Injectability is one of the screening criteria in determining the candidacy of protein therapeutics. It is determined by the required force during injection.

Every sample can be quite unique depending on what it is formulated of. In general, we have seen most proteins to show non-Newtonian behavior. As most samples are, proteins are quite complex and when it comes to being in formulation, manufacturing, or just in general a Protein Scientists, you may see this uphill battle where you need to reduce the viscosity of the proteins, while maintaining efficacy, and also reducing as much of the physical contributions injecting your proteins could have to a patient. 

When a sample shows non-Newtonian behavior, it is recommended to test the sample at a wide shear rate range (at least 25%, 50%, and 75% full scale with RheoSense viscometers). Some proteins may actually show shear thinning behavior at much higher shear rates, while other proteins show a nice shear thinning curve over standard shear rates. It is all different so it is important for you to review and understand the scope and behavior of your special protein. 

To learn about the differences between Newtonian vs. non-Newtonian, check out our educational page here: https://www.rheosense.com/applications/viscosity/newtonian-non-newtonian

1. VROC^® technology works in a fully enclosed system. This is beneficial as it will not be affected by air causing your viscosity values to be higher or lower and you will not see any strange behavior of your sample as air interacts during measurement.
2. We provide dynamic viscosity results or what is also commonly accepted in the pharma industry as "First Principle" and also in the general industry as "true viscosity." Why get apparent viscosity readings when your data needs to be real and accurate? 
3. We have direct control of shear rates. This is beneficial especially when we determine injectability. Understanding the scope of how your sample behaves at different shear rates will also mimic the final product in its environment.

Learn more via http://www.rheosense.com/technology