New approaches for quantifying hyaluronic acid in pharmaceutical semisolid formulations using HPLC and CZE

HA was quantified in pharmaceutical formulations using HPLC-UV-detector and spectrophotometrically after the digestion with concentrated H(2)SO(4). Intact HA was quantified by capillary zone electrophoresis (CZE) using direct and indirect methods. The results were compared with the carbazole reaction established by Bitter et al. (Anal. Biochem. 4 (1997) 330) and with established method from Pläzer et al. (J. Pharm. Biomed. Anal. 21 (1997) 491) regarding detection limits, linearity, reproducibility and simplicity. The present results show that the investigation using HPLC and CZE led to a considerable improvement of the detection limit [0.3 ng/ml (HPLC1), 1 microgram/ml (HPLC2) and 5 microgram/ml (CE-D1)] compared with other methods (10 microgram/ml).