Bulking agents as mannitol (Man) and glycine (Gly) require high bulking agent to stabilizer ratios to ensure their crystallization during the freeze-drying process. The aim of this study was to investigate several amino acids (AA) as potential alternative bulking agents in low AA to sucrose (Suc) ratios. A fast freeze-drying process was performed above the collapse temperature (Tc) of the amorphous phase challenging the crystalline AA scaffold. Lyophilizates and liquid formulations were characterized by differential scanning calorimetry. Karl-Fischer titration and X-ray powder diffraction as well as macroscopic cake appearance and reconstitution times were evaluated. Stability of a monoclonal antibody was investigated by UV–Vis spectroscopy, light obscuration and size exclusion chromatography. Phenylalanine (Phe), leucine (Leu) and isoleucine (Ile) crystallized upon freeze-drying at 5/45 and 10/40 AA/Suc ratios. 2.5/47.5 AA/Suc ratio showed less pronounced crystallization. Crystallization peaks were not suppressed by 2 or 50 mg/mL antibody in Leu and Ile lyophilizates. Reconstitution times could be improved by addition of surfactant. No signs of protein aggregation were detected after freeze-drying. Man and Gly yielded inacceptable cake appearance when dried with the fast freeze-drying cycle in such low bulking agent to Suc ratios. Leu, Ile and Phe can be used as alternate bulking agents at lower bulking agent to Suc ratios compared to Man or Gly. The selected AAs provided promising cake characteristics and good protein process stability.

甘露醇（Man）和甘氨酸（Gly）等填充剂需要高填充剂与稳定剂的比例，以确保它们在冷冻干燥过程中结晶。这项研究的目的是研究几种氨基酸（AA）作为低氨基酸对蔗糖（Suc）比例的潜在替代填充剂。在挑战结晶AA骨架的无定形相的崩解温度（Tc）以上进行了快速冷冻干燥过程。冻干物和液体制剂通过差示扫描量热法进行表征。评估了卡尔-费休滴定和X射线粉末衍射以及宏观滤饼外观和重构时间。单克隆抗体的稳定性通过紫外-可见光谱，光遮蔽和尺寸排阻色谱法进行了研究。苯丙氨酸（Phe），冷冻干燥后，亮氨酸（Leu）和异亮氨酸（Ile）以5/45和10/40 AA / Suc比结晶。2.5 / 47.5 AA / Suc比显示出不太明显的结晶。Leu和Ile冻干物中的2或50 mg / mL抗体未抑制结晶峰。通过添加表面活性剂可以改善重构时间。冷冻干燥后未检测到蛋白质聚集的迹象。当以如此低的填充剂与Suc的比率以快速的冷冻干燥循环干燥时，Man和Gly产生了不可接受的蛋糕外观。与Man或Gly相比，Leu，Ile和Phe可以以较低的填充剂与Suc的比例用作替代的填充剂。所选的AA具有良好的滤饼特性和良好的蛋白质加工稳定性。5 AA / Suc比显示较少的结晶。Leu和Ile冻干物中的2或50 mg / mL抗体未抑制结晶峰。通过添加表面活性剂可以改善重构时间。冷冻干燥后未检测到蛋白质聚集的迹象。当以如此低的填充剂与Suc的比率以快速的冷冻干燥循环干燥时，Man和Gly产生了不可接受的蛋糕外观。与Man或Gly相比，Leu，Ile和Phe可以以较低的填充剂与Suc的比例用作替代的填充剂。所选的AA具有良好的滤饼特性和良好的蛋白质加工稳定性。5 AA / Suc比显示较少的结晶。Leu和Ile冻干物中的2或50 mg / mL抗体未抑制结晶峰。通过添加表面活性剂可以改善重构时间。冷冻干燥后未检测到蛋白质聚集的迹象。当以如此低的填充剂与Suc的比率以快速的冷冻干燥循环干燥时，Man和Gly产生了不可接受的蛋糕外观。与Man或Gly相比，Leu，Ile和Phe可以以较低的填充剂与Suc的比例用作替代的填充剂。所选的AA具有良好的滤饼特性和良好的蛋白质加工稳定性。冷冻干燥后未检测到蛋白质聚集的迹象。当以如此低的填充剂与Suc的比率以快速的冷冻干燥循环干燥时，Man和Gly产生了不可接受的蛋糕外观。与Man或Gly相比，Leu，Ile和Phe可以以较低的填充剂与Suc的比例用作替代的填充剂。所选的AA具有良好的滤饼特性和良好的蛋白质加工稳定性。冷冻干燥后未检测到蛋白质聚集的迹象。当以如此低的填充剂与Suc的比率以快速的冷冻干燥循环干燥时，Man和Gly产生了不可接受的蛋糕外观。与Man或Gly相比，Leu，Ile和Phe可以以较低的填充剂与Suc的比例用作替代的填充剂。所选的AA具有良好的滤饼特性和良好的蛋白质加工稳定性。