By Marty Reyes, Weiler Engineering
Traditional vaccine production often includes an equally traditional vessel for end products: multi-dose glass vials, which have served as the standard for many drugs for decades. But the use of glass vials creates a number of challenges for manufacturers and providers alike ― a shortage of glass in some countries, coupled with the potential for contamination in both the manufacturing process and the drug’s administration, make the use of these vials an increasingly outmoded practice. Other factors, such as the potential for human error in administering the correct dose, can make single-dose vessels a more attractive option for pharmaceutical companies. This has led to recognition among regulators that advanced aseptic processing techniques like blow/fill/seal (BFS) offer greater safety and customization for drug product manufacturing.
In the BFS process, thermoplastic resin is melted and formed into a parison that is treated with sterile air, sealed at one end, filled with drug product, and hermetically sealed at the other end to form a discrete single-dose container. This end-to-end process, once initiated, occurs with little to no human intervention needed, greatly reducing the potential for contamination. It also allows for a wide range of container designs and product volumes, creating flexibility and ensuring greater end-use safety for patients.
- Extrusion: A thermoplastic resin is extruded as a hollow tube known as a parison.
- Parison cut: When the parison reaches the proper length, the holding jaw and main mold close. This pinches the bottom of the parison while the top is held in place as the cutting sequence occurs.
- Blow and Fill: The blow/fill nozzle is inserted into the parison, forming a seal with the neck of the mold. The nozzles blow sterile, filtered, compressed air or nitrogen into the parison to expand it before venting the air out. The sterile product is then deposited into the parison through the fill nozzle.
- Seal: Separate sealing molds close to form the top, which hermetically seals the container.
- Release: Finally, the mold opens, and the formed, filled, and sealed containers are conveyed out of the machine.