THEORY
The oxidation of the α-ketol
moiety present in the steroid under examination and the subsequent reduction of
triphenyltetrazolium chloride to the corresponding triphenylformazan are
depicted in the following reaction :
The triphenyltetrazolium chloride ring undergoes
cleavage, as shown by the dotted line, and 2H-atoms are given out by the
steroid prednisolone in being converted from C-21, —CH2OH to C-21,
—CHO function ; one of the H-atoms from above is utilized in the formation of
the open-chain compound i.e.,
triphenylformazan derivative ; whereas, the second H-atom abstracts the Cl–
ion as a mole of HCl. The above interaction is of a quantitative nature.
However, it is pertinent to mention here that certain
steroids esterified at C-21 position, such as : hydrocortisone acetate,
methylprednisolone acetate are duly hydrolyzed in the alkaline medium to give
rise to the corresponding free C-21 hydroxy steroids and hence, may also be
assayed by adopting the same procedure.
All these assays are to be
carried out strictly in the absence of light and atmospheric oxygen to get optimum results.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.