Acceleration of Heat Transfer in Vial Freeze-Drying of Pharmaceuticals. II. A Fluid Cushion Device

Samuel H. Yalkowsky, Suresh D. Patel

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


A simple device for the improvement of freeze-drying efficiency is described. The device is an aluminum foil bag which contains a small amount of glycerin. The device can be either reusable or disposable. When placed on a freeze-drying tray the liquid is about 1 mm thick. When vials are placed on the device it conforms to the shape of the vial bottoms. Since both the aluminum foil and the glycerin are better heat conductors than a vacuum, the device improves heat transfer from the shelf to the vial. Drying times obtained with and without the device are compared for different sizes as well as different types of vials. In most cases the use of the device reduces the drying time by nearly a factor of two. The use of the device also increases vial-to-vial uniformity and minimizes the effect of spillage.

Original languageEnglish (US)
Pages (from-to)753-758
Number of pages6
JournalPharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists
Issue number6
StatePublished - Jun 1992


  • fluid cushion device
  • freeze-drying
  • heat transfer
  • vials

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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