Keywords: Drug delivery / Vanadium / Hydrogen bonds / Micelles / MetforminA material that contains metformium cation and decavanadate anion was synthesized and characterized. The material is not soluble in water but slightly soluble in dimethyl sulfoxide and very soluble in the inhomogeneous environment of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles, which deviates significantly from the properties of sodium decavanadate. By considering the fact that decavanadate is reported to have insulin-enhancing activity in streptozotocin (STZ)-induced diabetic rats (Pereira et al., J. Inorg. Biochem. 2009, 103, 1687-1692, how this oxometalate interacts with interfaces was investigated using NMR and IR spectroscopy.