Packaging for Moisture Protection

The ability of materials to hold moisture depends on RH (moisture sorption isotherm)


Moisture Permeability (MVTR)
The transfer of moisture into or out of packaging depends on package permeability, or Moisture Vapor Transmission Rate (MVTR).  MVYR depends on temperature, as well as the difference between the relative humidity inside and outside of the package (which will change as the internal RH changes)

  • ASAPprime® software can estimate the moisture permeability of packaging based on its material and dimensions.  ASAPprime® software will also use this information to determine the RH inside a package as a function of time.
  • FreeThink laboratory services can measure packaging permeability/MVTR.
  • For blisters, our partner Klöckner Pentaplast can use Finite Element Analysis (FEA) to determine the moisture permeability of formed blisters based on tooling designs.
  • For bottles, FreeThink can determine the MVTR as a function of cap torque to set limits.  Bottles can be sealed with out heat induction sealer, and we can also determine the impact of overwrap materials on the moisture permeability.
  • For foil bags, we can determine the permeability as a function of pin-hole size.


The stability in packaging is linked to ASAPprime® fitting, which determines the moisture sensitivity (B factor) from a series of unpackaged product (controlled humidity) experiments.


In some cases, desiccants (silica gel, clay, molecular sieves) can be used to stabilize products by reducing the RH inside a package. The impact of type and amount of desiccant is calculated using ASAPprime® software.  FreeThink has expertise in all types of desiccants, and also partners with Clariant to provide additional services to our clients.


For liquid products, FreeThink can determine the increase in potency as a function of time, based on the packaging and the internal and external water activities (relative humidities).



Example of the RH inside a package (60-cc HDPE bottle with heat induction seal and 30 tablets).  The
exact RH profile that a product sees determines its shelf-life.  At FreeThink, we can use these methods
to determine the appropriate packaging for a product.


Go back to Packaging for Stability