Selenium-75-labeled sucralfate: comparison with other radiolabels and initial clinical studies.

Sucralfate was synthesized to include a 75Se label, then compared with 111In-sucralfate and 99mTc-Human serum albumin (HSA)-sucralfate in vitro and in an animal ulcer model. The 75Se label was the only one of the three that was stable in both human gastric juice and simulated intestinal fluid in vitro. In rats with gastric ulcers, ulcer:nonulcer ratios of bound radioactivity averaged 15.4, 6.3, and 5.6 for 75Se, 111In, and 99mTc-HSA labels, respectively. Biodistribution studies of 75Se-sucralfate indicated that little is absorbed from the gastrointestinal tract, and the distribution is similar to that of 14C-sucralfate. Selective binding of 75Se sucralfate was successfully imaged in patients with esophagitis (esophageal mean T1/2 binding = 65 +/- 32 min), gastritis (gastric mean T 1/2 binding = 118 +/- 34 min), and gastric ulcers (ulcer mean T 1/2 binding = 135 +/- 59 min). Duodenal ulcers were not successfully imaged. Normal subjects showed no abnormal localization of sucralfate, and esophageal and gastric clearances were rapid.