Correct spelling for the English word "formeston" is [fˈɔːmɛstən], [fˈɔːmɛstən], [f_ˈɔː_m_ɛ_s_t_ə_n] (IPA phonetic alphabet).
Aluminum acetoformate, a dusting powder similar to eston and subeston.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.