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HPLC ANALYSIS OF VINCLOZOLIN AND ITS METABOLITES IN SERUM
Citation:
SierraSantoya, A., H A. Barton, AND M F. Hughes. HPLC ANALYSIS OF VINCLOZOLIN AND ITS METABOLITES IN SERUM. Presented at Society of Toxicology 42nd Annual Meeting, Salt Lake City, Utah, March 9-13, 2003.
Description:
HPLC ANALYSIS OF VINCLOZOLIN AND ITS METABOLITES IN SERUM. A Sierra-Santoyo1,2, H A Barton1 and M F Hughes1. 1US EPA, ORD, NHEERL, ETD, RTP, NC; 2Toxicology Section, CINVESTAV-IPN, Mexico City, Mexico.
The fungicide vinclozolin (V) is used predominantly for treatment of grains, fruits, ornamental plants and turfgrass. V administered to rats is hydrolyzed to 2-[[(3,5-dichlorophenyl)-carbamoyl]oxy]-2-methyl-3-butenoic acid (M1), 3'5'-dichloro-2-hydroxy-2-methylbut-3-enanilide (M2), and 3,5-dichloroaniline (M3). V, M1 and M2 have antiandrogenic properties both in vivo and in vitro by interacting with the androgen receptor. However, data on V and its metabolites in biological samples is limited. The aims of this study were to optimize a method for the analysis of V and its metabolites by HPLC and to evaluate the stability of V in rat serum. A gradient program with a mobile phase consisting of 60-75% methanol:acetonitrile (70:30) and 0.05 M phosphate buffer (PB) pH 3.3 at 1 ml/min, C18 column and wavelength of 212 nm were used. The method was validated using spiked serum samples (pH 1.0) in a concentration range of 2-10 :g/ml. All analytes were extracted with acetonitrile (pH 2.5) from 100 :l aliquots. Retention times for M3, M1, M2 and V were 10.3, 12.8, 15.4 and 18.2 min, respectively. Detection limits for analytes ranged from 8.3 to 36.2 ng/ml. The recoveries were from 60 to 105% and the coefficient of variation was lower than 10% for all analytes. The relative concentration of V in PB pH 7.3 and serum (37 OC) decreased over 4 h and then stabilized. V was more stable in PB than in serum. M3, M2 and M1 were observed in both media and at 48 h M3 had the highest relative concentration (50-60%). High serum levels of V, M1 and M3 in rats orally exposed to V (100 mg/kg) during 24 h after dosing were observed. These results suggest that the metabolism of V is both enzymatic and non-enzymatic. A better understanding of the biotransformation and pharmacokinetics of V will clarify the relationship between toxicity and tissue dose of V and its metabolites. (Funded in part by cooperative agreement CR 828790 with the NRC. This abstract does not represent USEPA policy).