Purity >98% by NMR. AMMC iodide is a useful substrate for the human cytochrome P450 CYP2D6 isozyme. It is demethylated to the fluorescent product 3-[2-(N,N-diethyl-N-methyl ammonium)ethyl]-7-hydroxy-4-methylcoumarin (AMHC). After the AMMC is hydrolyzed, the pH is increased by addition of base for optimal fluorescence detection. AMMC has been used with human liver microsomes to determine CYP2D6 activity and inhibition.