316L Stainless Steel Powders for Additive Manufacturing: Relationships of Powder Rheology, Size, Size Distribution to Part Properties.

Laser-Powder Bed Fusion (L-PBF) of metallic parts is a highly multivariate process. An understanding of powder feedstock properties is critical to ensure part quality. In this paper, a detailed examination of two commercial stainless steel 316L powders produced using the gas atomization process is presented. In particular, the effects of the powder properties (particle size and shape) on the powder rheology were examined. The results presented suggest that the powder properties strongly influence the powder rheology and are important factors in the selection of suitable powder for use in an additive manufacturing (AM) process. Both of the powders exhibited a strong correlation between the particle size and shape parameters and the powder rheology. Optical microscope images of melt pools of parts printed using the powders in an L-PBF machine are presented, which demonstrated further the significance of the powder morphology parameters on resulting part microstructures.

A novel long-acting biodegradable depot formulation of anastrozole for breast cancer therapy.

The purpose of the present study was to fabricate PLGA 50:50 and PLA microspheres for controlled delivery of anastrozole. The microspheres were prepared by oil-in-water (o/w) emulsion/solvent evaporation technique and evaluated for particle size and encapsulation. The optimised formulations were studied for solid state characterization, in vitro release and pharmacokinetic studies. The maximum encapsulation efficiency for PLGA 50:50 and PLA microspheres with 40:1 polymer - drug ratio was observed to be 78.4±2.5 and 87.7±2.6%. The solid state characterization confirmed dispersion of drug at the molecular level in the polymeric matrix. Microspheres were spherical in shape with a very smooth surface texture. Drug release was found to be in a sustained fashion, releasing constantly up to 720h (30days) for PLGA and 60days for PLA microspheres. The pharmacokinetic study data revealed that the intramuscular administration of PLA microspheres showed improved pharmacokinetic profile as compared to PLGA microspheres, and therefore this formulation can be considered as the best optimised formulation with sustained exposure of the drug in vivo compared to other microspheres. From experimental results, PLA microspheres demonstrate the feasibility of employing biodegradable depot polymeric microspheres of anastrozole for long-term treatment of breast cancer.