Impact of fill-level in twin-screw granulation on critical quality attributes of granules and tablets

Meier, Robin; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter

doi:10.1016/j.ejpb.2017.02.010

Cited by 66 publications

(37 citation statements)

References 30 publications

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“…discounting the packing fraction) as 4-7.23%. These values are lower than the ranges observed in alternative twin-screw devices (10-30%) [58], however, 315 the method presented in this paper does not account for non-dynamic mass (i.e. material that is stuck to the walls), which could be significant as demonstrated in other experimental studies [56].…”

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confidence: 56%

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Analysing the effect of screw configuration using a stochastic twin-screw granulation model

McGuire

Mosbach

Reynolds

et al. 2019

Chemical Engineering Science

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In this work, a framework for modelling twin-screw granulation processes with variable screw configurations using a high-dimensional stochastic population balance method is presented. A modular compartmental approach is presented and a method for estimating residence times for model compartments based on screw element geometry is introduced. The model includes particle mechanisms for nucleation, primary particle layering, coalescence, breakage, and consolidation. A new twin-screw breakage model is introduced, which takes into account the differing breakage dynamics between two types of screw element.Additionally, a new sub-model for the layering of primary particles onto larger agglomerates is presented. The resulting model is used to simulate a twin-screw system with a number of different screw configurations and the predictive power of the model is assessed through comparison with an existing experimental data set in the literature. For most of the screw configurations simulated, the model predicts the product particle size distribution at large particle sizes with a reasonable degree of accuracy. However, the model has a tendency to over-predict the amount of fines in the final product. Nevertheless, the model qualitatively captures the reduction in fines associated with an increase in the number of kneading elements, as observed experimentally. Based on model results, a number of key areas for future model development are identified and discussed. 35 may be quickly assessed without the usage of excipient/API or the need to set-up the device etc. This has generally been attempted through the use of compartmental population balance models (PBM) [12]. Several examples of compartmental twin-screw PBMs exist in the literature [13,14,15, 16,17]. In these examples, the screw barrel domain is modelled as a number of connected 40 compartments that permit process conditions and thus particle morphology to vary along the length of the simulation domain. These examples have used a sectional solution approach [18,19,20] which allows the compartmental PBM to be approximated and solved as a system of ordinary differential equations.This numerical approach generally limits the particle representation to taken 45 3 on three dimensions at most. The Stochastic particle method [21,22,23, 24,25,26,27,28] is alternative approach that has been employed to solve PBMs for batch granulation systems [29, 30,31,32,33,34,35,36, 37], silica [38] and TiO 2 [39] nano-particle synthesis, soot formation [40,41], and more recently twin-screw granulation [42, 43]. Unlike sectional methods, stochastic particle 50 methods permit much more complex particle representations, which can then be leveraged within the process model description, whilst still yielding a numerical problem that can be solved with acceptable levels of computational effort.The main aims of this paper are:1. Improve the stochastic TSG model in McGuire et al. [42, 43] based on the 55 areas identified for improvement. 2. Construct a modelling framework that allows for the compar...

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confidence: 56%

“…while t < t stop (z) do 5 Apply global deferment Algorithm (1). 6 Compute R SWA total (z, t) according to (58). 7 Compute ∆t wait according to (57).…”

Section: Solver Implementation 435mentioning

confidence: 99%

Analysing the effect of screw configuration using a stochastic twin-screw granulation model

McGuire

Mosbach

Reynolds

et al. 2019

Chemical Engineering Science

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“…But subdividing the granules from 212–1400 µm into 212–600 µm, 600–1000 µm and 1000–1400 µm showed effect of granule size on the tablet tensile strength at different screw speed ( Figure 18 b). Increasing the granule size range from 212–600 µm to 600–1000 µm and to 1000–1400 µm, decreased the tensile strength of the tablet [ 43 , 44 ]. The smaller granule size range (212–600 µm) produced stronger tablets [ 36 , 45 ].…”

Section: Discussionmentioning

confidence: 99%

Twin Screw Granulation: Effects of Properties of Primary Powders

2018

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Lactose and mannitol are some of the most commonly used powders in the pharmaceutical industry. The limited research published so far highlights the effects of process and formulation parameters on the properties of the granules and the tablets produced using these two types of powders separately. However, the comparison of the performance of these two types of powders during twin screw wet granulation has received no attention. The present research is focused on understanding the granulation mechanism of different grades of two pharmaceutical powders with varying properties (i.e., primary particle size, structure, and compressibility). Three grades each of lactose and mannitol were granulated at varying liquid to solid ratios (L/S) and screw speed. It was noticed that primary powder morphology plays an important role in determining the granule size and structure, and tablet tensile strength. It was indicated that the processed powders such as spray-dried and granulated lactose and mannitol can be used in formulation for wet granulation where flowability of active pharmaceutical ingredient (API) is poor.

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“…However, there are few studies measuring the degree of fill of the resin in the TSEs. The degree of fill, also called as the filling ratio, fill ratio, filling level, or fill degree,, is a time‐dependent periodic state variable and is fundamentally important for mixing and devolatilizing gases in the operating TSEs . We believe that measuring the degree of fill quantitatively would be useful for the validation of numerical simulations and theoretical calculations, and would facilitate the design, operation, and maintenance of TSEs.…”

Section: Introductionmentioning

confidence: 99%

“…The degree of fill is measured through a transparent barrel in a non‐TSE by using four cameras; (3) the TSE in operation is stopped rapidly and the screws are quenched. Following this, the resin volume is measured gravimetrically after pulling out the screws in sections …”

Section: Introductionmentioning

confidence: 99%

Online Monitoring of the Degree of Fill in a Rotating Full‐Flight Screw of a Corotating Twin‐Screw Extruder

et al. 2018

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It is essential to understand the extent of partial filling of the flight screw, the degree of fill, which is an operational variable of the twin-screw extruder (TSE). This article reports the first attempt to measure, in situ, the degree of fill in a rotating full-flight screw using a specialized light-section method for a TSE. The thickness of the resin sticking to the pushing side decreased with increasing rotational speed. The degree of fill is inversely proportional to the rotational speed and proportional to the feed rate. This result agreed well with the results suggested by the conventional analysis of flow in the TSEs. The fast Fourier transformation of the degree of fill time series indicated that the period of fluctuation correlated with the screw speed rather than the feed rate or throughput. Keywords: twin-screw extruder, degree of fill, molten polymer, light section method As a fundamental research on the flow characteristics of TSEs, many studies have been carried out on the measurement of resin pressure at the barrel surface, the residence time distribution, and the resin temperature of the molten resin along the extrudate direction. 1-7 However, there are few studies measuring the degree of fill of the resin in the TSEs. The degree of fill, also called as the filling ratio, fill ratio, filling level, 8 or fill degree, 9 , is a time-dependent periodic state variable and is fundamentally important for mixing and devolatilizing gases in the operating TSEs. 10 We believe that measuring the degree of fill quantitatively would be useful for the validation of numerical simulations and theoretical calculations, and would facilitate the design, operation, and maintenance of TSEs. The evaluation of degree of fill is carried out by three different methods: (1) direct observation through a viewing window 11,12 ; (2) a transparent barrel is used to measure the

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Impact of fill-level in twin-screw granulation on critical quality attributes of granules and tablets

Cited by 66 publications

References 30 publications

Analysing the effect of screw configuration using a stochastic twin-screw granulation model

Analysing the effect of screw configuration using a stochastic twin-screw granulation model

Twin Screw Granulation: Effects of Properties of Primary Powders

Online Monitoring of the Degree of Fill in a Rotating Full‐Flight Screw of a Corotating Twin‐Screw Extruder

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