Freeze-drying is commonly used to improve stability of liquid formulations of labile biopharmaceuticals. Lyo- and cryoprotectants such as sucrose are traditionally utilized as excipients, but have low glass transition (Tg') and collapse temperatures (Tc). Consequently, these formulations require low primary drying temperatures making the lyophilization cycle time-consuming and costly. We investigated different dextrans (1, 40, 150, and 500 kDa) and mixtures of dextran with sucrose as alternative excipients. The influence of dextran on thermal properties, cake appearance, and other quality attributes in the solid state was studied using bovine serum albumin as model protein. Especially at higher weight ratios of dextran to sucrose, dextrans of medium to high molecular weight (MW) of 40-500 kDa showed up to 20 °C higher Tc compared to sucrose, which was reflected in elegant lyophilisates. However, this resulted in slower reconstitution times. Addition of dextran led to lower residual moisture levels and higher Tg values compared to sucrose. We confirmed the thermal properties for two monoclonal antibodies (mAb) at two weight ratios of sucrose and dextran with different MW, and tested for stability at 40 °C for 14 days. While no loss in relative potency of the antibodies was observed after storage, size exclusion chromatography and isoelectric focusing revealed a strong increase in high molecular weight species (HMWs) and acidic species, which were dependent on the MW of the dextrans. With further characterization of selected formulations (dextran 1 kDa) by boronate affinity chromatography and mass spectrometry analysis, we demonstrated that HMWs were a result of glycation by free terminal glucose of the dextran. This chemical modification was strongly reduced when adding sucrose, which protects the protein possibly by shielding its surface. Our results demonstrate that formulation scientists need to use dextrans as excipients in freeze-dried mAb formulations with caution. A binary mixture of sucrose and dextran in adequate ratio however might potentially be superior to pure sucrose formulations allowing for faster freeze-drying cycles resulting in elegant lyophilisates and good protein stability.

中文翻译：

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右旋糖酐对冻干制剂中热性质，产品质量属性和单克隆抗体稳定性的影响。

冷冻干燥通常用于提高不稳定生物药物的液体制剂的稳定性。传统上将抗冻剂和冷冻保护剂（例如蔗糖）用作赋形剂，但玻璃化转变温度（Tg'）和崩解温度（Tc）低。因此，这些制剂需要较低的初级干燥温度，从而使得冻干循环既费时又昂贵。我们研究了不同的右旋糖酐（1、40、150和500 kDa）以及右旋糖酐与蔗糖的混合物作为替代赋形剂。使用牛血清白蛋白作为模型蛋白，研究了葡聚糖对固态的热性能，滤饼外观和其他质量属性的影响。特别是在葡聚糖与蔗糖的重量比较高的情况下，与蔗糖相比，中高分子量（MW）为40-500 kDa的葡聚糖的Tc最高可提高20°C，这在优雅的冻干产品中得到了体现。但是，这导致重建时间变慢。与蔗糖相比，右旋糖酐的加入导致较低的残留水分含量和较高的Tg值。我们证实了两种单克隆抗体（mAb）在蔗糖和葡聚糖的两个重量比下具有不同MW的热性质，并在40°C下测试了14天的稳定性。虽然在储存后未观察到抗体的相对效力的损失，但是尺寸排阻色谱法和等电聚焦揭示了依赖于葡聚糖的MW的高分子量种类（HMWs）和酸性种类的强烈增加。通过硼酸亲和色谱和质谱分析进一步表征选定的制剂（葡聚糖1 kDa），我们证明，HMWs是右旋糖酐的游离末端葡萄糖糖基化的结果。当添加蔗糖时，这种化学修饰会大大降低，这可能通过屏蔽其表面来保护蛋白质。我们的结果表明，制剂科学家需要谨慎地在冻干mAb制剂中使用右旋糖酐作为赋形剂。但是，蔗糖和右旋糖酐的二元混合物以适当的比例可能会优于纯蔗糖配方，从而可以实现更快的冷冻干燥周期，从而产生出色的冻干物和良好的蛋白质稳定性。我们的结果表明，制剂科学家需要谨慎地在冻干mAb制剂中使用右旋糖酐作为赋形剂。但是，蔗糖和右旋糖酐的二元混合物以适当的比例可能会优于纯蔗糖配方，从而可以实现更快的冷冻干燥周期，从而产生出色的冻干物和良好的蛋白质稳定性。我们的结果表明，制剂科学家需要谨慎地在冻干mAb制剂中使用右旋糖酐作为赋形剂。但是，蔗糖和右旋糖酐的二元混合物以适当的比例可能会优于纯蔗糖配方，从而可以实现更快的冷冻干燥周期，从而产生出色的冻干物和良好的蛋白质稳定性。