Identification and quantitative determination of 3-chloro-2-hydroxypropylmercapturic acid and alpha-chlorohydrin in urine of rats treated with epichlorohydrin.
Epichlorohydrin (ECH) is used in many industrial processes. Different toxic effects of ECH were found in rodents. The metabolism of ECH was investigated before in rats using [14C]ECH. The aim of this investigation was the development of non-radioactive quantitative analytical methods for measuring two urinary metabolites of ECH, namely 3-chloro-2-hydroxypropylmercapturic acid (CHPMA) and alpha-chlorohydrin (alpha-CH). The identity of CHPMA and alpha-CH excreted in urine of rats treated with 5 to 35 mg/kg ECH was confirmed by GC-MS. The quantitative analysis of CHPMA, involving ethyl acetate extraction from acidified urine and subsequent methylation and analysis by gas chromatography-flame photometric detection (GC-FPD), showed a method limit of detection of 2 micrograms/ml. The analysis of alpha-CH based on ethyl acetate extraction and subsequent analysis by GC-ECD, showed a method limit of detection of 2 micrograms/ml. CHPMA and alpha-CH derivatives could be determined quantitatively down to concentrations of 0.5 and 0.4 micrograms/ml urine, respectively, by selected-ion monitoring GC-MS under EI conditions. Cumulative urinary excretion of CHPMA and alpha-CH by rats treated with ECH were found to be 31 +/- 10 and 1.4 +/- 0.6% (n = 13) of the ECH dose, respectively. For CHPMA, the dose-excretion relationship suggested partially saturated ECH metabolism. For alpha-CH, the doe-excretion relationship was linear. With fractionated urine collection it was found that approximately 74 and 84% of the total cumulative excretion of CHPMA and alpha-CH, respectively, took place within the first 6 h after administration of ECH. From these investigations it is concluded that the GC-FPD and GC-ECD based methods developed are sufficiently sensitive to measure urinary excretion of CHPMA and alpha-CH in urine from rats administered 5 to 35 mg/kg ECH. It is anticipated that the analysis of CHPMA and alpha-CH based on GC-MS may be sufficiently sensitive to investigate urinary excretion from humans occupationally exposed to ECH.
De Rooij
B M
BM
Leiden-Amsterdam Center for Drug Research (LACDR), Department of Pharmacochemistry, Free University, Amsterdam, Netherlands.
Commandeur
J N
JN
Ramcharan
J R
JR
Schuilenburg
H C
HC
Van Baar
B L
BL
Vermeulen
N P
NP
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000652:urine; D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage / Q000378:metabolism*; D002728:Chlorohydrins / Q000737:chemistry / Q000652:urine*; D002849:Chromatography, Gas / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004811:Epichlorohydrin / Q000008:administration & dosage / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012997:Solvents / Q000008:administration & dosage / Q000378:metabolism*; D013997:Time Factors
D002273:Carcinogens; D002728:Chlorohydrins; D012997:Solvents; D004811:Epichlorohydrin; C104663:3-chloro-2-hydroxypropylmercapturic acid; D000111:Acetylcysteine