Copolymers of lactic (or lactide) and glycolic (or glycolide) acids (PLGAs) are among the most commonly used materials in biomedical applications, such as parenteral controlled drug delivery, due to their biocompatibility, predictable degradation rate, and ease of processing. Besides manufacturing variables of drug delivery vehicles, changes in PLGA raw material properties can affect product behavior. Accordingly, an in-depth understanding of polymer-related “critical quality attributes” can improve selection and predictability of PLGA performance. Here, we selected 19 different PLGAs from five manufacturers to form drug-free films, submillimeter implants, and microspheres and evaluated differences in their water uptake, degradation, and erosion during in vitro incubation as a function of L/G ratio, polymerization method, molecular weight, end-capping, and geometry. Uncapped PLGA 50/50 films from different manufacturers with similar molecular weights and higher glycolic unit blockiness and/or block length values showed faster initial degradation rates. Geometrically, larger implants of 75/25, uncapped PLGA showed higher water uptake and faster degradation rates in the first week compared to microspheres of the same polymers, likely due to enhanced effects of acid-catalyzed degradation from PLGA acidic byproducts unable to escape as efficiently from larger geometries. Manufacturer differences such as increased residual monomer appeared to increase water uptake and degradation in uncapped 50/50 PLGA films and poly(lactide) implants. This dataset of different polymer manufacturers could be useful in selecting desired PLGAs for controlled release applications or comparing differences in behavior during product development, and these techniques to further compare differences in less reported properties such as sequence distribution may be useful for future analyses of PLGA performance in drug delivery.

Graphical abstract

中文翻译：

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用于受控药物递送的商业 PLGA 的体外降解和侵蚀行为

乳酸（或丙交酯）和乙醇酸（或乙交酯）酸 (PLGA) 的共聚物是生物医学应用中最常用的材料，例如肠胃外控制药物输送，因为它们具有生物相容性、可预测的降解速率和易于加工。除了给药载体的制造变量外，PLGA 原材料特性的变化也会影响产品行为。因此，深入了解与聚合物相关的“关键质量属性”可以提高 PLGA 性能的选择和可预测性。在这里，我们选择了来自 5 个制造商的 19 种不同的 PLGAs 来形成无药物薄膜、亚毫米植入物和微球，并评估了它们在体外孵育过程中吸水、降解和侵蚀的差异作为 L/G 比、聚合方法、分子量，封端和几何。来自不同制造商的未封端 PLGA 50/50 薄膜具有相似的分子量和更高的乙醇酸单元嵌段性和/或嵌段长度值，显示出更快的初始降解速率。从几何上看，与相同聚合物的微球相比，75/25 的较大植入物、未加盖的 PLGA 在第一周表现出更高的吸水性和更快的降解速率，这可能是由于 PLGA 酸性副产物无法有效逃逸的酸催化降解效果增强来自更大的几何体。制造商的差异（例如增加的残留单体）似乎会增加未加盖的 50/50 PLGA 薄膜和聚（丙交酯）植入物的吸水和降解。

图形概要