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Characterization of Dynamics in Complex Lyophilized Formulations: I. Comparison of Relaxation Times Measured by Isothermal Calorimetry with Data Estimated from the Width of the Glass Transition Temperature Region

机译：复杂冻干配方中动力学的表征：I.用等温量热法测量的弛豫时间与根据玻璃化转变温度区域的宽度估算的数据进行比较

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The purposes of this study are to characterize the relaxation dynamics in complex freeze dried formulations and to investigate the quantitative relationship between the structural relaxation time as measured by thermal activity monitor (TAM) and that estimated from the width of the glass transition temperature (ΔTg). The latter method has advantages over TAM because it is simple and quick. As part of this objective, we evaluate the accuracy in estimating relaxation time data at higher temperatures (50°C and 60°C) from TAM data at lower temperature (40°C) and glass transition region width (ΔTg) data obtained by differential scanning calorimetry. Formulations studied here were hydroxyethyl starch (HES)-disaccharide, HES-polyol and HES-disaccharide-polyol at various ratios. We also re-examine, using TAM derived relaxation times, the correlation between protein stability (human growth hormone, hGH) and relaxation times explored in a previous report, which employed relaxation time data obtained from ΔTg. Results show that most of the freeze dried formulations exist in single amorphous phase, and structural relaxation times were successfully measured for these systems. We find a reasonably good correlation between TAM measured relaxation times and corresponding data obtained from estimates based on ΔTg, but the agreement is only qualitative. The comparison plot showed that TAM data is directly proportional to the 1/3 power of ΔTg data, after correcting for an offset. Nevertheless, the correlation between hGH stability and relaxation time remained qualitatively the same as found with using ΔTg derived relaxation data, and it was found that the modest extrapolation of TAM data to higher temperatures using ΔTg method and TAM data at 40°C resulted in quantitative agreement with TAM measurements made at 50 °C and 60 °C, provided the TAM experiment temperature is well below the Tg of the sample.
机译：这项研究的目的是表征复杂冻干配方中的弛豫动力学，并研究通过热活度监测器（TAM）测量的结构弛豫时间与根据玻璃化转变温度的宽度估算的结构弛豫时间之间的定量关系（ΔTg） 。后一种方法比TAM具有优势，因为它既简单又快速。作为此目标的一部分，我们从较低温度（40°C）的TAM数据和通过微分获得的玻璃化转变区宽度（ΔTg）数据评估在较高温度（50°C和60°C）时估计弛豫时间数据的准确性扫描量热法。此处研究的配方为不同比例的羟乙基淀粉（HES）-二糖，HES-多元醇和HES-二糖-多元醇。我们还使用TAM得出的弛豫时间重新检查了蛋白质稳定性（人类生长激素，hGH）与弛豫时间之间的相关性，该研究在以前的报告中进行了探讨，该报告采用了从ΔTg获得的弛豫时间数据。结果表明，大多数冷冻干燥的制剂都存在于单个非晶相中，并且成功地测量了这些系统的结构弛豫时间。我们发现，TAM测得的弛豫时间与从基于ΔTg的估计值获得的相应数据之间有相当好的相关性，但一致性仅是定性的。比较图显示，在校正偏移后，TAM数据与ΔTg数据的1/3幂成正比。然而，hGH稳定性和弛豫时间之间的相关性在质量上与使用ΔTg得出的弛豫数据相同，并且发现使用ΔTg方法和40°C下的TAM数据将TAM数据适度外推到较高温度会导致定量如果TAM实验温度远低于样品的Tg，则与在50°C和60°C下进行的TAM测量结果一致。

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