- P-ISSN 1225-0163
- E-ISSN 2288-8985
Positive ion mass spectra of some corticosteroids were obtained by using liquid chromatography-mass spectrometry(LC-MS). The base peak of each compound showed the protonated molecular ion [<TEX>$MH^+$</TEX>], ammonium adduct ion [<TEX>${MNH_4}^+$</TEX>] or [<TEX>$MH^+-60$</TEX>] ion according to its chemical structure and other characteristic mass ions were [<TEX>$MH^+-18$</TEX>], [<TEX>${MNH_4}^+-18$</TEX>] and so on. Several rat urinary metabolites of methylprednisolone acetate after the oral administration were detected by the thermospray LC-MS. The identified major metabolites were 20-hydroxymethylprednisolone(20-HMP), methylprednisolone(MP) and methylprednisone(11-KMP), which were supposed to be formed by deacetylation at the position of C-21, reduction at C-20, oxidation at C-11, or due to the bond cleavage between C-17 and C-20.