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For decades, pharmaceutical production has revolved around batch processes—carefully weighed ingredients mixed, pressed, coated, and tested in sequential rooms, each with its own batch record and validation package.

Continuous manufacturing (CM) streamlines this process into a single, integrated line that converts raw materials into finished tablets in a continuous, unbroken stream.

The upside is compelling: smaller footprints, real-time quality assurance, and output scaled by runtime, not equipment size. But the shift from batch to continuous is not an equipment swap. It requires facility, operational, and cultural changes that depend on the context.

Drawing from our work in oral solid dosage (OSD) facilities, here are the considerations before launching.

Process reality: tradeoffs are inevitable

CM is not plug-and-play. A single continuous manufacturing process can replace 4–6 unit operations and process rooms, but complexity migrates from space to systems integration.

One of the biggest surprises is material handling. Powders are typically moved by vacuum transfer systems that rely on compressed-air Venturi pumps. These “air hogs” can easily overwhelm an existing plant’s compressed air capacity, requiring new compressors or expanded piping.

Cleaning is often underestimated. Unlike batch, partial cleaning is impossible. Residual active pharmaceutical ingredient (API) in a blender can contaminate weeks of production. Plan for dedicated cleanrooms adjacent to the line and automated clean-in-place (CIP) where feasible (e.g., tablet press feed frames).

Maintenance planning should shift from reactive to predictive. Sensors and controls generate abundant data for condition-based maintenance, but only if facilities have the digital infrastructure and personnel to interpret it.

Key takeaway: Labor doesn’t disappear—it shifts from sampling/staging to automation oversight, data analysis, and deep cleaning.

 

Utilities: plan for localized intensity

Moving to CM lines results in reduced floor space but concentrates utility demands. Here’s what to consider:

• Compressed air: Vacuum transfer systems and automated valves consume substantial air volume and pressure. Evaluate compressor capacity and redundancy before installation.
• Power: While total electrical load may not rise dramatically, CM lines run continuously, meaning power stability and quality (no flicker or sag) become essential for nonstop operation.
• Cooling and HVAC: The smaller footprint and fewer open transfers can reduce HVAC demand, but cooling loads around dense equipment may increase.
• Clean utilities: Consistent flow of clean air, water, and nitrogen must be maintained for uninterrupted runs.

Even with higher localized utility intensity, overall facility efficiency can improve. Combining multiple process rooms into one area reduces HVAC zone count and air changes. From a sustainability standpoint, the footprint reduction is the real win: less space to condition, fewer rooms to clean, and smaller energy use for air handling.

A combination of multistep equipment and quality control PAT tools in a single room with dedicated utilities significantly reduces the required capital and operational costs (capex and opex) as well as floor space and product storage needs, with expected savings of about 70%

Source: ISPE July/Aug 23, p 28

 

Rethink validation and quality assurance

The shift is this:

• Batch quality = end-product testing
• CM quality = process control + process analytical technology (PAT)

Modern systems utilize near-infrared (NIR) or Raman spectroscopy to monitor blend uniformity, moisture content, and active ingredient concentration in real-time. Instead of holding product until results clear the lab, manufacturers can use real-time release testing (RTRT) once they demonstrate that the system consistently meets specifications. Automated diversion quarantines off-spec material.

The FDA supports this approach, provided that data integrity and traceability are well-defined. To achieve this, a digital backbone is required.

• Traceability from drum barcode to tablet blister
• Control strategy defining “batch” as time-based (e.g., 24 hr = 1 batch) or mass-based
• Deviation handling via model predictive control (MPC)

Expect a new approach to scaling

In traditional manufacturing, scale-up is a major milestone. Lab batches increase by factors of ten until the process reaches commercial volumes. This can be a slow and costly path requiring new validation at each step.

Continuous manufacturing changes that logic. Because the ingredient ratios and processing conditions remain constant, production quantity becomes a function of run time, not batch size. Need more product? Run longer.

That flexibility shortens the path from pilot to full production and simplifies technology transfer to new facilities. Eliminating scale-up steps also reduces risk during product launch, a major advantage when timelines are compressed or supply reliability is under scrutiny.

For facility leaders, this means that validation plans now extend beyond equipment to the automation layer, encompassing sensors, data historians, and control logic, which must all be qualified and maintained under good manufacturing practice (GMP).

Consider where it makes sense

TechTarget reports compelling data from companies already adopting CM, reporting a “50% reduction in operating costs, a 33% reduction in waste and an 80% reduction in manufacturing and testing cycle time,” with some companies experiencing “up to a 66% reduction in time from testing to release.”

Source: TechTarget

With all the benefits, continuous manufacturing is a substantial investment which means the context matters.

Ideal For	Avoid If
High-volume OSD (>50M tablets/yr)	Low-volume injectables
Stable formulations (few changeovers)	Frequent product switches
Companies with PAT + automation expertise	Limited data infrastructure

The decision ultimately depends on lifecycle economics: the upfront cost of new equipment, controls, and utilities versus long-term savings in labor, footprint, and throughput. Early feasibility analysis, in partnership with engineering and automation experts, can clarify whether the return on investment (ROI) justifies the change.

How Salas O’Brien can help

Continuous manufacturing represents a fundamental shift in how pharmaceuticals are produced, and how facilities are designed to support them. For leaders considering the move, success depends on understanding the full picture: utilities, space, cleaning, digital infrastructure, and workforce readiness.

Salas O’Brien helps manufacturers bridge the gap between vision and execution, designing facilities and systems that support advanced processes with reliability and compliance at their core.

Contact our pharmaceutical manufacturing team at [email protected].

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