In general, all materials can be freeze dried, except for samples of oil rich products, sugar rich materials, products forming an impervious skin, and products containing high salt concentration.
The material can be in a liquid state as an emulsion, dispersion or as a solid of bulk materials.

The pressure must be below the ice vapor pressure of the frozen samples. However, very low pressures are often counterproductive since the vacuum is not the only factor facilitating the sublimation process. Since sublimation is an endothermic process, it is also important to supply the frozen samples with energy with respect to the critical sample temperatures.

The heated shelf provides the energy to increase the sublimation rate and as a result the drying time becomes shorter. Furthermore, the process is reproducible due to the consistent input of energy. Furthermore, the shelf can be heated up to 60°C which can dramatically decrease the moisture content to about 1%.
The Lyovapor Pro system with heatable shelves gives accurate heat distribution to within +/-1 °C across the entire shelf, thus improving the efficiency of the process.

In the primary phase the glass transition temperature (Tg`), the superior collapse temperature or the eutectic temperature of the frozen sample are the key parameters. In the secondary drying the glass transition temperature as well as the eutectic temperature of the solid sample should not be exceeded. The Lyovapor Pro system offers the sample protection mode preventing sample damages in consequence of the temperature rise above the critical values.

Pirani gauge for pressure measurement, capacitive gauge for highly accurate pressure measurement, RTD thermocouple for precise product temperature measurement.

The Lyovapor Pro systems depending on L-200 or L-300 have 3 options for endpoint determination, the temperature difference test, pressure difference test, pressure rise test. These tests are feasible with optional pressure and temperature sensors.

Infinite Control is the synergy of the Pro interface with access to heatable shelves, the Lyovapor software for data logging, process control, and the Monitor App for real-time process monitoring. This combination enables a convenient, efficient freeze drying cycle and optimum products.

It is advisable to place the temperature sensor (to determine the end-point) in a vial located in the middle of the drying shelf.