VALIDATION OF THE PROCEDURE FOR DETERMINING TOTAL PROTEIN/PROTEIN BOUND CONTENT IN THE PREVENAR VACCINE USING THE MODIFIED LOWRY METHOD

Abstract

The Modified Lowry method was validated for determining total protein and protein-bound content in the Prevenar vaccine (Pfizer). The procedure was fully validated according to ISO/IEC 17025:2017, including the following parameters: linearity, accuracy, precision (repeatability and intermediate precision), specificity, and limit of quantification (LOQ). The results showed that the method has high linearity (R² = 0.9929–0.9960), good repeatability with CV = 1.24% (total protein) and 1.16% (protein-bound), intermediate precision with CV = 2.11% and 1.87%, respectively. Recovery ranged from 95.66–107.91% (calibration standards) and 98.46–102.58% (spiked samples). The method demonstrated good specificity. The experimental LOQ was determined to be 5.11 µg/ml. The expanded measurement uncertainty (k = 2) was 4.25% for total protein and 3.81% for protein-bound content. The method fully meets the requirements and is suitable for routine quality control of the Prevenar vaccine in Vietnam.