A Kinetic analysis of freeze drying by immersion in an adsorbent fluidised bed process has been carried out in this paper. The process is described based on a uniformly retreating ice front model in spherical geometry. The model needs to know both temmperature and pressure driving forces, correlated as a function of water content. The influence exerted by operational conditions on the heat and mass coefficients has been studied. Transport coefficients are correlated as a function of the operating conditions to obtain equations that can be used for predicting purposes in fluid bed freeze drying. Kinetic aspects are related to quality indicators determined through shrinkage of product to select the most adequate operating conditions.