A new process control strategy for aqueous film coating of pellets in fluidised bed

TY - JOUR

T1 - A new process control strategy for aqueous film coating of pellets in fluidised bed

AU - Larsen, C.C.

AU - Sonnergaard, Jørn

AU - Bertelsen, Pernille Scholdan

AU - Holm, P.

PY - 2003/11/1

Y1 - 2003/11/1

N2 - The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit® NE 30D, Eudragit® RS 30D, Aquacoat ECD®) coating principle (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed to be the controlling factor. The type of pellets affected the maximum spray rate. A thermodynamic model for the coating process is employed throughout the process and not just during steady state. The thermodynamic model is incorporated into a new process control strategy. The process control strategy is based on in-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air temperature.

AB - The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit® NE 30D, Eudragit® RS 30D, Aquacoat ECD®) coating principle (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed to be the controlling factor. The type of pellets affected the maximum spray rate. A thermodynamic model for the coating process is employed throughout the process and not just during steady state. The thermodynamic model is incorporated into a new process control strategy. The process control strategy is based on in-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air temperature.

UR - http://www.scopus.com/inward/record.url?scp=0242270817&partnerID=8YFLogxK

U2 - 10.1016/S0928-0987(03)00206-9

DO - 10.1016/S0928-0987(03)00206-9

M3 - Journal article

AN - SCOPUS:0242270817

SN - 0928-0987

VL - 20

SP - 273

EP - 283

JO - Norvegica Pharmaceutica Acta

JF - Norvegica Pharmaceutica Acta

IS - 3

ER -