Hyaluronic acid-paclitaxel conjugate micelles: synthesis, characterization, and antitumor activity.

Chemical conjugates of paclitaxel and hyaluronic acid (HA) were synthesized by utilizing a novel HA solubilization method in a single organic phase. Hydrophilic HA was completely dissolved in anhydrous DMSO with addition of poly(ethylene glycol) (PEG) by forming nanocomplexes. Paclitaxel was then chemically conjugated to HA in the DMSO phase via an ester linkage without modifying extremely hydrophilic HA. A series of HA-paclitaxel conjugates with different conjugation percentages were synthesized and characterized. HA-paclitaxel conjugates self-assembled in aqueous solution to form nanosized micellar aggregates, as characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). An intact form of paclitaxel was regenerated from HA-paclitaxel conjugate micelles at acidic pH conditions. HA-paclitaxel conjugate micelles exhibited more pronounced cytotoxic effect for HA receptor overexpressing cancer cells than for HA receptor deficient cells, suggesting that they can be potentially utilized as tumor-specific nanoparticulate therapeutic agents.