Formulations are provided that contain single variable domains with a good solubility and good stability under different storage, transportation and stress conditions. The formulations are useful as pharmaceutical formulation. The formulation comprises an aqueous carrier with a pH of 5.5 to 8.0, a buffer selected from the group consisting of histidine pH 6.0-6.5, hepes pH 7.0-8.0, MES pH 6.0, succinate pH 6.0-6.5 and acetate pH 5.5-6.0； an excipient； and/or a surfactant selected from Tween 80, Tween 20 and poloxamers. The formulation is further characterized that it has an inorganic salt concentration of 150 mM or lower. The invention further relates to containers and pharmaceutical units comprising such formulations and to methods for preparing and prophylactic and therapeutic uses of the formulations and pharmaceutical units of the invention.
