Relationships between immunogen structure and antisera specificity in the narcotic alkaloid series.

We report the production and comparative specificities of antisera raised to different immunogens containing codeine, morphine, and oxycodone. Antisera raised to bovine serum albumin (BSA) conjugates of codeine-6-hemisuccinate, ethylmorphine-6-hemisuccinate, or oxycodone-6-carboxymethyloxime had greatest recognition of structural changes around the piperidine ring nitrogen atom and th 14-position. N-carboxypropylnormorphine-BSA, N-carboxypropylnorcodeine-BSA, and norcodeine-BSA (directly coupled) conjugates elicited antisera that recognized structural changes at the 3- and 6-positions best, but also clearly discerned changes in the 14-substituent. Attachment of codeine to BSA via the 8-position gave a conjugate that elicited antisera with specificity characteristics similar to those of the antiserum to N-carboxypropylnorcodeine-BSA. Thus clear relationships existed between immunogen structure and antiserum specificity. The utility of these antisera was illustrated by the application of antiserum to codeine-6-hemisuccinate-BSA and solvent extraction to a study of codeine disposition in the dog. The specific antisera of N-carboxypropylnormorphine-BSA and to norcodeine-BSA were applied directly to an examination of the distribution of codeine and metabolically produced morphine in the milk and plasma of a nursing mother.