Medical Product Desiccant Control and Verification

We have a desiccant pack that we include in our medical product.
The desiccant arrives in a PE bag from the manufacturer with a humidity indicator in the bag.
Once we open the bag we transfer the desiccants to a dispensing box so operators to remove individual desiccants while packing.
The humidity in the box is controlled through a supply of low humility air. The air supply provides positive pressure inside the box, preventing humid air getting in through the hand port.
We use a hydrometer to make sure that the humidity in the box is less than 10%.

I am concerned that the continuous flow of air may be passing a lot of moisture over the desiccant.

Is there a better way of controlling desiccant?
Is there any way to verify the desiccant capacity?

Thanks

How about nitrogen going in, vs the low humidity air. We use nitrogen blankets to ensure that moisture doesn't come into contact with the materials we process which include extremely hydroscopic powers.

A simple way to learn about your desiccant's characteristics is to monitor how much and how fast it absorbs moisture from the surrounding air. You will only need a suitable lab balance. Start with fresh desiccant, let it sit in an environment that is typical for the use of the device, weigh the desiccant in suitable time intervals, and plot the weight against time. In this way you can find out how fast the desiccant absorbs moisture and also how much moisture it can absorb (= its capacity, but this will most probably vary with the relative moisture in the surrounding air).