Determination of different types of polysaccharides in 23-valent pneumococcal polysaccharide vaccine by rate nephelometry

Objective To develope rate nephelometry (RN) for accurate determination of different types of polysaccharides (PSs) in 23-valent pneumococcal polysaccharide vaccine (PPV23). Methods The 23-valent PS references and anti-sera were prepared. The RN for determination of different types of PSs in PPV23 was developed. The linearity, precision, accuracy, and specificity of the developed RN were validated. The application research was carried out using the RN within the quality control range. Results Under the designed condition, when PS concentrations were in a range of 1.0-5.0 μg/ml, a good linear correlation was shown between PS concentration and its corresponding instrumental response value with coefficient of determination>0.99. The method had good precision and accuracy. The coefficients of variation of intra- and inter-assay were 0.50%-4.98% and 2.81%-9.52%, respectively, and the adding recovery rates were 90.3%-118.8%. The specificity of the method was good as the pneumococcal anti-sera only reacted with homotype PS, not heterotype PSs. The application research showed that the RN could accurately detect different types of PSs in PPV23. Conclusion The developed RN can effectively control the internal quality of PPV23, and can be applied to determination of different types of PSs in PPV23. Key words: Pneumococcal vaccines; Nephelometry and turbidimetry; Polysaccharides