title: Stereoselective degradation kinetics of theta-cypermethrin in rats.
abstract: The enantioselective degradation and chiral conversion of theta-cypermethrin (TCYM) in rats have been studied via intravenous (i.v.) injection. The degradation kinetics and the enantiomer fraction (EF) were determined by means of normal-phase high-performance liquid chromatography (HPLC) with diode array detection (DAD) and a cellulosetris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase (CDMPC-CSP). The degradation followed pseudo-first-order kinetics. The degradation of the (+)-TCYM was much faster than that of the (-)-TCYM in plasma, heart, liver, kidney, and fat after administration of racemic TCYM (rac-TCYM). The EFs were over 0.500 in these tissues and muscle. The results showed the conversion of (+)-enantiomer to (-)-enantiomer in plasma after injection of (-)- and (+)-TCYM separately. The results for the major differences in the degradation of the enantiomers may have some implication for the environmental and ecological risks assessment for chiral pesticides.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing 100094, China.
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Qiu
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhu
authors.forename: Guifang
authors.initials: G
authors.lastname: Jia
authors.forename: Junling
authors.initials: J
authors.lastname: Li
authors.forename: Chenglu
authors.initials: C
authors.lastname: Bi
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D011722:Pyrethrins / Q000378:metabolism*; D051381:Rats; D018570:Risk Assessment
chemical_list: D004785:Environmental Pollutants; D007306:Insecticides; D011722:Pyrethrins; C017160:cypermethrin