Fluorometric determination of trifluoromethyl-substituted 2,3-bis(4-methoxyphenyl)indoles in biological materials.

Interest in the 5-, 6-, and 7-trifluoromethyl-substituted 2,3-bis(4-methoxyphenyl)indoles as potent, orally active anti-inflammatory agents required a method for their determination in serum, urine, and feces to permit studies of their absorption, metabolism, and excretion. A simple, rapid, sensitive, and specific procedure was developed based on an ethyl acetate extraction of alkaline specimens and subsequent fluorometric analysis of ethanolic solutions of the extract residues. The method is sensitive to 0.1 microgram/ml, 0.5 microgram/ml, and 0.7 microgram/100 mg of these compounds in serum, urine, and feces, respectively. Overall mean recoveries and standard deviations of the 5-, 6-, and 7-trifluoromethyl-substituted compounds from biological samples were 102.2 +/- 3.0, 102.2 +/- 5.4, and 100.5 +/- 5.7%, respectively. The procedure was applied successfully to absorption studies with 2,3-bis(4-methoxyphenyl)-7-(trifluoromethyl)indole in the dog.