Learning Objective A metered-dose inhaler (MDI), introduced in 1950s is a device that delivers a specific amount of medication to the lungs, in the form of a short burst of aerosolized medicine that is inhaled by the patient. It is the most commonly used delivery system for medications such as bronchodilator, corticosteroid or a combination…
The metering valves (Figure 12.13) are necessary for potent medicaments where the dose is important. These valves operate on the principle of a chamber, whose capacity determines the amount of medicament delivered per dose. Approximately 50 to 150 mg ± 10% of liquid material can be dispensed at a time. Figure 12.13 Metering Valves
Learning Objective Actuators are specially designed buttons required for easy opening and closing of the valve. The type and quantity of the propellant and the design and dimension of the actuator determine the type of product discharge whether it is in spray or foam or a solid stream. Special actuators are available for use with…
Learning Objective An aerosol valve is an assembly of following different components: The different parts in an aerosol valve (Figure 12.5) and their basic function are described in the following section. Figure 12.5 Aerosol Valve Components
Learning Objective The valve regulates the flow of the therapeutic agent and propellant from the container. The diameter, location and the number of orifices determine the spray characteristics of the aerosol. Aerosols meant for topical products provide continuous spray operations, whereas those meant for oral and nasal use utilize metered-dose valves, which deliver a uniform…
Glass containers can also be used for aerosol packaging. They are available with or without plastic coating. The plastic coating may be totally adhered or non-adhered and vented. These containers pose less compatibility problems, and hence corrosion problems are eliminated. The level of the contents in the glass container can be easily visualized. Glass is…
These are limited to smaller containers due to the production problems and the costs involved. They are extremely strong and resistant to most materials. They are the containers of choice for inhalation aerosols. These containers can be used as such without any internal coating. Containers that are made of stainless steel are shown in Figure 12.4.…
These are lightweight and less reactive compared to other metal containers. Hence, these containers pose less compatibility problems and have a greater resistance to corrosion. Further coatings of phenolic, vinyl or epoxy resins confer greater protection against corrosion. Anodization of aluminum containers to form a stable coating of aluminum oxide can also be done. The…
Tin-free steel (TFS) is also called electrolytic chromium/chromium oxide coated steel. The material consists of mild steel base with a coating of chromium-chromium oxide, to protect the steel base from corrosion prior to fabrication. TFS containers need to be coated on the inside and outside with additional protective coatings like enamels and lacquers to make…
These are steel containers that are plated with a sheet of tin on both sides. Numbers like #25, #50 and #100 are used to denote the thickness of the tin plating. The size of the container is indicated by a measure of diameter and height of the container. These containers are lightweight and relatively inexpensive.…