There are lots of different ways of removing water...
The process chosen to formulate a particular drug depends on the intended delivery method as well as the stability of the substance.
一.Classical Freeze Drying
Classical freeze drying refers to freeze drying under vacuum, which is used to produce the majority of today’s dried pharmaceuticals. By removing water from the frozen rather than the liquid state, morphology, solubility and chemical integrity of the product are for the most part maintained after freeze drying. Meanwhile, in the presence of vacuum, the drying rate is accelerated and the drying temperature can be set at a lower value compared with other drying methods,
二.Solution Enhanced Dispersion with Supercritical Fluid (SEDS)
Solution enhanced dispersion with supercritical fluid (SEDS) is a novel technique which enables the production of highly characterised small particles which can be used for inhalable and transdermal delivery,
三.Atmospheric Freeze Drying
Classical freeze drying is carried out under vacuum and SEDS is conducted at high pressures. Both of these options require expensive equipment. However, atmospheric pressure freeze drying does provide another option
