PRODUCTION OF SPECIFIC ANTIBODIES AND DEVELOPMENT OF A NONISOTOPIC IMMUNOASSAY FOR CARBAMAZEPINE BY THE CARBONYL METALLO-IMMUNOASSAY (CMIA)METHOD

As part of our ongoing work to extend the range of applications of the non-isotopic carbonyl metalloimmunoassay (CMIA), previously developed in our laboratory, we describe here the first CMIA study of carbamaze pine. The CMIA method uses a metal carbonyl complex as a non-isotopic tracer, and in this case we chose to employ the dicobalt hexacarbonyl moiety (Co-2(CO)(6)) attached to an alkyne. Two organometallic tracers , ($) under bar 3 and ($) under bar 7, were synthesized, differentiate d by the nature and length of the spacer arm of the Co-2(CO)(6) moiety . Two different coupling methods were subsequently used to synthesize the immunogens I and 2, the first one used a carbodiimide, while the s econd, employed dimethyl adipimidate as coupling agent. Titer values o f the antisera obtained by injection of these immunogens into rabbits, were determined by CMIA, using one of the organometallic complexes, ( $) under bar 3 or ($) under bar 7, as tracer. Both antisera had higher titer values with the long-chain tracer, ($) under bar 7, than with t he short-chain tracer, ($) under bar 3. However these titer values wer e very different: low for antiserum I and high for antiserum 2. The cr oss-reactivity of antiserum 2 with other antiepileptic drugs was negli gible. For competition curves, there was good sensitivity with the ant ibody 2/($) under bar 3 pairing, while a broad assay range was obtaine d with antibody 2/($) under bar 7 pairing. These results demonstrate t he viability of CMIA as an immunoassay method for carbamazepine, and o pen the way to development of a simultaneous multiassay by CMIA of the principal antiepileptic drugs.