Evaluation of spectrophotometric methods for determination of proteins in capsular polysaccharide of haemophilus influenzae type b (PRP)

Abstract

Haemophilus influenzae type b (Hib) bacteria that occur worldwide can cause serious infectious diseases that may lead to death. Vaccines made from Hib capsular polysaccharide (polyribosyl ribitol phosphate; 5-D-ribitol-(1 1)-D-ribose-3-phosphate; PRP) can prevent against these diseases. In PRP purification, the major contaminants (nucleic acids, proteins and endotoxins) are selectively removed and the classic Lowry method has been used in quality control for protein quantification, but has been shown to be inadequate for the level of this impurity found in PRP. This work aimed to select a suitable spectrophotometric method for the determination of residual protein levels in PRP samples. The results indicated the superiority of the Peterson method, with sesitiit of . ?g L-1, uatifiatio liits of . ?g L-1, precision of 5.0% and accuracy of 97%.