The Stability of Radioactive Iodinated Serum Albumin Preparations in Man

Abstract

During the past few years there has been an increasing interest in the possible use of radio-iodine-labelled human serum albumin (I.H.S.A.) for the measurement of plasma volumes and for the study of changes in the distribution of protein in the various body fluid compartments. This material might provide a means of investigating protein turn-over in a variety of disorders such as multiple myelomatosis, cirrhosis of the liver, chronic renal disease and ascites. Inconsistent behaviour of various I.H.S.A. preparations was encountered at the Middlesex Hospital during a search for a suitable compound with which to study lymphatic drainage in man following subcutaneous injection; and at the Royal Marsden Hospital during attempts to measure changes in plasma volume in patients with poly-cythaemia vera treated by 32P. This led us to investigate the in vivo stability of the radioactive human serum albumin prepared by the Radio-chemical Centre at Amersham, and to compare it with that of two other preparations of the same compound. Since there is a demand for radioactive serum albumin from medical centres in this country and abroad, we are prompted to report our findings in order to indicate the limitations and range of usefulness of these preparations, and to show how gross instability of the material can be demonstrated. It has already been recognised that different batches of 131I-labelled albumin may contain variable quantities of rapidly degraded components (Berson, Yalow, Schreiber and Post, 1953).