Study of solid-liquid and solid-vapour equilibria in tenatoprazole potassium salt/solvents systems

SMS Laboratory, EA 3233 IMR4114, University of Rouen, F-76821 Mont Saint Aignan Cedex, France

Abstract

Tenatoprazole, 5-methoxy-2-{[(4-methoxy-3,5-dimethyl-2-pyridyl)-methyl]-sulfinyl}-imidazo-[4,5-b]-pyridine, is a proton pump inhibitors (PPI). A conglomerate screening of (±) tenatoprazole by crystallisation of various salts and solvates led to the detection of potassium salts dihydrate and efflorescent ethanol and methanol solvates giving a full chiral discrimination in the solid state. The aim of this study was to determine solid-liquid and solid-vapour equilibria of the system [tenatoprazole potassium salt / methanol / ethanol] by combining structural, thermal and dynamic sorption / desorption data. The isothermal section at 20°C of this system was determined by using DITA (Discontinuous Isoperibolic Thermal Analysis) measurements and structural studies (in situ XRPD). Despite extensive structural similarities the study performed here suggests the existence of a partial solid solution between methanol and ethanol solvates.