Determination of the concentration and size-distribution of residual capsular poly(N-acetyl neuraminic acid) from outer membrane vesicle vaccines by micellar electrokinetic capillary chromatography.

BACKGROUND

Vaccines based on Outer Membrane Vesicles (OMVs) against Neisseria meningitidis require the quantification and characterization of residual capsular polysaccharides (CapsPS) that are not completely removed during the production process. This task is challenging due to the complexity of the CapsPS composition and the presence of OMVs in the samples.

RESULTS

Micellar Electrokinetic Chromatography (MEKC) using a negatively charged polyelectrolyte multilayer coating (SMIL) enabled complete separation of CapsPS and OMV residues in approximately 40 min. The use of a 4-layer SMIL coating was crucial for achieving good repeatability of migration times (tm). The method allowed the quantification of CapsPS at concentrations between 80 and 600 mg L-1. The average number and weight degrees of polymerization were also determined for each batch of OMVs, with polydispersity indexes between 1.2 and 1.5 and degrees of polymerization (DPn) between 30 and 70.

SIGNIFICANCE: This method can be readily implemented in the pharmaceutical industry for the monitoring and documentation of process development.