AN1304: Low-Molecular-Weight Heparin Analysis by SEC-MALS

The US Pharmacopeia (USP) monograph for low-molecular-weight heparin (LMWH) specifies single-detector SEC with the usual column calibration in order to verify that it has been properly fractionated. The European Pharmacopeia (EP) monograph for LMWH specifies characterization of molar mass via size-exclusion chromatography (SEC) coupled with downstream detection by tandem 234 nm ultraviolet (UV) and refractive index (RI) detectors, known as the Nielsen method.

We have developed a SEC-MALS method and found it to be very suitable for the analysis of LMWHs. In order to cross-validate the SEC-MALS method against the EP method, we implemented the UV-RI method described in the EP monograph and compared the molecular weight results generated for LMWH using each analytical technique.