PHARMACOKINETICS, METABOLISM AND TOXICITY OF THE PLANT-DERIVED PHOTOXIN ALPHA-TERTHIENYL

The plant-derived insecticide, alpha-terthienyl was prepared by synthe sis as 3',4'-di[C-14]-alpha-terthienyl for pharmacokinetic and metabol ism studies. When administered orally to rats at a single dose of 50 m g/kg, excretion of the labelled material was maximal one day after adm inistration and declined to no measurable quantities by day 4. Two met abolites [1,4-di(2'-thienyl)1,4-butadione and 2-2'-bithiophene-5-carbo xylic acid] and trace quantities of the parent material were isolated from the urine and chemically identified. These represent the first me tabolites of alpha-terthienyl identified. In pilot acute and subacute trials, unlabelled alpha-terthienyl was non-toxic when administered or ally to rats as the ''ready to use'' formulation (0.1% active ingredie nt). The pure compound had an LD(50) of 110 mg/kg when administered in traperitoneally to rats. The results suggest that there is considerabl e separation with respect to mosquito larvae and non-target mammal sen sitivity.