4-(2,3,6,7-Tetrahydro-1,3-dimethyl-2,6-dioxo-1H-purin-8-yl)benzenesulfonic acid 8-(4-Sulfophenyl)theophylline 8-(p-Sulfophenyl)theophylline 8-Pspt 8-SPT 8-Sulfophenyltheophylline 8-Sulphophenyltheophylline 80206-91-3 Benzenesulfonic acid, 4-(2,3,6,7-tetrahydro-1,3-dimethyl-2,6-dioxo-1H-purin-8-yl)- Psp-theophylline