Rapid Transfer Ports – Smart Technologies for Filling and Sealing
Last updated: 10. February 2026
Rapid Transfer Ports (RTP) are mechanical interfaces for the contamination-free transfer of components. These ports enable the safe, aseptic transfer of materials or instruments into a closed container, such as an isolator. In this way, everything enters or exits the sterile area in a germ-free state. Pharmaceutical companies use this system in the production of medicinal products or vaccines.
Material Transfer via RTP: Aseptic Material Transfer via Alpha-Beta Interface
Material transfer via Rapid Transfer Port (RTP) utilizes a closed system consisting of two parts: the Alpha-Beta system. This is based on the double-door transfer system principle. Fundamentally: the two separate areas only touch each other when their sealing surfaces are completely closed.
The barrier functions smoothly during material transfer because a mechanical interlock precisely closes the interface. This ensures that both areas remain clean and the integrity of the partition is maintained. The material finally reaches its destination without any contamination.
The technical system uses two complementary components for this purpose:
- The Alpha Port is permanently installed on the isolator.
- The Beta Container (or a Beta Bag) forms the flexible component of the system as a mobile transfer module.
A germ-free transition channel only opens when these two parts are connected with a mechanical seal.
Aseptic Filling Systems from Rommelag
The bottelpack systems from Rommelag, manufactured in Germany, set global standards in aseptic filling. According to EU-GMP Annex 1, these systems enable a significant reduction in the background cleanroom classification (often Class C) due to their closed-system design. The critical filling area (Class A) is kept spatially minimal, which drastically reduces operating costs and contamination risks.
Castus RTP systems move components germ-free into the sterile core of the equipment. This process is fully automated and protected from harmful external influences, thereby ensuring product quality.
Sterile Filling Lines for Ampoules
Rommelag equipment processes liquid medications in small quantities, such as eye drops, inhalation solutions, or injectables. Depending on the configuration and container size, these systems achieve an output of up to 35,000 units per hour with filling volumes between 0.1 and 60 milliliters. Thanks to the modular design and optimized molds, efficient format changes are possible, minimizing downtime.
Two Foundations for Sterile Material Transfer
Sterile material transfer only succeeds when two essential processes harmonize perfectly:
- Rapid Transfer Ports (RTP) enable the safe exchange of the material to be processed within the process engineering.
- Blow-Fill-Seal Technology (BFS), on the other hand, manufactures the containers within the closed system, fills them, and seals them immediately. This makes the entire process highly secure and germ-free.
Innovation: Blow-Fill-Seal Technology
Rommelag revolutionized aseptic filling over 60 years ago with the development of Blow-Fill-Seal (BFS) technology. BFS links the steps of container production, filling, and sealing in a single, fully automated operation.
Blow – Shaping the Container
In the BFS process, a thermoplastic polymer is extruded into a tube under high pressure. Immediately after the mold closes, the container is shaped using sterile air or vacuum assistance within the mold cavity. Since the inner surface of the container is only created at the moment of formation and the material is processed at high temperatures, no separate container sterilization is required.
Fill – Filling
Specialized devices then fill the container with the precise amount of liquid or high-viscosity media (such as gels or suspensions). The dosing systems work with high precision, guaranteeing a homogenous product quality throughout.
Seal – Sealing
Due to the residual heat of the material, the polymer melts immediately after filling, forming a hermetic seal. This sealing reliably prevents the ingress of germs or particles.
Material Selection and Types
Rommelag provides Rapid Transfer Ports as an integral part of aseptic BFS and isolator technologies. Every RTP consists of high-quality, GMP-compliant materials.
Material Variants
- Stainless Steel (316L): The standard material for high-purity pharmaceutical applications.
- High-Density Polyethylene (HDPE): A chemical-resistant and lightweight alternative for specific requirements.
- Plastic Beta Containers: A cost-effective solution for the transfer of less sensitive substances.
- Aluminum Beta Containers: A robust and lighter alternative to stainless steel.
- Silicone Seals (FDA-certified): The standard solution for sterile sealing between the Alpha and Beta port.
Designs for RTP Systems
- Alpha Port Variants: Permanently installed standard ports or rotating Alpha ports to facilitate the loading process.
- Beta Port Containers: Available in stainless steel (for demanding/toxic media), plastic, or aluminum.
- Automatic Systems: As Auto-Ports, these enable automated loading and unloading as well as seamless digital process monitoring (Audit Trail).
Useful Sizes
The systems are available in common industry standards with inner diameters of 105, 190, and 270 millimeters and are primarily designed for use in BFS isolator systems.