What is an active moiety?
The part of a drug that makes the drug work the way it does.
The molecule or ion, excluding those appended portions of the molecule that cause the drug to be an ester, salt (including a salt with hydrogen or coordination bonds), or other noncovalent derivative (such as a complex, chelate, or clathrate) of the molecule, responsible for the physiological or pharmacological action of the drug substance. 21 CFR 314.108(a)
Many different drug products may be marketed with the same active moiety.