Evaluation of monoclonal antibody formulation propensity for dripping at the filling nozzle tip end

Nonionic surfactants are commonly used as excipients in monoclonal antibody formulations. The interfacial activity of surfactants may contribute to the elongation of solution droplets at the filling nozzle tip end, leading to dripping that may impact dose accuracy and process consistency. Axisymmetric drop shape analysis was used to evaluate the propensity of monoclonal antibody solution droplets for elongation in the presence of a nonionic surfactant (polysorbate 20, polysorbate 80, poloxamer 188, Brij®35, Brij®58 or FM1000). A droplet was created using a syringe and dosing needle, or a pump and filling nozzle. Droplet elongation rate was defined as the slope of a linear regression of droplet interfacial surface area over time. An increase in elongation rate led to a quicker occurrence of droplet pinch-off, meaning a higher propensity for dripping. Elongation rate increased with both initial droplet volume and surfactant concentration. The evolution of elongation rate with initial droplet volume provided some insights into interface stretching capacity. We propose droplet elongation rate as an indicator of monoclonal antibody formulation propensity for dripping.