Design of the immunogen and label for use in a fluoroimmunoassay for paracetamol

The design of immunogens for raising antisera containing antibodies specifically directed against paracetamol is discussed. A derivative of the drug with minimal structural alteration was synthesised, coupled to the carrier protein key-hole limpet haemocyanin, and used to immunise sheep. The evaluation of the resulting antisera is described. Preparation of a fluorescent label with reduced bridge-binding then allowed the development of a polarisation fluoroimmunoassay for paracetamol in buffer, suitable for conversion to a direct serum assay.