Different Approaches

1.Whenauthenticsamplesofrelatedsubstanceare available. Analyze

stresseddrugproduct,placebo,drugsubstance,stressedplacebo,and

solutions spiked with authentic samples of related substances. The HPLC

chromatograms are used to show the resolution among related substances,

drugsubstance,andotherpotentialinterferences.Inaddition,check

thepeak homogeneityof thesignificant degradation products and drug

substance by a photodiodearray detector (PDA) or mass spectrometer.

This verifies that no significant related substance coelute with each other.