Distribution and elimination of o-125I-benzoate in rats

125I-labelled o-iodobenzoate (OIB) was prepared by means of an isotopic exchange reaction; its distribution and excretion were determined and its pharmacokinetic parameters in rats were calculated. The calculated value of the half-life of OIB elimination was 38.7 +/- 0.7 min, the distribution volume was 278.2 +/- 53.5 ml . kg-1. The rate of elimination activity in urine was in agreement with the above values. On the basis of the developed technique of separation of OIB metabolites by thin-layer chromatography, their relative proportion in rat urine was determined; within 24 h 50% of the eliminated activity was in the original form (as OIB) and the metabolites of o-iodohippurate and o-iodobenzoylglucuronide formed approximately 25% of the activity eliminated in urine each.