Alignment of absolute and relative molecular size specifications for a polyvalent pneumococcal polysaccharide vaccine (PNEUMOVAX®23)

An approach was developed to align release and end-expiry specifications for molecular size for the polyvalent pneumococcal polysaccharide vaccine (PNEUMOVAX®23). Each of the 23 polysaccharide components of the vaccine was separately subjected to ultrasonication to produce a series of preparations of decreasing weight-average molecular mass (Mw). These size-reduced polysaccharides were analysed as monovalent solutions by high-performance size exclusion chromatography (HPSEC) with multi-angle laser light scattering (MALLS) and refractive index (RI) detection to measure their Mw. These samples were also analysed by HPSEC with rate nephelometry (RN) detection to measure their relative molecular size (r-MS). The data from the two molecular size measurements established a correlation between Mw and r-MS. For each polysaccharide component of the vaccine, this correlation permits the direct alignment of the r-MS specification in the final formulated product with the Mw specification for the monovalent polysaccharide preparation. The alignment of specifications provides a high level of assurance that the quality control of the final vaccine product is consistent with that of the polysaccharide starting materials.