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With the in-depth study of related substances and the development of consistency evaluation of generic drugs, relative correction factors are gaining increasing attention. By analyzing the domestic and foreign literature on correction factors in recent years, this paper describes the correction factor component, the current measurement method and its application. The rules and key points of use of an impurity correction factor and its determination and application are described, and some problems in its determination and application are discussed, providing a reference and basis for the standardization of research on impurity correction factors in the future.
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OBJECTIVE: To establish the self contrast and correction factor method for the content determination of the related substances in compound ezetimibe and rosuvastatin calcium tablets simultaneously. METHODS: RP-HPLC method was adopted. The determination was performed on Kromasil 100-5 C18 Dimensions column (4.6 mm × 250 mm, 5 μm) with mobile phase A consisting of methanol-acetonitrile-0.05 mol·L-1 potassium dihydrogen phosphate (adjusted to pH 4.0 with phosphoric acid) (10:30:60) and mobile phase B consisting of tetrahydrofuran-acetonitrile-0.05 mol·L-1 potassium dihydrogen phosphate (adjusted to pH 4.0 with phosphoric acid) (10:50:40) at a flow rate of 1.0 mL·min-1. The detection wavelength was set at 242 nm. The injection volume was 20 μl. The slope of linear equation was used to determine the correction factors between ROS impurities 1, 2, 3, EZT impurities 1, 2, 3, 4, 5, 6, 7 and ezetimibe or rosuvastatin calcium. The relative retention time was used to determine the positions of impurities. RESULTS: The relative retention time of ROS impurities 1, 2, 3, 4 and EZT impurities 1, 2, 3, 4, 5, 6, 7 to rosuvastatin calcium was 1.5, 1.9, 2.1, 1.1, 1.7, 2.5, 2.6, 2.8, 2.9, 3.0, and 4.0, respectively. The correction factors of ROS impurities 1, 2, 3, 4 and EZT impurities 1, 2, 3, 4, 5, 6, 7 were 1.1, 1.1, 1.0, 1.0, 1.3, 1.1, 1.0, 1.3, 1.4, 0.5, and 1.0, respectively. The content of ROS impurity 4 was 0.15% in three batches of samples, the other impurities were less than 0.1%, and the contents of total impurities were 0.27%, 0.27%, and 0.26%, respectively. CONCLUSION: The method is simple, efficient, and accurate for analyzing the related substances in compound ezetimibe and rosuvastatin calcium tablets.
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Objective:To determine the content of six main flavonoids in herba epimedii by self contrast with correction factor. Methods:HPLC was carried out with reversed-phase technique on an Agilent ZORBAX Eclipse XDB-C18 (150 mm × 4. 6 mm, 5 μm) column with the mobile phase consisting of acetonitrile-water with gradient elution. The detection wavelength was 268nm and the col-umn temperature was 30℃. The correction factor was established through the increase value of chromatographic peak area for the self internal standard. The relative retention time and spectrum reference method were used to determine the position of impurities. Re-sults:The relative retention time of epimedin A1 , epimedin A, epimedin B, epimedin C and baohuoside I was 0. 750,0. 810,0. 865, 0. 939 and 1. 651, respectively. The correction factor of them was 0. 998 6, 0. 998 7, 0. 998 8, 0. 989 4 and 0. 985 6, respectively. Conclusion:The self contrast with correction factor can be use to quantitatively determine the components with the same kind of chem-istry environment. The method is simple, efficient and accurate in the quantitative analysis of multi components in Chinese medicines.