5. ROUTES OF EXPOSURE
5.1 Oral
Readily absorbed from the gastro-intestinal tract and
buccal mucosa. It Is resistant to metabolism by monoamine
oxidase.
5.2 Inhalation
Amphetamine is rapidly absorbed by inhalation and is
abused by this route (Brust, 1993).
5.3 Dermal
No data available.
5.4 Eye
No data available.
5.5 Parenteral
Frequent route of entry in abuse situations.
5.6 Other
No data available.
6. KINETICS
6.1 Absorption by route of exposure
Amphetamine is rapidly absorbed after oral ingestion.
Peak plasma levels occur within 1 to 3 hours, varying with
the degree of physical activity and the amount of food in the
stomach. Absorption is usually complete by 4 to 6 hours.
Sustained release preparations are available as resin-bound,
rather than soluble, salts. These compounds display reduced
peak blood levels compared with standard amphetamine
preparations, but total amount absorbed and time to peak
levels remain similar (Dollery, 1991).
6.2 Distribution by route of exposure
Amphetamines are concentrated in the kidney, lungs,
cerebrospinal fluid and brain. They are highly lipid soluble
and readily cross the blood-brain barrier. Protein binding
and volume of distribution varies widely, but the average
volume of distribution is 5 L/kg body weight (Dollery, 1991).
