Sucrose octasulfate (SOS), a component of the gastrointestinal protectant sucralfate, is an alkaline aluminum-sucrose complex that inhibits peptic hydrolysis and raises gastric pH, protecting esophageal epithelium against acid injury. It can bind to exosite II of thrombin (KD = ~1.4 μM) and inhibit its catalytic activity (IC50 = 4.5 μM) and, as such, has been used as a surrogate for heparin. Furthermore, SOS has been shown to inhibit tumor growth in mouse melanoma and lung carcinoma models by preventing fibroblast growth factor 2 (FGF-2) binding to endothelial cells and also by removing any pre-bound FGF-2 from these cells (IC50 = ~2 μg/ml).