ABSTRACT
This study constructed a LHCGR-CRE-luc-HEK293 transgenic cell line according to the activation of the cAMP signaling pathway after recombinant human chorionic gonadotropin binding to the receptor. The biological activity of recombinant human chorionic gonadotropin was assayed using a luciferase assay system. The relative potency of the samples was calculated using four-parameter model. And the method conditions were optimized to validate the specificity, relative accuracy, precision and linearity of the method. The results showed that there was a quantitative potency relationship of human chorinonic gonadotropin (hCG) in the method and it was in accordance with the four-parameter curve. After optimization, the conditions were determined as hCG dilution concentration of 2.5 μg·mL-1, dilution ratio of 1∶4, cell number of 10 000-15 000 cells/well, and induction time of 6 h. The method had good specificity, relative accuracy with relative bias ranging from -8.9% to 3.4%, linear regression equation correlation coefficient of 0.996, intermediate precision geometric coefficient of variation ranging from 3.3% to 15.0%, and linearity range of 50% to 200%. This study successfully established and validated a reporter gene method to detect hCG biological activity, which can be used for hCG biological activity assay and quality control.
ABSTRACT
In this study, we established a novel bioassay to determine the activity of polyethylene glycolated recombinant human growth hormone (PEG-rhGH) using Nb2-11 cells. We performed experimental condition optimization and methodological verification, and then detected the relative potency of PEG-rhGH products using this method. We demonstrated that the bioactivity of PEG-rhGH in promoting Nb2-11 cell proliferation displays a dose-response relationship, which conformed to the four-parameter model. Using PEG-rhGH reference as a control, we analyzed the relative potency of six batches of PEG-rhGH products, as well as linearity, regression and parallelism of the obtained curves. The relative potency of six batches of PEG-rhGH products was 95% to 105%. These results implied that the new bioassay established may be employed in quality control of PEG-rhGH products.
ABSTRACT
The goal of this work was to explore the prospect of standardized application of an in-vitro bioactivity assay for recombinant human follicle-stimulating hormone based on a reporter gene. The relative accuracy, intermediate precision, linearity and applicable range of the method were validated according to the General Rules of Chinese Pharmacopoeia 2020 edition Volume IV (9401). Three laboratories used this method to determine the in-vitro biological activities of six batches of drug product and three batches of drug substance manufactured by two different companies. The consistency of the potency determined by three laboratories, the intra-laboratory precision and inter-laboratory precision were analyzed. The method was optimized during the collaborative validation. The results of method validation meet the requirements of the General Rules of Chinese Pharmacopoeia 2020 edition Volume IV (9401). Aiming to resolve the problems found in the collaborative validation, the medium for cell seeding, the pre-diluted buffer solution of standard and sample, and the means of removing and discarding supernatant after stimulation were optimized. After optimization, there was no significant difference in the bioactivity among the different laboratories (P > 0.05), indicating statistical equivalency. Intra-laboratory and inter-laboratory precision were good and the geometric coefficient of variation (GCV%) were both less than 15%. In conclusion, the reporter gene assay has good intra-laboratory repeatability and inter-laboratory reproducibility and is suitable for analyzing recombinant human follicle-stimulating hormone drug product and drug substance by different manufacturers. It is expected to be used as a standardized method for the determination of the in-vitro bioactivity of such products.