Metabolism of Pyriproxyfen in Rats. 1. Absorption, Disposition, Excretion, and Biotransformation Studies with [phenoxyphenyl-14C]Pyriproxyfen

• Published in: Journal of agricultural and food chemistry 1995-01, Vol.43 (1), p.235-240
• Main Authors: Matsunaga, Haruyuki, Yoshino, Hiromi, Isobe, Naohiko, Kaneko, Hideo, Nakatsuka, Iwao, Yamada, Hirohiko
• Format: Article
• Language: English
• Subjects: INHIBIDORES DESARROLLO INSECTOS; METHODE D'APPLICATION; METODOS DE APLICACION; PIRETRINAS SINTETICAS; PYRETHRINE DE SYNTHESE; REGULATEUR CROISSANCE INSECTE
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf00049a042

Male and female rats were given a single oral dose of [phenoxyphenyl-14C]pyriproxyfen [4-phenoxyphenyl (R,S)-2-(2-pyridyloxy)propyl ether] at 2 (low dose) or 1000 (high dose) mg/kg. 14C was rapidly excreted into feces and urine, with the former route predominating (about 90% of the dose). Peak 14C concentrations in blood, kidney, liver, and other tissues except for fat occurred 2 - 8 h after administration, being 0.4, 0.4, 2.5, and 0.2 microgram of pyriproxyfen equivalents/g of tissue (ppm), respectively. Peak 14C concentration in fat occurred 12-24 h after administration, being 0.3 - 0.5 ppm. 14C tissue residues on the seventh day were below 0.02 and 10 ppm for the low and high doses, respectively. The major metabolic reactions were hydroxylation at the 2- or 4-position of the terminal phenyl ring, hydroxylation at the 5-position of the pyridyl ring, cleavage of the ether linkages, and conjugation of the resultant phenols with sulfuric acid. No marked sex-related differences were observed for 14C excretion or 14C tissue residues. However, a slight sex-related variation was found for the extent of metabolic reactions