When assessing BFS equipment for an ophthalmic application, machine model and headline production speed only tell part of the story. The more important question is whether the particular system can support the required product, container and production strategy.
So what should manufacturers actually be looking at?
Product Requirements
The product should always be the starting point.
Formulation characteristics, sensitivity, filling conditions, required accuracy and compatibility with the proposed polymer can all influence the required BFS configuration.
Understanding what was previously manufactured on an existing machine can be useful, but it does not automatically mean another product can be transferred directly onto the same system.
Container and Tooling
For ophthalmic BFS, tooling is particularly important.
Manufacturers need to understand:
- Existing container geometry
- Fill volume
- Number of cavities
- Mould dimensions
- Neck and dispensing design
- Closure/opening mechanism
- Polymer
- Potential for alternative tooling
Existing tooling can provide an important indication of how closely a machine aligns with the intended format, but BFS tooling is highly application-specific. Even apparently similar containers can require changes to the mould, extrusion head or die arrangement, parison configuration, filling-needle or mandrel spacing, filling system, flash-removal equipment, controls or validated process parameters.
Production Output
Headline machine speed can also be misleading when viewed in isolation.
Theoretical output should be calculated from the format actually produced: Theoretical output (containers/hour) = containers per cycle × 3,600 ÷ cycle time (seconds)
For connected ophthalmic strips or blocks, containers produced per cycle should reflect the total number of individual units produced across the mould....not simply the number of mould cavities.
Indicative saleable output = theoretical output × availability × performance efficiency × quality yield
Planning assumptions should be supported by data from comparable validated production runs wherever possible, including the demonstrated reject rate. Two machines of the same basic model can therefore have very different practical production capabilities depending on their tooling, process configuration and sustained operating performance.
Filling System and Machine Configuration
The existing filling arrangement, product-contact path, dosing principle, controls, automation, critical utilities and overall machine specification all need to be assessed against the intended application.
For existing equipment, understanding modifications and upgrades made during the machine’s operating life can be just as important as understanding its original specification.
Current EU GMP Annex 1 provides a useful technical lens for that assessment. Relevant controls include cleaning-in-place and sterilisation-in-place (CIP/SIP) of product pipelines and filling needles or mandrels; extrusion temperature, speed and parison thickness; mould temperature and cooling; fill volume, speed and uniformity; critical wall thickness; environmental controls; 100% integrity testing; and flash-removal settings.
For an existing machine, the practical question is not only whether these functions are present, but whether they can be qualified, maintained and supported by adequate drawings, software records, manuals, material data, validation evidence and maintenance history.
Facility Integration
Moving a BFS machine into another facility introduces another set of considerations.
These can include:
- Cleanroom integration
- Utilities
- Product preparation
- Material and personnel flows
- Environmental controls
- Downstream handling
- Inspection
- Container integrity strategy
- Qualification and validation
This is why assessing an existing BFS machine requires considerably more than reviewing a specification sheet.
Existing Equipment as a Project Opportunity
Where the configuration aligns with the intended product, existing BFS equipment can provide manufacturers with an alternative route to adding capacity.
However, the commercial opportunity needs to be considered alongside the engineering work required to bring the system into its next application.
Machine condition, documentation, tooling, controls, upgrades, refurbishment, installation and commissioning all form part of that assessment.
Ultimately, the right question isn’t:
“Can this machine produce ophthalmics?”
It is:
“How closely does this particular machine configuration align with the ophthalmic product we want to manufacture?”