Dose content uniformity through container life is the test which ensures the uniform dose distribution of active drug(s) throughout the life of an MDI/DPI/NSP canister/bottle/container. The same test for Nasal Spray (NSP) is called Single Actuation Content (SAC) through container life. The test checks the active drug(s) content of one (sometimes two or three) MDI/DPI/NSP container(s). For Example, 1 MDI unit is randomly collected from a lot. Then the MDI is actuated 10 times (3 in the beginning + 4 in the middle + 3 at the end) in 10 different collection tubes to collect the doses. These 10 collection tubes containing the actuated doses are then assayed to measure the active drug content. The result of this assay helps to identify if there is any unapproved variation in active drug contents in the tested MDI product throughout its life.
Particle Size Distribution is a very important parameter to be tested before drug product release. A correct particle size distribution ensures the bioavailability of the active drug on the target site of action. An unapproved particle size distribution may lead to waste of drug doses and decreased efficacy of the dose. For example, a very fine particle/droplet distribution of Nasal Spray (<10 micron) will deposit more spray droplets in the lungs and gastrointestinal tract than the nasal passageway which is the target site of action. To ensure maximum deposition of the spray droplets in the nasal passageway the particle size should be more than 10 micron. Therefore, particle size distribution analysis is an obligatory test before product release.
The devices used for inhaled and nasal drug delivery are collectively referred as Orally Inhaled and Nasal Drug Products, OINDPs. The OINDPs comprises Inhalers (metered dose, dry powder and aqueous droplet), Nebulizers (jet, ultrasonic and vibrating mesh) and Nasal (aqueous based, dry powder and propellant based).
Have you ever wondered what shape the spray or aerosol you have really produces from your MDI/DPI or NSP? For a variety of reasons, these drug delivery methods need characterization. Following is a piece of information from CMC guideline on the importance of Spray Pattern and Plume Geometry analysis. Characterization of spray pattern and plume geometry is important for evaluating the performance of the pump. Various factors can affect the spray pattern and plume geometry, including the size and shape of the nozzle, the design of the pump, the size of the metering chamber, and the characteristics of the formulation. Spray pattern testing should be performed on a routine basis as a quality control for release of the drug product. However, the characterization of plume geometry typically should be established during the characterization of the product and is not necessarily tested routinely thereafter. Ref: "Guidance for Industry Nasal Spray and Inhalation Solution, Suspension, and Spray Drug Products - Chemistry, Manufacturing, and Controls Documentation" U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), July 2002.
Dose content uniformity (DCU) is the test which ensures the uniform distribution of active drugs in the MDIs/DPIs/NSPs/Nebulizers of a batch. The same test for Nasal Spray (NSP) is called Spray Content Uniformity (SCU) which is also performed within a batch. The test checks the active drug content of a number of MDIs/DPIs/NSPs/Nebulizers from a batch. For Example, 10 MDI units are randomly collected from a lot. Then the 10 MDIs are actuated in 10 different collection tubes to collect the doses.
