Izutsu Ken-Ichi, Yoshida Hiroyuki, Shibata Hiroko, Goda Yukihiro
National Institute of Health Sciences.
Chem Pharm Bull (Tokyo). 2016;64(12):1674-1680. doi: 10.1248/cpb.c16-00442.
The objective of this study was to elucidate the mixing state of proteins and amino acid excipients concentrated in the amorphous non-ice region of frozen solutions. Thermal analysis of frozen aqueous solutions was performed in heating scans before and after a heat treatment. Frozen aqueous solutions containing a protein (e.g., recombinant human albumin, gelatin) or a polysaccharide (dextran) and an amino acid excipient (e.g., L-arginine, L-arginine hydrochloride, L-arginine monophosphate, sodium L-glutamate) at varied mass ratios showed single or double T' (glass transition temperature of maximally freeze-concentrated solutes). Some mixture frozen solutions rich in the polymers maintained the single T' of the freeze-concentrated amorphous solute-mixture phase. In contrast, amino acid-rich mixture frozen solutions revealed two T's that suggested transition of concentrated non-crystalline solute-mixture phase and excipient-dominant phase. Post-freeze heat treatment induced splitting of the T' in some intermediate mass ratio mixture solutions. The mixing state of proteins and amino acids varied depending on their structure, salt types, mass ratio, composition of co-solutes (e.g., NaCl) and thermal history. Information on the varied mixing states should be valuable for the rational use of amino acid excipients in lyophilized protein pharmaceuticals.
本研究的目的是阐明浓缩于冷冻溶液非晶态无冰区域的蛋白质和氨基酸辅料的混合状态。在热处理前后的加热扫描过程中对冷冻水溶液进行了热分析。含有蛋白质（如重组人白蛋白、明胶）或多糖（右旋糖酐）以及氨基酸辅料（如L-精氨酸、L-精氨酸盐酸盐、L-精氨酸单磷酸盐、L-谷氨酸钠）且质量比不同的冷冻水溶液显示出单一或双重T'（最大冷冻浓缩溶质的玻璃化转变温度）。一些富含聚合物的混合冷冻溶液保持了冷冻浓缩非晶态溶质-混合物相的单一T'。相比之下，富含氨基酸的混合冷冻溶液显示出两个T'，这表明浓缩非晶态溶质-混合物相和辅料主导相发生了转变。冷冻后热处理在一些中等质量比的混合溶液中导致了T'的分裂。蛋白质和氨基酸的混合状态因其结构、盐类型、质量比、共溶质（如氯化钠）组成以及热历史而异。关于不同混合状态的信息对于在冻干蛋白质药物中合理使用氨基酸辅料具有重要价值。
