The method of capillary electrophoresis for quantitative determination of hydrophobized hyaluronic acid in its micellar forms

Micelles based on hydrophobized hyaluronic acid (HA) are frequently used in targeted drug delivery systems. Capillary zone electrophoresis (CZE) was utilized for the quantitative determination of hydrophobized and native HA. A universal methodology was developed, suitable for the quantitative analysis of amphiphilic derivatives of hyaluronan (oleyl hyaluronan and hyaluronan conjugate with naphthalimide fluorophore) and native HA with varying molecular weights (15, 150, and 800 kDa). Furthermore, methodologies were proposed for the simultaneous quantification of a drug substance and oleyl hyaluronan in micellar forms based on the latter. The CE technique was applied for analyzing oleyl-hyaluronan-based micellar forms of two poorly soluble drug substances with oppositely charged ionic forms (loperamide and rifabutin). The examples contained in the study demonstrate a range of analytical sensitivity (LOD) for hyaluronan from 11 to 40 μg/mL and for the drug substance from 0.4 to 0.6 μg/mL. The study also showcases the accurate quantitative determination of rifabutin and loperamide in oleyl-hyaluronan-based micellar forms without the need for sample preparation. Thus, the proposed methodologies can be used to quantify native HA or its amphiphilic derivatives and simultaneously determine drug substances of various nature.