Kawai Kiyoshi, Suzuki Toru
Tokyo University of Technology Institution, School of Bionics, 1404-1 Katakura, Hachioji, Tokyo, 192-0982, Japan.
Pharm Res. 2007 Oct;24(10):1883-90. doi: 10.1007/s11095-007-9312-6. Epub 2007 May 8.
In order to understand the stabilizing effects of disaccharides on freeze-dried proteins, the enzymatic activity of lactate dehydrogenase (LDH) formulations containing four types of disaccharide (trehalose, sucrose, maltose, and lactose) at two relative humidity (RH) levels (about 0 and 32.8%) was investigated after three processes: freeze-thawing, freeze-drying, and storage at three temperatures (20, 40, and 60 degrees C) above and/or below the glass transition temperature (T(g)).
The enzymatic activity was determined from the absorbance at 340 nm, and T(g) of the samples was investigated by differential scanning calorimetry.
At each RH condition, T(g) values of sucrose formulations were lower than those of other formulations. Although effects of the disaccharides on the process stability of LDH were comparable, storage stability was dependent on the type of disaccharide. All the formulations were destabilized significantly during storage at temperature above T(g). During storage at temperature below T(g), the LDH activity decreased with increases in the storage temperature and moisture. Maltose and lactose formulations showed significant destabilization with the change of color to browning.
Taking the storage stability of freeze-dried proteins under the various conditions (temperature and RH) into consideration, trehalose is better suited as the stabilizer than other disaccharides.
为了解二糖对冻干蛋白质的稳定作用，研究了含有四种二糖（海藻糖、蔗糖、麦芽糖和乳糖）的乳酸脱氢酶（LDH）制剂在两个相对湿度（RH）水平（约0和32.8%）下，经过冻融、冻干以及在高于和/或低于玻璃化转变温度（T(g)）的三个温度（20、40和60摄氏度）下储存这三个过程后的酶活性。
通过340nm处的吸光度测定酶活性，并采用差示扫描量热法研究样品的T(g)。
在每种RH条件下，蔗糖制剂的T(g)值均低于其他制剂。虽然二糖对LDH过程稳定性的影响相当，但储存稳定性取决于二糖的类型。在高于T(g)的温度下储存期间，所有制剂均显著失稳。在低于T(g)的温度下储存期间，LDH活性随储存温度和湿度的增加而降低。麦芽糖和乳糖制剂随着颜色变为褐色而出现显著失稳。
考虑到冻干蛋白质在各种条件（温度和RH）下的储存稳定性，海藻糖比其他二糖更适合作为稳定剂。
