Determination of amezinium in body fluids.

Possible approaches to the determination in body fluids of 4-amino-6-methoxy-1-phenyl-pyridazinium methyl sulfate (ameziniummetilsulfate, LU 1631, Regulton), in this study briefly called amezinium, are investigated and the methods developed on the basis of results obtained in pilot experiments described. These methods, which are primarily based on radioactive tracer techniques, allow both labelled and unlabelled amezinium to be determined in urine, bile, blood, and plasma in concentrations down to about 2 n/ml. Relative standard deviations of 0.5%-9% and 96-102% accuracy are obtained. Advantages and disadvantages of individual methods for various types of samples are discussed.