Methylecgonidine
Methylecgonidine (anhydromethylecgonine; anhydroecgonine methyl ester; AEME) is a chemical intermediate derived from ecgonine or cocaine. Methylecgonidine is a pyrolysis product formed when crack cocaine is smoked, making this substance a useful biomarker to specifically test for use of crack cocaine, as opposed to powder cocaine which does not form methylecgonidine as a metabolite.