Cocaine Radioimmunoassay-Structure Versus Reactivity

Abstract

Twenty-seven different cocaine-related substances were analyzed by radioimmunoassay (RIA) at several concentrations. An attempt was made to relate structural differences to the affinity of the compounds with the RIA benzoylecgonine (cocaine metabolite) antibody. The effects of substituent placement in the cocaine molecule were studied. Adding an alkyl group to the 2-carboxylic acid (conversion to an alkyl ester) increased reactivity, whereas changes in all other positions reduced reactivity.