[Comparative studies on freeze dryers of one and two chamber systems]

Authors carried out a comparative study on freeze--dryers of one--and two chamber-systems. Samples containing dextran and mannitol were used for the control of process-uniformity. Moisture content of the products were monitored during the sublimation process and after closing the ampules by colouring of the CoCl2 labelled samples. They put forward proposals for the combined measurement of barometric vapor pressure and product temperature in order to improve safety.