[SBJ]

While developing an analytical UV-visible assay method for two component drugs system in a given formulation, if one drug concentration is 500 mg showing high absorbance and the other drug is just 5 mg in the dosage form showing very less absorbance even at higher ratio, how do i proceed? even when I use the standard addition method, the additional amount of drug to be used extends the 1:1 ratio.
Is it possible to develop UV spectral assay method for this combination drug? or do I have to move onto other assay method development?