Physically targeted intravenous polyurethane nanoparticles for controlled release of atorvastatin calcium

Background: Intravenous drug delivery is an advantageous choice for rapid administration, immediate drug effect, and avoidance of first-pass metabolism in oral drug delivery. In this study, the synthesis, formulation, and characterization of atorvastatin-loaded polyurethane [PU] nanoparticles were investigated for intravenous route of administration

Method: First, PU was synthesized and characterized. Second, nanoparticles were prepared in four different ratios of drug to polymer through two different techniques, including emulsion-diffusion and single emulsion. Finally, particle size and polydispersity index, shape and surface morphology, drug entrapment efficiency [EE], drug loading, and in vitro release were evaluated by dynamics light scattering, scanning electron microscopy, and UV visible spectroscopy, respectively

Results: Within two methods, the prepared nanoparticles had a spherical shape and a smooth surface with a diversity of size ranged from 174.04 nm to 277.24 nm in emulsion-diffusion and from 306.5 nm to 393.12 in the single-emulsion method. The highest EE was 84.76%, for [1:4] sample in the emulsion-diffusion method. It has also been shown that in vitro release of nanoparticles, using the emulsion-diffusion method, was sustained up to eight days by two mechanisms: drug diffusion and polymer relaxation

Conclusion: PU nanoparticles, that were prepared by the emulsion-diffusion method, could be used as effective carriers for the controlled drug delivery of poorly water soluble drugs such as atorvastatin calcium

Porous Crosslinked Polycaprolactone Hydroxyapatite Networks for Bone Tissue Engineering

In this study, porous scaffolds were produced by a thermal crosslinking of polycaprolactone diacrylate in the presence of hydroxyapatite (HA) and particulate leaching technique with sodium chloride as the water soluble porogen for bone tissue engineering applications. The prepared scaffolds were characterized using techniques such as Field Emission Scanning Electron Microscopy, Differential Scanning Calorimetry, and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy. Moreover, dynamic mechanical properties were investigated using Dynamic Mechanical Thermal Analysis. The obtained scaffolds present a porous structure with interconnected pores and porosity around 73%. It was found that the incorporation of HA particles to polycaprolactone (PCL) matrix resulted in an increased crystallinity. Moreover, both the storage modulus (E′) and glass transition temperature (T(g)) increased, while the loss factor (tan δ) decreased due to the hindrance of the HA particles to the mobility of polymer segments. Cytocompatability of the scaffolds was assessed by MTT assay and cell attachment studies. Osteoconductivity of the scaffolds was investigated with cells alkaline phosphatase extraction. The levels of alkaline phosphatase activity were found to be higher for PCL/HA network scaffold than for PCL network scaffold. In addition, cytocompatibility of the PCL/HA network scaffold indicated no toxicity, and cells were attached and spread to the scaffold walls.