Preparation of pH Sensitive Pluronic-Docetaxel Conjugate Micelles to Balance the Stability and Controlled Release Issues

A novel polymer-drug conjugate was prepared by the chemical reaction between the copolymer Pluronic P123 and the docetaxel via a pH sensitive hydrazone bond. These pluronic P123-docetaxel (DTX) conjugates (P123-DTX) could form the stable drug-loaded materials that can self-assemble into the defined nano-micelles in aqueous solution because of their obvious amphiphilic property and low critical micelle concentration. The spherical morphology and particle size of the prepared nano-micelles were characterized by transmission electron microscopy and dynamic light scattering, respectively. Moreover, after the introduction of pH sensitive hydrazone bond, P123-DTX micelle showed a pH dependent drug release behavior. At pH 5.0 (in 48 h), the cumulative release amount of DTX were ~84.9%, which is about six times higher than that at pH 7.4. The prepared novel p123-DTX conjugates may offer a great benefit for drug delivery and controlling the drug release.