Stereoselective degradation kinetics of theta-cypermethrin in rats.
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.
Wang
Qiuxia
Q
Department of Applied Chemistry, China Agricultural University, Beijing 100094, China.
Qiu
Jing
J
Zhu
Wentao
W
Jia
Guifang
G
Li
Junling
J
Bi
Chenglu
C
Zhou
Zhiqiang
Z
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
D004785:Environmental Pollutants; D007306:Insecticides; D011722:Pyrethrins; C017160:cypermethrin