How to Select a Spray Drying CDMO

The short answer: Select a spray drying CDMO on three things: amorphous-solid-dispersion (ASD) science — proven experience turning poorly soluble molecules into stable amorphous dispersions, with polymer and process selection driven by data, not habit; scale continuity — spray dryers from milligram-sparing lab units through to registered commercial dryers, so the process you develop is the process you launch rather than one you re-invent at scale; and the analytical and stability package that proves the material is and stays amorphous (XRPD, modulated DSC, physical-stability studies). If your compound is highly potent, add containment to the list. Spray drying is usually one step inside a larger drug-product program, so also confirm the CDMO can carry the dispersion forward into the final dosage form.

Spray drying rarely appears on a program because someone wanted to spray dry. It appears because a molecule is poorly soluble and its bioavailability has to be rescued, and an amorphous solid dispersion is the enabling technology of choice. That framing matters: you are not buying a drying service, you are buying the science that decides whether your drug is absorbable — and the process engineering that keeps it that way from the clinic to commercial supply.

What spray drying is actually for

In drug-product development, spray drying is used chiefly to produce an amorphous solid dispersion: the drug is dissolved with a polymer in a solvent, then rapidly dried into particles where the API is held in a high-energy amorphous state that dissolves far better than its crystalline form. Done well, it converts a compound that would fail on exposure into a viable oral product. It is also used for particle engineering — controlling size and morphology for downstream processing or inhalation.

The two things that make it hard are the reasons to choose carefully: an amorphous form is thermodynamically driven to recrystallise (so physical stability is the whole game), and the drying process is sensitive to parameters that do not translate automatically across dryer scales.

1. Assess dispersion science, not drying equipment

The differentiator is formulation and process understanding, evidenced by outcomes:

Polymer and process selection driven by data — miscibility screening, solubility parameters, and a rationale for the carrier polymer and drug loading, not a default recipe.
A track record of stable dispersions taken into the clinic, ideally in your solubility class — ask how many and what became of them, not what equipment they own.
Solvent-system and process design appropriate to your molecule and its residual-solvent constraints.

"We have a spray dryer" is a capability; "we have taken multiple amorphous dispersions through Phase I with defined physical stability" is evidence. This mirrors the wider point about buying formulation science over capacity.

2. Insist on scale continuity

This is the axis that quietly wrecks spray-drying programs. Process parameters that give a good amorphous dispersion on a lab dryer do not transfer one-to-one to a large commercial unit, and re-developing at scale is slow and risky. Confirm the CDMO has:

A continuous scale ladder — lab-scale (API-sparing) through pilot to registered commercial spray dryers, under one roof or via a defined, proven transfer,
Scale-up experience for ASDs specifically, with an understanding of how atomisation, drying gas, and thermal history change with scale, and
Commercial supply capability so a successful clinical dispersion has a home at launch.

A CDMO that can develop but not scale, or scale but not develop, hands you a transfer at the worst possible moment.

3. Verify the amorphous analytical and stability package

An amorphous dispersion is only as good as your ability to prove it is amorphous and stays that way. Confirm the analytical group can:

Confirm amorphicity and detect early recrystallisation (XRPD, modulated DSC), and characterise the dispersion,
Run the physical-stability program under relevant conditions that a filing requires, and
Support dissolution methods that reflect the bioavailability benefit you are claiming.

Weak analytics here is not a detail — it is the difference between a dispersion you can file and one you merely hope is stable.

4. Check containment if your compound is potent

Many poorly soluble development candidates are also highly potent. Spray drying handles fine powders and open-handling steps, so if your molecule needs a low occupational exposure limit, confirm the CDMO's containment and handling capability at each scale — the same discipline required for potent-compound work. A CDMO with the science but not the containment cannot run your program safely.

Common pitfalls

Treating spray drying as a commodity drying service rather than the bioavailability-enabling science it is.
Developing on a lab dryer with no scale path, then discovering the parameters do not transfer.
Under-scoping physical-stability analytics, so recrystallisation surfaces after you have committed.
Missing the containment requirement for a potent, poorly soluble compound.

Where this fits

Choosing a spray drying CDMO is a specialised case of CDMO selection and, more specifically, of formulation-development sourcing — weighted toward dispersion science, scale continuity, and physical-stability analytics. Screen every candidate site against its FDA compliance record as you would any supplier.

PharmaTek maps drug-product and CDMO capabilities to each company's GMP and FDA compliance record across a directory of 22,000+ pharmaceutical companies, so a spray-drying shortlist can be built for capability and screened for compliance in one place.

Frequently asked questions

When should I use a spray drying CDMO? When a poorly soluble (typically BCS Class II/IV) molecule needs its bioavailability enhanced and an amorphous solid dispersion is the chosen route. Spray drying dissolves the drug with a polymer and rapidly dries it into a high-energy amorphous form that dissolves far better than the crystalline drug. It is also used for particle engineering. Choose it for the science, not the drying step.

What is the most important thing to check in a spray drying CDMO? Amorphous-solid-dispersion science evidenced by stable dispersions taken into the clinic — data-driven polymer and process selection, not a default recipe — combined with a continuous scale ladder from lab to commercial dryers and the analytical program (XRPD, modulated DSC, physical stability) that proves the material is and stays amorphous.

Why is scale-up such a risk in spray drying? Because the process parameters that produce a good amorphous dispersion on a small lab dryer do not transfer one-to-one to a large commercial unit — atomisation, drying-gas dynamics and thermal history all change with scale. A CDMO without a continuous scale ladder and ASD-specific scale-up experience forces costly re-development at the worst time, near launch.

Do I need a spray drying CDMO with containment capability? Often, yes. Many poorly soluble development candidates are also highly potent, and spray drying involves handling fine powders and open steps. If your molecule has a low occupational exposure limit, confirm the CDMO's containment and handling capability at each scale — a partner with the dispersion science but not the containment cannot run the program safely.

Can one CDMO do spray drying and the final dosage form? Ideally. The amorphous dispersion is usually an intermediate that must be carried into a tablet, capsule or other final form. A CDMO that can take the dispersion through to the finished drug product removes a technology transfer and keeps accountability in one place; if it cannot, plan the transfer to a drug-product partner deliberately.

Sourcing a spray drying partner? Explore the supplier directory or book a demo to screen candidates against live FDA compliance data.