ABSTRACT
Human chorionic gonadotrophin (hCG), a glycohormone widely used in treatment of infertility, is a heterodimer composed of an alpha-and a beta-subunit. The heterodimer could be dissociated during production and storage with an impact on its bioactivity. A CE-SDS method for quantitative analysis of hCG subunit dissociation was established in this study by optimization of a variety of method conditions including sample preparation buffer compositions, incubation temperature, separation voltage, and capillary temperature. This method was validated for good sensitivity, linearity, precision, and accuracy for both α-and β-subunit. CE-SDS also showed much better precision and accuracy than SDS-PAGE. The method was successfully used in both recombinant hCG (r-hCG) produced by cell culture and hCG (u-hCG) derived from urine. The CE-SDS method was used in the study of hCG development and stability. Therefore, it is an useful tool for the quality control of hCG.
ABSTRACT
The composition and potency of the high temperature (40℃) stress induced size variants of a recombinant humanized monoclonal antibody (rhumAb1) were characterized by means of SEC-HPLC, nonreduced CE-SDS, liquid chromatography coupled with mass spectrometry (LC-MS) and antibody dependent cell-mediated cytotoxicity (ADCC) assay. The molecular masses of the four size variants (SEC-1-SEC-4) separated by SEC-HPLC and seven size variants (NR-1-NR-7) detected by non-reduced CE-SDS were all characterized by LC-MS. The major low molecular weight variants were generated due to the hinge region fragmentation of heavy chain. The hinge region cleavage was found mainly in the Ser221-Cys-Asp-Lys-Thr-His-Thr-Cys228 sequence, in which C222-D223 and H226-T227 were the major cleavage sites. The size variants of rhumAb1, namely dimer and fragments, have significantly reduced ADCC activity in comparison with the intact rhumAb1 drug product. This study provided insights into the stability profiling for rhumAb1 drug product. The study protocols presented here may be applicable to the analytical characterization of other monoclonal antibody-based therapeutic products.
ABSTRACT
Objective To compare the capability of capillary electrophoresis-sodium dodecyl sul-fate ( CE-SDS) and size exclusion-high performance liquid chromatography ( SE-HPLC) for analysis of size heterogeneity of monoclonal antibody products .Methods The size heterogeneity of one humanized anti-VEGF monoclonal antibody was analyzed by using non-reduced and reduced CE-SDS, and conventional , de-natured and denatured reduced SE-HPLC.Results The percentage of aggregates detected by non-reduced CE-SDS (0.82%±0.01%) was equal to that by using denatured SE-HPLC (1.05%±0.02%), but it was significantly lower than that by using conventional SE-HPLC analysis (5.08%±0.10%).With regard to fragments analyzed with non-reduced antibodies, its percentage was (7.12±0.04)% measured by non-re-duced CE-SDS analysis that was significantly higher than that by conventional SE -HPLC analysis (0.02%± 0.01%) and denatured SE-HPLC analysis (0.62%±0.01%).Using reduced antibodies , the percentage of fragments was (3.19±0.50)%tested by reduced CE-SDS analysis that was significantly higher than that by using denatured reduced SE-HPLC analysis (0.07%±0.01%).Conclusion Conventional SE-HPLC was more objective than CE-SDS for content analysis of aggregates , as both the covalent and non-covalent forms of aggregates could be detected .Non-reduced CE-SDS could demonstrate the content of clips , while reduced CE-SDS showed the degraded fragments .Therefore, CE-SDS had an advantage over conventional SE-HPLC for content analysis of fragments .The use of the two analytical methods in combination provided solid techni-cal supports for the quality control of size heterogeneity of monoclonal antibodies .