AMBIGUITIES IN IR AND X-RAY CHARACTERIZATION OF AMPHOTERICIN-B
AMBIGUITIES IN IR AND X-RAY CHARACTERIZATION OF AMPHOTERICIN-B
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DOI：
10.1002/jps.2600670334
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发表时间：
1978-01-01
影响因子：
3.8
通讯作者：
TAYLOR, J
中科院分区：
文献类型：
--
作者：
SCHWARTZMAN, G;ASHER, I;TAYLOR, J
两性霉素B有两个不同的红外光谱。这些差异可以通过样品制备方法的微小变化从同一样品中获得。I型光谱（手工研磨样品）在1692 cm−1处有一个锐利的C=0拉伸带，II型光谱（振动器研磨样品）在1710 cm−1附近有一个宽的C=0拉伸带。x射线粉末衍射表明，振动器磨削促进了晶相向非晶相的转变。这两种相不是生物等效的。差热分析显示157°附近的转变，加热到158°的样品只给出II型红外光谱。然而，伴随这种加热的是明显的颜色变化（即影响发色团的结构变化已被热诱导），而x射线光谱显示非晶含量仅增加了约30%。此外，手磨样品加热到120°仍然只显示I型红外光谱。因此，振子诱导的跃迁不仅仅是一种静态热效应。许多观测到的光谱线可以被分配到特定的官能团。
Two distinct IR spectra of amphotericin B have been reported. These differences can be obtained from the same sample by surprisingly small changes in the method of sample preparation. Type I spectra (hand-ground samples) are characterized by a sharp C=0 stretching band at 1692 cm− 1, and Type II spectra (vibrator-ground samples) are characterized by a broad C=0 stretching band near 1710 cm− 1. X-ray powder diffraction demonstrates that vibrator grinding promotes a transition from a crystalline to an amorphous phase. The two phases are not bioequivalent. Differential thermal analysis reveals a transition near 157°, and samples heated to 158° give only Type II IR spectra. However, a marked color change accompanies such heating (i.e.,structural changes affecting the chromophore have been thermally induced), while X-ray spectra show an increase of only about 30% in amorphous content. Furthermore, hand-ground samples heated to 120° still display only Type I IR spectra. Thus, the vibrator-induced transition is not solely a static thermal effect. Many observed spectral lines can be assigned to specific functional groups.