Ultrafast high-resolution analysis of human milk oligosaccharides by multicapillary gel electrophoresis.

There is recently growing interest towards synthesized human milk oligosaccharides (HMOs) as baby formula additives, and interestingly also as dietary supplements for adults. Currently quite a few manufacturers synthesize HMOs, however, their analysis is challenging, both in resolution and speed. In this paper an ultrafast high-resolution method is introduced for the separation of HMOs by multicapillary gel electrophoresis. Two gel compositions were evaluated with complementary resolving power. One was a conventionally used industrial standard carbohydrate separation matrix, resolving oligosaccharides according to their charge to hydrodynamic volume ratios. The other one was a borate-buffered dextran gel, which utilized the secondary equilibrium of the borate-vicinal diol complexation to enhance resolution. Considering the rapid analysis time and multiplexing (12-channel system), a 96 well sample plate can be analyzed in less than 80 min with the conventional type carbohydrate separation matrix and in less than one hour with the borate-buffered dextran gel. Exploiting the one fluorophore per molecule labeling stoichiometry, the limit of detection (S/N > 3) and limit of quantitation (S/N > 10) were determined as 0.025 and 0.100 mg/mL, respectively, with good linearity. Based on the calibration plot, the quantities of several low concentration HMOs were determined from a human milk sample.

N-glycan Analysis in Molecular Medicine: Innovator and Biosimilar Protein Therapeutics.

The market segment of new biological drugs (monoclonal antibodies, fusion proteins, antibody-drug conjugates, and new modality protein therapeutics) is rapidly growing, especially after the patent expiration of the original biologics, initiating the emergence of biosimilars. N-glycosylation of therapeutic proteins has high importance on their stability, safety, immunogenicity, efficacy, and serum half-life. Therefore, Nglycosylation is considered to be one of the critical quality attributes. Consequently, it should be rigorously monitored during the development, manufacturing, and release of glycoprotein biologicals. In this review, first, the regulatory considerations for biosimilars are shortly summarized, followed by conferring the analytical techniques needed for monitoring and characterization of the N-glycosylation of biological drugs. Particular respect is paid to liquid phase separation techniques with high sensitivity and highresolution detection methods, including laser-induced fluorescence and mass spectrometry.

N-glycosylation analysis of biopharmaceuticals by multicapillary gel electrophoresis: Generation and application of a new glucose unit database.

As glycomics research is gaining momentum in the biopharmaceutical industry, there is an increasing need for reproducible high throughput glycoanalytical methods to monitor and characterize the N-glycosylation of therapeutic glycoproteins. Since the glycosylation pattern of glycobiotherapeutics influences their important biological functions, approaches to comprehensively analyze these complex molecules is of high importance. This paper reports on the use of multicapillary gel electrophoresis in high throughput analysis of fluorophore labeled partitioned N-glycan libraries to generate a new glucose unit database that was consequently applied to identify the carbohydrate structures of two high profile biopharmaceuticals, adalimumab and etanercept.

Glycosimilarity assessment of biotherapeutics 1: Quantitative comparison of the N-glycosylation of the innovator and a biosimilar version of etanercept.

The carbohydrate moieties on the polypeptide chains in most glycoprotein based biotherapeutics and their biosimilars play essential roles in such major mechanisms of actions as antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, anti-inflammatory functions and serum clearance. In addition, alteration in glycosylation may influence the safety and efficacy of the product. Glycosylation, therefore, is considered as one of the important critical quality attributes of glycoprotein biotherapeutics, and consequently for their biosimilar counterparts. Thus, the carbohydrate moieties of such biopharmaceuticals (both innovator and biosimilar products) should be closely scrutinized during all stages of the manufacturing process. In this paper we introduce a rapid, capillary gel electrophoresis based process to quantitatively assess the glycosylation aspect of biosimilarity (referred to as glycosimilarity) between the innovator and a biosimilar version of etanercept (Enbrel® and Benepali®, respectively), based on their N-linked carbohydrate profiles. Differences in sialylated, core fucosylated, galactosylated and high mannose glycans were all quantified. Since the mechanism of action of etanercept is TNFα binding, only mannosylation was deemed as critical quality attribute for glycosimilarity assessment due to its influence on serum half-life.

Quantitative assessment of mAb Fc glycosylation of CQA importance by capillary electrophoresis.

The attached carbohydrates at the highly conserved asparagine-linked glycosylation site in the CH 2 domain of the fragment crystallizable (Fc) region of monoclonal antibody therapeutics can play an essential role in their mechanism of action, including ADCC, CDC, anti-inflammatory functions, and serum half-life. Thus, this particular glycosylation represents one of the important critical quality attributes (CQA) of therapeutic monoclonal antibodies, which should be closely monitored and controlled during all stages of biopharmaceutical manufacturing. To study Fc glycosylation related quantitative critical quality attributes, the N-glycan pool of adalimumab (Humira® ) was spiked with increasing amounts of mannose-5 oligosaccharide, a glycan with high CQA importance. The method enabled precise quantitative CQA assessment with high detection sensitivity.

On the glycosylation aspects of biosimilarity.

The recent expiration of several protein therapeutics opened the door for biosimilar development. Biosimilars are biologic medical products that are similar but not identical copies of already-authorized protein therapeutics. Critical quality attributes (CQA), such as post-translational modifications of recombinant biotherapeutics, are important for the clinical efficacy and safety of both the innovative biologics and their biosimilar counterparts. Here, we summarize biosimilarity CQAs, considering the regulatory guidelines and the statistical aspects (e.g., biosimilarity index) and then discuss glycosylation as one of the important attributes of biosimilarity. Finally, we introduced the 'Glycosimilarity Index', which is based on the averaged biosimilarity criterion.