.beta.-crystalline form of the compound of formula (I): ##STR00001## characterised by its powder X-ray diffraction diagram. Medicinal products containing the same which are useful as inhibitors of angiotensin I converting enzyme.
.alpha.-crystalline form of the compound of formula (I): ##STR00001## characterized by its powder X-ray diffraction diagram.Medicinal products containing the same which are useful as inhibitors of angiotensin I converting enzyme.