Non-Aqueous Suspensions Could Push Antibody Concentrations Above 400 mg/mL, Says Nanoform’s Chris Worrall

High-concentration antibody formulations are central to moving biologics toward subcutaneous delivery, but stability and viscosity have kept them below a practical ceiling. In this first part of a two-part interview with BioPharm International® ahead of the AAPS PharmSci 360 2026 conference in New Orleans, Chris Worrall, PhD, vice president of US business development at Nanoform, discusses what limits antibody concentration today and how his company’s particle engineering approach is designed to get past it.

According to Worrall, approximately 50 marketed antibody products have concentrations above 100 mg/mL, but none has yet exceeded 200 mg/mL. He identifies two main reasons. The first is stability. “When you pack more antibody into a solution, you have an increase in protein-protein interactions, and so that can lead to a decrease in colloidal stability,” Worrall says. Those interactions can also increase aggregation, leading to the formation of high-molecular-weight species.

The second is viscosity. Worrall explains that solutions typically show an almost exponential rise in viscosity in the 100 to 200 mg/mL range, which creates problems with injection force. Developers have turned to additional excipients to stabilize the protein or reduce viscosity, which has brought some products close to 200 mg/mL. “When you start talking about those kind of higher concentrations above 200, that’s really where novel approaches need to be discovered,” he says.

How does Nanoform’s particle engineering process produce high-concentration antibody suspensions?

Nanoform’s proprietary process is evaporative. It starts with a feedstock solution of the antibody formulated with standard excipients, such as sugars and buffering agents. The solution is nebulized, and the resulting mist is guided into a drying chamber, where a drying gas is typically set at 50 °C or below.

Rather than falling, the particles travel upward against gravity and dry slowly, over seconds to tens of seconds. Worrall says this produces spherical, dense particles of the size and shape suited to suspension formulations. “The fact that it’s low temperature, we don’t have large shear stresses, means that we can maintain the activity of the protein after having gone through this process,” he explains. The particles are then given an electrostatic charge so they can be collected in an electrically charged chamber and isolated as a dry powder.

The powder is then suspended in a non-aqueous vehicle, which Worrall notes removes the protein-protein interactions that drive up viscosity in aqueous solutions. Because the non-aqueous vehicles are non-Newtonian, they thin under shear stress, lowering viscosity during injection. According to Worrall, the approach can support concentrations above 400 mg/mL, and in some cases above 500 mg/mL, while maintaining suitable stability and injectability.

AAPS PharmSci 360 2026 took place October 24–28 in New Orleans. To explore more of our conference coverage, click here.

About the Speaker

Chris Worrall, PhD, vice president of US business development, Nanoform
Chris Worrall is vice president of US business development at Nanoform, based in San Diego. A synthetic chemist by training, he holds a PhD in synthetic chemistry and has spent about 19 years in particle engineering. His work focuses on how controlling the morphology and shape of particles influences their performance in formulations. Initially concentrated on small molecules, his work now spans both small- and large-molecule products, including approaches to formulating biologics at high concentrations.