Effects of Calibration Approaches on the Accuracy for LC鈥揗S Targeted Quantification of Therapeutic Protein
详细信息 查看全文
- 作者：Eslam Nouri-Nigjeh ; Ming Zhang ; Tao Ji ; Haoying Yu ; Bo An ; Xiaotao Duan ; Joseph Balthasar ; Robert W. Johnson ; Jun Qu
- 刊名：Analytical Chemistry
- 出版年：2014
- 出版时间：April 1, 2014
- 年：2014
- 卷：86
- 期：7
- 页码：3575-3584
- 全文大小：594K
- 年卷期：v.86,no.7(April 1, 2014)
- ISSN：1520-6882
文摘
LC鈥揗S provides a promising alternative to ligand-binding assays for quantification of therapeutic proteins and biomarkers. As LC鈥揗S methodology is based on the analysis of proteolytic peptides, calibration approaches utilizing various calibrators and internal standards (I.S.) have been developed. A comprehensive assessment of the accuracy and reliability of these approaches is essential but has yet been reported. Here we performed a well-controlled and systematic comparative study using quantification of monoclonal-antibody in plasma as the model system. Method development utilized a high-throughput orthogonal-array-optimization, and two sensitive and stable signature-peptides (SP) from different domains were selected based on extensive evaluations in plasma matrix. With the purities of all protein/peptide standards corrected by quantitative amino acid analysis (AAA), five calibration approaches using stable-isotope-labeled (SIL) I.S. were thoroughly compared, including those at peptide, extended-peptide, and protein levels and two 鈥渉ybrid鈥?approaches (i.e., protein calibrator with SIL-peptide or SIL-extended-peptide I.S.). These approaches were further evaluated in parallel for a 15 time point, preclinical pharmacokinetic study. All methods showed good precision (CV% < 20%). When examined with protein-spiked plasma QC, peptide-level calibration exhibited severe negative biases (鈭?3 to 鈭?2%), highly discordant results between the two SP (deviations of 38鈥?6%), and misleading pharmacokinetics assessments. Extended-peptide calibration showed significant improvements but still with unacceptable accuracy. Conversely, protein-level and the two hybrid calibrations achieved good quantitative accuracy (error < 10%), concordant results by two SP (deviations < 15%), and correct pharmacokinetic parameters. Hybrid approaches were found to provide a cost-effective means for accurate quantification without the costly SIL-protein. Other key findings include (i) using two SP provides a versatile gauge for method reliability; (ii) evaluation of peptide stability in the matrix before SP selection is critical; and (iii) using AAA to verify purities of protein/peptide calibrators ensures accurate quantitation. These results address fundamental calibration issues that have not been adequately investigated in published studies and will provide valuable guidelines for the 鈥渇it for purpose鈥?development of accurate LC鈥揗S assays for therapeutic proteins and biomarkers in biological matrices.