Vacuum freeze-drying of a liquid in a vial: determination of heat and mass-transfer coefficients and optimisation of operating pressure

Abstract The kinetics of freeze-drying and temperature changes in the product core have been established for milk and water frozen in vials. The influence of heating plate temperature, working pressure and initial water content on the sublimation kinetics have been studied. The operating pressure is paramount since it causes dehydration speeds to vary by a factor of 1–2. Through the use of a simple model of the ‘uniformly retreating ice front’ type, it has been possible to identify the transfer parameters of the model. Correlations with the operating pressure have been established. The results show a working pressure optimum at 200 Pa.

[1]  Armstrong Jg.  Use Of The Capacitance Manometer Gauge in Vacuum Freeze-Drying , 1980 .

[2]  M. Pikal,et al.  Process control in freeze drying: determination of the end point of sublimation drying by an electronic moisture sensor. , 1989, Journal of parenteral science and technology : a publication of the Parenteral Drug Association.

[3]  F. Rodolphe,et al.  Vacuum freeze-drying kinetics and modelling of a liquid in a vial , 1989 .

[4]  P. Fito,et al.  Thermal conductivity of porous bodies at low pressure: Part I , 1984 .

[5]  M. Pikal,et al.  Use of laboratory data in freeze drying process design: heat and mass transfer coefficients and the computer simulation of freeze drying. , 1985, Journal of parenteral science and technology : a publication of the Parenteral Drug Association.

[6]  M. Pikal,et al.  Mass and heat transfer in vial freeze-drying of pharmaceuticals: role of the vial. , 1984, Journal of pharmaceutical sciences.

[7]  Samuel Abraham Goldblith,et al.  Freeze-drying and advanced food technology. , 1975 .

[8]  S L Nail,et al.  Advances in control of production freeze dryers. , 1985, Journal of parenteral science and technology : a publication of the Parenteral Drug Association.