Alpha crystalline form of perindopril arginine salt (I), characterized by the X-ray diffraction diagram on powder, measured by a diffractometer (copper anticathode) and exhibited a Bragg angle 2 theta, an interreticular distance (d), an intensity and a relative intensity, as given in table of the specification, is new. Alpha crystalline form of perindopril arginine salt of formula (I), characterized by the X-ray diffraction diagram on powder, measured by a diffractometer (copper anticathode) and exhibited a Bragg angle 2 theta, an interreticular distance (d), an intensity and a relative intensity, as given in table of the specification, is new. Independent claims are included for: (1) a composition comprising (I) in combination with inert and nontoxic vehicles； and (2) the preparation of (I). [Image] ACTIVITY : Cardiovascular-Gen； Hypotensive； Cardiant. MECHANISM OF ACTION : Angiotensin I converting enzyme inhibitor. No biological data given.
