Scale-down of a high-shear pelletisation process: Flow profile and growth kinetics

Ramaker, J.S; Jelgersma, M. Albada; Vonk, P; Kossen, N. W. F.

doi:10.1016/s0378-5173(98)00030-1

Cited by 82 publications

(42 citation statements)

References 8 publications

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“…When the destructive force resulting from the intensive agitation exceeds the bonding force, the equilibrium between granule growth and break-up is disrupted and the latter is preferred. 10) This means that further growth is retarded and the proportion of fines is increased. This equilibrium point is also determined by the properties of the starting material.…”

Section: Resultsmentioning

confidence: 99%

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Investigation of High Shear Wet Granulation Processes Using Different Parameters and Formulations

Wang

Heng

et al. 2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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High shear mixers have been widely used in the pharmaceutical industry. There are several advantages of granulation in a high shear mixer: a shorter processing time; a need for less liquid binders compared with fluid bed granulators and, thus, a shorter drying process is obtained; voluminous materials can be densified. Moreover, granulation is performed in a closed system, which can include drying (microwave or vacuum); the porosity of the product can be influenced by the massing time and impact of the impeller; cleaning operations can be carried out easily either manually or by a clean-inplace system. 1) Different phases of growth were identified for high shear granulation: nucleation, fragmentation, densification, exponential growth due to coalescence, and break up. 2)Scale-up of the wet granulation processes from laboratory scale to pilot and production scale is problematic. Even within the same manufacture of machine, liquid requirement and granule properties in terms of granule size distribution and granule porosity might change by scaling-up due to the difference space and impact force between large-scale and small-scale machines. However, in many situations, pharmaceutical researchers have to deal with a shortage of active substances and granulation materials. In order to develop a formulation and study the process effectively, laboratoryscale equipment is used during the early stages of research. 3)Because of the similar structure design to the pilot and production equipments, lab-scale machines are supposed to provide useful information for subsequent granulation in large scale machines of the same type and it is believed that this information will facilitate subsequent large-scale processing. 4,5) High shear granulation is a multivariate process and the product properties are sensitive to changes in the process variables such as impeller speed, chopper speed and kneading time hence it is important to work out the effects of these critical parameters.2,4,6-8) The microcrystalline cellulosebased (MCC-based) system and starch-based system are two main material systems used for high shear granulation; however, researchers usually chose one of the two systems for their investigations. 5,9) Because of the popularity of these two systems and the difficulty in scaling up the process, comparison of the high shear granulating process with the two systems mentioned using lab-scale equipment that is representative of large-scale circumstances is necessary for the application of this technique. In addition, it has been found that the toroidal motion of the wet mass during the granulating process could have marked impact on the product properties and the reproducibility of the manufacturing process. 10)However, few studies report the possibility of maintaining this flow pattern of wet mass by adjusting the process parameters and the raw material.The aims of present study are to compare the manufacturing process for the two main material systems used for high shear granulation and to try to obtain information about p...

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Section: Resultsmentioning

confidence: 99%

“…In addition, it has been found that the toroidal motion of the wet mass during the granulating process could have marked impact on the product properties and the reproducibility of the manufacturing process. 10) However, few studies report the possibility of maintaining this flow pattern of wet mass by adjusting the process parameters and the raw material.…”

mentioning

confidence: 99%

Investigation of High Shear Wet Granulation Processes Using Different Parameters and Formulations

Wang

Heng

et al. 2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…The rotational speed of the equipment, its diameter and the processed material mass exert the greatest effect on bed dynamics during granulation, and consequently on the scale of disintegration processes [28]. The authors of the paper [29] determined the impact of destructive mechanisms on the granulometric composition of the material undergoing granulation processes.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric analysis of disintegration mechanisms (abrasion and crushing) of agglomerates during the disc granulation of dolomite

Obraniak

Ławińska²

2017

Granular Matter

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The analysis of mechanisms which affect the formation of agglomerates and determine the granulation process in a broad sense encounters difficulties related to the many ways of the formation of granules. The aim of the study was to perform a qualitative and quantitative analysis of granulation mechanisms with special reference to agglomerates' disintegration in the disc granulation process. This paper contains an analysis of disintegration mechanisms (abrasion and crushing) of agglomerates during the disc granulation of dolomite. The analysis of the mechanisms taking place during the process concerns the granulation stage after wetting. During the research, each time after the wetting stage, the size fraction 10-12.5 mm was substituted with an analogous fraction wetted by means of an aqueous solution of a coloring agent and the process was continued. After the specified time of granulation, the obtained product was sieved through laboratory sieves and then the content of the provided coloring agent in different size fractions was analyzed by means of a spectrophotometer. Measuring the absorbance of the analyzed samples and granulometric composition of the bed, the level and cause of the migration of material of the tested fraction into other size classes were determined, and at the same time, the occurring granulation mechanisms were analyzed. The proposed model and measurement method consisting of determining the absorbance of the tested granulometric fraction enable the qualitative and quantitative analysis of granulation mechanisms are encountered during the carrying-out of the process after wetting the bed.

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“…in ball mills (Olejnik, 2013) or in pearl mills (Heim and Solecki, 2000) take place. and Ramaker (1998) carried out analysis of granulation process with the use of coloured liquid for a more detailed examination of disintegration mechanism. Similar experiments were performed by Obraniak and Gluba (2012) and Obraniak (2017) who analysed changes in absorbance of individual fractions of granulated bed.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Disaccharide Concentration in a Liquid Binder on The Mechanisms and Kinetics of Disc Granulation

Obraniak

Gluba

2017

Chemical and Process Engineering

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Analysis of granulation kinetics was carried out using a laboratory disc granulator with a diameter D of 0.5 m. A liquid binder was delivered to the tumbling bed at a constant flow rate with a nozzle generating droplets with a size of approx. 4-5 mm. Fine-grained chalk was used as a model of raw material and water or disaccharide solution with concentrations of 20 -40% as a wetting liquid. Different times of droplet delivery ranging from 2 to 6 min were utilized. Granulometric composition of the bed for selected lengths of process, bed moisture and the moisture of individual size-fractions were assessed. Mass of granulated material, which was transferred from nuclei fraction to other size fractions was determined on the basis of mass balance analysis and the assessment of liquid migration between fractions. The influence of disaccharide concentration in wetting liquid on the aforementioned phenomena was also examined.

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Scale-down of a high-shear pelletisation process: Flow profile and growth kinetics

Cited by 82 publications

References 8 publications

Investigation of High Shear Wet Granulation Processes Using Different Parameters and Formulations

Investigation of High Shear Wet Granulation Processes Using Different Parameters and Formulations

Spectrophotometric analysis of disintegration mechanisms (abrasion and crushing) of agglomerates during the disc granulation of dolomite

The Effect of Disaccharide Concentration in a Liquid Binder on The Mechanisms and Kinetics of Disc Granulation

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