QUANTIFICATION OF POLYSACCHARIDE IN HAEMOPHILUS-INFLUENZAE TYPE-B CONJUGATE AND POLYSACCHARIDE VACCINES BY HIGH-PERFORMANCE ANION-EXCHANGE CHROMATOGRAPHY WITH PULSED AMPEROMETRIC DETECTION

A sensitive method for the quantification of polysaccharide (PS) in Ha emophilus influenzae type b (Hib) conjugate and PS vaccines has been d eveloped. It is based on measurement of the Hib PS subunit after depol ymerization of the PS in sodium hydroxide to produce the subunit, whic h is characterized by chemical composition and P-31 n.m.r. analyses as ribitol-ribose-phosphate. The Hib vaccines were first treated with 0. 1 M sodium hydroxide. The Hib PS subunit in the treated vaccines was t hen analysed directly by high-performance anion-exchange chromatograph y using a CarboPak PA-1 column, and quantified by pulsed amperometric detection. The PS contents of three conjugate vaccines and three PS va ccines from different manufacturers were determined. Their values were in the expected ranges. This method is particularly useful for vaccin es with a sugar stabilizer such as lactose which would interfere with the colorimetric orcinol assay currently used for determination of the PS. The method can measure 0.1 mu g of PS and its sensitivity is at l east 30-fold higher than that of the orcinol assay. It may be used for stability studies of conjugate vaccines since a breakdown as low as 5 % of the PS from the PS-protein conjugates would be detected.