TY - JOUR

T1 - Physical stability of a microcrystalline beta-sitosterol suspension in oil

AU - von Bonsdorff-Nikander, Anna

AU - Karjalainen, Milja

AU - Rantanen, Jukka

AU - Christiansen, Leena

AU - Yliruusi, Jouko

PY - 2003/7

Y1 - 2003/7

N2 - Sterols have been shown to reduce plasma cholesterol by blocking the absorption of cholesterol from the gut. The physical properties of crystalline plant sterols limit their use in foods. A coarse-grained structure can be avoided by recrystallisation, a method that affords a reduction in the particle size. A previous work described how to produce a microcrystalline beta-sitosterol suspension. The present study deals with the stability of that suspension. Recrystallisation was carried out by two different methods; one based on rapid the other based on slow cooling, whereby six different compositions were made containing 5-30% of beta-sitosterol and secondly either 5 or 20% water was added. The particle size and habit were evaluated during a 16 weeks storage period (+4 or -19 degrees C) by way of optical microscopy. The crystal structure and degree of crystallinity was analysed by X-ray diffraction. Suspensions can, in most cases, be stored for 16 weeks without any changes to the size and habit. The only evidence of crystal growth came from a suspension with a low sterol concentration at a temperature of +4 degrees C. This is due to the dissolution-diffusion process which is affected by temperature and viscosity. Suspensions containing higher amounts of sterol remained stable, if stored at +4 or -19 degrees C, for 16 weeks. The suspensions included both hemihydrous and monohydrous beta-sitosterol crystals. Suspensions containing less sterol showed greater amounts of monohydrated crystals. This illustrates more water penetration into the crystals. A higher sterol concentration led to a larger number of smaller crystals creating reflections similar to hemihydrated crystals.

AB - Sterols have been shown to reduce plasma cholesterol by blocking the absorption of cholesterol from the gut. The physical properties of crystalline plant sterols limit their use in foods. A coarse-grained structure can be avoided by recrystallisation, a method that affords a reduction in the particle size. A previous work described how to produce a microcrystalline beta-sitosterol suspension. The present study deals with the stability of that suspension. Recrystallisation was carried out by two different methods; one based on rapid the other based on slow cooling, whereby six different compositions were made containing 5-30% of beta-sitosterol and secondly either 5 or 20% water was added. The particle size and habit were evaluated during a 16 weeks storage period (+4 or -19 degrees C) by way of optical microscopy. The crystal structure and degree of crystallinity was analysed by X-ray diffraction. Suspensions can, in most cases, be stored for 16 weeks without any changes to the size and habit. The only evidence of crystal growth came from a suspension with a low sterol concentration at a temperature of +4 degrees C. This is due to the dissolution-diffusion process which is affected by temperature and viscosity. Suspensions containing higher amounts of sterol remained stable, if stored at +4 or -19 degrees C, for 16 weeks. The suspensions included both hemihydrous and monohydrous beta-sitosterol crystals. Suspensions containing less sterol showed greater amounts of monohydrated crystals. This illustrates more water penetration into the crystals. A higher sterol concentration led to a larger number of smaller crystals creating reflections similar to hemihydrated crystals.

KW - Cholesterol

KW - Drug Stability

KW - Hypolipidemic Agents

KW - Phytosterols

KW - Sitosterols

KW - Soil

KW - Suspensions

KW - Time Factors

KW - Viscosity

KW - Water

KW - X-Ray Diffraction

M3 - Journal article

C2 - 12885381

VL - 19

SP - 173

EP - 179

JO - Norvegica Pharmaceutica Acta

JF - Norvegica Pharmaceutica Acta

SN - 0928-0987

IS - 4

ER -