Poly (lactic-co-glycolic acid) (PLGA) copolymers have been broadly used in controlled drug release applications. Because these polymers are biodegradable, they provide an attractive option for drug delivery vehicles. There are a variety of material, processing, and physiological factors that impact the degradation rates of PLGA polymers and concurrent drug release kinetics. This work is intended to provide a comprehensive and collective review of the physicochemical and physiological factors that dictate the degradation behavior of PLGA polymers and drug release from contemporary PLGA-based drug-polymer products. In conjunction with the existing experimental results, analytical and numerical theories developed to predict drug release from PLGA-based polymers are summarized and correlated with the experimental observations. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1692-1716, 2017.

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A stereological method is described for estimating the distribution of grain-boundary types in polycrystalline materials on the basis of observations from a single planar section. The grain-boundary distribution is expressed in terms of five macroscopically observable parameters that include: three parameters that describe the lattice misorientation across the boundary and two parameters that describe the orientation of the grain-boundary plane normal. The grain-boundary distribution is derived from measurements of grain orientations and the orientations of the lines formed where grain boundaries intersect the plane of observation. Tests of the method on simulated observations illustrate that the distribution of boundaries in a material with cubic symmetry can be reliably determined with about 10º of resolution from the analysis of 5 ϫ 10 4 or more line segments. Furthermore, grain-boundary distributions directly observed from serial sections of a SrTiO 3 polycrystal are compared to those resulting from the stereological analysis of a single plane. The comparison shows that the stereological method provides a reasonable estimate of the measured distribution. The differences between the directly observed grain-boundary distribution and that derived from the stereological analysis are consistent with the results from the simulation.