Simple method for determination of the active metabolite of the inotropic drug pimobendan in rat liver microsomes.
A rapid and sensitive high-performance liquid chromatographic method for quantitation of the O-demethylated active metabolite formed in a liver microsomal assay system has been developed. The metabolite was separated on an Inertsil ODS-2 column and quantitated by fluorescence detection (excitation at 338 nm, emission at 405 nm). The retention times for pimobendan and its metabolite were 5.6 and 2.8 min, respectively. The intra- and inter-assay relative standard deviations in the measurement of pimobendan O-demethylase activity at the substrate concentrations of 1 microM and 500 microM were 2.0%, 6.8%, 2.1% and 5.6%, respectively, and the limit of detection was 0.1 ng for the demethylated metabolite.
Kuriya
S
S
Division of Pharmacy, Chiba University Hospital, Japan.
Ohmori
S
S
Hino
M
M
Senda
C
C
Sakai
K
K
Igarashi
T
T
Kitada
M
M
D000818:Animals; D002138:Calibration; D002316:Cardiotonic Agents / Q000032:analysis / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D011724:Pyridazines / Q000032:analysis* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
D002316:Cardiotonic Agents; D011724:Pyridazines; C041648:pimobendan