Phenylboronic acid-based complex micelles with enhanced glucose-responsiveness at physiological pH by complexation with glycopolymer.

Polymeric nanoparticles with glucose-responsiveness under physiological conditions are of great interests in developing drug delivery system for the treatment of diabetes. Herein, glucose-responsive complex micelles were prepared by self-assembly of a phenylboronic acid-contained block copolymer PEG-b-P(AA-co-APBA) and a glycopolymer P(AA-co-AGA) based on the covalent complexation between phenylboronic acid and glycosyl. The formation of the complex micelles with a P(AA-co-APBA)/P(AA-co-AGA) core and a PEG shell was confirmed by HNMR analysis. The glucose-responsiveness of the complex micelles was investigated by monitoring the light scattering intensity and the fluorescence (ARS) of the micelle solutions. The complex micelles displayed an enhanced glucose-responsiveness compared to the simple PEG-b-P(AA-co-APBA) micelles and the sensitivity of the complex micelles to glucose increased with the decrease of the amount of P(AA-co-AGA) in the compositions. The cytotoxicity of the polymers and the complex micelles was also evaluated by MTT assay. This kind of complex micelles may be an excellent candidate for insulin delivery and may find application in the treatment of diabetes.

Development of liposomal Ginsenoside Rg3: formulation optimization and evaluation of its anticancer effects.

The Ginsenoside Rg3 has been shown to possess antiangiogenic and anticancer properties. Because of its limited water solubility, we decided to design and synthesize liposomal Rg3 (L-Rg3), to optimize preparation conditions, and to investigate further whether liposome could enhance the anticancer activity of Rg3. L-Rg3 was prepared using a film-dispersion method and the preparation conditions were optimized with response surface methodology (RSM). The mean encapsulation efficiency (EE) of 82.47% was close to the predicted value of 89.69%. Therefore, the optimized preparation condition was predicted correctly. We evaluated the cytotoxicity, pharmacokinetics, biodistribution and antitumor activities of L-Rg3. HepG2 and A549 cells were treated with Rg3 or L-Rg3 at different concentrations in vitro. Pharmacokinetics and biodistribution studies were carried out in Wistar rats. Tumor model was established by inoculating a suspension of A549 cells into BALB/c nude mice. The mice were divided into Saline, Rg3 solution, and L-Rg3 groups with the drug given by i.p. injection. Survival of the mice and tumor volume were monitored. In addition, CD34 immunohistochemical analysis was used for measuring microvessel density (MVD) of the tumor tissues. The cytotoxicity and ratio of tumor inhibition of L-Rg3 group were significantly higher than the Rg3 solution group. MVD values in the Rg3 solution and L-Rg3 groups decreased, especially in the L-Rg3 group. Compared to Rg3 solution, the L-Rg3 showed increased Cmax and AUC of Rg3 by 1.19- and 1.52-fold, respectively. This liposomal formulation could potentially produce a viable clinical agent for improving the anticancer activity of Rg3.