Editing Controlled Substances Act (section)

== Research exemptions ==
A common misunderstanding amongst researchers is that most national laws (including the Controlled Substance Act) allows the supply/use of small amounts of a controlled substance for non-clinical / non-in vivo research without licenses. A typical use case might be having a few milligrams or microlitres of a controlled substance within larger chemical collections (often tens of thousands of chemicals) for in vitro screening or sale. Researchers often believe that there is some form of "research exemption" for such small amounts. This incorrect view may be further re-enforced by R&D chemical suppliers often stating and asking scientists to confirm that anything bought is for research use only.

A further misconception is that the Controlled Substances Act simply lists a few hundred substances (e.g. MDMA, Fentanyl, Amphetamine, etc.) and compliance can be achieved via checking a CAS number, chemical name or similar identifier. However, the reality is that in most cases all ethers, esters, salts and stereoisomers are also controlled and it is impossible to simply list all of these. The act contains several "generic statements" or "chemical space" laws, which aim to control all chemicals similar to the "named" substance, these provide detailed descriptions similar to [[Markush structure|Markushes]], these include ones for [https://www.ecfr.gov/current/title-21/chapter-II/part-1308/subject-group-ECFRf62f8e189108c4d/section-1308.11#p-1308.11(h)(i) Fentanyl] and also [https://www.govinfo.gov/content/pkg/PLAW-112publ144/pdf/PLAW-112publ144.pdf synthetic cannabinoids].

Due to this complexity in legislation, the identification of controlled chemicals in research or chemical supply is often carried out computationally on the chemical structure, either by in-house systems maintained a company or by the use of commercial [[software]] solutions.<ref name=":0">{{Cite web |title=Controlled Substances Squared |url=https://www.scitegrity.com/controlled-substances}}</ref> Automated systems are often required as many research operations can have collections of 10,000–100,000 different [[Chemical substance|substance]]s at the 1–5 milligram scale, which are likely to include controlled substances, especially within [[medicinal chemistry]] research, even if the core focus of the company is not narcotic or psychotropic drugs. These may not have been controlled when created, but they have subsequently been declared controlled, or fall within chemical space close to known controlled substances, or are used as tool compounds, precursors or synthetic intermediates to a controlled substance.