Desiccants for IPGs: What Engineers Need to Know About Moisture Control

Implantable pulse generators, or IPGs, leave little margin for moisture-related risk. Even limited environmental exposure can affect long-term reliability, especially when electronics, seals, adhesives, and nearby materials all need to perform consistently through storage, handling, sterilization, and use. That’s why desiccants for IPGs should be considered within the full moisture-control approach rather than treated as design afterthought. Material choice and validation all shape how effective that approach will be. At ProMed, we see this most clearly in implantable-device work, where moisture control must fit the design, the available volume within the IPG, and the path to production.

 

Why moisture control matters in IPGs

IPGs operate in a category where reliability expectations are high and avoidable risk carries real weight. Moisture can affect electronics, interfaces, and nearby materials in ways that may not be obvious at first but can still influence long-term performance.

That doesn’t mean every implantable pulse generator needs the same moisture-control strategy. It does mean the issue should be addressed early, while teams are making decisions about package design, seals, assemblies, manufacturability, validation, and long-term supply.

 

Define the moisture threshold first

Before comparing materials or formats, teams need to define the moisture threshold that the device or package can’t be allowed to reach.  What level is unacceptable for this application? The answer shapes how aggressive the moisture-control approach needs to be and how much sorbent capacity may be required. This will drive material selection as well as the final design of the desiccant component. 

For an implantable pulse generator, that limit should be tied to actual device and risk. If the available free volume is small, material selection becomes more demanding. If the target is less severe or if significant free internal volume is available, the range of viable options may widen.

 

Low-RH (relative humidity) targets can point toward a molecular sieve

When the goal is tighter, low-RH control, a molecular sieve often warrants consideration. Its performance profile can make it a strong fit when the application calls for an extremely dry internal environment or in designs where desiccant space is severely limited.  

That doesn’t make it the default answer, but it does make it worth evaluating when low relative humidity is central to the package strategy.

 

Format and placement affect how the solution is used

Material selection and volumes are only part of the decision. Format matters too, especially when space is limited, placement needs to stay controlled, or where available spaces are inconveniently shaped.  

For IPG applications, that means the discussion should move beyond sorbent type alone. A desiccant material may be technically appropriate from an absorption perspective but still be a poor choice if the format does not work with the package, the assembly, or the broader design.

In tighter or more design-sensitive applications, a more integrated component may make better sense. That can be especially relevant when moisture control needs to fit a defined space, stay in a fixed position, or and be incorporated more easily in the overall assembly.

 

Package format should work with production realities

Format affects performance, handling, and manufacturability. A desiccant material can be technically appropriate and still create problems in production if it takes up the wrong amount of space, shifts during handling, or introduces avoidable process issues.

 

Placement, handling, and space constraints all matter

A few practical questions help narrow the options:

• Is there enough room for a standard insert without compromising the design?
• How will the design ensure that the desiccant material remains in its fixed position within the IPG?
• Will a single desiccant component be sufficient?  Or do space and shape constraints within the design mandate the use of multiple desiccant components?
• Does the material or component design create assembly concerns?

 

Hermetic IPG housings make the distinction more important

FDA classification materials describe permanent implantable pulse generators as having a hermetically sealed outer can that houses the electronics. In that context, moisture control in the outer packaging should be treated as a critical design and process risk consideration.

That’s why default sizing is weak practice. Two implantable-device projects may look similar at a glance and still call for different approaches because their desiccant requirements, available internal volumes, or distributions of available volumes are different.

 

Where molded desiccants make sense

Molded desiccants can support an integrated moisture-control approach. Injection-molded silicone components that combine silicone rubber with zeolite create durable desiccant components.

 

Better placement and handling in tighter assemblies

Loose inserts still have their place, but they aren’t always the right option. In tighter assemblies, molded desiccants can offer more controlled placement, better physical stability, and a geometry that works with the available space instead of competing with it.

That matters when the moisture-control element needs to function more like part of the design than a separate insert.

 

Why this work aligns with ProMed

Moisture control in an IPG program is rarely a stand-alone packaging decision. It has to work within the wider demands of the device, the assembly, and the validation path behind it.

ProMed’s implantable-device experience, molded silicone capabilities, and regulated manufacturing background support a more integrated view of moisture control. That work stays tied to geometry, material behavior, handling, manufacturability, and long-term production needs.

 

Moisture control has to work within the full program

In implantable-device development, moisture control is part of a broader design and manufacturing picture. The right approach has to make sense not only for storage stability, but also for assembly flow, package constraints, process control, and scale-up.

That broader view is especially important when standard inserts are not the best answer and the desiccant needs to be evaluated as part of the design itself.

 

Frequently asked questions:

 

1)  What does moisture control do in an implantable pulse generator application?

It helps limit moisture exposure that could affect electronics, seals, adhesives, and nearby materials during storage and handling, supporting more consistent performance and reducing avoidable reliability risk before the product is used.

 

2)  Do all IPGs use the same moisture-control approach?

No. The right approach depends on device architecture, package design, shelf-life goals, validation requirements, and where moisture creates the real risk within the broader system.

 

3)  How do engineers choose between molecular sieve and other desiccant approaches?

They start with the moisture threshold that the device or package can’t be allowed to reach. Lower-RH targets often point toward molecular sieve.

 

Conclusion

Desiccants aren’t a one-step packaging decision. The right approach depends on the moisture requirement and how best to effectively engineer the required desiccant into the finished device.  

At ProMed, we support that work with implantable-device manufacturing experience and molded moisture-control capabilities that stay tied to design, validation, and long-term production needs. To discuss your options, reach out at (763) 331-3800 or through our contact page.

 

 

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