Risk Management & Compliance

Effects of Moisture

Defining the Moisture Problem

Moisture is now recognised as one of the most important factors in drug product stability. Nearly 25 years ago the first Quality guideline (Q1) was drafted for “Stability Testing of New Drug Substances and Products” and included the requirement for controlled humidity testing. This document renamed as Q1A, was adopted as an ICH harmonised tripartite guideline in October 1993.

Over this long period there has not been, until now, an acceptable analytical method that directly measures the impact on the moisture status of drug products as a result of exposure to different humidity conditions. Relequa Moisture Profiling™ precisely fulfils this need. Moisture Profiling™ gives you a sensitive method based on the

movement of moisture in and out of your products. Other techniques such as Loss-on-Drying or Dynamic Vapour Sorption (DVS), use weight as a surrogate marker for a change in moisture content. Although these techniques have their uses, only Relequa’s Moisture Profiling™ is specific for changes in moisture status as a direct result of water vapour loss or gain.

Our advances in understanding how moisture is adsorbed by materials has led to Relequa offering a technique for analysing moisture status in a very precise way. Thus assuring repeatability and reproducibility of moisture results.

More about Moisture Profiling

Fluctuations in Humidity

Not surprisingly, many of the moisture issue cases we come across are moisture problems arising from stability trials. However, moisture is always present across the entire manufacturing process. In fact, any point where materials are exposed to environmental conditions, moisture will be entering or leaving your materials. Water molecules in the air are never static and move at very high speed. Your materials will respond instantly to air exposure, with the extent of moisture interaction depending on the physical-chemical properties of your material, its equilibrium point for moisture (see WVEP), and the ambient relative humidity (%RH).

Unlike the conditions in a controlled humidity cabinet, ambient humidity fluctuates all the time. This fluctuation is primarily due to:

  • An increase or decrease in room moisture, for example, evaporating process water, or the HVAC system’s normal fluctuations and in response to external weather.
  • Changes in room temperature which will directly change %RH, even for the same absolute amount of water vapour in the air.
  • Movement of drugs from one area to another.

Relequa’s Moisture Profiling™ gives you a sensitive method for detecting the movement of moisture in and out of your products. Moisture Profiling™ is specific for changes in moisture status as a direct result of exposure to local humidity conditions. Our advances in understanding how moisture is adsorbed means we can now offer you a technique for analysing the moisture status of your products in a very precise way.

If you are experiencing actual, or suspected, moisture issues. Or, if you would like the peace-of-mind of knowing that the moisture status of your products is acceptably stable:

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Packaging Choices and Moisture Effects

A key role of pharmaceutical packaging is to limit the exposure of pharmaceutical products to moisture and its consequential effects on the product’s chemical and physical stability. An early indication during product development on a suitable choice of packaging, for clinical trials and finished product stability testing, can save time and cost as well as reducing the risk of product failure. Moisture-sensitive products require a higher degree of protection facilitated by more efficient barrier properties of the packaging material. We have used Relequa’s Moisture Profiling™ as a novel approach for testing the barrier effectiveness of different types of blister packing

materials. Our studies show that changes in moisture status, as a direct result of water vapour ingress through the walls of packaging, is seen as a change in the moisture profile of the packed product. Moisture ingress results in an increase in the WVEP, easily seen by comparing moisture profiles over time. Our Moisture Profiling™ software allows you to overlay moisture profiles for easy comparison. A change in the WVEP can be detected in as little as a few hours.


See our poster “Study of a Range of Blister Packaging Materials Using the New Technique of Moisture Profiling to Give Early Indications of Moisture Barrier Properties” that shows how the barrier effectiveness in three types of packaging were differentiated in just one day at ICH Q1A(R) real time and accelerated stability conditions.