Tackling Challenges in Filling Highly Viscous Products into Syringes

Advancements in pharmaceuticals and biologics have led to innovative formulations that often bring new complexity to manufacturing. Among the most persistent challenges is the precise, aseptic filling of highly viscous products into syringes—a task that demands specialized equipment and sophisticated know-how to ensure safety, accuracy, and quality.

Why Viscosity Matters

Highly viscous products—like concentrated protein drugs, suspensions, and certain specialty injectables—don’t flow easily, which makes moving them through standard filling systems difficult. They are prone to problems such as air entrapment, inconsistent dosing, needle clogging, and process-yield losses if not carefully managed. These obstacles can lead to product waste and potential risk to dose accuracy and sterility.

Engineering Around Viscosity

Success in syringe filling starts by matching the right technology to the product. For viscous products, conventional peristaltic pumps will struggle to maintain throughput; piston pumps and pressure-assisted filling are often used, as they deliver greater mechanical efficiency for higher viscosity ranges. Colanar’s pumps handle viscosities up to 250,000 cP, making them ideal for everything from thin solutions to highly viscous dermal fillers. Reinforced tubing, customized nozzles, and optimized processing parameters help reduce pressure drops, prevent bulging, and ensure accurate fill volumes. Careful mixing and vacuum application help reduce air bubbles, which can otherwise cause dosing inconsistencies and challenges during fill-finish operations.

Advancements for Reliable Filling

Modern filling solutions include modular systems designed for maximum adjustability. By tailoring pump type, fill rates, and tubing materials, manufacturers can minimize product loss and maximize fill accuracy, even as viscosity varies from batch to batch. Recent innovations allow gentle handling of shear-sensitive bioproducts and enable safety for both operators and end-users.

Colanar’s Commitment

At Colanar, we partner with customers to solve these challenges. Our syringe filling systems are customized to the characteristics of each product—from viscosity and container type to desired throughput—ensuring GMP compliance, process safety, and a reliable path from R&D scale to full commercial production.