Pharmaceutical patent applications in freeze-drying

Edmond Ekenlebie, Tomaž Einfalt, Arianna Irò Karytinos, Andrew Ingham

Research output: Contribution to journalReview articlepeer-review


Injectable products are often the formulation of choice for new therapeutics; however, formulation in liquids often enhances degradation through hydrolysis. Thus, freeze-drying (lyophilization) is regularly used in pharmaceutical manufacture to reduce water activity. Here we examine its contribution to 'state of the art' and look at its future potential uses. A comprehensive search of patent databases was conducted to characterize the international patent landscape and trends in the use of freeze-drying. A total of 914 disclosures related to freeze-drying, lyophilization or drying of solid systems in pressures and temperatures equivalent to those of freeze-drying were considered over the period of 1992-2014. Current applications of sublimation technology were contrasted across two periods those with patents due to expire (1992-1993) and those currently filed. The number of freeze-drying technology patents has stabilized after initial activity across the biotechnology sector in 2011 and 2012. Alongside an increasing trend for patent submissions, freeze-drying submissions have slowed since 2002 and is indicative of a level of maturity.

Original languageEnglish
Pages (from-to)407-416
Number of pages10
JournalPharmaceutical patent analyst
Issue number6
Publication statusPublished - 2 Nov 2016

Bibliographical note



  • batch production
  • continuous
  • freeze-drying
  • lyophilization
  • lyoprotectant
  • solvent systems


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