Stability of corticosteroids under anaerobic conditions. VII. 17a-hydroxy-17a-hydroxymethyl-17-keto-D-homosteroid phosphate.

The major decomposition product of prednisolone phosphate formed under anaerobic decomposition conditions in aqueous solution at pH = 8.3 is identified as 17a-hydroxy-17a-hydroxymethyl-17-keto-D-homosteroid phosphate. The chromatographic properties, the isolation and the structure elucidation of both the D-homosteroid phosphate and its specific dephosphorylated analogue are given. Finally a mechanism leading to the D-homosteroid phosphate is postulated.