Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A radioimmunoassay has been developed for the quantitation of triamcinolone‐acetonide (TAAc) at the picogram level. For use of TAAc as an antigenic epitope, first the drug was hemisuccinoylated at C‐21 as confirmed by <jats:sup>13</jats:sup>C‐NMR‐ and mass spectroscopy after derivatization. This hapten was conjugated to the carrier‐protein bovine serum albumin (BSA) or keyhole limpet hemocyanin (KLH) by different amide‐bond generating methods (imidazolide‐, carbodiimide‐, carbodiimide/sulfo‐<jats:italic>N</jats:italic>‐hydroxysuccinimde‐, mixed anhydride‐method) yielding antigens of quite different conjugation number, solubility and usefulness. The mixed anhydride‐method yielded most useful soluble conjugates bearing 0.3–31.5 mol TAAc per mol carrier‐protein. Coupling by the carbodiimide‐method yielded insoluble conjugates, inappropriate for antigen synthesis in hapten immunoassays because of formation of coupling agent modified residues and crosslinking of the carrier‐protein. Specificity of the antisera obtained by immunization with TAAc‐BSA and TAAc‐KLH was assessed by isolation of the soluble hapten‐antibody complex and a RIA protocol was developed providing a detection limit of 200 pg (0.46 pmol) TAAc/ml sample.</jats:p>