Preparation of bromosulfophthalein injection solution labelled with iodine radioisotopes

Bromosulfophthalein is used in clinical liver diagnosis for more than 50 years, the labelled preparation for about 20 years. Because the labelled preparation is imported in large quantities, the authors developed a labelling technique. The monoderivative of bromosulfophthalein is labelled by isotopic exchange. The composition of the final product constitutes a certain problem as the reaction yields mono- and diiododerivatives with the iodine atom in position 5 or 5,5', respectively. Analytical methods for radiochemical purity control were studied which would definitely separate the two products. The end product is obtained with a fairly high yield and is free of the above mentioned impurities. (author)