The relationship of hygroscopicity and humidity control is essential in the quality outcome of
products. This requirement is especially important in FDA regulated industries, such as
pharmaceutical, biotechnology, medical device, and food. For example, Section 211.142 (b) under
Warehousing Procedures of the Current Good Manufacturing Practices states: "Storage of drug
products under appropriate conditions of temperature, humidity, and light so that the identity,
strength, quality, and purity of the drug products are not affected" shall be established.
For example: how can we determine the appropriate conditions for humidity controls during manufacturing?
Let us consider Product A having the moisture uptake rate of
What %RH control would be required to encapsulate Product A?
- 0.8 mg/min. at 43.2 %RH,
- 2.2 mg/min. at 75.3 %RH, and
- 3.0 mg/min. at 93.6 %RH.
Based on the measurements we can extrapolate the maximum allowed humidity (i.e. 28 %RH at 0 mg/min. moisture uptake rate)
Hygroscopicity, active water content of substances, and container/closure moisture
permeability/penetration are also pivotal in the control of stability and expiry dating of