Experimental Analysis of Tablet Properties for Discrete Element Modeling of an Active Coating Process

Abstract

Abstract. Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tabletcoating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young's modulus, coefficient of restitution (CoR), and coefficients of friction (CoF) of gastrointestinal therapeutic systems (GITS) and of activecoated GITS were measured experimentally. The dynamic angle of repose of these tablets in a drum coater was investigated to revise the CoF. The resulting values were used as input data in DEM simulations to compare simulation and experiment. A mean value of Young's modulus of 31.9 MPa was determined by the uniaxial compression test. The CoR was found to be 0.78. For both tablet-steel and tablet-tablet friction, active-coated GITS showed a higher CoF compared with GITS. According to the values of the dynamic angle of repose, the CoF was adjusted to obtain consistent tablet motion in the simulation and in the experiment. On the basis of this experimental characterization, mechanical parameters are integrated into DEM simulation programs to perform numerical analysis of coating processes.

A multivariate regression parametric study on DEM input parameters of free-flowing and cohesive powders with experimental data-based validation

“…From Fig. 11a, it can be seen that the angle of repose increases with an increase in the sliding and rolling friction coefficients, which is proven in other studies as well [25,46,[71][72][73][74]. This positive correlation is similar in both freeflowing and cohesive powders.…”

Modeling of an Active Tablet Coating Process

“…The values were taken from measurements reported in Ref. . It is known that the friction parameter (particle–particle and particle–wall) has a significant influence on the outcome .…”

Estudo da influência dos coeficientes de atrito estático e fricção de rolamento em simulações DEM de tambores rotativos com suspensores

“…A abordagem Lagrangeana, conhecida também como DEM (Discrete Element Method), consiste no acompanhamento de cada partícula individualmente, juntamente com a conseqüente aplicação do balanço de forças, levando em consideração interações com as demais partículas, esta abordagem se sobressai por permitir a visualização e utilização de partículas irregulares (JUST et al, 2013). Dentre as dificuldades encontradas na abordagem Lagrangeana é possível ressaltar a necessidade de se utilizar coexistências para descrever as interações partícula-parede, partícula-partícula e partícula-gás, e a dificuldade de prever as variáveis de campo para a fase particulada, dificultando assim a visualização científica dos fenômenos que influenciam as trajetórias das partículas.…”