Probenecid and benzamide: cocrystal prepared by a green method and its physico-chemical and pharmaceutical characterization

The eco-friendly method of kneading was here used to synthesize a cocrystal of probenecid, an uricosuric drug used in treating gout and hyperuricemia, with the aim to improve its pharmaceutical behavior. Benzamide was selected as a co-former showing functional groups favorable to the formation of supramolecular synthons with the active principle. The kneading product was characterized by a range of experimental techniques (microscopic, spectroscopic, thermal and diffractometric) all proving the formation of the new multicomponent crystal. In particular, the FT-IR and NMR techniques showed that an important change of hydrogen bonds network takes place in the kneading product and that the acid-acid interaction in the pristine drug is replaced with the related acid-amide one in the cocrystal. The cocrystal solubility and dissolution rate measured in several biorelevant fluids showed an actual improvement with respect to the pure drug.