This photo shows four filter presses used for washing the magaldrate material at Wyeth-Ayerst Laboratories. Magaldrate is the generic name for Riopan, an antacid for relieving heartburn and indigestion that was made at the factory. The factory was later bought by Pfizer, and the Rouses Point plant closed in 2006. 1970s. Rouses Point, NY. Photo courtesy of the Rouses Point-Champlain Historical Society.