Antibody detection of marihuana.

A reliable chemical means of assaying small quantities of marihuana or tetrahydrocannabinol (THC) isomers in body fluids and cell preparations has long been sought. A possible immunological approach was suggested by work with oestrogen haptens. It was established earlier that diazobenzoic acid under appropriate conditions enters the A ring by virtue of the phenolic function of C-3, yielding oestrogen azobenzoic acid derivatives1, 2. These compounds are coupled readily through the benzoyl carboxyl to proteins and solid matrices containing accessible NH2 groups, retaining the important antigenic specificities contributed by the reactive −OH and = O groups as well as those associated with the ringed backbone1, 3. Other biologically important molecules which lend themselves to similar manipulation are the principal psychotomimetics. In our search for useful haptens and active antibodies to be used in a reliable model assay system, we have chosen to report the investigation of THC. Similar results have been achieved with the phenanthrene alkaloids (S. J. G., unpublished) preserving all the determinant functional groups * unlike the reagent for morphine assay recently reported4.