Di Xiang

pH-responsive controlled-release system based on mesoporous bioglass materials capped with mineralized hydroxyapatite

A controlled release system with pH-responsive ability has been presented. Mesoporous bioglass (MBG) was used as the drug carrier and a spontaneous mineralization method was adopted to cap the pores of the carrier with hydroxyapatite (HAp) and to restrict the drug release. It is a simple and green method to realize the ingenious pH-sensitive controlled release. The model drug, metformin hydrochloride (MH), was loaded simultaneously with the mineralization process. Due to the degradation of HAp at acid environments, the system shows well pH-sensitive drug release ability. The release kinetics can be easily adjusted by the mineralization time and the ion concentration of media. The system is recommended as a promising candidate as a pH-sensitive vehicle for drug controlled release to low pH tissues, such as inflammatory sites and tumors.

Hierarchical porous bioactive glasses/PLGA-magnetic SBA-15 for dual-drug release

The hierarchical porous bioglass combined with magnetic SBA-15 was synthesized. The bioactive glass materials possess a hierarchical porous structure with the macroporous (50μm) and the mesoporous (3.86nm) structures derived from the plant template (cattail stem) and triblock polyethylene oxide-propylene oxide block copolymer (P123), respectively. Magnetic SBA-15 was synthesized by adopting the post assembly method using Fe(NO3)3 as iron source and ethylene glycol as reduction. After coating PLGA, PLGA-IBU-magnetic SBA-15 also possessed super-paramagnetism and the corresponding saturation magnetizations (Ms) could reach 2.6emug(-1). Metformin HCl (MH) and ibuprofen (IBU) were used as model drugs, and the drug release kinetics was studied. MH and IBU could release 60% and 85% from the sample respectively. The system shows excellent dual-drug controlled delivery performance and good bioactivity in vitro that leads to good potential application on bone regeneration.

Synthesis of hierarchical porous bioactive glasses for bone tissue regeneration

A novel hierarchical porous bioactive glasses were synthesised with cattail stem and triblock polyethylene oxide-propylene oxide block copolymer (P123) as macroporous template and mesoporous template, respectively. The structural and textural properties of materials were characterised by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption, energy dispersive spectrometer and vibrating sample magnetometer technique. The results reveal the bioglasses possess multilevel porous structure with the macroporous size about 50 μm and the mesopore with the diameter of 3.86 nm. Furthermore, metformin HCl was used as the model drug. The drug release kinetics and hydroxyapatite (HAP, (Ca10(PO4)6(OH)2)) inducing-growth ability of the composites were studied, respectively. The system exhibits the fast HAP inducing-growth ability and long-term drug delivery, making them a good candidate for bone tissue regeneration.

A novel pH-responsive controlled release system based on mesoporous silica coated with hydroxyapatite

With well bioactive and nontoxic, hydroxyapatite (HAp) was employed to seal the nanopores of mesoporous silica (MCM-41) to realize the pH-responsive controlled release. First, MCM-41 was modified with cationic polymer, poly-(diallyldimethylammoniumchloride) (PA). And after the addition of Ca2+/PO43−, HAp precipitation can take place based on the cationic sites derived from PA. It is a simple and effective way to obtain HAp coating MCM-41 system (MHAs). The structure of the system was characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, N2 adsorption–desorption and so on. Metformin hydrochloride was used as the model drug, and the drug release performance and the release kinetics of the system were investigated in detail. Because of the degradation of HAp under acid condition, the drug loading MHAs showed a well pH-sensitive controlled release behavior. From above investigation, MHAs is a promising platform to construct a pH-responsive controlled drug delivery system, especially for some low pH tissues, such as inflammatory and tumor.

Simple way to obtain pH-sensitive drug release from functional mesoporous silica materials.

A novel pH-sensitive drug release system has been synthesised by functional mesoporous silica materials. SBA-15, calcium modified SBA-15 (Ca-SBA-15) and phosphate modified SBA-15 (PO4-SBA-15) were synthesised using solvent evaporation method. It is a simple and feasible way to prepare the doping mesoporous silica materials. They show the large surface are, high pore volume and uniform pore size. Metformin hydrochloride was used as the model drug, and the control release behaviour was investigated. The functional mesoporous silica materials show the pH sensitive drug release behaviour because of the adjustable interaction between the drug molecule and the host.