Table 5

UV absorption maxima and chromatographic retention times of several phase I and phase II metabolites

Metaboliteλmax(nm)Retention Times (min) HPLC-System I
R-Glucuronide I40810.2
R-Glucuronide II41213.7
R-Glucuronide III40416.8
R-Sulfate I41213.6
R-Sulfate II41015.9
R-Acylglucuronide I431/43618.6
R-Acylglucuronide II431/43619.1
R-Acylglucuronide III431/43619.5
R-Diglucuronide (Ether-Ether)3706.8
OHR-Glucuronide I43610.2
OHR-Glucuronide II—13.7
OHR-Glucuronide III—13.8
OHR-Glucuronide IV—16.8
OHR-Acylglucuronide I—18.6
OHR-Acylglucuronide II—19.1
OHR-Acylglucuronide III—19.5
Metaboliteλmax(nm)Retention Times (min) HPLC-System III
Rhein43117.0
OHR I43416.4
OHR II—17.5
OHR III—17.9
CHR I—17.1
CHR II51019.7
CHR III500–52022.4
Unknown37714.3

  • R, rhein, OHR, hydroxylated rhein, CHR, quinoid oxidation product of rhein (HPLC-system I or HPLC-system III).