Formulation as a stage in downstream processing and what it entails
Formulation refers to the maintenance of stability and activity of a biotechnological product during
distribution and storage. It is a stage in downstream processing. Formulation of low molecular
weight products can be achieved by removing of most water. Formulation can be done by
crystallization for small molecules by adding salt.
Proteins formulation requires special care as they are highly susceptible for loss of biological activity.
In order to prolong the shelf life of proteins, certain stabilizing additives are added. These stabilizers
include sugars, salts, polymers and polyhydric alcohols.
Below are essential components of product formulation in downstream processing
Drying
Spray drying
Freeze drying
Drying is an essential component when it comes to product formulation in downstream processing.
It involves the transfer of het to a wet product in order to remove moisture. Most of biological
products of fermentation are very sensitive to heat and they therefore require gentle drying methods.
Drying devices may be categorised as; convention, radiation dryers and contact dryers, etc.
The Spray drying is mainly implemented for ventilation of huge liquid volumes in downstream
processing. In this type of drying, small droplets of liquid containing the product are passed through a
nozzle which directs it over a stream of hot gas. The hard elements are left behind as the water
evaporates.
Freeze drying is most favoured technique for formulating a wide range of products and drying in
downstream processing. It is used in formulating products like foodstuffs, diagnostics, bacteria,
viruses and pharmaceuticals. Freeze drying does not cause loss of biological activity of the desired
product and this is the main reason why it is preferred.
Freeze drying is based on the principle of sublimation of liquid from a frozen state. The liquid that
contains the product is frozen and dried in a freeze dryer under a vacuum. As the vacuum is released,
the product containing vials is sealed.
