Gravimetric Measurement of Momentary Drying Rate of Spray Freeze-Dried Powders in Vials

Production and Characterization of Rapidly Dissolving Cryopellets

“…Cryopellets produced from solutions containing 10% (w/v) solid or more are therefore resistant to a postfreeze‐drying filling process with a falling height of about 5 cm. This allows a freeze‐drying step in containers that show better heat transition compared with standard freeze‐drying vials, for example, aluminum or steel trays, combined with a filling process of the dry product.…”

“…Product temperature during the freeze‐drying process was observed using T‐type thermocouples that were placed in the center of a droplet during freezing. All pellets were in contact with the bottom of the stainless steel bowl, as heat transfer between spherical products during freeze‐drying is poor . The freeze‐drying cycle reported in Table was used for the cryopellet batches that was the same for all batches except for the annealing step that was performed for mannitol‐based batches only.…”

“…During a cryopelletization or SFD process, the solution is not frozen in vials within the freeze dryer but dropped or sprayed into a cryogen, resulting in spherical particles because of the inverse Leidenfrost effect . Different cryogenics are reported in the literature including isopentane and propane, but the most commonly used cryogen used is liquid nitrogen (LN 2 ) because it is chemically inert, needs no recycling, is not flammable, and has a low boiling point (77 K). As the freezing step cannot be so precisely controlled as in a standard freeze‐drying procedure, its detailed characterization is crucial.…”

Comminution of Carbohydrate and Protein Microparticles on Firing in a Ballistic Powder Injector

“…The dispersion of frozen particles was then transferred to the precooled shelf of a Christ Δ 1–24 kDa freeze‐dryer at −40°C. After evaporation of the remaining liquid nitrogen the powder was freeze‐dried using the cycle given in Table 1 that is taken from the literature 10. All the SFD powders were stored under dry nitrogen at room temperature until used for investigation.…”

Spray Freeze-Drying as a Solution to Continuous Manufacturing of Pharmaceutical Products in Bulk

“…SFD has been effectively employed to produce dry biomacromolecule powders for specific applications such as pulmonary delivery, microencapsulation, and enhancing the solubility of poorly water-soluble drugs. It has also been used to produce microparticles with characteristic morphology and adequate stability by developing particle formulations [100].…”