Enantio-separation of entecavir opticalisomers by HPLC on Chiralpak AD-H column

A chiral HPLC method was established for the separation and determination of entecavir opticalisomers. Chiral separation of 5 entecavir opticalisomers was achieved under normal-phase chromatographic mode by the Chiralpak AD-H chiral stationary phase. The optimized chromatographic conditions were a mobile phase consisting of n-hexane-isopropanol-alcohol-diethylamine (70 : 6 : 24 : 0. 1) with a flow rate of 0. 5 mL/min, and an UV detector at 254 nm. The column temperature was set at 30 ^°C. The influences of the kinds and proportion of organic solvents, acid and base addictives, flow rate and column temperature on the enantio-separation were studied. Under the chromatographic conditions, 5 entecavir opticalisomers can be completely separated from each other and the resolution values were not less than 1. 9. The validated method is suitable for the quality control of entecavir.