A host-guest complex, wherein the host is a cyclodextrin or a mixture of cyclodextrins (the Cyclodextrin) and the guest is 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione- , (Compound (I)) or a pharmaceutically acceptable derivative thereof or a mixture thereof; a process for the preparation of said complex, a pharmaceutical composition comprising such complex and the use of such complex in medicine.