A kit-like procedure is described for the labelling of Hippuran by exchange in a melt with carrier-free iodide-123 directly
formed from the decay of123Xe. Decay and subsequent melting for 15 min at 180°C are performed in one and the same ampoule. This results in a transfer
of 95% of the123I-activity into Hippuran with a residual123I-content of <1.0%. Quality control is based on thin-layer chromatography. Contaminants are discussed and a comparison is
made with commercial preparations of Hippuran-131I.