Acid salts (2s, 3s) -3 - [[(1s) -1-isobutoximetil-3-metilbutil] carbamoil] oxirano-2-carboxilico.

(2S, 3S) -3 - [[(1S) -1-isobutoxymethyl-3-methylbutyl] carbamoyl] oxirane2-crystalline sodium carboxylate having the following characteristics: DSC: exothermic peak observed at a temperature in the range of 170 to 175 ° C with weight reduction; and absorption bands characteristic of the infrared absorption spectrum measured in KBr tablet: 3255, 2950, 2860, 1670, 1630, 1550, 1460, 1435, 1395, 1365, 1310, 1260, 1110, 890 cm -1.