This problem may be exacerbated by the move to smaller cannulas and quicker injection times, which require an increased flow rate of fluid through the needle.Д¬oncurrent with the rise of higher concentrations of mAbs has been a shift in delivery trends. This can result in aggregation and a loss of solubility, to the point that the protein can no longer perform its intended function. 3 Shear force can break apart weaker hydrogen bonds present in the structure, which can denature or вЂњtearвЂќ proteins. Many higher molecular weight formulations can also be susceptible to molecular shear at higher flow rates. For viscous fluids (50 cP), the required pressure can be as high as 600 psi for a 2.25 mL volume.ДЇigure 1: Pressure drop needed to deliver 1 mL or 2.25 mL of fluid of indicated viscosities in 15 seconds. Increased viscosity requires a corresponding increase in pressure to ensure delivery of the volume in the same length of time. D is the internal diameter of the needle.ДЇigure 1 shows the pressure drop needed to deliver the indicated volume in 15 seconds.The force needed to push a fluid through a cylinder is governed by the Hagen-Poiseuille equation: 2 The higher the viscosity, the greater the force required to push the drug through the narrow cannulas typically used for parenteral delivery, especially at lower temperatures. As the concentration of drug formulations increases, so does the drugвЂ™s viscosity or вЂњthicknessвЂќ. 1 The molecules that comprise most biologics, including monoclonal antibodies (mAbs), have molecular weights in the hundreds of thousands of Daltons (Da). In 2020, biologics accounted for more than half of the worldвЂ™s 20 top selling drugs. Michael Roe discusses the development of the Aerioв„ў Platform of gas-powered injection systems.

Citation: Roe MJ, вЂњChallenges in High-Viscosity, High-Volume Drug DeliveryвЂќ.

High viscosity