Quantitative analysis of factor P (Properdin) in monkey serum using immunoaffinity capturing in combination with LC-MS/MS

Aim: Factor P (Properdin), an endogenous glycoprotein, plays a key role in innate immune defense. Its quantification is important for understanding the pharmacodynamics (PD) of drug candidate(s). Results: In the present work, an immunoaffinity capturing LC-MS/MS method has been developed and validated for the first time for the quantification of factor P in monkey serum with a dynamic range of 125 to 25,000 ng/ml using the calibration standards and QCs prepared in factor P depleted monkey serum. The intra-and inter-run precision was <= 7.2% (CV) and accuracy within +/- 16.8% (% Bias) across all QC levels evaluated. Results of other evaluations (e.g., stability) all met the acceptance criteria. Conclusion: The validated method was robust and implemented in support of a preclinical PK/PD study.