Physical changes of β-sitosterol crystals in oily suspensions during heating
| Autor: | Milja Karjalainen, Jouko Yliruusi, Jukka Rantanen, Leena Christiansen, Anna von Bonsdorff-Nikander, Satu M. Lievonen |
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| Rok vydání: | 2005 |
| Předmět: |
Hot Temperature
Materials science Chemical Phenomena Pharmaceutical Science Aquatic Science Article law.invention Differential scanning calorimetry Suspensions law Drug Discovery medicine Dehydration Crystallization Thermal analysis Ecology Evolution Behavior and Systematics Ecology Chemistry Physical Recrystallization (metallurgy) General Medicine Dynamic mechanical analysis medicine.disease Sitosterols Crystallography Microcrystalline Chemical engineering lipids (amino acids peptides and proteins) Particle size Oils Agronomy and Crop Science |
| Zdroj: | AAPS PharmSciTech. 6:E413-E420 |
| ISSN: | 1530-9932 |
| DOI: | 10.1208/pt060351 |
| Popis: | The aim of this research was to describe the thermal behavior of beta-sitosterol crystals in oil-suspensions with a focus on the role of water during heating. The suspensions were prepared by recrystallization in order to achieve a microcrystalline particle size. The structural changes together with the mechanical properties of the suspensions during heating were studied by using variable temperature X-ray powder diffractometry (VT-XRPD), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). Hydrated beta-sitosterol crystals in an oil-suspension dehydrated, despite the composition of the suspensions, at low temperatures. At high beta-sitosterol concentration, the monohydrate crystal form changed partially to a hemihydrated form, and when only a small amount of water was initially incorporated, the hemihydrate crystal form dehydrated to a mostly anhydrate crystal form. The released water, which was immiscible in the surrounding oil, caused the recrystallization of hydrated beta-sitosterol during cooling. This procedure indicated a reversible dehydration process. Structural and thermal analysis of beta-sitosterol crystals in suspensions, together with mechanical analysis made it possible to understand various physical changes during heating. |
| Databáze: | OpenAIRE |
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