Exogenous administration of
chondroitin sulfate (CS) is widely practiced for the treatment of
osteoarthritis, although the efficacy of this treatment has not been completely established by clinical studies. A reason for the inconsistency of the results may be the quality of the CS preparations, which are commercially available as dietary supplements. In this article, we describe the development of a new method of capillary electrophoresis (CE) for the quantification of CS concentrations, screening for other
glycosaminoglycan or
DNA impurities and determination of
hyaluronan impurities in CS raw materials,
tablets, hard capsules, and liquid formulations. Analysis is performed within 12 min in bare fused
silica capillaries using reversed polarity and an operating
phosphate buffer of low pH. The method has high sensitivity (lower limit of quantitation [LLOQ] values of 30.0 microg/ml for CS and 5.0 microg/ml for
hyaluronan), high precision, and accuracy. Analysis of 11 commercially available products showed the presence of
hyaluronan impurities in most of them (up to 1.5%). CE analysis of the samples
after treatment with
chondroitinase ABC and ACII, which depolymerize the chains to unsaturated
disaccharides, with a previously described method (Karamanos et al., J. Chromatogr. A 696 (1995) 295-305) confirmed the results of
hyaluronan determination and showed that the structural characteristics (i.e.,
disaccharide composition) of CS are very different, showing the different species or tissue origin and possibly affecting the therapeutic outcome.