Many in the pharmaceutical and vaccine industries are incredulous that a cheap high-temperature process like spray drying can safely dry vaccines or labile drugs without harm. The secret is:-
During drying, the tiny droplets of formulation solution sprayed into the hot gas stream experience extreme evaporative cooling which prevents the liquid contents from being heated to temperatures much above 40°C
As they dry, they form solid glass microspheres and although evaporative cooling stops, the active molecules are now protected against thermal damage by being embedded in the stable glass. Finally, total residence time in the dryer and cyclone is only a few seconds so that damage is further minimised. In fact the stress of spray drying is considerably less than freeze dying.
Computational Fluid Dynamic (CFD) analysis shows the temperature profiles in particles of two different diameters as they pass through the drying chamber to dry in less than 200 milliseconds.
The world's first commercial sterile spray dryer for producing injectable vaccines has been commissioned by Cambridge Biostability Limited (CBL). Now operational, the £1million Aseptic Spray Drying facility (ASD1) will be able to produce sterile, clinical trials material manufactured to the highest pharmaceutical quality and approved by regulatory authorities - accelerating the time to market as a precursor to large-scale stable liquid vaccine manufacture.
Production at the facility which has been installed at Nova Laboratories, Leicester, will include material for a stable childhood pentavalent vaccine for which CBL was awarded a grant from the UK's Department for International Development. It is anticipated that the production facility will shave a year off the development time, allowing clinical trials to start in 2008.
Dr Bruce Roser, Chief Scientific Advisor, CBL comments that there is already demand from its partners and from outside companies for the facility and that it was important the first facility was built in the UK: "This is a radically new technology that will enable batches of 10,000 - 30,000 doses to be produced under cGMP (Current Good Manufacturing Practice). The plant allows us to address scale up issues and perfect the process. The next sterile facility will be for commercial production of stable liquid vaccines and will be ten times bigger."
"Traditionally vaccines are made in a batch process; measles for example is made by batch tissue culture and takes 3 days to freeze dry. With a spray dryer, drying takes seconds and the equipment can run continuously until sufficient quantity is made. If all vaccines were made by spray drying we could ease the problems of shortages due to production bottlenecks, enabling supply to be linked more precisely to demand."
As a service to the industry CBL is already scheduling contract manufacturing on the ASD1 for other companies wishing to evaluate cGMP sterile spray drying for their products before they commit to major expenditure on new plant. More details can be obtained by contacting our Director of Business Development Kiran Gulati:
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alternatively contact us on +44 (0) 1223 437400 and we will be happy to help answer your questions.
Cambridge Biostability Limited is a limited company registered in England & Wales with registered number 003630055 and having its registered office at Unit 184, Cambridge Science Park, Milton Road, Cambridge, CB4 0GA, UK.
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