Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Irina A. Selivanova
Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Nonna A. Tyukavkina
Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Igor R. Ilyasov
Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Anastasiya K. Zhevlakova
Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Alexander V. Dzuban
Department of Chemistry, Lomonosov Moscow State University, Leninskiye Gory 1-3, 119991 Moscow, Russia
Anatoliy G. Bogdanov
Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1-32, 119991 Moscow, Russia
Georgiy N. Davidovich
Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1-32, 119991 Moscow, Russia
Gennadii V. Shylov
Laboratory of Structural Chemistry, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Acad. Semenov av. 1, 143432 Chernogolovka, Russia
Andrey N. Utenishev
Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya st. 8-2, 119991 Moscow, Russia
Dmitriy Yu. Kovalev
Laboratory of X-ray Investigation, Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Acad. Osipyan str. 8, 142432 Chernogolovka, Russia
Anatoliy A. Fenin
Institute of Materials for Modern Power Engineering and Nanotechnology, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125947 Moscow, Russia
Tatyana G. Kabluchko
Department of Technology, Ametis JSC, Naberezhnaya st. 68, 675000 Blagoveshchensk, Russia
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.
