Vial filling in the classical sense describes the aseptic filling of pharmaceutical products into prefabricated glass vials. A technological alternative is offered by Blow-Fill-Seal (BFS) technology: in this process, the containers – often referred to as plastic vials – are formed, filled, and hermetically sealed directly within the system. Thermoplastics such as polyethylene (LDPE/HDPE) or polypropylene (PP) serve as materials. The corresponding systems are characterized by a compact footprint in the cleanroom and are designed to meet high requirements for product safety.
Since the containers extruded from granulate are processed in a closed system without manual intervention, the risk of contamination is systemically reduced. The aseptic chain is supported by the elimination of cleaning and transport of open empty containers throughout the process steps.
Where is vial filling used?
The production and filling of rigid as well as flexible plastic vials – for example with a Luer-Lock connection – is carried out in compliance with Good Manufacturing Practice (GMP) guidelines. This technology is used in the pharmaceutical industry for:
- Ophthalmics: Eye drops or sterile gels.
- Parenterals: Injection and infusion solutions.
- Inhalation solutions: For respiratory therapy.
Product protection is ensured by the hermetic sealing in the BFS process. Due to their thermal stability, PP containers are also suitable for subsequent terminal sterilization in an autoclave, provided the product allows it. For heat-sensitive substances such as biologics or vaccines, the special cool-BFS process is used, which reduces thermal stress during the formation of the container to preserve active ingredient integrity. Specific closure designs and precise wall thickness distribution also enable exact dosing by the user.
What characterizes the process?
The efficiency of vial filling in integrated systems enables the combination of production, filling, and sealing at high output rates of over 30,000 units per hour. By forming the containers directly in the process, the logistics and warehousing for empty containers are eliminated, which influences operating costs and process complexity.
A technological difference compared to conventional glass lines is the elimination of cleaning steps such as depyrogenation. While glass vials must be closed with separate stoppers and caps, in the case of plastic vials, the material of the container itself forms the hermetic seal through fusion. This eliminates the risk of glass breakage and reduces the number of required primary packaging components. However, when choosing between glass and plastic, factors such as gas permeability and potential interactions between the active ingredient and the polymer (leachables) must be considered.
Qualification and regulatory safety
The commissioning of systems for vial filling is subject to strict regulatory requirements according to the specifications of EU-GMP Annex 1 for sterile products as well as Annex 15 and FDA requirements. A structured qualification process begins with Design Qualification to ensure specification-compliant planning and continues through Installation and Operational Qualification.
The process concludes with Performance Qualification, which provides evidence of consistently high product quality under real production conditions. A regulatorily compliant validation typically includes validated test protocols, risk analyses according to the FMEA standard, as well as the execution of Factory Acceptance Tests (FAT) and Site Acceptance Tests (SAT). This holistic approach ensures that international standards for the prevention of particulate or microbial contamination are maintained.