Iodination of morphine and dihydromorphine, as related to radioimmunoassay.

Direct iodination of morphine or dihydromorphine with iodine-125 results in products that bind to antibody raised by immunization of animals with a 3-O-carboxymethylmorphine/bovine serum albumin immunogen. Iodination of morphine or dihydromorphine with iodine-127 under identical conditions failed to yield these immunologically active products, suggesting that the results obtained with iodine-125 are in part due to a radiolytic reaction not observed with the iodine-127.