biologics delivery

Question 1

viscosity issue

Answer 1

need for very concentrated formulations because the required doses are often on the order of hundreds of miligrams but the injection of 1mL in a single dose has historically been the upper threshold of acceptability.
Viscosity is important for ‘syringeability’ - the force required to inject a given solution at a given rate via a chosen needle length and gauge, flow through a hollow needle in inversely proportional to viscosity.

Formulations with high viscosity can lead to high injection forces and long injection times

The creation of formulations with lower viscosities is
therefore advantageous. Approaches to achieve this include the addition of
hydrophobic salts or inorganic salts or the addition of amino
acids lysine or arginine. However, the approaches to reduce viscosity by adjusting pH
and/or ionic strength are typically limited, as these influence
the stability of the protein as well

Question 2

structure

Answer 2

Biopharmaceutical drugs offer the advantages of high specificity and potency compared to small molecules, due to their macromolecular nature, which provides the structural complexity that is often required for specificity.
However, this structural complexity also makes
them some of the most challenging molecules
to formulate and deliver. The efficacy and safety of therapeutic proteins affected by their secondary, tertiary, and quaternary structures