Multiscale Modelling Methodology for Virtual Prototyping of Effervescent Tablets

Computational methodology for virtual tablet prototyping has been developed. The methodology consists of two steps: construction of virtual particle compacts of varying composition using the discrete element method (DEM), and the simulation of their dissolution by eroding individual components from the tablet microstructure according to their intrinsic dissolution rates, using the volume-of-fluid (VOF) method. The effective erosion rate obtained from simulations at the particle assembly length-scale is used for the calculation of dissolution time at the tablet length-scale. The methodology is demonstrated on the case of a simple effervescent formulation consisting of sodium bicarbonate-acetic acid effervescent system, sodium chloride as a model active substance, and lactose filler. The experimentally measured dependence of tablet dissolution time on composition and compaction force was found to be in very good agreement with outputs from computer simulations. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association.