Direct chloride measurement of [4-36Cl]chlorobiphenyl and [4,4'-36Cl]dichlorobiphenyl dechlorination in the rat.

A reverse-phase HPLC system was used for the determination of inorganic chloride liberated in vivo from two biphenyl compounds in the rat. Oral administration of [4-36Cl]chlorobiphenyl resulted in a total yield of 27.6% of the original dose excreted over 10 d in the urine and included 1.7% of the dose as inorganic chloride. For [4,4'-36Cl]dichlorobiphenyl, the radioactivity of the original dose in the urine was 39.8% after 10 d, which included 11.5% of the dose as inorganic chloride. These results appear to represent the first direct determination of dechlorination by measurement of the inorganic chloride and suggest that biodechlorination plays a greater role in the metabolism of these compounds than previously expected.