetics of Np deposition in the skeleton, which depends on the Np valence.