Oliva A, Santoveña A, Llabres M, Fariña J B
Departamento Ingeniería Química y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de La Laguna, Tenerife, Spain.
J Pharm Pharmacol. 1999 Apr;51(4):385-92. doi: 10.1211/0022357991772574.
The influence of temperature on the stability of human serum albumin (HSA) pharmaceutical preparations has been studied by size-exclusion high-performance liquid chromatography with multi-angle laser-light-scattering detection and by particle-size analysis. The behaviour of HSA in two pharmaceutical preparations stored at different temperatures (40, 55 and 70 degrees C) followed the same pattern--an increase in the relative percentage of dimer (MW 132 000 Da) and aggregate (MW > 200 000 Da), and then a decrease in the concentration of all species and, finally, sudden protein coagulation. These results suggest a time- and temperature-dependent process. At 70 degrees C, monomer only was detected for both preparations; the amount remaining was 83 and 72% for formulations A and B, respectively. Analysis of size-distribution curves also seems to confirm these results. Initially, three distributions were observed with length-volume mean diameters (d1,v) of 1.67, 10.6 and 57 microm. After 80 days at 55 degrees C, only two distributions were observed, with d1,v of 3.07 and 76 microm. An additional study using pure HSA at different concentrations (0.3, 2.5, 5 and 10% w/v) and storage at 75 degrees C was performed to determine the influence of the concentration of auxiliary substances and of the HSA. Only when the HSA concentration was 0.3% w/v did the remaining fraction of HSA fit a Prout-Thompkins nucleation model. Initially three distributions with mean sizes of 2, 20 and 40 microm were observed whereas at the end of the assay only one distribution, mean size 129 microm, was seen. The methodology used enabled us to separate the HSA degradation products and to determine the absolute molecular weight of albumin monomer and dimer. It is possible to conclude that the degradation mechanism for the formulations studied is complex, and that it is possible to fit the degradation data to Prout-Thompkins kinetics only when the concentration of HSA is low enough (0.3% w/v).
采用尺寸排阻高效液相色谱-多角度激光散射检测法和粒度分析法，研究了温度对人血清白蛋白（HSA）药物制剂稳定性的影响。两种药物制剂中的HSA在不同温度（40、55和70℃）下储存时，表现出相同的模式——二聚体（分子量132000 Da）和聚集体（分子量>200000 Da）的相对百分比增加，随后所有物种的浓度降低，最终蛋白质突然凝固。这些结果表明这是一个时间和温度依赖性过程。在70℃时，两种制剂均仅检测到单体；制剂A和B剩余的量分别为83%和72%。粒度分布曲线分析似乎也证实了这些结果。最初观察到三种分布，长度-体积平均直径（d1,v）分别为1.67、10.6和57微米。在55℃下储存80天后，仅观察到两种分布，d1,v分别为3.07和76微米。进行了另一项研究，使用不同浓度（0.3、2.5、5和10% w/v）的纯HSA并在75℃下储存，以确定辅料浓度和HSA的影响。仅当HSA浓度为0.3% w/v时，HSA的剩余部分才符合普劳特-汤普金斯成核模型。最初观察到三种平均尺寸分别为2、20和40微米的分布，而在试验结束时仅观察到一种平均尺寸为129微米的分布。所采用的方法使我们能够分离HSA降解产物，并确定白蛋白单体和二聚体的绝对分子量。可以得出结论，所研究制剂的降解机制很复杂，并且只有当HSA浓度足够低（0.3% w/v）时，降解数据才有可能符合普劳特-汤普金斯动力学。
