Quality Control and Stability Studies of ¹⁶⁹Yb-DTPA, and Its Application to Determination of Glomerular Filtration Rate in Rabbits

Abstract

¹⁶⁹Yb-DTPA, which was developed by Dr. H. N. Wagner, et al., was confirmed to be a very stable compound by the method of paperchromatography and thin layer chromatography, in which acetone-H₂O (1: 1) was used as developer. Rf value of ¹⁶⁹YbDTPAwith this developer was between 0.7-0.8, while¹⁶⁹YbCl₃remained at origin. Any radiochemical impurities were not detected by these methods after repeated autoclaving of the substance and storage for two months.
To confirm its applicability to determination of glomerular filtration rate (GFR), ¹⁶⁹Yb-DTPA and¹³¹I-iothalamate were injected simultaneously into a rabbit and concentrations of each compound in plasma and urine samples were analyzed by a pulse height analyzer from their gamma energies. GFR values obtained with both compounds showed good correlation and its correlation factor was 0.991. Furthermore GFR values calculated from the blood clearance curve method of the both compounds showed good agreement. It would appear that¹⁶⁹Yb-DTPAis therefore a satisfactory substitute for¹³¹Iiothalamate clearances.