ABSTRACT
The stimulants related to amphetamine belong to the sympathomimetic group of drugs, which have been widely used to effect bronchodilation, respiratory stimulation, and appetite suppression, as well as for their central stimulant action. The central stimulant effect has led to widespread misuse of some of the group, in particular, amphetamine and methamphetamine. The principles of immunoassay techniques are based on competitive displacement of a labeled drug from an antigen/antibody complex by an unlabeled drug present in the sample. Prior separation of the drug in the sample is not required, thus the manipulative procedures of solvent extraction or adsorption methods are avoided. The urinary excretion of the amphetamine-related drugs depends largely on the lipid solubility of the undissociated drug; this amount, in turn, is governed by the degree of dissociation of the drug at physiological pH. Immunoassay methods measure the drug directly without the requirement of sample extraction.
