A stability study is usually conducted to ensure that a drug product can me
et the approved specifications prior to its expiration dating period (shelf
life). Several approaches for determination of drug shelf life assuming ra
ndom batches have been proposed. In this paper, we examine sampling distrib
utions of the estimated shelf lives proposed by Shao and Chow (1994, Biomet
rics 50, 753-763). An application to some stability data from the pharmaceu
tical industry is presented.