Izutsu K, Yoshioka S, Kojima S
National Institute of Health Sciences, Tokyo, Japan.
Pharm Res. 1995 Jun;12(6):838-43. doi: 10.1023/a:1016252802413.
The stabilizing effect of amphiphilic excipients and sugars against protein inactivation during freeze-drying was studied in relation to their physical states in freeze-dried cakes.
Physical states of amphiphilic excipients were studied by powder X-ray diffractometry and differential scanning calorimetry (DSC). Stabilizing effects of excipients were studied using lactate dehydrogenase (LDH) as a model protein.
Although poly(ethylene glycols) (PEGs) 1000 to 2000 crystallized when freeze-dried alone, the addition of sugars decreased their crystallinity by dispersing PEG into sugar-dominant matrices. Sugars species, molecular weight of PEGs, and buffer concentration also affected the crystallinity of PEGs. Sugars also dispersed some of other amphiphilic excipients, which tended to crystallize or become "microscopically liquid" when freeze-dried without sugar. Only the amphiphilic excipients that remained amorphous solid state protected the enzyme during freeze-drying in the absence of sugars. However, combinations of sucrose and all the amphiphilic excipients studied increased the stabilizing effects markedly. The remaining activities were greater than the sum of their individual ones.
Various amphiphilic excipients are good stabilizers for freeze-drying of proteins when dispersed into sugar-dominant matrices.
研究两亲性辅料和糖类在冷冻干燥过程中对蛋白质失活的稳定作用，并探讨其与冷冻干燥块状物物理状态的关系。
通过粉末X射线衍射和差示扫描量热法（DSC）研究两亲性辅料的物理状态。以乳酸脱氢酶（LDH）作为模型蛋白，研究辅料的稳定作用。
虽然聚乙二醇（PEG）1000至2000单独冷冻干燥时会结晶，但加入糖类可通过将PEG分散到以糖为主的基质中降低其结晶度。糖类种类、PEG分子量和缓冲液浓度也会影响PEG的结晶度。糖类还能分散一些其他两亲性辅料，这些辅料在无糖冷冻干燥时往往会结晶或变成“微观液态”。只有保持无定形固态的两亲性辅料在无糖冷冻干燥过程中能保护酶。然而，蔗糖与所有研究的两亲性辅料组合显著提高了稳定效果。剩余活性大于它们各自活性之和。
各种两亲性辅料分散到以糖为主的基质中时，是蛋白质冷冻干燥的良好稳定剂。
