Mercaptopurine and metformin salt as well as preparation method and crystal structure thereof

The invention provides mercaptopurine and metformin salt as well as a preparation method and a crystal structure thereof and relates to the field of pharmaceutical chemistry. A molecular formula of the mercaptopurine and metformin salt is C9H15N9S; a basic structure unit is composed of one metformin cation and one mercaptopurine anion. The salt belongs to a monoclinic crystal system and a space group is Cc. The high-purity mercaptopurine and metformin salt is prepared by taking a mercaptopurine crude drug and a metformin free alkali as raw materials, mixing and dissolving the raw materials into methanol according to the mol ratio of 1 to 1 and reacting, and taking ethanol as a solvent and recrystallizing. According to the mercaptopurine and metformin salt provided by the invention, the solubility of the mercaptopurine is improved so that the bioavailability of the mercaptopurine is easy to improve. The structure of the salt does not contain any crystallized solvent molecule, so that aframework structure of a