Preparation, in vitro release and antibacterial activity evaluation of rifampicin and moxifloxacin-loaded poly(D,L-lactide-co-glycolide) microspheres.

Osteomyelitis is difficult to treat because infective bone is poorly accessible for intravenously administering antibiotics and biofilm formation increases bacterial resistance. In this study, microspheres prepared using poly(lactide-co-glycolide) (PLGA) and embedded with moxifloxacin (MOX-PLGA microspheres) and rifampicin/moxifloxacin (RIF/MOX-PLGA microspheres) using the water-in-oil-in-water double emulsion solvent evaporation technique were used for local delivery. Shape of MOX-PLGA microspheres and RIF/MOX-PLGA microspheres were spherical, mean particle size of them were 20.52 µm and 16.62 µm, respectively. Encapsulation efficiency of the MOX-PLGA microspheres was 17.35% ± 2.42%. However, the encapsulation efficiency for MOX and RIF in RIF/MOX-PLGA microspheres was 33.25% ± 7.51% and 49.0% ± 11.25%, respectively. Moxifloxacin and rifampicin were released slowly from microspheres. Both microspheres can efficiently release antibiotics in vitro. Antibacterial and bacterial biofilm-inhibition properties of the released solution were investigated from RIF/MOX-PLGA, MOX-PLGA, and blank PLGA microspheres at varying time points in vitro. RIF/MOX-PLGA microspheres demonstrated the strongest antibacterial activity and bacterial biofilm-inhibition property than the other two microspheres (p < .05). This study suggests that the novel RIF/MOX-PLGA microspheres can be used as a promising carrier for osteomyelitis treatment.

Preparation and in vitro study of hydrochloric norvancomycin encapsulated poly (d,l-lactide-co-glycolide, PLGA) microspheres for potential use in osteomyelitis.

HNV-loaded PLGA microspheres (HNV-PLGA MSs) were prepared by water-in-oil-in-water (w/o/w) double emulsion solvent evaporation technique. The surface of prepared HNV-PLGA MSs is smooth and nonporous with an average diameter of 69.9 µm. The drug-loading rate and encapsulation rate of HNV-PLGA MSs are 4.40 ± 0.26% and 48.51 ± 14.83%, respectively. Additionally, 43.36% of HNV was released from PLGA MSs after seven days of incubation. The antibacterial effects of HNV released from PLGA were as good as the pure HNV. HNV-loaded PLGA microspheres were successfully prepared using double emulsion solvent evaporation technique and their properties met the requirements for local anti-infection.

Mechanical properties and in vitro bioactivity of injectable and self-setting calcium sulfate/nano-HA/collagen bone graft substitute.

Calcium sulfate hemihydrate (CSH) was introduced into the mineralized collagen (nHAC) to prepare an injectable and self-setting in situ bone graft substitute. The mechanical properties of materials, which are dependant on the L/S ratio, the content of nHAC and setting accelerator, were discussed based on the satisfying injectability and setting properties. It was found that the compressive strength and modulus of materials increased with the decrease of nHAC content and L/S ratio. CSD as setting accelerator hardly had an effect on the compressive properties of materials because it is not only the reactant of preparing CSH but also the final solidified product of CSH instead of a foreign body. Though the compressive properties of nHAC/CSD composites changed with the variety of nHAC content and L/S ratio, the compressive strength and modulus of the materials ranged from 2.0 to nearly 20.0 MPa and 100.0 to 800.0 MPa, respectively, which are similar to that of cancellous bone. In vitro cell behavior demonstrated that the composites could provide adequate environment for cell adhesion and proliferation. All these indicated that the nHAC/CSH composites were a potential scaffold for bone tissue engineering.