An approach was developed to align release and end-expiry specifi cations for molecular size for the quality control of Merck’s polyvalent pneu-

mococcal polysaccharide vaccine (PNEUMOVAX®23). Each of the 23 polysaccharide components of the vac-cine was separately subjected to ultrasonication to pro-duce a series of preparations of decreasing weight-aver-age molar mass (Mw).

These size-reduced polysaccharides were ana-lyzed as monovalent solutions by high-performance size exclusion chromatography (HPSEC) with multi-angle light scattering (MALS) and refractive index (RI) detection to measure their absolute Mw

1. Analyses were performed with a miniDAWN and Optilab.

These samples were also analyzed as polyvalent formulations by HPSEC with rate nephelometry (RN) detection to measure their relative molecular size (r-MS) based on chromatographic elution volumes2. The data from the two distinct molecular size analyses were used to establish a correlation between Mw and r-MS for each polysaccharide component of the vaccine. This correlation permitted the determination of each polysaccharide’s r-MS end-expiry specifi cation for the fi nal formulated product that is in alignment with the corresponding monovalent polysaccharide Mw release specifi cation.

The alignment of specifi cations provides a high level of assurance that the quality control of the fi nal vaccine product is consistent with that of the poly-saccharide starting materials. This work was recently published3 in Biologicals.

1 Bednar, B., Hennessey, J. P., Jr. Molecular Size Analysis of Capsular Poly-saccharide Preparations from Streptococcus pneumoniae. Carbohydr Res, 243, 115-130 (1993).

2 Sweeney, J. A., Sumner, J. S. and Hennessey, J. P., Jr. Simultaneous Evalua-tion of Molecular Size and Antigenic Stability of PNEUMOVAX®23, a Mul-tivalent Pneumococcal Polysaccharide Vaccine. In: Brown, Corbel, Griffi ths, editors. Physico-Chemical Procedures for the Characterization of Vaccines: Dev Biol, 103, 11-26 (2000).

3 MacNair, J., Desai, T., Teyral, J., Abeygunawardana, C., and Hennessey, J. P., Jr. Alignment of Absolute and Relative Molecular Size Specifi cations for a Polyvalent Pneumococcal Polysaccharide Vaccine (PNEUMOVAX®23). Biologicals, 33, 49-58 (2005).

Polyvalent Pneumococcal Polysaccharide Vaccine (PNEUMOVAX®23)

DAWN®, miniDAWN®, ASTRA®, Optilab®, DynaPro®, Protein Solutions® and the Wyatt Technology logo are registered trademarks of Wyatt Technology Corporation. ©2005 Wyatt Technology Corporation

Light Scattering for the Masses™

This note graciously submitted by J. MacNair, T. Desai, J. Teyral, C. Abeygu-nawardana, and J. Hennessey, Jr., Merck Research Laboratories, P.O. Box 4, Sumneytown Pike, West Point, PA

Figure 1. HPSEC/MALS/RI analysis of serotype 19A polysac-charide prior to ultrasonic size reduction (Mw = 270 kDa).Figure 1. HPSEC/MALS/RI analysis of serotype 19A polysac-

Figure 2. HPSEC/MALS/RI analysis of serotype 19A poly-saccharide after 360 minutes of ultrasonic size reduction (Mw = 110 kDa).