Outsourcing commercial manufacturing is never only a capacity decision. For creams, gels, ointments and non-sterile liquids, it is a quality, supply continuity and patient safety decision.
A sponsor can transfer a formula, a method and a target batch size. What it cannot transfer casually is process understanding. Semisolid and liquid pharmaceutical products are highly sensitive to mixing, shear, temperature, hold time, water quality, packaging interactions and raw material variability. A CDMO may be able to manufacture a batch. The real question is whether it can manufacture the product repeatedly, commercially and under GMP control.
For commercial programmes, sponsors should look beyond “basic GMP capabilities”. The right partner should operate a mature Pharmaceutical Quality System aligned with current GMP expectations, including 21 CFR Parts 210 and 211 where applicable, and supported by modern quality systems and risk management principles. FDA guidance describes quality systems and risk management as consistent with CGMP expectations, while process validation is expected to follow a lifecycle approach from process design through qualification and continued process verification.
As one practical rule puts it:
“For semisolids, the product is inseparable from the process. The formula matters, but so do the mixing sequence, shear history, cooling profile, hold time, filling conditions and packaging system.”
What GMP capabilities should a semisolid and liquid CDMO have?
A CDMO for commercial semisolid and liquid pharmaceutical manufacturing should be able to demonstrate control across facilities, equipment, process validation, microbiology, cleaning, QC testing, packaging and lifecycle management.
For sponsors, the evidence should not be generic. It should be specific to the dosage form, commercial scale and target market.
Qualified facilities, utilities and manufacturing suites
Commercial manufacturing of creams, gels, ointments and non-sterile liquids requires qualified production areas with appropriate material and personnel flows, segregation, line clearance, environmental controls and contamination prevention.
For aqueous products, utility control is especially important. Purified water systems, HVAC, compressed gases, temperature-controlled storage, cleaning systems and transfer pathways must be qualified, monitored and maintained. The FDA CGMP framework includes requirements for drug manufacturing, processing, packing and holding under 21 CFR Parts 210 and 211.
Sponsors should expect to review evidence of equipment qualification, preventive maintenance, calibration, cleaning status control and facility suitability for the product class.
Dosage-form-specific manufacturing equipment
Semisolid and liquid manufacturing is not interchangeable with oral solid dose manufacturing. The CDMO should have vessels, mixers, homogenisers, transfer systems and filling equipment designed for the product’s physical behaviour.
For creams, gels and ointments, this may include controls for:
- Mixing speed and shear
- Heating and cooling rate
- Vacuum or deaeration
- Homogenisation time
- Order of addition
- Bulk temperature
- Bulk and filling hold times
- Viscosity and rheology
- pH and preservative system performance
For non-sterile liquids, sponsors should also assess solution or suspension control, sedimentation risk, re-dispersibility, fill volume, microbial robustness and packaging compatibility.
The practical question is simple: can the CDMO reproduce the product’s critical quality attributes at commercial scale, not just match the formulation on paper?
Why technology transfer and scale-up are high-risk
Technology transfer and scale-up are among the most important challenges in CDMO outsourcing for semisolid and liquid pharmaceutical manufacturing.
A cream that performs well at pilot scale can behave differently in a larger vessel. Heat transfer changes. Shear distribution changes. Mixing dead zones may appear. Air entrainment may increase. Cooling may no longer create the same microstructure. These differences can affect viscosity, appearance, assay uniformity, droplet size, phase stability, spreadability and patient acceptability.
The CDMO should therefore have a structured technology transfer and scale-up model that includes:
- A formal transfer protocol
- Process parameter mapping
- Equipment equivalency assessment
- Gap assessment between sending and receiving sites
- Engineering or demonstration batches where appropriate
- Analytical method transfer or verification
- Defined acceptance criteria for process and product attributes
- PPQ strategy and continued process verification plan
FDA process validation guidance describes process validation as a lifecycle activity, including process design, process qualification and continued process verification. This is directly relevant to commercial scale-up and routine manufacturing control.
The quality systems sponsors should expect
A capable CDMO should operate an integrated Pharmaceutical Quality System, not a collection of disconnected SOPs.
Document control and data integrity
Sponsors should expect controlled SOPs, approved master batch records, complete executed batch records, validated or controlled spreadsheets, audit trails, secure data storage and clear review workflows.
For commercial supply, data integrity is not an administrative detail. It is the basis for batch release, deviation decisions, regulatory confidence and inspection readiness. ALCOA+ principles should be visible in laboratory records, batch records, equipment logs, environmental monitoring data and electronic systems.
Deviation, OOS, OOT and CAPA management
Problems will happen. A mature CDMO is not defined by the absence of deviations. It is defined by how quickly, honestly and scientifically it detects, escalates, investigates and prevents recurrence.
For semisolids and liquids, recurring signals may include viscosity drift, microbial excursions, fill weight variation, pH shift, phase separation, yield loss, air entrapment, appearance defects or complaints linked to texture or delivery.
The CDMO should have clear processes for:
- Deviation triage and containment
- Phase 1 and Phase 2 OOS investigations
- OOT assessment and stability trending
- Root cause analysis
- CAPA definition and ownership
- CAPA effectiveness checks
- Product quality review and trend escalation
Quality risk management should be systematic, science-based and proportionate to patient risk, as described in ICH Q9(R1).
Change control
Change control is especially sensitive for semisolid and liquid products. A change that looks operationally minor can affect product performance.
Examples include:
- New excipient supplier or grade
- Revised mixing time or speed
- Different homogeniser or vessel geometry
- Batch size increase
- New tube, bottle, pump or closure supplier
- Updated cleaning agent
- Revised analytical method
- New filling line
- Different bulk hold condition
The CDMO should assess each change for GMP impact, validation impact, regulatory impact, stability impact and comparability requirements. For approved commercial products, sponsor notification and approval rules must be clear in the quality agreement.
Supplier qualification and material risk management
Raw material variability is one of the most underestimated challenges in semisolid pharmaceutical manufacturing.
Carbomers, waxes, petrolatum, fatty alcohols, emulsifiers, preservatives, solvents and gelling agents may meet compendial specifications while still behaving differently in the formulation. A technically capable CDMO understands functional equivalence, not just certificate of analysis compliance.
Sponsors should expect a supplier qualification programme covering APIs, excipients, primary packaging components, printed packaging materials, contract laboratories and critical service providers. This should include risk-based supplier approval, quality agreements where appropriate, incoming material controls, periodic supplier review and clear escalation pathways for supplier deviations.
Microbiological control for non-sterile products
Non-sterile does not mean low risk. Aqueous creams, gels and oral or topical liquids can be vulnerable to microbial contamination if water systems, equipment cleaning, bulk holds and preservative systems are weak.
The CDMO should demonstrate a microbiological control strategy covering:
- Purified water system monitoring
- Bioburden and objectionable organism risk
- Equipment cleaning and sanitisation
- Environmental monitoring where appropriate
- Raw material microbiological risk
- Bulk hold times and storage conditions
- Preservative effectiveness strategy
- Microbial limits testing
- Investigation of excursions and adverse trends
For sponsors, the key question is whether microbiology is embedded into process design, not treated only as final release testing.
Cleaning validation and cross-contamination control
Semisolids are often difficult to clean. Greasy bases, viscous polymers, sticky gels, pigments, fragrances and low-solubility actives can remain in tanks, transfer lines, pumps, gaskets and filling equipment.
Cleaning validation should be scientifically justified and supported by:
- Product contact surface mapping
- Worst-case product selection
- Residue limits
- Swab and rinse recovery data
- Validated analytical methods
- Dirty and clean hold time studies
- Visual inspection criteria where appropriate
- Campaign length controls
- Changeover verification
- Periodic review
This becomes even more important for potent actives, hormones, steroids, antibiotics, antifungals or sensitising substances in shared facilities.
Analytical and QC capability
A CDMO may be able to manufacture a semisolid product but still struggle to test it properly. Semisolid matrices can make sample preparation, extraction and assay reproducibility more difficult than for simpler dosage forms.
Sponsors should expect appropriate QC capability for:
- HPLC or UPLC assay
- Impurity profiling
- Content uniformity or homogeneity
- pH
- Viscosity and rheology
- Particle or globule size where relevant
- Microbial limits
- Preservative effectiveness testing
- Water content where relevant
- Residual solvents where relevant
- Stability testing
- Packaging compatibility or extractables and leachables risk assessment where warranted
Laboratory controls are a core element of the finished pharmaceutical CGMP framework under 21 CFR Part 211.
Key outsourcing challenges for creams, gels and ointments
The most common outsourcing challenges are not abstract. They show up as practical manufacturing and quality risks.
A semisolid product may pass assay and impurity specifications but still show unacceptable texture, viscosity drift, air entrapment, phase separation, poor pumpability or inconsistent patient experience. A gel may be sensitive to order of addition. An ointment may be difficult to remove from shared equipment. A cream may depend on cooling profile and emulsification energy. A topical product may be stable in one tube configuration but incompatible with another.
The main outsourcing risks include:
- Process transfer failure
- Scale-up variability
- Rheology mismatch
- Raw material functional variability
- Microbiological contamination
- Cleaning validation complexity
- Packaging incompatibility
- Weak in-process controls
- Subtle stability failures
- Difficult analytical methods
- Incomplete CMC documentation
- Poor change control discipline
- Long changeover and scheduling constraints
- Limited semisolid-specific expertise
This is why due diligence should go deeper than capacity, price and lead time. Sponsors should test whether the CDMO understands the product’s failure modes.
Practical due diligence questions for sponsors
Before selecting a CDMO, sponsors should ask direct, evidence-based questions:
- Have you commercially manufactured this dosage form before: cream, gel, ointment, lotion, solution, syrup or suspension?
- What commercial batch size range do you routinely manufacture?
- How do you control mixing speed, shear, temperature, vacuum, deaeration and hold time?
- How do you validate homogeneity, viscosity, pH, bulk hold and filling hold time?
- What is your purified water monitoring and objectionable organism strategy?
- How are cleaning limits established and justified for shared equipment?
- Which QC tests are in-house and which are outsourced?
- How do you manage OOS, OOT, deviations, CAPA and recurring trend signals?
- What recent inspection experience do you have for comparable operations?
- How do you assess supplier changes, packaging changes and post-approval regulatory impact?
Final takeaway
For commercial semisolid and liquid pharmaceutical manufacturing, the right CDMO should bring more than available tanks and filling lines. It should bring process understanding, GMP discipline, microbiological control, analytical capability, supplier oversight, lifecycle validation and a quality culture that can withstand inspection and routine commercial pressure.
In CDMO outsourcing for semisolid and liquid pharmaceutical manufacturing, the decisive question is not only “Can they make it?” It is: “Can they control it, document it, investigate it, improve it and keep supplying it safely over the product lifecycle?”
For sponsors planning technology transfer and scale-up of creams, gels, ointments or non-sterile liquids, the best time to challenge the quality system is before the first commercial batch is scheduled.
