聚乙二醇400分子量测定方法比较研究

Comparative Study on the Methods of Molecular Weight Determination of Polyethylene Glycol 400

目的:建立高效凝胶渗透色谱法(HPGPC)测定聚乙二醇400(PEG400)分子量及其分布,并与《中国药典》所用的端基分析滴定法比较。方法:采用Shodex OHpak SB-802.5HQ与Shodex OHpak SB-803HQ色谱柱串联分离,以0.1 mol·L^(-1)硝酸钠(0.02%叠氮钠)为流动相,流速0.5 mL·min^(-1),柱温30℃,样品浓度2 mg·mL^(-1),采用示差折光检测器进行测定。结果:HPGPC测定的聚乙二醇400的分子量结果与《中国药典》2015年版所用的端基分析法测得的平均分子量结果接近,采用不同厂家色谱柱、对照品可影响PEG400的分子量测定结果,选用Shodex OHpak SB色谱柱串联测定聚乙二醇400重均分子量的范围为407~440,分子量分布宽度1.0~1.1,该方法的精密性RSD为0.2%,重复性为2.89%,24 h内样品稳定性RSD为0.66%。结论:经方法学验证,HPGPC法准确、重复性好,可用于聚乙二醇400分子量及其分布测定。

Objective： To establish the method of high performance gel permeation chromatography（HPGPC） to determine the molecular weight of polyethylene glycol 400（PEG400） and its distribution and to compare it with the end-based titration method in the Chinese Pharmacopoeia. Methods： Shodex OHpak SB-802.5 HQ and Shodex OHpak SB-803 HQ columns were used to separate the samples. 0.1 mol·L^（-1） NaNO_3（0.02%NaN_3） was used as the mobile phase, the flow speed was 0.5 mL·min^（-1）, the column temperature was set at 30 ℃, and the sample concentration was 2 mg·mL^（-1）, The refractive index detector was used to measure the results. Results： The results of the molecular weight of PEG400 measured by HPGPC was similar to those of the average molecular weight measured by the end-based titration method in the Chinese Pharmacopoeia（2015 edition）. Different columns and reference standards could affect the molecular weight results of PEG400. The molecular weight range was from 407 to 440 and the distribution index was from 1.0 to 1.1 by using the method of Shodex OHpak column in series. The precision of the method was 2.2%, the reproducibility of the method was 2.89%,and the RSD of stability within 24 hours was 0.66%. Conclusion： Validated by methodology, HPGPC method is proved to be accurate, repeatable and can be used to determine the molecular weight and the distribution of PEG400.