From batch to flow: continuous manufacturing and what it means for tablet plants
Regulators now have a global guideline, and continuous lines have shortened release times and approvals. Where the technology stands.
In this article
Most medicines are still made in batches: a quantity of powder is blended, granulated, dried, compressed and coated, step by step, with tests and waiting in between. Continuous manufacturing links those steps into one flowing line, monitored as it runs.
The milestones
| Year | Milestone |
|---|---|
| 2015 | Vertex’s Orkambi becomes the first FDA approval made by continuous manufacturing |
| 2016 | FDA allows Janssen to switch Prezista (darunavir) from batch to continuous — the first such switch |
| 2020 | FDA approves four drugs made by continuous manufacturing |
| November 2022 | ICH adopts guideline Q13 on continuous manufacturing of drug substances and products |
Other approved examples include Vertex’s Symdeko and Trikafta, Pfizer’s Daurismo and Eli Lilly’s Verzenio.
What it has delivered
- Janssen said its switch reduced testing-to-release time from 30 days to a target of 10 days.
- An FDA self-audit in 2022 found continuous-manufacturing applications were approved in the first review cycle, about nine months faster than comparable batch applications against target, and reached the market 12 months faster after submission.
- FDA lists benefits including less manual handling, online quality monitoring, smaller equipment and space, and faster response to shortages.
The global rulebook
ICH Q13 covers both active ingredients and finished products and explains that continuous processes still produce defined batches, set by quantity or run time. It applies to new products and to converting existing batch processes.
The barriers
The industry’s installed base is still batch, and moving requires investment in equipment, process analytical technology (PAT) and training. Changing an approved product also needs regulatory change control.
How a continuous line works
In a continuous tablet line, ingredients are fed by gravimetric feeders at precisely controlled rates into a continuous blender. The blend flows on to granulation (or straight to compression in a direct-compression process), then to the tablet press and coater, without stopping between steps. Sensors along the line — often near-infrared spectroscopy and other process analytical technology (PAT) — measure the blend and the product as it moves, and a control system adjusts the process in real time.
Because material moves constantly, two ideas become important:
- Residence time distribution — how long material spends in each unit. It tells the manufacturer which tablets came from which raw material lot, which is essential for traceability.
- Diversion — if a sensor detects material outside specification, the system automatically diverts the affected portion so that only good product continues.
Batch and continuous compared
| Batch | Continuous | |
|---|---|---|
| Quality testing | Mainly at the end of each step | Continuous monitoring during production |
| Scale-up | Larger equipment, repeated development | Run longer on the same equipment |
| Footprint | Several rooms and hold steps | A compact, connected line |
| Skills needed | Established and widely available | Process control, data and PAT expertise |
Where it fits best
Continuous manufacturing suits high-volume products made for long periods, products whose demand changes and must be scaled quickly, and new products developed with the approach in mind. It is less attractive for small-volume products that share equipment with many others. That is why most companies start with one product, often a new one, rather than converting an entire plant.
Questions to ask before investing
- Which products have the volume and lifetime to justify a dedicated continuous line?
- Do we have, or can we hire, people with process-control and data skills?
- Which regulators will review the change, and what data will they expect?
- Can parts of the approach — inline monitoring, automated feeding — improve our batch lines first?
Asking these questions early helps a company choose the right first project and avoid buying technology it is not yet ready to run.
What it means for Pakistan
Few plants will switch overnight, but the building blocks — inline monitoring, automation, data systems — pay off in batch plants too, and matter for export-grade quality. Machinery suppliers show these technologies at Pharma Asia 2026; see also AI and digital twins.
Sources
- DCAT Value Chain Insights, “Continuous manufacturing takes the next big step”, 8 December 2022
- BioPharma Dive, “In first, FDA approves Janssen’s switch to continuous manufacturing for HIV drug”, 14 April 2016
- GMP-Compliance.org (ECA Academy), “ICH Q13: final version of guideline for continuous manufacturing published”
