Development and evaluation of a dimensionless mechanistic pan coating model for the prediction of coated tablet appearance

•A mechanistic model of a pharmaceutical tablet pan coating process to predict coated tablet appearance quality is developed.•Prediction of tablet appearance prior to experiment or production.•Characterisation of tablet coating process using dimensionless quantities – dimensionless spray flux and Niblett Number.•Dimensionless regime map for tablet film coating created and evaluated – over-wetting defect region identified.•The Niblett Number differentiates processes based on droplet drying thermodynamics and kinetics.