(S)-4-isobutyl-1-(((2R,3R,4S,5R)-2,3,4-trihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)methyl)pyrrolidin-2-one compound with (S)-4-isobutyl-1-(((2R,3S,4R,5R)-2,3,4,5-tetrahydroxytetrahydro-2H-pyran-2-yl)methyl)pyrrolidin-2-one (1:1),(S)-4-isobutyl-1-(((2R,3R,4S,5R)-2,3,4-trihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)methyl)pyrrolidin-2-one compound with (S)-4-isobutyl-1-(((2R,3S,4R,5R)-2,3,4,5-tetrahydroxytetrahydro-2H-pyran-2-yl)methyl)pyrrolidin-2-one (1:1),Impurity of Pregabalin;Impurity in commercial preparations of Pregabalin,Pregabalin Therapeutic