Once a promising therapy has been identified (often in liquid form by default) the question becomes whether it could be converted into a powder through lyophilisation or spray drying to improve stability or shelf life. But at that point, progress often stalls. Developers draw a blank, unsure whether it’s even possible to fill powders of their intended fill weight into a syringe, because it simply isn’t something that’s commonly done. Yet what still surprises many in the industry is that it is possible, you can fill syringes with spray-dried powders. And when you do, you bring all the benefits of powder drug forms directly into the hands of clinicians, unlocking new efficiencies for therapy developers and significant advantages for patients, providers and manufacturers alike.
Why spray-dried powder in a syringe?
The powder drug dosage form is quickly becoming the go-to choice for a wide range of high-value, time-sensitive, and personalised therapies. With superior stability, longer shelf life, and reduced reliance on cold chain logistics, powders (especially spray-dried powders) offer a cleaner solution compared to traditional liquid formulations.
But when you take that same powder and fill it directly into a syringe, you eliminate even more friction from the system, for example:
- No transfer steps. No vial-to-syringe drawing, no extra prep.
- Quicker administration. In urgent care, oncology, or advanced therapy settings, this means faster treatment and potentially better outcomes.
- Faster reconstitution. Spray-dried powders reconstitute in seconds, compared to the slower, more fragile lyophilised “cake.”
Reduce complexity of liquid formulations
Liquid formulations may sound convenient, but in practice, they can create unnecessary complexity. Many drugs are unstable in aqueous form, limiting shelf life and complicating shipping. For heat-sensitive or biologic products, terminal sterilisation isn’t an option. Freeze-drying (lyophilisation) is one workaround, but it's costly and often doesn’t scale well for small batches or early-stage therapies. Some products can’t be lyophilised at all.
Known challenges with lyophilised formulations:
- Formulation issues: pH changes during freezing, cold denaturation and the limited choice of excipients that work with the process.
- Instability: Molecules can lose activity during freezing or show increased aggregation and unfolding after reconstitution.
- Process-related issues: Long freeze-drying times, cake collapse, cracking, and variable reconstitution times. This is especially problematic for high-concentration formulations.
- Moisture-related degradation, over-drying and crystalline heterogeneity also add risk.
- Even after reconstitution, foaming and nanobubbles can impact administration quality and consistency.
Spray-dried powder, by contrast, provides a scalable, stable solution that doesn’t compromise on quality, even for very small production runs.
How is powder filled into a syringe?
Many powder filling technologies, such as an auger or dosator, commonly deliver the dose of powder at the top of the primary drug container. This is often a function of the design of the powder filling system and leads to powder around the top of the drug container. With other technologies, such as 3P innovation's proprietary Fill2Weight system, the powder is dosed through a relatively narrow nozzle which makes the powder behave more like liquid. This allows the powder to be dosed close to the tip end of the syringe barrel and avoids contamination of the stoppering area.
What’s next?
The pharmaceutical industry is rapidly embracing drug-device combinations, including lyophilised formats. But spray-dried powders filled directly into syringes present a faster, more agile path forward for clinical trials and personalised therapies. By eliminating vial transfer steps to enable rapid reconstitution, this approach simplifies delivery, making life easier for clinicians and faster for the patients who rely on them.
Automated solutions like roboFIL® can fill tubs of RTU syringes, cartridges and/or vials with spray-dried powder and are helping therapy developers move quickly from concept to clinic.
