Analysis of 1,4-dimorpholino-7-phenylpyrido[3,4-d]pyridazine (DS-511) and its metabolites in biological specimens. III. Fluorodensitometric method for the simultaneous determination of DS-511 and its metabolites in urine and bile.

Abstract

A simple and rapid fluorodensitometric method for the simultaneous determination of 1, 4-dimorpholino-7-phenylpyrido [3, 4-d] pyridazine (DS-511) and its metabolites in urine and bile was established. The biological specimens containing DS-511 and its metabolites were separated into lipophilic and hydrophilic layers by extraction with ethyl acetate. The hydrophilic layer was incubated at 37° for 24 hr with β-glucuronidase and arylsulfatase, then separated again into two layers by a similar extraction procedure. The lipophilic layers were purified by two-dimensional thin-layer chromatography with chloroform-methanol (10 : 1) and ethyl acetate-benzene (3 : 2). The hydrophilic layer was passed through a column of Amberlite XAD-2 (100-200 mesh), eluting with ethanol, and the eluate was purified by stepwise thin-layer chromatography with ethyl acetatebenzene (3 : 2) and chloroform-methanol (2 : 1). After moistening the air-dried chromatogram with 1-butanol, the fluorescent spots were quantitatively determined with a spectrodensitometer in the fluorescence mode. The recoveries and the coefficients of variation (c. v.) with this method were 89-116% (c. v. 6-14%) for lipophilic compounds and 93.0-95.0% (c. v. 5-6%) for hydrophilic compounds at concentrations between 0.1-1.0 μg/ml in biological specimens. This method could be used to analyze biological specimens from rats and dogs after administration of DS-511 and should also be applicable to human specimens.