The determination of phosphorus in Haemophilus influenzae type b conjugatevaccines by inductively coupled plasma-atomic emission spectrometry

This study describes a method for the determination of phosphorus in lyophi lized Haemophilus influenzae type b conjugate vaccines by inductively coupl ed plasma-atomic emission spectroscopy (ICP-AES). The concentration of poly saccharide is directly related to the concentration of phosphorus as measur ed in the laboratory. Phosphorus is present in the polyribosyl-ribitol phos phate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. T he repeating unit of PRP is 3-B-D ribose[1-1]ribitoi-5-phosphate. Phosphoru s in the final container is measured in mug per dose. The amount of PRP is calculated from this and reported in mug per dose. The Haemophilus influenz ae type b conjugate vaccine was analyzed for phosphorus content within the range of 1.34 to 2.02 mug phosphorus per mi. The relative difference of pho sphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2.2 to 10.6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1.93+/-0.13 mug P/ml). The phosphorus determination of NIS T SRM 3139 phosphorus spectrometric solution differed by 30% from the certi fied phosphorus value (1000 mg P/ml).