Abstract

Novel compositions are provided for the determination of one or a group of organic materials (hereinafter referred to as "ligands"), where the compositions have a ligand or ligand counterfeit bonded to an enzyme, the conjugate referred to as "enzyme-bound-ligand." Specifically, the ligands are benzdiazocycloheptane drugs, which are conjugated to an enzyme, so that upon binding of a receptor, usually an antibody, the activity of the enzyme changes. Determinations of the benzdiazocycloheptane drugs in a physiological fluid are performed by combining the enzyme conjugate, the physiological fluid and receptor under conditions whereby the amount of receptor bound to the conjugate is related to the amount of the benzdiazocycloheptane drug present in the sample. By metering the enzyme activity of the assay mixture and comparing the result to known standards, the amount of benzdiazocycloheptane drug present in the sample may be determined.