CAS 5402-20-0 appears in our catalog under these names: 4–Pyridinesulfonic acid, 4-Pyridinesulphonic acid, Pyridine-4-sulphonic acid 96%, 4-Pyridinesulfonic acid, 4-Pyridinesulphonic acid, min. 95 %, 250 mg. Offered by: GLPBio, Biosynth, Ambeed, Chemat, Roth. Available pack sizes: 1g, 200mg, 50mg, 5g, 250mg, 500mg, 1000mg, 100mg.