Spray dryers are shrinking in size

The smallest spray dryer ever made is the claim of the new SDMicro from Danish company Niro. It is a miniature spray drying plant that replicates the operation of large industrial spray dryers, and gives pharmaceutical companies working with small quantities of high value product the opportunity to assess the applicability of spray drying technology for future scaled-up manufacture.

The SDMicro has a two-fluid nozzle for atomising the liquids, a 200mm diameter drying chamber which maintains the same gas flow pattern as in full-scale units, a cyclone for primary separation of powders and a bag filter with compressed air pulse cleaning.

The drying chamber may be either glass or stainless steel. The glass version allows observation of the spray drying process and the atomisation and formation of possible product deposits. Once the optimum process parameters have been determined, the chamber can be replaced by the stainless steel version, which has better surface characteristics and fewer seams. The SDMicro can be used for product quantities as small at 200mg dry powder, from which it is expected to collect 20-80% useful powder, says Niro.