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首页> 外文期刊>Journal of pharmaceutical sciences. >Physicochemical, crystallographic, thermal, and spectroscopic behavior of crystalline and X-ray amorphous ciclesonide.
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Physicochemical, crystallographic, thermal, and spectroscopic behavior of crystalline and X-ray amorphous ciclesonide.

机译：晶体和X射线无定形ciclesonide的物理化学，晶体学，热学和光谱学行为。

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摘要

Single crystal structure experiments revealed that the orthorhombic needles of Ciclesonide crystallized in P2(1)2(1)2(1) space group with four independent molecules in the unit cell. Amorphous Ciclesonide was prepared by lyophilization and characterized in comparison with crystalline material by differential scanning calorimetry (DSC), Fourier transformed (FT)-Raman spectroscopy, powder X-ray diffraction, dissolution, and saturation solubility experiments. Significant differences in the dissolution, thermal, and spectrometric behavior were observed for both solid-state phases. DSC- and FT-Raman methods for the determination of amorphous content in crystalline Ciclesonide samples were established. Isothermal and dynamical recrystallization studies on amorphous Ciclesonide were conducted using dispersive hot-stage Raman microscopy. The recrystallization was observed to be a two-step process with an induction period (most likely nuclei formation) followed by the actual recrystallization (crystal growth). The recrystallization rate constants and Avrami exponents (n = 2) were determined from the isothermal experiments at various temperatures using Johnson-Mehl-Avrami theory. Isothermal activation energies were obtained from Arrhenius plots using the temperature dependence of (a) the rate constants (160.4 kJ/mol) and (b) the induction time (140.9 kJ/mol) of the isothermal hot-stage experiments.
机译：单晶结构实验表明，Ciclesonide的正交晶状体在P2（1）2（1）2（1）空间群中结晶，在晶胞中有四个独立分子。通过冷冻干燥制备无定形的Ciclesonide，并通过差示扫描量热法（DSC），傅立叶变换（FT）-拉曼光谱，粉末X射线衍射，溶解和饱和溶解度实验与结晶材料进行比较。对于两种固态相，在溶解，热和光谱行为方面均观察到显着差异。建立了DSC-和FT-Raman方法测定结晶的Ciclesonide样品中的非晶态含量。使用分散热台拉曼显微镜进行了非晶Ciclesonide的等温和动态重结晶研究。观察到重结晶是一个两步过程，其中有一个诱导期（很可能是核形成），然后是实际的重结晶（晶体生长）。使用Johnson-Mehl-Avrami理论在不同温度下的等温实验确定了重结晶速率常数和Avrami指数（n = 2）。等温活化能是利用等温热阶段实验的温度依赖性（a）速率常数（160.4 kJ / mol）和（b）诱导时间（140.9 kJ / mol）的温度依赖性从阿伦尼乌斯图获得的。

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