this invention relates to a process for controlling the hydrate mix of a compound , or a composition comprising the compound , the compound being capable of forming a plurality of hydration forms of differing stability and also of dissolution to give a solution that , when frozen below the eutectic point , is a eutectic mixture . this invention further relates to disodium salt of fosfluconazole in the form of its trihydrate , its hexahydrate , or as a mixture of tri - and hexahydrates .