Wet film dimensions of capsule walls during dip coating.

The objective of the present study was to improve our understanding of the relationships between wet film dimensions, dip sequences, and the physicochemical properties of the dip solutions as they pertain to the dip-coating process for the manufacture of hard-shell capsules. To achieve this objective, it was necessary to develop a technique to quantify wet film dimensions. A further objective was to develop a predictive model for dip coating with hydroxypropyl methylcellulose (HPMC) solutions. It is hoped that the information contained in this article on significant variables controlling wet film thickness will help manufacturers develop consistent manufacturing controls and processes.