A density-functional model for controlled release

Multiple Drug Delivery from Mesoporous Coating Realizing Combination Therapy for Bare Metal Stents

The simultaneous loading of multifunctional drugs has been regarded as one of the major challenges in the drug delivery system. Herein, a mesoporous silica coating was constructed on a bare metal stent surface by an evaporation-induced self-assembly method, in which both hydrophilic and hydrophobic drugs (heparin and rapamycin) were encapsulated by a one-pot method for the first time, and the release behaviors of these drugs were studied. The releasing mechanisms of these drugs were investigated in detail. Rapid release of heparin can achieve anticoagulation and endothelialization, whereas slow release of rapamycin can realize antiproliferative therapy for long term. In vitro hemocompatibility and promotion for proliferation of vein endothelial cells and the inhibition of smooth muscle cells were conducted. In vivo stent implantation results verify that the mesoporous silica coating with both heparin and rapamycin can successfully accelerate the endothelialization process and realize the antiproliferative therapy for as long as 3 months. These results indicate that this multifunctional mesoporous coating containing both hydrophilic and hydrophobic drugs might be a promising stent coating in the future.

Preparation and characterization of intravenously injectable curcumin nanosuspension

The interest in nanosuspensions by the pharmaceutical industry is increasing given several nanosuspension products currently on the market for poorly soluble drugs. In this study, a novel dosage form for curcumin (CUR), CUR nanosuspension (CUR-NS), was successfully prepared by high pressure homogenization to improve CUR's cytotoxicity, as well as improve its application via intravenous injection. Characterization of the CUR-NS was evaluated by morphology, size, zeta potential, solubility, dissolution rate, and crystal state of drug. The nanoparticles for CUR-NS presented a sphere-like shape under transmission electron microscopy with an average diameter of 250.6 nm and the zeta potential of CUR-NS was -27.92 mV. Solubility and dissolution rate of CUR in the form of CUR-NS were significantly increased due to the small particle size and the crystalline state of CUR was preserved to increase its stability against degradation. Superior cytotoxicity in Hela and MCF-7 cells was obtained for CUR-NS compared with CUR solution. The safety evaluation showed that, compared with the CUR solution, CUR-NS provided less local irritation and phlebitis risks, lower rate of erythrocyte hemolysis. These findings suggest that CUR-NS may represent a promising new drug formulation for intravenous administration in the treatment of certain cancers.