One important study objective is to estimate the shelf-life of the drug, which is used to determine the expiration
date that is printed on the package label of the drug. According to the Guideline for Stability Testing, ICHQ1 (which is
harmonized among US, EU and Japan, and can be viewed at http://www.ich.org/ich5q.html), the shelf-life is defined as
the time point where the 95% pointwise lower confidence limit for the regression line crosses the lowest acceptable limit
for drug content, which is usually 90% of the labelled amount.