Amphetamines

Early development and uses

First synthesised in 1877

Clinically used as CNS stimulant for narcolepsy and depression in 1930s

Use in WWII

• used by American, Japanese, and German soldiers to maintain alertness during long missions

• stay awake and aggressive

Use in 50s and 60s

• marketed as appetite suppressants and mood enhancers

• ‘mothers little helpers’

• cultural acceptance in music and media, influencing public perception

• normalisation and subsequent abuse

Common examples

• Amphetamines

• Methamphetamines - crystal meth

• Ecstacy - MDMA

• Adderal

• Dexedine

Absorption and distribution

Administered: intravenously, orally, intranasally, smoking

Highly lipid soluble allowing for rapid absorption and distribution

Metabolism and excretion

Metabolised in the liver

Excreted in urine

Rate of excretion based on urine pH

Theraputic uses

• depression

• narcolepsy

• obesity

• hyperactive disorders (ADHD)

• parkinsons

• specific formulations (benzedrine inhalor) for respiratory issues

Adverse effects

• CNS stimulation, euphoria, increased dopamine which can lead to addiction

• Overdose: convulsions, hyperthermia, behavioural changes

• Long term use can result in complications

  • Disseminated intravascular coagulation

  • Acute renal failure

Physical characteristics

• White powder

• Off brown granular lumps

Presumptive tests

Marquis reagent: yellow-orange colour

TLC

confirmatory tests

GCMS

LCMS

Detection of amphetamines in blood and urine

Blood concentrations: 0.02-0.05mg/l are theraputic, 0.2 mg/l above indicate abuse

Urine: can detect amphetamines for 1-4 days post use, up to a week for chronic users.

isomers

Compounds with the same molecular formula but different arrangements of atoms or groups.

Structural and stereoisomerism

structural: different connectivity

stereo: same connectivity, different spatial arrangement

Chirality

A molecule with a carbon atom bonded to four different groups, its mirror images are different from one another, different enantiomers

Enantiomers

Different enantiomers have different properties to one another

One isomer might be theraputic and the other might have side effects

drugs may be single isomer and illicit may be mixture of both

seperating the enantiomers can help determine pathway used to produce a drug - see whether it is illicit or theraputic