Self-assembled hydrophobic honokiol loaded MPEG-PCL diblock copolymer micelles.

PURPOSE: Honokiol showed potential application in cancer treatment, but its poor water solubility restricts its clinical application greatly. So, we designed a self-assembled monomethoxy poly(ethylene glycol)-poly(epsilon-caprolactone) (MPEG-PCL) micelle to load honokiol to overcome its poor water solubility. METHODS: We synthesized MPEG-PCL diblock copolymer that could self-assemble into monodisperse micelles at the particle size of ca.18 nm in water. Honokiol was loaded into MPEG-PCL micelle by direct dissolution method assisted by ultrasound, without any surfactants, organic solvents, and vigorous stirring. RESULTS: The blank MPEG-PCL micelles (100 mg/mL) did not induce any hemolysis in vitro and showed very low toxicity ex vivo and in vivo. Honokiol could be molecularly incorporated into MPEG-PCL micelles at the drug loading of about 20% by direct dissolution method assisted by ultrasound. After loaded into MPEG-PCL micelles, honokiol maintained its molecular structure and anticancer activity in vitro. Honokiol could be sustained released from MPEG-PCL micelles in vitro. The honokiol loaded MPEG-PCL micelles could be lyophilized without any adjuvant. CONCLUSION: The prepared honokiol formulation based on self-assembled MPEG-PCL micelle was stable, safe, effective, easy to produce and scale up, and showed potential clinical application.

Poly(epsilon-caprolactone)/poly(ethylene glycol)/poly(epsilon-caprolactone) nanoparticles: preparation, characterization, and application in doxorubicin delivery.

Biodegradable poly(epsilon-caprolactone)/poly(ethylene glycol) (PCL/PEG) copolymer nanoparticles showed potential application in drug delivery systems. In this article, monodisperse poly(epsilon-caprolactone)/poly(ethylene glycol)/poly(epsilon-caprolactone) (PCL/PEG/PCL, PCEC) nanoparticles, approximately 40 nm, were prepared by solvent extraction method using acetone as the organic solvent. These PCL/PEG/PCL nanoparticles did not induce hemolysis in vitro and did not show toxicity in vitro or in vivo. The prepared PCL/PEG/PCL nanoparticles were employed to load doxorubicin by a pH-induced self-assembly method. In vitro release study indicated that doxorubicin release from nanoparticles at pH 5.5 was faster than that at pH 7.0. The encapsulation of doxorubicin in PCL/PEG/PCL nanoparticles enhanced the cytotoxicity of doxorubicin on a C-26 cell line in vitro. Meanwhile, compared with free doxorubicin, doxorubicin in nanoparticles could more efficiently treat mice bearing subcutaneous C-26 tumors. The doxorubicin-loaded PCL/PEG/PCL nanoparticles might be a novel doxorubicin formulation for cancer therapy.