Blow-fill-seal manufacturing steps

Blow-Fill-Seal (BFS) Manufacturing Steps: Ensuring Sterility by Design

The Blow-Fill-Seal (BFS) technology is a fully automated aseptic manufacturing process that demonstrates the highest level of pharmaceutical expertise. By combining container formation, filling and sealing in a single continuous operation, BFS ensures unmatched sterility, efficiency and product safety for unit-dose pharmaceutical products.

From Pharmaceutical-Grade Polymer to Sterile Packaging

The BFS process begins with pharmaceutical-grade low-density polyethylene (LDPE), stored in granular form in silos located outside the manufacturing facility. Each year, the plant consumes several thousand tons of LDPE, underscoring the industrial scale and robustness of the process. The polymer is conveyed directly to the BFS packaging lines, where it is heated in extrusion screws to temperatures between 220°C and 230°C. At this temperature, the molten polyethylene is inherently sterile.

The molten polymer is then extruded and blown into molds within the BFS machine to form the lower part of the unit-dose container. This step marks the first critical phase in creating a sterile packaging system.

Aseptic Filling and Hermetic Sealing in a Single Step

Once the container base is formed, sterile filling needles are introduced into the open container. The drug product, which has undergone two filtration steps including a sterilizing filtration, is filled into the unit dose. Immediately after filling, a second blowing step forms the upper part of the container, followed by hermetic sealing. This entire sequence—forming, filling and sealing—takes only a few seconds.

Depending on the configuration, the BFS process produces strips or “gobs” of typically ten unit doses connected together. The operation takes place under a sterile air shower, further reinforcing aseptic conditions. As a result of high-temperature polymer extrusion, sterilized drug filtration and controlled sterile airflow, the medication is considered sterile by construction.

Debottlenecking and Material Recovery

After formation, the gobs move to the debottlenecking step, where individual unit doses are separated. Polyethylene scraps generated during this process are collected and recovered for resale and further use, contributing to a more sustainable manufacturing approach.

The separated unit doses are then transferred via a tiered conveyor system to the downstream inspection steps.

Quality Control: Fill Level and Leak Testing

Each unit dose undergoes rigorous in-line quality control. The first inspection checks the fill level to ensure accurate dosing. This is followed by a leak test to verify the integrity of the container and confirm proper sealing. These controls are critical to guaranteeing product safety, stability and compliance with regulatory requirements.

Labeling and Secondary Packaging

Once approved, unit-dose containers can be labeled according to product and market requirements. For certain products, an additional bagging step is applied. Unit doses with small filling volumes—typically below 5 mL—are often placed in protective pouches for stability reasons.

Smaller volumes have a higher surface-to-volume ratio, which increases exchanges with the container surface and can shorten shelf life. Bagging provides protection against light and environmental factors, helping to maintain product quality and extend expiration dates.

Why BFS Technology Is a Benchmark in Pharmaceutical Manufacturing

The Blow-Fill-Seal process delivers a unique combination of sterility assurance, operational efficiency and product integrity. By eliminating human intervention and consolidating multiple steps into one continuous aseptic process, BFS sets the benchmark for unit-dose manufacturing in ophthalmology, respiratory therapies and injectable products.

These BFS manufacturing steps highlight the technical excellence of the production site and its ability to deliver high-quality, sterile pharmaceutical products at industrial scale.