[Use of 2H-labeled compound and GC-MS in the isolation and identification of a metabolite of biphenyldimethyl-dicarboxylate in rat urine].
Dimethyl-4, 4'-dimethoxy-5, 6, 5', 6'-dimethylenedioxy-biphenyl-2, 2'-dicarboxylate (biphenyldimethyldicarboxylate; BDD), a synthetic compound, has been used in the treatment of chronic hepatitis with good results in reducing s-GPT. Previous work in our laboratory studied its metabolites using 3H-labeled compound in combination with TLC and found that its main metabolic pathway is demethylation followed by conjugation with glucuronic acid. This paper reports the isolation and identification of a metabolite of BDD from rat urine using 2H-labeled compound and GC-MS. Rats fasted for 12 h were intragastrically given a mixture of 2H-labeled (consisting of monodeutero- and dideutero-BDD in the ratio about 1:1.3) and non-labeled BDD 150 mg/kg and placed in metabolism cages for urine collection. The 24 h urine was filtered and extracted three times each with 5 ml of methylenedichloride. The extracts were pooled and evaporated to dryness under reduced pressure at 35 degrees C. The residue was redissolved in chloroform and subjected to GC-MS analysis. The mass spectrum (m/z: 404, 405, 406; 373, 374, 375; 345, 346, 347; 330, 331, 332; etc) indicates that the molecular ionic and fragment peaks of the metabolite all have 14 amu less than those of BDD. This means that the metabolite isolated is mono-O-demethylated BDD. The result confirmed our findings reported previously.
Xu
R M
RM
Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing.
Han
C
C
Xie
J X
JX
Song
Z Y
ZY
D000818:Animals; D001713:Biphenyl Compounds; D004149:Dioxoles / Q000378:metabolism* / Q000652:urine; D004365:Drugs, Chinese Herbal / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D001713:Biphenyl Compounds; D004149:Dioxoles; D004365:Drugs, Chinese Herbal; C041398:7,7'-dimethoxy-(4,4'-bi-1,3-benzodioxole)-5,5'-dicarboxylic acid dimethyl ester; C043146:7-hydroxy-7'-methoxy-4,4'-bis(1,3-benzodioxole)-5,5'-dicarboxylic acid dimethyl ester