We review information on impurity testing provided in drug applications and when inspecting manufacturing facilities.

Manufacturers are required to test for impurities that may be introduced or developed during their manufacturing processes.

We review that information in drug applications, including requests to change the manufacturing process.

We employ organic chemists to review applications and referenced information to look for steps – and manufacturing changes – where these risks could be introduced.

We also inspect manufacturing facilities around the world, and in routine current good manufacturing practices inspections we can review a manufacturer’s records regarding impurity testing.

However, the review of records depends on manufacturers conducting appropriate tests that are capable of detecting the impurity.

Tests are selected based on assessments of what impurities may develop based on the manufacturing process.

In other words, it needs to be recognized that there is a risk of an impurity occurring to know that it should be tested for.

Before we undertook this analysis, neither regulators nor industry fully understood how the nitrosamines could form during the manufacturing process.