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 impact extrusion process used in the manufacturing of these containers produces seamless containers. Hence, they have greater safety against leakage, corrosion and incompatibility. Aluminum containers (Figure 12.3) are used in MDIs, since they are made with a 20 mm neck finish that adapts to the metered valves. Containers that have neck finishes ranging from 15 to 20 mm are also available for special purposes and applications. The containers are available in sizes ranging from 10 ml to over 1,000 ml.

Figure 12.3 Aluminum Containers