(306b) Understanding Thermodynamics of Aqueous Film Coating Process Using Data Logger

Understanding
Thermodynamics of Aqueous Film Coating Process Using Data Logger

Authors: G.
Subramanian, P. Pandey, S. Gour, D. Bindra, S. Badawy

Abstract:

Pharmaceutical film coating
process is typically monitored by inlet and exhaust condition of temperature
and humidity with measurement devices located outside the coating pan. Current
configurations of coating pans do not allow continuous measurement of the
temperature and humidity within the tablet bed.  Vast differences in heat and mass transfer
efficiencies across different coating pan sizes can result in differences in
drying and film forming dynamics across various coating pans at the same outlet
temperature and humidity. Similarly, different local temperature and humidity
conditions (and hence film forming dynamics) can be expected for coating
operations carried out at same exhaust temperature, if such temperature is
achieved by different means such as changing inlet air volume, air temperature,
suspension spray rate or suspension solids concentration. Considerable insight
into the dynamics of the coating process can be gained by using data loggers
that can be incorporated in the tablet bed and placed such that they can collect
temperature and humidity conditions in the tablet bed continuously. A design of
experiments (DOE) with coating process performed at various macro-environmental
conditions was carried out to determine their effects on the local-environmental
thermodynamics in the tablet bed. The data collected from the data loggers
enabled correlation between the changes to the macro-environment with changes in the local environment temperature and
humidity in the tablet bed. Data from the data logger was used to develop a
simple thermodynamic model based on heat and mass balance at different coating conditions
across different pan sizes.