Taking into account the above-mentioned disadvantages, it can be noted that as an alternative to the process of vacuum sublimation is atmospheric freeze drying, which allows to obtain a product that is not inferior in quality to the product produced by vacuum freeze drying, as well as provides an opportunity to intensify dehydration and reduce production costs.

Atmospheric spray freeze drying. Transition from vacuum conditions to atmospheric pressure allows to exclude from the technological process expensive and energy-consuming vacuum equipment, reduce operating costs. The intensity of vacuum sublimation drying in a fixed layer in comparison with similar sublimation drying at atmospheric pressure is much higher, which is explained by an increase in the driving force of the process in low pressure conditions – the temperature difference between the dried material and the environment.

Atmospheric freeze drying in conditions of convective heat supply (for example, in a spray chamber or fluidized bed apparatus) allows to intensify the process of moisture removal dozens of times.

A special feature of the spray drying chamber design is the perforated walls through which the drying agent is fed. The created gas flows prevent particles from sticking to the chamber walls. Free-flowing powders of thermolabile pharmaceutical materials containing highly porous microparticles with good aerodynamic properties were obtained on this unit.