[Study of the epimers of dexamethasone sodium phosphate and betamethasone sodium phosphate by FTIR, FT-Raman and SERS].

Abstract Infrared spectroscopy (FTIR), normal Raman spectroscopy (NRS) of the solids and saturated solutions and surface-enhanced Raman spectroscopy (SERS) on the silver colloidal substrate were reported. The vibrational modes of each group were analyzed, and the enhanced peaks were assigned and compared. The results showed that the major differences between the epimers were the frequency of the CH3 asymmetric stretching vibration and symmetric in-plane deformation vibration of them. According to the mechanism and laws of SERS, the epimers were absorbed on the silver colloid through the P-O bond, carboxyl group and the five-membered ring perpendicularly. The establishment of this adsorption model which realized the rapid identification and the discrimination between the epimers provided important information and useful reference of the adrenal cortical hormone drugs.