One of the first and most important questions when choosing a pharmaceutical filling machine is simple: is the product sterile or non-sterile?
The answer changes almost everything about the machine and the line around it. A sterile injectable needs clean, depyrogenated containers, a protected filling zone, sterilisable product-contact parts and a cleanroom. An oral syrup or a topical cream needs good hygiene and accurate filling, but the environment, machine design and supporting equipment are very different, and so is the cost.
This guide explains how to choose the right filling machine for sterile and non-sterile pharmaceutical production. It covers how sterile products are made, what the filling machine must do in each case, the design and cleaning differences, the supporting equipment each line needs and the main cost drivers.
Other guides in this series look at choosing by dosage form and by container type. This one focuses on the sterility requirement.
Sterility and environmental requirements are set by regulators and differ between markets. This article gives a general overview; your quality and regulatory teams should confirm the specific requirements for your products.
Which Pharmaceutical Products Are Sterile?
| Category | Typical Products | Sterility Requirement |
|---|---|---|
| Parenterals (injectables) | Liquid injectables, sterile powders, vaccines, biologics | Sterile |
| Ophthalmic products | Eye drops, eye ointments | Usually sterile |
| Some other products | Irrigation solutions, some nasal or inhalation products | Depends on product and market |
| Oral liquids | Syrups, suspensions, solutions | Non-sterile, with microbial limits |
| Oral powders | Dry syrups, oral powders | Non-sterile, with microbial limits |
| Topicals | Creams, ointments, gels, lotions (non-ophthalmic) | Usually non-sterile, with microbial limits |
“Non-sterile” does not mean uncontrolled. Non-sterile products must still meet microbial limits and GMP requirements, and the filling machine must be hygienic and easy to clean.
How Sterile Products Are Made: Two Routes
Sterile products reach the patient by one of two routes, and the route affects the filling machine.
Terminal Sterilisation
The product is filled and sealed, then the sealed containers are sterilised, typically by heat. Where the product can withstand this, terminal sterilisation is generally preferred by regulators because it gives high assurance of sterility.
Filling machine impact: filling still takes place in a clean environment with clean containers, but the final sterility comes from the sterilisation step after sealing. Containers and closures must be able to withstand the sterilisation process. Ampoules, being fully glass-sealed, are well suited to terminal sterilisation.
Aseptic Processing
Many products, such as biologics, vaccines and some heat-sensitive drugs, cannot be terminally sterilised. Instead, the product is sterilised separately (often by filtration), the containers and closures are sterilised separately, and they are brought together in a highly protected environment. The filling machine must keep everything sterile until the container is closed.
Filling machine impact: this is the most demanding application. The filling zone must be protected, interventions minimised, product-contact parts sterilised and the whole process validated, including simulation of the aseptic process.
What a Sterile Filling Machine Must Do
1. Receive Clean, Depyrogenated Containers
Glass vials and ampoules are washed to remove particles and then depyrogenated (heated to destroy pyrogens) before filling. This is done by:
- a washer, such as a rotary ampoule washing machine or a linear vial washer
- a depyrogenation tunnel, such as a sterilizing tunnel for ampoules and vials, which delivers containers directly into the filling zone
2. Protect the Filling Zone
The point where the container is open and product is dispensed must be kept at the highest level of cleanliness. Common approaches include:
- Unidirectional (laminar) airflow over the filling and closing area
- Restricted Access Barrier Systems (RABS), which separate operators from the critical zone with a physical barrier and glove ports
- Isolators, which fully enclose the process and are decontaminated before use
Our article on the rise of RABS and isolators in modern vial filling machines compares these options.
3. Fill Accurately With a Sterilisable Product Path
The product path, including pumps, tubing and needles, must be clean and sterile. Options include:
- piston pumps that can be removed and sterilised
- peristaltic pumps with sterile, disposable tubing that keeps the product out of contact with the pump
Accuracy matters even more with high-value sterile products, where every overfill or rejected container is costly. A servo based vial filling machine offers precise, recipe-controlled dosing.
4. Close the Container Immediately
Containers should be closed as soon as possible after filling:
- vials are stoppered on the same machine, then capped
- ampoules are flame-sealed, as on an automatic four head closed ampoule filling and sealing machine or a high speed eight head vertical ampoule filling and sealing machine
- sterile powders are filled and stoppered together, as on an injectable dry powder filling machine with vial rubber stoppering
5. Minimise Interventions
Every time an operator reaches into the critical zone, contamination risk increases. Sterile filling machines should be designed so that routine tasks, such as clearing jams, adding stoppers or adjusting settings, need as few interventions as possible.
6. Support Aseptic Validation
For aseptic products, the process must be validated, including media fills that simulate production using a growth medium in place of the product. The machine design, interventions and procedures are all part of this.
Our cGMP compliance guide for sterile vial filling machinery explains these features in more detail.
What a Non-Sterile Filling Machine Must Do
Non-sterile filling machines focus on accuracy, speed, hygiene and flexibility.
1. Clean Containers
Plastic and glass bottles are cleaned before filling, often by air-jet and vacuum cleaning or by washing. Depyrogenation is not normally required.
2. Accurate, Efficient Filling
Filling technology is chosen for the product:
- Oral liquids: gravity, piston or peristaltic fillers, such as an automatic liquid syrup filling machine. A liquid bottle filling and capping monoblock fills and caps in one machine. See our full range of liquid filling machines.
- Creams and ointments: piston fillers for tubes and jars, such as an automatic double head tube filling machine or other cream and ointment filling machines.
- Oral powders: auger or other powder dosing systems.
3. Hygienic, Easy-to-Clean Design
Product-contact parts are made from suitable materials, drain fully and can be removed quickly for cleaning. Cleaning must be validated to prevent cross-contamination between products, but sterilisation of parts is not usually required.
4. Speed and Flexibility
Non-sterile lines often run larger volumes and more product changes. Fast changeovers, matched machine speeds and reliable capping and labelling are key to efficiency.
Sterile vs Non-Sterile: Side-by-Side Comparison
| Factor | Sterile Filling | Non-Sterile Filling |
|---|---|---|
| Typical products | Injectables, eye drops, sterile powders | Oral liquids, creams, oral powders |
| Container preparation | Washing and depyrogenation | Cleaning (air or water) |
| Filling environment | Cleanroom with highest-grade critical zone | Clean, controlled area |
| Filling zone protection | Laminar airflow, RABS or isolator | Hygienic enclosure as required |
| Product path | Sterilised or sterile disposable | Cleaned and sanitised |
| Closing | Immediate stoppering, capping or flame sealing | Capping, sealing or tube crimping |
| Validation | Includes sterilisation and, for aseptic, media fills | Cleaning and process validation |
| Operator practice | Strict gowning and aseptic technique | GMP hygiene and gowning |
| Typical cost | Higher (machine, facility, utilities, validation) | Lower |
How the Choice Shapes the Whole Line
The sterility requirement affects not just the filler but the entire line.
A Typical Sterile Liquid Vial Line
- Vial washer
- Depyrogenation tunnel
- Filling and stoppering machine under protected airflow or barrier system
- Cap sealing machine
- External vial washer
- Inspection and labelling
An integrated automatic liquid vial filling line combines these steps with matched speeds and controlled transfers.
A Typical Non-Sterile Oral Liquid Line
- Bottle unscrambler
- Air-jet or washing machine
- Filling machine
- Capping machine (screw or ROPP)
- Induction sealing (if required)
- Labelling and coding
Cost Drivers to Consider
A sterile filling project usually costs more than a non-sterile one, and much of the extra cost lies outside the filling machine itself. Consider:
- Cleanroom construction and HVAC: sterile filling needs classified areas with controlled air quality, pressure and temperature.
- Container preparation: washers and depyrogenation tunnels add cost, space and utilities.
- Barrier systems: RABS and isolators add equipment cost but can reduce contamination risk and, for isolators, background cleanroom requirements.
- Sterilisation: autoclaves for parts and, where used, terminal sterilisers.
- Validation: sterilisation, depyrogenation and aseptic process validation add time and cost.
- Utilities: purified water, water for injection, clean steam and compressed gases.
- Operating costs: gowning, environmental monitoring and stricter training.
For non-sterile lines, cost depends mainly on output, automation level and the number of machines, with lower facility and validation costs.
Choosing the Right Machine: Key Questions
- Is the product sterile? If yes, can it be terminally sterilised, or does it need aseptic processing?
- What container and closure will you use? Vials, ampoules, bottles, tubes or others.
- What output and batch sizes do you need? This sets the number of heads and level of automation.
- What filling zone protection is required? Laminar airflow, RABS or isolator, based on your product, risk assessment and regulatory requirements.
- How will product-contact parts be cleaned and sterilised? Removable parts, disposable paths or in-place systems.
- What facility do you have or plan? Cleanroom grades, space and utilities.
- Will the line run both sterile and non-sterile products? In practice, sterile and non-sterile products are normally filled on separate lines in separate areas.
Planning for Future Products
Your product portfolio may change over the life of the line. Before you buy, think about what you may fill in five or ten years:
- If you plan to add sterile products later, decide now whether the facility layout leaves room for a separate sterile suite.
- If you may move from terminally sterilised to aseptically filled products, check whether the chosen line can be upgraded with barrier systems.
- If you expect higher volumes, ask whether heads can be added or speeds increased.
- If you expect new container sizes, confirm the machine’s format range and the cost of extra change parts.
Planning ahead avoids buying a line that limits your business later.
Common Mistakes to Avoid
- Assuming a non-sterile machine can be “upgraded” for sterile use. Sterile filling requires specific design features from the start.
- Planning the filler without the facility. The cleanroom, HVAC and utilities often take longer to build than the machine.
- Underestimating validation. Sterile validation needs careful planning and time.
- Over-specifying non-sterile lines. Not every product needs sterile-level equipment; matching the specification to the product saves cost.
- Ignoring interventions. For sterile lines, a design that needs frequent operator access raises contamination risk.
For more on applying GMP to filling lines of both types, see our article on the importance of GMP compliance in filling lines.
Frequently Asked Questions
Can the same filling machine be used for sterile and non-sterile products? In general, sterile and non-sterile products are filled on different machines in different areas, because the design, environment and validation requirements are very different.
Which is better: terminal sterilisation or aseptic processing? Where the product can withstand it, terminal sterilisation is generally preferred. Aseptic processing is used for products that cannot be terminally sterilised. The choice is made by your product development and regulatory teams.
Do eye drops need a sterile filling machine? Eye drops are usually sterile products, so they are filled under appropriate controlled conditions. Confirm the requirements for your specific product.
Is an isolator always required for aseptic filling? Not always. Laminar airflow, RABS and isolators are all used. The choice depends on the product, risk assessment, regulatory expectations and budget.
Are non-sterile filling machines subject to GMP? Yes. All pharmaceutical filling must comply with GMP, including hygienic design, cleaning validation and documentation.
Talk to Harsiddh About Your Sterile or Non-Sterile Filling Line
Harsiddh Unimach manufactures filling machines and complete lines for both sterile and non-sterile pharmaceutical products: vial and ampoule washers, depyrogenation tunnels, vial and ampoule fillers, powder fillers, oral liquid fillers, tube fillers, cappers and labellers. Our team can help you choose the right equipment for your product, sterility route, containers and output.
Get in touch through our contact page or send your requirements through our inquiry form.