Stability Testing

Stability is an important quality characteristic of pharmaceutical products. The purpose of evaluating stability is to demonstrate how the quality of a drug substance or drug product varies under the influence of a variety of environment factors, such as temperature, humidity, and light, and to establish the recommended storage conditions and shelf-life for the drug product.

Here are some of the main reasons to perform a stability study:

  • Accelerated stability
  • Comparator stability
  • Excipient/API compatibility
  • Finished product release
  • ICH requirements Q1A, Q1B
  • Intermediate stability
  • Long term stability
  • Product development
  • Packaging stability
  • Photostability
  • Reference materials storage
  • Shelf life
  • Stability indicating method development and validation
  • Supplier changes

In stability studies, products are packaged in suitable containers and stored under a variety of environmental conditions. Most commonly, the products are stored under exaggerated (also known as “accelerated”) and normal (or “long term”) conditions. Under accelerated conditions, the product is subjected to elevated levels of temperature and humidity. Under long term conditions, the product is stored in an environment that is designed to mimic that of a normal room atmosphere.

Galbraith Laboratories offers commonly requested storage conditions:


25°C ± 2°C / 60% RH ± 5% RH

40°C ± 2°C / 75% RH ± 5% RH

At pre-defined time intervals, samples of the product are removed from storage and tested for characteristics such as purity, degradation products, and observed for physical changes. These types of studies enable product manufacturers to select the optimum formulation, packaging containers, recommended storage conditions, and expiration dates for final packaged products.

The temperature/humidity chambers are monitored 24/7 with alerts and emergency backup generators to ensure continuous power during electrical events and maintain compliance with FDA 21 CFR 11.


Photostability Confirmatory Testing

Photostability testing of finished drug substances and drug products are critical to evaluating and documenting the stability of the drug under light exposure. Confirmatory testing is a staged series of photostability tests which evaluate the drug, intermediate packaging, and final packaging to confirm that the drug will not degrade due to white-light or UV irradiation, or to determine if modifications are needed to the packaging to better protect the API.

Photostability testing is a type of accelerated stability testing, whereby the raw API and/or the packaged drug are exposed to intense light irradiation equivalent to multiple years of light exposure in a typical household in only a matter of days. The samples are then retrieved and tested by a stability indicating method, previously designed via a forced degradation study, to separate potential degradants and determine whether the packaging will allow the product to meet shelf life expectations.

ICH Q1B guidelines require an exposure of at least 1.2 million lux·hours of white-light and 200 Watt·hours/square meter of UV irradiation. Our photostability chamber is equipped to simultaneously evaluate both white-light and UV irradiation per ICH Q1B guidelines.

More information on method development & validation or forced degradation testing can be found at these links.


Method Development & Validation

Forced Degradation Testing


To learn more about ICH Q1A guidelines for stability testing, click here. For more information regarding our stability testing services, contact us at 877.449.8797 or click Request a Quote below.