Project Summary/Abstract
Physical Sciences Inc. (PSI), in collaboration with the University of Connecticut (UConn), and with
industry participation form Merck, proposes to develop and verify a fundamental model of Microwave-
Assisted Freeze Drying (MAFD) to enable its implementation for pharmaceutical manufacturing. This effort
will leverage primary drying models of traditional shelf-based freeze drying in vials developed and tested with
support from the National Institute for Innovation in Manufacturing Biopharmaceuticals (NIIMBL). Our goal is
to develop a heat and mass transfer model of the primary drying, or ice sublimation phase of MAFD freeze-
drying, the most time consuming and critical phase. The model will predict the temperature of the product
throughout primary drying and the drying time based on input parameters for the container system (e.g. vial,
tray or dual chamber syringe), the product formulation (e.g. dielectric properties, resistance to drying, etc.),
and the process conditions (e.g. microwave frequency, microwave power, chamber pressure).
This program supports the advancement of regulatory science to facilitate the implementation of
emerging manufacturing technology in the pharmaceutical sector. Microwave-assisted freeze drying (MAFD)
is emerging as an alternative to traditional freeze drying as MAFD can significantly reduce processing costs
and time compared to traditional freeze drying while maintaining product efficacy and stability. For example,
studies have shown an approximately 80% reduction in cycle time using MAFD over traditional freeze drying.
MAFD has more commonly been used in the food industry, and has not been applied to drying of
pharmaceutical products at a large scale. This is partially due to a lack of knowledge of formulation response
to microwave energy, and heat and mass transfer in MAFD processes to ensure efficient process design
while maintaining product quality attributes. The successful completion of this program will result in a heat
and mass transfer model of MAFD and a database of formulation microwave power absorption that can be
used by industry to enable implementation of MAFD processes. Transitioning from traditional freeze drying
to MAFD will result in reduced processing costs and cycle times and enable more agile manufacturing
including on-demand and semi-continuous processes.
This effort is particularly relevant during this current global pandemic. Administration of the current
COVID-19 vaccines was limited by cold chain storage requirements. As COVID-19 vaccination programs
transition from emergency response to routine administration, the economics of production and distribution
will become more crucial. It is likely that future development of the COVID-19 vaccines will focus on freeze
drying for product stabilization and distribution. Many common vaccines require freeze-drying, including
those to prevent measles, yellow fever, Hib, BCG, H1N1, etc. Development of economical freeze-drying
cycles will be critical for production of COVID-19 vaccines in manufacturing facilities around the world.
