TIBA [2,3,5-Triiodobenzoic Acid] 
In studies with rats, pigs and chickens, iodide, 2,5-diiodobenzoic 
acid and 3,5-diiodobenzoic acid were found in the organs (7/06, 1676). 
Two whole body retention components were observed--one with a biological 
half-life of 11.8 - 17.9 hours and the second 395 - 423 hours. Thyroid 
uptake was also indicated (706, 707). 
When dairy cows were fed TIBA, no residues were found in the milk 
or feces. Some free TIBA and free and conjugated 2,5-diiodobenzoic acid 
were found in the urine. In steers fed TIBA, there were indications of 
urinary excretion of 2,5-diiodobenzoic acid and other partially de-iodi- 
nated benzoic acids. TIBA was stable when incubated with rumen fluid, 
thyroid or liver (581). 
In lactating cows and goats, the primary route of excretion was via 
the kidney. Metabolic studies of the urine indicated TIBA and nine 
metabolites. Four of these were identified as 2,5-DIBA, 2,3-DIBA, OIBA 
and iodide ion. The remainder was thought to be conjugated forms of 
OIBA, TIBA, and DIBA. Residues of TIBA and/or its metabolites were distri- 
buted throughout all tissue samples analyzed with highest concentrations in 
thyroid and lowest in the brain (707). 
Whole body retention studies indicated two biological half-life 
components represented by 
Y = 19.9e (-0.0164) (xX hr.) (0:05:12) (X hr.) 
+ 71.8¢e 
Where Y is the percent retained at '"X" hours (707). 
Exposure of Cots earhony labeled TIBA to UV gave rise to 2,5- and 
3,5-diiodobenzoic acids (707). 
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