Study On Preparation And Purification Of Digoxin Reference Material Raw

Digoxin was a potent glycoside,widely used in heart disease treatment,which could effectively enhance myocardial contractility,slow heart rate down,and inhibit cardiac conduction.The therapeutic drug monitoring window of digoxin was narrow,and its toxic response was a common and serious problem in clinical treatment.It was necessary to fast and effective monitor of the drug concentration in clinical,which was contribute to help physicians to adjust the treatment of different patients timely to ensure the therapeutic effect,and avoid ineffective treatment dose.Digoxin was unstable,trended to isomerization and degradation that lead to instability and so on in the purification process,while similar the structure of impurities occurrence in the digoxin raw material.A variety of purification methods were needed for the purification preparation in order to prepare purer raw material to meet clinical requirements.The qualitative and quantitative analysis was performed on commercially digoxin raw material.The raw material was qualitatively analyzed by the IR,NMR for confirmation of principal component,while LC/MS-IT-TOF also was used to analyze the impurities,and the three impurities was identified as:digoxigenin,diginatin,digitoxin.The chromatography purity of the digoxin raw material was 98.24%.According to the mass balance method,then the content of water,inorganic elements,ash,volatile solvent impurities respectively were determined.As a result,the content of digoxin was 97.94%by mass balance method.The method of column chromatography was established to isolate and purify digoxin raw material:using magnesium silicate,alumina,silica gel as adsorbents respectively with methanol,dichloromethane,acetone,ethyl acetate as eluting agents.Investigating the effects of the adsorbent filler height,inject volume,mobile phase ratio,elution flow rate on digoxin product purification according to orthogonal experiments.The optimal experimental conditions were determined by experimental optimization:using magnesium silicate as adsorbent filler and ethyl acetate/dichloromethane/methanol as mixed eluting solvent,the concentration of the sample was 3 mg·g-1,the packing height was 20 cm,and the ratio of ethyl acetate/dichloromethane/methanol was 4:6:2(v/v/v),elution flow rate was 5mL·min-1.The chromatography purity of digoxin product was 99.07%,the recovery rate was 75.45%Semi-preparative liquid chromatography(semi-prep HPLC)was applied in order to digoxin raw material purification process,the optimized conditions were determined:concentration of raw material was 3 mg·mL-1,acetonitrile-water as the mobile phases were in gradient elution,detection wavelength was 220 nm,flow rate was 12 mL·min-1,injection volume was 2.0 mL.The collected products were dried by freeze drying.The chromatography purity of product could be 99.88%,the recovery rate was 25.79%.At room temperature in the dark or 4℃,digoxin products in a month of short-term stability was good.Effective avoidance of the process of degradation or isomerization in preparation,and accurate qualitative and quantitative measurement of the impurities,was intended to develop high purity material with the international advanced level.