The number of small, clandestine laboratories making methamphetamine in the U.S. has mushroomed in recent years, particularly in western, southwestern, and midwestern states. Last year, according to the National Clandestine Laboratory Database at the El Paso Intelligence Center, authorities seized 15,994 methamphetamine labs, dump sites, or meth-making equipment in 49 states. That's up from 7,438 seizures in 43 states in 1999.
One way authorities are trying to thwart these mom-and-pop methamphetamine operations is by cutting off their supply of pseudoephedrine, which is used as a starting material.
Pseudoephedrine--an active ingredient in Sudafed, NyQuil, and several other over-the-counter decongestants--can be made into methamphetamine via a simple reduction reaction, according to Shawn R. Hitchcock, an associate professor of organic chemistry at Illinois State University, Normal. Hitchcock says that this reaction "can be easily carried out on a large scale without much difficulty in the hands of a properly trained person."
Last year, Oklahoma became the first state to classify pseudoephedrine as a Schedule V drug, and several other states have either passed or are considering similar legislation. The new classification means that Sudafed and other medicines that contain the compound can only be purchased from a pharmacist. Consumers are limited to 9 g of pseudoephedrine in a 30-day period, and they must show identification and sign a logbook when they buy the medication.
Pfizer, the company that makes Sudafed, introduced a pseudoephedrine-free decongestant called Sudafed PE in late 2004. Sudafed PE uses phenylephrine, a decongestant patented in 1933, as its active ingredient. Pfizer has sold a phenylephrine-based decongestant in the U.K. for several years.
Pfizer scientists Dennis Nelson and Mike Nichols explain that, although the two molecules are structurally similar, phenylephrine has a two-carbon chain whereas pseudoephedrine has a three-carbon chain with an extra stereogenic center. That extra methyl group is key to methamphetamine's pharmacological effects, the scientists say.
From a chemical standpoint, it's not hard for an amateur chemist to reduce phenylephrine, Nichols explains, "but the addition of that third carbon onto the chain in phenylephrine isn't easy."
"The chemical conversion [of phenylephrine to methamphetamine] would involve multiple steps--oxidation, alkylation, reduction, etcetera--that cannot be accomplished with simple, readily available materials," Hitchcock adds.
Rogene Waite, of the Drug Enforcement Administration's Public Affairs Office, tells C&EN that phenylephrine "cannot readily serve as a precursor to make any controlled substances."
Although it is adding more phenylephrine-based products to its line of decongestants, Pfizer has no plans to take the pseudoephedrine-based medicines off the market. Also, the new decongestant is a bit more expensive than the original. According to Pfizer, a 24-dose bottle of the original Sudafed costs the same as an 18-dose bottle of Sudafed PE.