Monobasic sodium ste is used in a wide variety of rmaceutical formulations as a buffering agent and as a sequestering agent. Therapeutically, monobasic sodium ste is used as a mild sative and in the treatment of hypostemia. Monosodium ste, Anhydrous (MSPa) Powder is a white powder, which complies with the specifications of the current Food Chemicals Codex for Sodium ste, Monobasic. It is used as an acidulant, buffering agent, emulsifying agent, and protein modifier. Monosodium ste (MSP), also known as monobasic sodium ste and sodium dihydrogen ste, is an inorganic compound of sodium with a dihydrogen ste (H2PO4â) anion. One of many sodium stes, it is a common industrial chemical. The salt exists in an anhydrous form, as well as mono- and dihydrates.