Prospects for ion chromatography in quality assessment of biologicals

Quantitative characterisation of excipients in biologicals is an important part of the quality assurance process both at the level of finished products and intermediates, as well as active pharmaceutical ingredients. Ion chromatography with amperometric and conductometric detection of separation products has a number of advantages. The main of the advantages is the possibility of direct determination of semivolatile compounds that have neither chromophoric groups, nor intrinsic fluorescence. The aim of this study was to compare ion chromatography with alternative methods in order to identify promising areas for its use in assessing the quality of biologicals. The authors analysed regulatory documents and literature and summarised the methods applied for quantitative determination of ionic excipients in biological medicinal products. The authors investigated the possibility of using ion chromatography for determination of the main active pharmaceutical ingredient in polysaccharide vaccines and excipients in biologicals. The study demonstrated the feasibility of ion chromatography for simultaneous quantitation of cations (ammonium, calcium, magnesium) and anions (chlorides, sulfates, nitrates) in reconstitution solvents for lyophilised biologicals; quality assessment of active pharmaceutical ingredients in biologicals (quantitative analysis of polysaccharides in polysaccharide vaccines, profiling of glycosylated proteins, etc.); and determination of several carbohydrate stabilisers in biologicals with the same analytical procedure. According to the conclusions, ion-exchange chromatography with conductometric and amperometric detection, aimed at quality assessment of biological products, can shortly take a leading position in quantitation of ionic excipients, carbohydrate stabilisers, and main active ingredients (polysaccharides) in polysaccharide vaccines, including the vaccines in the immunisation schedule.