Cardiac glycosides and metabolites--problems of recovery in tissue extracts. Separation of visible substance spots in the nanogram range (author's transl)

Abstract

The recovery measurements in rat tissues performed via i.p. injected radioactive digoxin derivates (3H-digoxin, 125J-digoxin derivative) showed that approximately 50% of the total glycoside content will be extracted. Thus, an addition of digoxin standards to drug-free tissues may lead to false negative determinations. By comparison of the radioactivity before and after extraction the following results were obtained: Recovery from tissues 3H-digoxin 50% 125J-digoxin 40% from serum 3H-digoxin 60% added to drug free tissue homogenates 3H-digoxin 85% After i.p. application of 15 mg/kg of beta-methyldigoxin to BD9 (Berlin)-rats the resulting tissue concentrations were extracted by Amberlite XAD-2. beta-Methyldigoxin and its metabolites digoxin and digoxinbisdigitoxide could be separated and distinguished from artifacts by fluorescence detection on HPTLC-plates with a detection limit of 60 ng/spot. Concentration determined by radioimmunoassay are in satisfactory agreement with HPTLC results.