Molecular Weight Determination of LMWH SEC–MALS vs. SEC–UV–RI
The Application Notebook
Wyatt Technology Corporation
Low-molecular-weight heparins (LMWHs) are obtained by fractionation or depolymerization of natural heparins. They are defined as having a mass-average molecular weight of less than 8000 and for which at least 60% of the total weight has a molecular mass less than 8000.
Size-exclusion chromatography (SEC) has been the most common way of measuring the molecular weight and molecular weight distributions of LMWHs by using the two most common detection technologies: ultraviolet (UV) coupled with refractive index (RI) detection. However, these detectors embody a relative method to determine molecular weights, requiring calibration standards. A newer, absolute method involves the use of multi-angle light scattering (MALS), which does not require any standards. The European Pharmacopeia (EP) monograph for LMWH specifies the use of the UV–RI detection method and provides a known calibration standard. Many laboratories around the world have adopted this method.
Figure 1: Examples of UV and RI traces for an LMWH sample.
We previously developed an SEC–MALS method and found it to be very suitable for the analysis of LMWHs. We have recently adopted the UV–RI method described in the EP monograph and compared the molecular weight results generated for LMWH using each detection type. The adopted method uses an Agilent LC-1200 series HPLC, 0.2 M sodium sulphate pH 5.0 mobile phase, Tosoh TSK-gel G2000 SWxl column with Tosoh TSK-gel Guard SWxl, Waters 2487 dual wavelength UV detector, and Wyatt Optilab rEX refractive index detector. For MALS analysis, the UV detector was replaced with a Wyatt miniDAWN TREOS detector; all other method aspects remained the same.
Figure 2: Examples of LS and RI traces for an LMWH sample.
The results indicated that both detection types are suitable and acceptable for the analysis of LMWHs. The molecular weight and distribution results generated using each detection type are comparable. This indicates that a SEC–MALS method could be adopted in place of the SEC–UV–RI method currently required by the EP monograph, and that it would result in less time because it obviates the need for calibration standards.
This note was graciously submitted by Lin Rao and John Beirne of Scientific Protein Laboratories LLC.
Wyatt Technology Corporation
6300 Hollister Avenue, Santa Barbara, California 93117, USA
Tel: +1 (805) 681 9009 fax: +1 (805) 681 0123
Website: www.wyatt.com
AI and GenAI Applications to Help Optimize Purification and Yield of Antibodies From Plasma
October 31st 2024Deriving antibodies from plasma products involves several steps, typically starting from the collection of plasma and ending with the purification of the desired antibodies. These are: plasma collection; plasma pooling; fractionation; antibody purification; concentration and formulation; quality control; and packaging and storage. This process results in a purified antibody product that can be used for therapeutic purposes, diagnostic tests, or research. Each step is critical to ensure the safety, efficacy, and quality of the final product. Applications of AI/GenAI in many of these steps can significantly help in the optimization of purification and yield of the desired antibodies. Some specific use-cases are: selecting and optimizing plasma units for optimized plasma pooling; GenAI solution for enterprise search on internal knowledge portal; analysing and optimizing production batch profitability, inventory, yields; monitoring production batch key performance indicators for outlier identification; monitoring production equipment to predict maintenance events; and reducing quality control laboratory testing turnaround time.
