Development, Optimization, and Validation of an <i>in vitro</i> Cell-Based Bioassay to Determine the Biological Activity of Teriparatide (PTH1–34)

Abstract

This study aimed to establish an efficient in vitro cell-based assay to measure the activity of teriparatide (PTH1–34). In this study, a rat osteosarcoma cell line (UMR-106) was treated with various concentrations of PTH1–34, and the biological activity of PTH1–34 was determined by quantitatively measuring intracellular cyclic adenosine monophosphate levels using a time-resolved fluoroimmunoassay. A four-parameter fitting analysis was used to calculate the relative potency of the samples. The experimental conditions were optimized. The method's specificity, relative accuracy, precision, and linearity were validated. Our data suggested that this method had good specificity, a relative bias of relative accuracy ranging from −0.8 to 1.4%, a correlation coefficient for the linear regression equation of 0.9953, a geometric coefficient of variation for intermediate precision ranges from 2.0 to 3.5%, and a linear range of 50 to 150%. This method significantly improves the quality control and release inspection efficiency of PTH1–34 and may be further developed and validated as an alternative to the existing United States Pharmacopeia and European Pharmacopoeia inclusion methods. This method also provides a platform for the high-throughput screening of PTH1–34 analogs.

Keywords

• teriparatide
• in vitro bioassay
• cAMP
• time-resolved fluoroimmunoassay
• method verification