Method for monitoring stability of polysaccharide-protein conjugate vaccines

A method for determining the stability of a polysaccharide-protein conjugate vaccine comprising: a) performing high performance size exclusion liquid chromatography (HPLC-SEC, HPSEC, SEC-HPLC, SEC) on the vaccine, wherein the SEC (gel filtration, molecular sieve) comprises a set of three chromatography columns in series to obtain an eluate; b) passing the eluate through detectors to obtain the molecular weight (MW) distribution; and c) analysing the molecular weight and/or molar mass profile based on the percentage of high molecular weight (HMW), average molecular weight (AMW), and low molecular weight (LMW). The set of three chromatography columns may be connected with a guard column. The columns may have different particle sizes. The detector may be an ultraviolet (UV) detector, refractive index detector (RI), or multiangle light scattering (MALS) detector. The polysaccharide may be a bacterial capsular polysaccharide, such as a bacterial polysaccharide from Neisseria meningitidis (N. meningitidis) for example. The protein may be a carrier protein, such as CRM197, diphtheria toxin/toxoid (DT), or tetanus toxin/toxoid (TT) for example. The vaccine may be multivalent or monovalent. The invention uses HPLC-SEC to analyse a multivalent meningitidis vaccine (MenFive), wherein high molecular weights indicate aggregation and low molecular weights indicate degradation into free saccharides or protein/peptides.