Final rule issued for positional isomers of Schedule I drugs

December 7, 2007

DEA issues rule on Schedule I positional isomers

The Drug Enforcement Administration (DEA) has issued a final rule that adds the definition of positional isomers to 21 CFR 1300.01 (b) (21). The change will allow for the systematic determination of which isomers of Schedule I substances would be subject to Schedule I control, according to the DEA. The Controlled Substances Act states that all salts, isomers, and salts of isomers of these substances are also Schedule I controlled substances. Specifically, positional isomers are defined as any substance possessing the same molecular formula and core structure and having the same functional group(s) and/or substituent(s) as those found in the respective Schedule I hallucinogen, attached at any position(s) on the core structure, but in such manner that no new chemical functionalities are created and no existing chemical functionalities are destroyed relative to the respective Schedule I hallucinogen. The complete definition can be found at