Amphetamine in human plasma: a sensitive and specific enzymatic assay.

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biochemistry

Background:

• Accurate quantification of plasma amphetamine is crucial for pharmacokinetic and toxicological studies.
• Existing methods may lack the required sensitivity or specificity for low-concentration detection.

Purpose of the Study:

• To develop and validate a sensitive and specific enzymatic-isotopic assay for determining plasma amphetamine concentrations in humans.
• To report plasma concentrations of d- and l-amphetamine following oral ingestion.

Main Methods:

• Utilized an enzymatic-isotopic assay involving the transfer of a tritiated methyl group from S-adenosyl-L-[methyl-(3H]methionine to amphetamine.
• Employed partially purified N-methyltransferase from rabbit lung as the enzyme catalyst.
• Validated the assay for accuracy and sensitivity, determining a lower limit of quantification.

Main Results:

• The developed assay demonstrated high sensitivity, accurately quantifying as little as 10 nanograms of amphetamine per milliliter of plasma.
• The method proved specific for amphetamine detection in biological samples.
• Plasma concentrations of both d- and l-amphetamine were reported in human subjects after ingesting 20-30 mg of the drug.

Conclusions:

• A novel, sensitive, and specific enzymatic-isotopic method for plasma amphetamine determination has been established.
• This assay provides a reliable tool for therapeutic drug monitoring and forensic analysis.
• The study reports relevant pharmacokinetic data for amphetamine in human subjects.