Melt pelletization in a high shear mixer. VIII. Effects of binder viscosity

Schæfer, Torben; Mathiesen, Christina

doi:10.1016/0378-5173(96)04549-8

Cited by 96 publications

(48 citation statements)

References 16 publications

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“…The same was assumed for PEG, which has been investigated extensively in other melt pelletization experiments. 10,18) However, viscosity cannot be used to explain the differences in the granule growth between the various types of binders tested. Binder volume as a single factor could not explain the differences either.…”

Section: Resultsmentioning

confidence: 99%

“…This is in contradiction of the experiments mentioned above and could not be confirmed by findings in literature. It should be mentioned that the critical limit for viscosity, above which a further increase leads to an increased potential for granule growth, 10) was not reached. The experiments described above with a variation in jacket temperature showed a deceleration of granule growth with a further increase in viscosity.…”

Section: Resultsmentioning

confidence: 99%

“…This is contradictory to findings of other authors. 10,13) However, the influence of viscosity on the granule growth is complex. 9,10) The distribution of a high viscous binder might need more time compared to the distribution of a low viscous binder, which can cause a delay in granule growth.…”

Section: Resultsmentioning

confidence: 99%

“…10,13) However, the influence of viscosity on the granule growth is complex. 9,10) The distribution of a high viscous binder might need more time compared to the distribution of a low viscous binder, which can cause a delay in granule growth. A higher viscosity will increase the viscous contribution to the force of dynamic pendular liquid bridges, increasing the potential of the granule growth process.…”

Section: Resultsmentioning

confidence: 99%

“…This was related to the increased force of dynamic pendular bridges due to the viscous contribution. 10) Consequently, the growth promoting effect of increasing viscosity dominates beyond an upper critical limit. Below that limit, decreasing binder viscosity leads to a faster granule growth.…”

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confidence: 99%

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Melt Pelletization of a Hygroscopic Drug in a High Shear Mixer. Part 3.<SUP>1)</SUP> Effects of Binder Variation

Thies¹,

Kleinebudde

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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Melt pelletization in a high shear mixer is a process used to produce pellets by agitation of a mixture of particulate solids and a meltable binder at a certain temperature, which enables the liquefying or softening of the binder. The equipment used, the process parameters, and the chosen formulation influence this process.2)The amount of binder was found to be important to control the granule growth.3,4) The granulation cannot be achieved if the binder amount is too low. In contrary, an excess and/or high binder amount results in an uncontrollable granule growth. Generally, only little variation is tolerable, if the other variables are kept constant.2) Also, changing the type of binder liquid requires adjustment of the amount of binder.The physicochemical properties of the binder (e.g. viscosity or polarity) and substrate-binder interactions were found to influence the granule growth and the strength of the agglomerates. This was examined in wet granulation 5,6) as well as in melt granulation. 7,8) Binder viscosity strongly depends on the product temperature, which is in turn influenced by process variables such as jacket temperature and impeller speed. The effect of viscosity on granule growth is complex, as demonstrated by Ennis et al. 9) Experiments with extremely viscous binders showed an increased potential for agglomeration growth by coalescence. This was related to the increased force of dynamic pendular bridges due to the viscous contribution.10) Consequently, the growth promoting effect of increasing viscosity dominates beyond an upper critical limit. Below that limit, decreasing binder viscosity leads to a faster granule growth.In a previous work, it has been shown that the pelletization of sodium valproate (SV) with glycerol monostearate was successful using 1.1 to 14.1% glycerol monostearate (GMS) as a binder and by adjusting the impeller speed and massing time.11) As seen, the appropriate binder concentration for successful pelletization was very low. It was assumed that the high solubility of SV is associated with the low amount of binder.In the present study, melt pelletization with three different types of binder was investigated. The binders differed in polarity and in the ability to dissolve SV. The aim was to examine the effect of the binder type on the pelletization process and to elucidate the critical binder properties in determining the granule growth. Moreover, in aiming to obtain a better understanding of how the viscosity of the binder liquid influences the process, some experiments were carried out separately. ExperimentalMaterials The model drug, SV (Katwijk, NL), is a hygroscopic and freely water soluble substance, which takes up water at relative humidity (rh) higher than 40% at 20°C. 12) At higher humidity it liquefies quickly. The water content of untreated SV was 0.10% measured by Karl-Fischer-titration (nϭ3).Fine powders of GMS (Myvaplex 600P, Eastman Kodak, U.S.A.), hydrated castor oil (HCO) (Cutina HR, Henkel, Germany), and polyethylene glycol (PEG) (Lutrol E 1500, BASF AG,...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%