Abstract
This paper presents the results of our investigation on the cause of yellow coloring of pharmaceutical ointments containing vitamin A, D and E. Yellowish substance of the colored ointments was analyzed by cdumn-, thin layer- and gas-chromatographies, UV-spectra, IR-spectra, and NMR. It was identified as 3,5,3', 5'-tetra-tert-butylstilben-4,4'-quinone. This compound is one of the oxidation products of BHT which is contained in vitamine A preparation as antioxidant. a-Tocopherol is a trigger of the oxidative reaction of BHT.
