Through vial impedance spectroscopy (TVIS) provides a new process analytical technology for monitoring a development scale lyophilization process, which exploits the changes in the bulk electrical properties that occur on freezing and subsequent drying of a drug solution. The development of TVIS by Professor Geoff Smith's Group at the De Montfort University Leicester, UK, in collaboration with its partners (GEA Lyophil GmbH, the National Institute for Biological Standards and Control, BlueFrog Design, Sanofi-Ireland, OncoLytika and Sciospec) marks the first time that impedance spectroscopy has been used to characterize materials within conventional glass freeze-drying vials, without having to insert the electrodes into the product (i.e. the solution under-going freeze-drying).

A commercial system has been developed by Sciospec which replicates the capability of De Montfort University’s early laboratory demonstrator, but with the additional benefit of an extended frequency range to 10 MHz and a temperature stabilized operational amplifier to reduce instrumentation drift.