Spectral Service AG, Emil-Hoffmann-Straße 33, 50996 Köln, Germany; Institute of Chemistry, Saratov State University, Astrakhanskaya Street 83, 410012 Saratov, Russia.
Spectral Service AG, Emil-Hoffmann-Straße 33, 50996 Köln, Germany.
J Pharm Biomed Anal. 2018 Feb 5;149:128-132. doi: 10.1016/j.jpba.2017.11.016. Epub 2017 Nov 4.
Apart from the characterization of impurities, the full characterization of heparin and low molecular weight heparin (LMWH) also requires the determination of average molecular weight, which is closely related to the pharmaceutical properties of anticoagulant drugs. To determine average molecular weight of these animal-derived polymer products, partial least squares regression (PLS) was utilized for modelling of diffused-ordered spectroscopy NMR data (DOSY) of a representative set of heparin (n=32) and LMWH (n=30) samples. The same sets of samples were measured by gel permeation chromatography (GPC) to obtain reference data. The application of PLS to the data led to calibration models with root mean square error of prediction of 498Da and 179Da for heparin and LMWH, respectively. The average coefficients of variation (CVs) did not exceed 2.1% excluding sample preparation (by successive measuring one solution, n=5) and 2.5% including sample preparation (by preparing and analyzing separate samples, n=5). An advantage of the method is that the sample after standard 1D NMR characterization can be used for the molecular weight determination without further manipulation. The accuracy of multivariate models is better than the previous results for other matrices employing internal standards. Therefore, DOSY experiment is recommended to be employed for the calculation of molecular weight of heparin products as a complementary measurement to standard 1D NMR quality control. The method can be easily transferred to other matrices as well.
除了杂质的表征外，肝素和低分子量肝素（LMWH）的全面表征还需要测定平均分子量，这与抗凝药物的药物特性密切相关。为了确定这些动物源性聚合物产品的平均分子量，利用偏最小二乘回归（PLS）对一组有代表性的肝素（n=32）和 LMWH（n=30）样品的扩散有序光谱 NMR 数据（DOSY）进行建模。相同的样品集通过凝胶渗透色谱（GPC）进行测量，以获得参考数据。PLS 应用于数据得到了校准模型，对于肝素和 LMWH，预测均方根误差分别为 498Da 和 179Da。平均变异系数（CVs）不超过 2.1%，不包括样品制备（连续测量一个溶液，n=5），包括样品制备（制备和分析单独的样品，n=5）时不超过 2.5%。该方法的一个优点是，在经过标准 1D NMR 特征化后，样品可以在无需进一步操作的情况下用于分子量测定。与以前使用内标法的其他基质的多元模型相比，该方法的准确性更好。因此，建议将 DOSY 实验作为标准 1D NMR 质量控制的补充测量方法用于肝素产品的分子量计算。该方法也可以很容易地转移到其他基质。
