[Determination of impurity diketo aldehyde in bulk drug and preparations of dihydroartemisinin].

Diketo aldehyde (DKA),one of the most important impurities in dihydroartemisinin,was synthesized through reaction between dihydroartemisinin and anhydrous ferrous bromide under a N₂ atmosphere, and an HPLC method was established for the determination of DKA in bulk drug and in DHA tablet. DKA was prepared from dihydroartemisinin in the presence of FeBr₂.The chromatographic separation was achieved through an Agilent Eclise XDB-C₁₈ column (4.6 mm×250 mm,5 μm), and the optimal mobile phase consisted of acetonitrile and water in the ratio of 37:63 at flow rate of 1.0 mL·min⁻¹.The detection was carried out at 216 nm, and column temperature was 15 °C.The injection volume was 40 μL.The method featured a good linearity (=0.999 9),precision (1.0%),repeatability (1.3%),stability (DKA standards RSD=1.0% and in tablet form instability),recovery (92.88%),limits of detection (0.20 mg·L⁻¹) ,and limits of quantification (0.78 mg·L⁻¹). The result show that the content of DKA in bulk drug was 0.086 7%-2.622 9%, and the content of DKA in tablet was 0.068 3%-0.615 1%.