Canagliflozin alpha-Isomer Impurity; (2R,3R,4R,5S,6R)-2-(3-((5-(4-Fluorophenyl)thiophen-2-yl)methyl)-4-methylphenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol; Canagliflozin α-Isomer ;