Description of Amphetamine
Amphetamine, a compound discovered over 100 years ago, is one of the more restricted controlled drugs. It was previously used for a large variety of conditions and this changed until this point where its use is highly restricted. This product, with the chemical formula alpha-methylphenethylamine, was discovered in 1910 and first synthesized by 1927.
After being proven to reduce drug-induced anesthesia and produce arousal and insomnia, amphetamine racemic mix was registered by Smith, Kline and French in 1935. The structure presents one chiral center and it exists in the form of dextro- and levo-isomers. The first product of Smith, Kline and French was approved by the FDA on 1976.
During World War II, amphetamine was used to promote wakefulness in the soldiers. This use derived into a large over production and all the surplus after the war finalized end up in the black market which produced the initiation of the illicit abuse.
Absorption of Amphetamine
Amphetamine is well absorbed in the gut and as it is a weak base hence the more basic the environment the more of the drug is found in a lipid-soluble form and the absorption through lipid-rich cell membranes is highly favored.
The peak response of amphetamine occurs 1-3 hours after oral administration and approximately 15 minutes after injection and it presents a bioavailability of over 75%. Complete amphetamine absorption is usually done after 4-6 hours.
Elimination of Amphetamine
The elimination is mainly via the urine from which about 40% of the excreted dose is found as unchanged amphetamine. About 90% of the administered product is eliminated 3 days after oral administration.
The rate of elimination of amphetamine highly depends on the urine pH in which acidic pH will produce a higher excretion of amphetamine and basic pH produces a lower excretion.