The disfunction or deficiency of the C1 esterase inhibitor (C1INH) is associated with hereditary or acquired angioedema (HAE/AAE), a rare life-threatening condition characterized by swelling in the skin, respiratory and gastrointestinal tracts. The current treatment options may carry the risks of either viral infection (plasma-derived Berinert^®) or immune reaction (human recombinant C1INH from rabbit milk, Ruconest^®). This study describes the physicochemical and biological characterization of a novel recombinant human C1 esterase inhibitor (rhC1INH) from Chinese hamster ovary (CHO) cells for the treatment of hereditary angioedema compared to the marketed products Berinert^® and Ruconest^®. The mass spectrometry results of total deglycosylated rhC1INH revealed a protein with a molecular mass of 52,846 Da. Almost full sequence coverage (98.6%) by nanoLC-MS/MS peptide mapping was achieved. The purity and C1s inhibitory activity of rhC1INH from CHO cells are comparable with Ruconest^®, although we found differences in charge isoforms distribution, intact mass values, and N-glycans profile. Comparison of the specific activity (IC₅₀ value) of the rhC1INH with human C1 esterase inhibitor from blood serum showed similar inhibitory properties. These data allow us to conclude that the novel rhC1INH molecule could become a potential therapeutic option for patients with HAE/AAE.

Peptide mapping is a key method for studying the primary structure of proteins. With its sensitivity to the slightest changes in the covalent structure of a protein, this method is applicable both to medicinal product identification at the control stage and to production process stability monitoring.The aim of the study was to develop and validate a peptide-mapping procedure for the identification of a novel highly glycosylated recombinant C1 esterase inhibitor.Materials and methods. The authors studied recombinant human C1 esterase inhibitor products and trypsin. The study involved peptide mapping using reverse-phase high-performance liquid chromatography and high-resolution mass spectrometry. The following statistics were calculated to evaluate the results: mean, standard deviation, and coefficient of variation. The validation parameters included specificity, precision, and robustness.Results. The authors tested several variants of sample preparation for tryptic digests, including additional N-glycanase treatment and complete deglycosylation, and established the optimal conditions for sample preparation and chromatographic separation of C1 esterase inhibitor peptides to obtain consistent chromatographic profiles (peptide maps). The authors identified characteristic peaks and the corresponding relative retention time and area ranges. The absolute retention time of the second (characteristic) peak was approximately 16.5–16.9 minutes. The relative retention times were 2.14–2.21 for peak 9, 2.55–2.64 for peak 12, 2.97–3.14 for peak 14, 3.11–3.29 for peak 15, and 6.20–6.63 for peak 28.Conclusions. The authors developed a peptide-mapping procedure for C1 esterase inhibitors and optimised the conditions to achieve an over 18-hour reduction in sample preparation time. This procedure met the established acceptance criteria for specificity, precision, and robustness.

In this study, an ion-pair reverse-phase high-performance liquid chromatography–electrospray ionization mass spectrometry (RP-HPLC-ESI-MS) method was optimized and validated for purity determination for the quality control of the proposed generic nusinersen oligonucleotide drug substance and drug product. The optimization and considerations of sample preparation, chromatographic and mass spectrometry conditions are discussed. The limit of detection was 2.5 × 10⁻⁵ mg/mL and the limit of quantitation was 4.9 × 10⁻⁵ mg/mL. The linearity of the signal (XIC) for all impurities was linear with correlation coefficients of R² ≥ 0.9669. This study, associated with the development of therapeutic oligonucleotides, examines the subject of product-related impurities. The authors consider an ion-pair reverse-phase high-performance liquid chromatography in combination with mass spectrometry for impurity quantitative control. This study contributes to the field by elucidating several critical aspects that, while previously unaddressed in the existing literature, are essential for developing effective analytical methods.

INTRODUCTION. Glycan profile is a critical quality parameter for therapeutic monoclonal antibodies (mAbs) that is consistently estimated during development and release of each drug batch. The need to develop a reproducible sample preparation protocol for glycan profiling brings about the relevance of the study. The profile should be adapted to the conditions of a standard physicochemical laboratory, so that it avoids using commercial preparation kits that are currently in short supply. AIM. This study aimed to develop an alternative sample preparation procedure for quantitation of glycans in therapeutic monoclonal antibodies without using commercial kits. MATERIALS AND METHODS. Omalizumab, ustekinumab, canakinumab, tocilizumab, natalizumab, and human anti-PD IgG2 were used as the study objects. N-glycans were released from mAbs by peptide-N-glycosidase (PNGase F) and labeled with fluorescent tags 2-aminobenzamide (2-АВ) or 2-aminobenzoic acid (2-АА) or InstantAB. Subsequently, glycan samples were cleaned from impurities. Glycan compounds were analyzed using hydrophilic interaction liquid chromatography (HILIC-FLD) on Alliance e2695 and Acquity Arc Bio chromatographic systems equipped with FLR 2475 fluorescence detector. The glycan profile was assessed by the content of functional glycan groups. RESULTS. Conditions for preparing therapeutic mAbs N-glycans were chosen as follows: incubation with 2 mEU PNGase F per 100 µg protein in 10 mM Tris-HCl (pH 8.0) at 37 °C for 3 h without protein denaturation; derivatization of glycans with 2-AA at 65 °C for 1.5 h; extraction of 2-AA excess with acetonitrile. Centrifugation of labeled glycans with acetonitrile is suitable for purification and concentration of samples. Minor glycans with a content not more than 0.1–0.2% were determined using HILIC-FLD. Comparison with data obtained using a commercial kit for sample preparation indicated acceptable comparability of the results. When preparing the samples, we took into account structural features of specific mAbs, for instance, desialylation control during the staining was found necessary for high-sialylated mAbs. CONCLUSIONS. The developed sample preparation procedure is suitable for the analysis of N-glycans of omalizumab, canakinumab and natalizumab and may be used to develop the analysis methods of the glycan profile of other glycoproteins using HILIC-FLD mode.