The decline in spectral absorbance is due to the presence of BMDBM and OMC. Both these UV-filters when studied as single ingredients mixed with petroleum jelly and exposed to UVA, showed a significant reduction in absorbance which was rapid and dose-dependent for BMDBM (Tarras-Wahlberg et al., 1999). However, even their combination within a formulation has long been known to be a photounstable one if adequate stabilizing molecules are not present .