Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia.
Department of Chemistry, Lomonosov Moscow State University, Leninskiye Gory 1-3, 119991 Moscow, Russia.
Molecules. 2020 Nov 20;25(22):5437. doi: 10.3390/molecules25225437.
A large amount of the current literature dedicated to solid states of active pharmaceutical ingredients (APIs) pays special attention to polymorphism of flavonoids. Taxifolin (also known as dihydroquercetin) is an example of a typical flavonoid. Some new forms of taxifolin have been reported previously, however it is still unclear whether they represent polymorphic modifications. In this paper, we tried to answer the question about the taxifolin polymorphism. Taxifolin microtubes and taxifolin microspheres were synthesized from raw taxifolin API using several methods of crystal engineering. All forms were described with the help of spectral methods, scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and thermal analysis (TA). SEM reveals that the morphology of the solid phase is very specific for each sample. Although XRPD patterns of raw taxifolin and microtubes look similar, their TA profiles differ significantly. At the same time, raw taxifolin and microspheres have nearly identical thermograms, while XRPD shows that the former is a crystalline and the latter is an amorphous substance. Only the use of complex analyses allowed us to put the puzzle together and to confirm the polymorphism of taxifolin. This article demonstrates that taxifolin microtubes are a pseudopolymorphic modification of raw taxifolin.
大量目前致力于活性药物成分（APIs）固态的文献特别关注黄酮类化合物的多态性。栎精（也称为二氢槲皮素）就是黄酮类化合物的一个典型例子。先前已经报道了一些栎精的新形式，但它们是否代表多态性修饰仍然不清楚。在本文中，我们试图回答关于栎精多态性的问题。使用几种晶体工程方法，从原始栎精 API 中合成了栎精微管和栎精微球。所有形式都通过光谱方法、扫描电子显微镜（SEM）、X 射线粉末衍射（XRPD）和热分析（TA）进行了描述。SEM 揭示了固相的形态对于每个样品都是非常特殊的。尽管原始栎精和微管的 XRPD 图谱相似，但它们的 TA 曲线差异很大。同时，原始栎精和微球的热图谱几乎相同，而 XRPD 表明前者是结晶态，后者是无定形态物质。只有使用复杂的分析方法，我们才能将拼图拼凑起来，并证实栎精的多态性。本文表明，栎精微管是原始栎精的拟多态性修饰。
