分子排阻色谱法测定低浓度肝素钠注射液的相对分子质量与相对分子质量分布

目的： 建立分子排阻色谱法测定低浓度肝素钠注射液相对分子质量与相对分子质量分布的方法。方法： 采用分子排阻法，检测器为示差检测器，TSK G4000SWXL（300 mm×7.8 mm，5 μm）和TSK G3000SWXL（300 mm×7.8 mm，5 μm）色谱柱串联，柱温为30℃，流动相为0.1 mol·L^-1醋酸铵溶液，流速为0.6 mL·mL^-1。结果： 该方法专属性强，回收率试验中重均相对分子质量（M_w）的RSD为0.38%，相对分子质量大于24 000级分的RSD为1.81%，相对分子质量8 000~16 000与16 000~24 000级分之比的RSD为0.42%。样品定量限为2.0 mg·mL^-1，测定结果符合《中国药典》2015年版标准。结论： 本方法操作简便，重复性好，结果准确可靠，可用于测定低浓度肝素钠注射液相对分子质量与相对分子质量分布。

Determination of molecular weight and its distribution of low concentration heparin sodium injection by size-exclusion chromatography

OBJECTIVE To establish a method for determination of molecular weight and its distribution of low concentration heparin sodium injection.METHODS The samples were analyzed by size-exclusion chromatography with refractive index detector on a TSK G4000SW_XL column (300 mm×7.8 mm, 5 μm) in series with a TSK G3000SW_XL column (300 mm×7.8 mm, 5 μm) at column temperature 30℃. 0.1 mol·L^-1 ammonium acetate was used as mobile phase with flow rate of 0.6 mL·min^-1.RESULTS The method was hightly specific, for the RSDs were 0.38%, 1.81% and 0.42% for weight average molecular weight (M_w),the percent of the fraction with M_w more than 24 000 and the ratio of the fraction with M 8 000-16 000 to M16 000-24 000, respectively. The limit of quantitationwas 2.0 mg·mL^-1. All the results conformed to Chinese Pharmacopoeia criterion.CONCLUSION The method is simple, accurate, reliable, and suitable to determine molecular weight and its distribution of low concentration heparin sodium injection.