Search

Capillary electrophoresis with sodium dodecyl sulfate (CE-SDS) has long been proven to have excellent performance in the analysis and characterization of therapeutic proteins. However, it is rarely used for the detection of low-molecular-weight proteins or peptides. Our research has proved the ability of CE-SDS to characterize the purity of low-molecular-weight proteins (i.e., <10 kDa) and even polypeptides. In this article, insulin glargine was used as a model protein, and CE-SDS was used to analyze the samples damaged by heating and light exposure. The monomers, dimers, and trimers of insulin glargine were effectively separated, and the results of the mass spectrometry also confirmed the existence of two kinds of insulin aggregates. For comparison, the size-exclusion high-performance liquid chromatography (SE-HPLC) only showed a single aggregate peak. In addition, the denaturation conditions caused only the covalent aggregates to appear in the CE-SDS analysis. These advantages also make CE-SDS an excellent supplementary technology to the traditional SE-HPLC, providing biopharmaceutical analysts with more information. • Low-molecular-weight protein aggregation was first characterized by CE-SDS. • Insulin glargine aggregation was compared between CE-SDS and SE-HPLC. • CE-SDS achieved higher resolution and distinguished covalent from noncovalent aggregates. [ABSTRACT FROM AUTHOR]

Objective: Critical process parameters (CPPs) identification is an important step of the implementation of quality by design (QbD) concept. There are many CPP identification methods, such as risk analysis method, sensitivity analysis method, multiple linear regression method, standard partial regression coefficient (SPRC) method, and so on. The SPRC method can consider multiple process critical quality attributes (CQAs) simultaneously, but the determination of CPP number is subjective. Therefore, new CPP identification method is still required., Methods: The manufacturing process of Astragali Radix extract, which contained water reflux extraction, concentration, and ethanol precipitation, was used as an example. First, the multiple process CQAs were determined to be the yield of pigment, dry matter, sugars, and active ingredients. Second, the potential CPPs were determined by a knowledge organization method. Plackett-Burman designed experiments were then performed. A weighted determination coefficient ( R w 2 ) method was presented to identify CPPs. In this method, the importance of different CQAs was considered. Process parameters were removed one-by-one according to their importance index. The decrease in R w 2 was used to characterize the importance of the removed parameter. If the decrease of R w 2 was less than a preset threshold, the removed parameter was not a CPP., Results: During the manufacturing process of Astragali Radix extract, the potential CPPs determined by the knowledge organization method were water consumption, reflux extraction time, extraction frequency, ethanol content, ethanol consumption, and concentration endpoint. Reflux extraction time, the first ethanol consumption, the second ethanol consumption, and the second ethanol precipitation refrigeration temperature were found to be CPPs using the weighted determination coefficient method with the threshold of 10%., Conclusion: Using the weighted determination coefficient method, CPPs can be determined with all the CQAs considered based on their importance. The determination of CPP number is more objective compared with the SPRC method., Competing Interests: The authors declare no conflict of interest., (© 2019 Tianjin Press of Chinese Herbal Medicines. Published by Elsevier B.V.)