Have you ever wondered how the expiration date on a pharmaceutical product, medical device, food product, or beverage is calculated? The standard technique for determining an expiration date is a stability study. Also known as shelf life testing or degradation testing, stability studies ensure that the products you use and consume are safe and effective.
Drug Stability Testing
As an example, let’s look at how pharmaceutical companies use stability testing. In the pharmaceutical industry, most countries use the International Council of Harmonization (ICH) guidelines to determine the expiration date on your medication. While these guidelines are primarily used in the pharmaceutical industry, other industries such as the medical device and food and beverage industries tend to borrow from these as well.
The ICH guidelines include different types of studies including long-term, intermediate, accelerated, stress tests, and photostability. For the purposes of this blog post, we will focus on long-term studies.
Long-term studies last over a year. These studies assess the stability of a drug substance or product over its proposed shelf life under recommended storage conditions. Typically, for a long-term study we select three batches that are representative of the process and take samples from these batches on a regular basis. In year one, the batches are sampled every 3 months. In year 2, sampling usually spreads out to every 6 months and then we subsequently look at key metrics annually. With each sample, metrics such as active ingredient amount, moisture content, and particulate count are tracked to ensure that the product remains fit for human consumption.
To set yourself up for a long-term stability study, consider entering and storing your stability data in Minitab Connect. Because the stability study runs over a long period of time, it is important to have tools and methods in place to consistently enter and store the resulting data.
Using a Minitab Connect form, analysts can pick the appropriate batch from a drop-down list as opposed to the error-prone method of entering batch information manually. Additionally, Minitab Connect forms provide a useful tool for data validation. For example, when an entered value is outside the expected range, an alert pops up. Finally, the Connect data warehouse automates data management, eliminating the need for manual spreadsheets and re-uploads of incoming data.
Learn more about determining product shelf life with Minitab, watch our "behind the expiration date" webinar:
Results from Shelf Life Test
From the Minitab Statistical Software online version, you can easily connect to your stability data stored in Minitab Connect for further analysis. Let’s say you want to estimate the shelf life of a medication based on the proportion of active ingredient remaining in the product with a lower specification of 0.9. Just follow the simple steps below and let Minitab Statistical Software take care of the rest.
Choose Stat > Regression > Stability Study > Stability Study, complete the dialog box as shown below and click OK.
While there are additional advanced options available in the dialog box, the defaults are already created using the ICH guidelines.
As shown below, the shelf life for this medication is estimated at 28.7 months. If the expiration date was originally set at 2 years, we can be confident that our active ingredient will last beyond that date.
Regardless of whether you are actively involved in running these studies at work or just want to evaluate how quickly you should eat your home-baked cookies, stability studies affect us all. Let Minitab Statistical Software and Minitab Connect simplify your work.