Crystalline modification A of (1R, 2R) -3- (3-dimethylamino-1-ethyl-2-methylpropyl) enol which includes an X-ray diffraction peak at 15.58 + - 0.20 (2Θ), in addition to minus an X-ray diffraction peak selected from the group consisting of 28.37 + - 0.20 (2Θ) and 34.45 + - 0.20 (2Θ), and additionally at least one X-ray diffraction peak selected among the group consisting of 13.71 + - 0.20 (2Θ), 14.80 + - 0.20 (2Θ), 16.89 + - 0.20 (2Θ), 17.79 + - 0.20 ( 2Θ), 18.45 + - 0.20 (2Θ), 20.20 + - 0.20 (2Θ), 20.92 + - 0.20 (2Θ), 22.50 + - 0.20 (2Θ) , 24.37 + - 0.20 (2Θ) and 25.33 + - 0.20 (2Θ).Modificación cristalina A de (1R,2R)-3-(3-dimetilamino-1-etil-2-metilpropil)enol que incluye un pico de difracción de rayos X a 15,58 +- 0,20 (2Θ ), adicionalmente al menos un pico de difracción de rayos X seleccionado entre el grupo consistente en 28,37 +- 0,20 (2Θ ) y 34,45 +- 0,20 (2Θ ), y adicionalmente al menos un pico de difracción de rayos X seleccionado entre el grupo consistente en 13,71 +- 0,20 (2Θ ), 14,80 +- 0,20 (2Θ ), 16,89 +- 0,20 (2Θ ), 17,79 +- 0,20 (2Θ ), 18,45 +- 0,20 (2Θ ), 20,20 +- 0,20 (2Θ ), 20,92 +- 0,20 (2Θ ), 22,50 +- 0,20 (2Θ ), 24,37 +- 0,20 (2Θ ) y 25,33 +- 0,20 (2Θ ).
