Estimation of the probability of passing the USP dissolution test

To ensure that a drug product will meet standards for identity, strength and stability as specified in the United States Pharmacopedia and National Formulary (USP/NF), it needs to pass a number of tests such as the content uniformity test and dissolution test at various stages of the manufacturing process. The sponsors usually have in-house specification limits based on some lower bounds of the probabilities of passing USP/NF tests to make sure that there is a high probability of passing the tests. Several probability lower bounds for dissolution test have been provided in the literature. In this paper, a method of calculating the probabilities of passing the dissolution tests is proposed. For the population mean and variance in some specified range, the probability derived from the methodology is very close to the exact probability. Therefore, the proposed method can provide an easy and accurate way to calculate the probability.