New Guidance for Nasal Aerosols and Sprays
FDA's new draft guidance, "Bioavailability and Bioequivalence Studies for Nasal Aerosols and Nasal Sprays for Local Action," contains some recommendations related to the container closure systems for such products.
Crucially, the agency recommends that when ensuring bioequivalence as part of an Abbreviated New Drug Application, the same brand and model of actuator and metering valve or pump that is used in the reference product should be used in the test product. If that's not possible, then the critical dimensions of the components' designs should be as close as possible. Metering chamber volumes and actuator orifice diameters should be the same. In addition, the external dimensions of the test actuator should ensure comparable depth of nasal insertion to the reference actuator.
If a nasal aerosol or nasal spray comes in more than one container size containing the same components, composition, metering valve, and actuator, and the largest container size has passed bioavailability and bioequivalence tests, then the tests do not need to be performed on smaller container sizes. Much of the document is devoted to outlining seven tests for characterizing bioavailability and bioequivalence studies, among them single actuation content through container life and spray pattern.
The draft guidance, published April 2, 2003, can be viewed at www.fda.gov/cder/guidance/5383DFT.pdf. This version is the second draft guidance. The first, published in June 1999, received so many comments, and the agency made so many changes, that FDA decided to publish it again in draft form.