A Primer on Drug Stability Testing in Stability Chambers

As described by the FDA, stability testing provides evidence of the effect of time and environmental factors on the quality of pharmaceuticals and medicinal products.  Such factors include light, humidity and temperature.  Stability tests also establish a re-test period for the drug substance or a shelf life for the medicinal product along with recommended storage conditions.

Stability tests are conducted in validated stability chambers such as manufactured by Norlake for pharmaceutical (ICH), biological (BOD), scientific and laboratory applications. These tests, which subject the product samples to variations in temperature and humidity, are conducted during drug product development as well as once a candidate drug reaches use and are governed by current good manufacturing practices (cGMPs). They are regulated in the U.S. by 21 CFR Part 211 Section 166. (www.gmp1st.com/drreg.htm#211.166)

While these tests are conducted in stability test chambers, it is not simply a matter of buying a chamber and plugging it in.  A written Stability Test Program must be established and followed according to a standard operating procedure signed off by all persons involved in the manufacturing and testing activities. Typical procedures deal with handling out-of-spec humidity levels or unacceptable variations in temperature distribution.

Chambers must be qualified at three stages before being used to conduct stability testing: IQ (installation) OQ (operation) and PQ (performance). These tests are conducted by metrology or validation personnel using calibrated measuring and testing equipment; records are kept by the Quality Assurance department for a specified length of time.  Performance maintenance and verification tests likewise must be conducted periodically to make sure the testing chamber is operating properly.

Today’s stability test chambers such as the Norlake line offered by Tovatech are high-tech units equipped with programmable microprocessor controls and an LCD control panel and message center.  All critical functions of the units are monitored and alarmed if out-of-spec conditions occur, for doors left ajar, power failures and similar operating anomalies.   These events are date and time stamped then logged in a nonvolatile flash memory for critical record keeping.


What procedures does your company follow with respect to its stability test chambers?  How often are your chambers subject to performance maintenance and verification tests?  Are these tests handled internally or do you contract to a third party such as the chamber’s manufacturer?

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More