Degradation of vitamin D3 in a stressed formulation:: The identification of esters of vitamin D3 formed by a transesterification with triglycerides

Four unknown degradants in the LC-UV profile of a stressed experimental tablet formulation that contains vitamin D-3 have been identified by a combination of Ag+-cationization electrospray ionization (ESI) LC/MS and atmospheric pressure chemical ionization (APCI) LC/MS/MS. The peaks elute in the method chromatography in two pairs of two peaks. The first pair of peaks has m/z 511 while the second pair has mlz 539. The major, first peak of each set of peaks corresponds to the octanoate and decanoate ester of vitamin D-3, respectively. These are formed by a transesteritication with the two major fatty acid components (octanoate and decanoate) of the triglycerides present in the formulation. The formation of two degradation products with each fatty acid is due to the presence of both vitamin D-3 (major component) and the isomeric pre-vitarnin D-3 (minor component) in the stressed formulation. (c) 2006 Elsevier B.V. All rights reserved.